Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
fredag den 10. november 2023 kl. 00.14.58 UTC+1 skrev Klaus Kragelund:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
why a transformer instead of an isolated driver?
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?seems to me DK has plenty of 1:1 pulse transformers much cheaper than that double inductor
https://www.digikey.dk/en/products/filter/pulse-transformers/166
On Friday, 10 November 2023 at 00:40:13 UTC+1, Lasse Langwadt Christensen wrote:Speaking of LCSC, it's quite amazing that one can get a transformer like this for less than 10cents:
fredag den 10. november 2023 kl. 00.14.58 UTC+1 skrev Klaus Kragelund:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
why a transformer instead of an isolated driver?
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?seems to me DK has plenty of 1:1 pulse transformers much cheaper than that double inductor
https://www.digikey.dk/en/products/filter/pulse-transformers/166Yeah, I was looking at those. But except for LAN transformers, they approach 1USD/pcs, which is awful high
I was even thinking doing a planar transformer, but production assembly of ferrites are not straight forward
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
On 09/11/2023 23:14, Klaus Kragelund wrote:
Dual inductors (like DRQ family) have super coupling but high winding-winding capacitance and insulation is just the minimal enamel so useless for anything HV.
I have even used low cost Murata and Panasonic common mode chokes as HV separated gate driver transformers!
On Friday, 10 November 2023 at 01:15:37 UTC+1, Klaus Kragelund wrote:
On Friday, 10 November 2023 at 00:40:13 UTC+1, Lasse Langwadt Christensen wrote:Speaking of LCSC, it's quite amazing that one can get a transformer like this for less than 10cents:
fredag den 10. november 2023 kl. 00.14.58 UTC+1 skrev Klaus Kragelund:Yeah, I was looking at those. But except for LAN transformers, they approach 1USD/pcs, which is awful high
Hiwhy a transformer instead of an isolated driver?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127seems to me DK has plenty of 1:1 pulse transformers much cheaper than that double inductor
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
https://www.digikey.dk/en/products/filter/pulse-transformers/166
I was even thinking doing a planar transformer, but production assembly of ferrites are not straight forward
https://www.lcsc.com/product-detail/RJ45-Transformer_CND-tek-TF-1601DG_C408875.html
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
KlausSuggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund ><klaus.kragelund@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
On Fri, 10 Nov 2023 08:28:15 -0500, legg <legg@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.kragelund@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
John Larkin <jl@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <legg@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.kragelund@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main >FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with >its source connected to the transformer and its gate and drain to the main >FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >FET on, and a negative one conducts via transistor action, turning it off. >It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil HobbsClever.
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a highside flop or schmitt.
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with >its source connected to the transformer and its gate and drain to the main >FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >FET on, and a negative one conducts via transistor action, turning it off. >It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil HobbsClever.
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
John Larkin <j...@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with its source connected to the transformer and its gate and drain to the main FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main FET on, and a negative one conducts via transistor action, turning it off. It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
On Friday, November 10, 2023 at 11:24:08 AM UTC-5, Phil Hobbs wrote:
John Larkin <j...@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:There’s the common-gate FET trick, where you use a small extra FET, with >> its source connected to the transformer and its gate and drain to the main >> FET’s source and gate, respectively, with a small storage cap.
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >> FET on, and a negative one conducts via transistor action, turning it off. >> It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
How does that increase volt-seconds?
It's just a single component replacement of the reverse biased gate discharge speed-up transistor technique. PNP used on NFET.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
On Friday, November 10, 2023 at 1:27:19?PM UTC-5, john larkin wrote:
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >> >>
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >> >>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main >> >FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. ) >> >
Using NFETs, a positive edge conducts via the body diode, turning the main >> >FET on, and a negative one conducts via transistor action, turning it off. >> >It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a
highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
fredag den 10. november 2023 kl. 19.27.19 UTC+1 skrev john larkin:
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >> >>
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >> >>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main >> >FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. ) >> >
Using NFETs, a positive edge conducts via the body diode, turning the main >> >FET on, and a negative one conducts via transistor action, turning it off. >> >It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a
highside flop or schmitt.
so basically an analogdevices iCoupler
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:
John Larkin <jl@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <legg@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.kragelund@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with >>its source connected to the transformer and its gate and drain to the main >>FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. ) >>
Using NFETs, a positive edge conducts via the body diode, turning the main >>FET on, and a negative one conducts via transistor action, turning it off. >>It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Clever.
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a >highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
On 10/11/2023 7:20 pm, Fred Bloggs wrote:
On Friday, November 10, 2023 at 11:24:08 AM UTC-5, Phil Hobbs wrote:
John Larkin <j...@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>>>There’s the common-gate FET trick, where you use a small extra FET, with >>> its source connected to the transformer and its gate and drain to the main >>> FET’s source and gate, respectively, with a small storage cap.
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >>> FET on, and a negative one conducts via transistor action, turning it off. >>> It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
How does that increase volt-seconds?
It's just a single component replacement of the reverse biased gate
discharge speed-up transistor technique. PNP used on NFET.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / >>> Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
I suppose it doesn't really increase volt-seconds asmuch as allow a
lower v-s rated transformer to be used.
Between the initial turn-on and the turn-off the main transistor gate is
held up by its own (or the added) capacitance so it doesn't matter if
the transformer induced secondary voltage collapses.
piglet
On Fri, 10 Nov 2023 11:22:55 -0800 (PST), Fred Bloggs <bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 1:27:19?PM UTC-5, john larkin wrote:
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >> >> a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a
highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.May as well buy an SSR.
On Friday, November 10, 2023 at 3:10:07?PM UTC-5, john larkin wrote:
On Fri, 10 Nov 2023 11:22:55 -0800 (PST), Fred Bloggs
<bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 1:27:19?PM UTC-5, john larkin wrote:May as well buy an SSR.
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >> >> >> a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with >> >> >its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a
highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
Sounds like it's not quite the same as a pulsed drive. The switch is turned on and stays on indefinitely etc...you can't do that with an ac pulsed drive.
On Fri, 10 Nov 2023 16:27:25 -0800 (PST), Fred Bloggs <bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 3:10:07?PM UTC-5, john larkin wrote:
On Fri, 10 Nov 2023 11:22:55 -0800 (PST), Fred Bloggs
<bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 1:27:19?PM UTC-5, john larkin wrote:May as well buy an SSR.
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look >> >> >> good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct >> >> tiny spikes at the leading and trailing edge of the pulse, and drive a >> >> highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or >> >> a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
Sounds like it's not quite the same as a pulsed drive. The switch is turned on and stays on indefinitely etc...you can't do that with an ac pulsed drive.Some of the bidirectional LED-mosfet SSRs have zero offset, a few ohms
Ron, and picoamp leakage. 1 mA drive is usually plenty.
Switching times are in the ballpark of 1 ms.
On Friday, November 10, 2023 at 9:46:16?PM UTC-5, John Larkin wrote:trigger a trip on the smart circuit protection technology these days. Things like nuisance tripping, death by transient, smoke or other odd odors, are not good public relations.
On Fri, 10 Nov 2023 16:27:25 -0800 (PST), Fred Bloggs
<bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 3:10:07?PM UTC-5, john larkin wrote:Some of the bidirectional LED-mosfet SSRs have zero offset, a few ohms
On Fri, 10 Nov 2023 11:22:55 -0800 (PST), Fred Bloggs
<bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 1:27:19?PM UTC-5, john larkin wrote:May as well buy an SSR.
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look >> >> >> >> good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct >> >> >> tiny spikes at the leading and trailing edge of the pulse, and drive a >> >> >> highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or >> >> >> a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
Sounds like it's not quite the same as a pulsed drive. The switch is turned on and stays on indefinitely etc...you can't do that with an ac pulsed drive.
Ron, and picoamp leakage. 1 mA drive is usually plenty.
Switching times are in the ballpark of 1 ms.
Most be using those PV gate drives... Conceptualizing the electronics is relatively simple, the hard part is armor plating it against the real world, the mains are really harsh. Then if the transient protection overreacts in the wrong way, you can
https://www.emc-directory.com/community/what-is-a-power-line-transient
On Fri, 10 Nov 2023 08:28:15 -0500, legg <legg@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund >><klaus.kragelund@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
On Friday, November 10, 2023 at 1:27:19 PM UTC-5, john larkin wrote:It needs to switch fast, since transient loss might be very large, and exceed transient thermal resistance constraints
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >> a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil HobbsClever.
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct tiny spikes at the leading and trailing edge of the pulse, and drive a highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
On Thursday, November 9, 2023 at 6:14:58 PM UTC-5, Klaus Kragelund wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?If you're looking for cheap, you can't beat capacitor coupling the gate drive. Phillips has a whole chapter in their MOSFET applications handbook on how to do this reliably-wasn't in the market for the technique at the time and skipped it.
see page 36 AC-Coupled Gate-Drive Circuits
https://www.ti.com/lit/ml/slua618a/slua618a.pdf
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
KlausAre you driving the gate of a fet? What fet?
On Fri, 10 Nov 2023 07:22:13 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund >><klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to driveISDN tfx for POE are a good example of what will or will not work.
a fet through a transformer, but nothing reasonable works.
I had to test a bunch for temperature rise/Lp when passing
POE current levels. The spec isn't often clear.
For technique:
- there are a lot of pulse width extension/termination
methods that use the pulse transformer to pass info, not
necessarily power.
- Small transformers can also pass gate power at higher frequencies
than the PWM fundamental. Pwm is conveyed through a modulation
method.
John Larkin <j...@997PotHill.com> wrote:
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with its source connected to the transformer and its gate and drain to the main FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main FET on, and a negative one conducts via transistor action, turning it off. It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
On Sat, 11 Nov 2023 04:00:11 -0800 (PST), Fred Bloggs <bloggs.fred...@gmail.com> wrote:trigger a trip on the smart circuit protection technology these days. Things like nuisance tripping, death by transient, smoke or other odd odors, are not good public relations.
On Friday, November 10, 2023 at 9:46:16?PM UTC-5, John Larkin wrote:
On Fri, 10 Nov 2023 16:27:25 -0800 (PST), Fred Bloggs
<bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 3:10:07?PM UTC-5, john larkin wrote:Some of the bidirectional LED-mosfet SSRs have zero offset, a few ohms
On Fri, 10 Nov 2023 11:22:55 -0800 (PST), Fred Bloggs
<bloggs.fred...@gmail.com> wrote:
On Friday, November 10, 2023 at 1:27:19?PM UTC-5, john larkin wrote: >> >> >> On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil HobbsMay as well buy an SSR.
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap. >> >> >> >
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the >> >> >> small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a
highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
Sounds like it's not quite the same as a pulsed drive. The switch is turned on and stays on indefinitely etc...you can't do that with an ac pulsed drive.
Ron, and picoamp leakage. 1 mA drive is usually plenty.
Switching times are in the ballpark of 1 ms.
Most be using those PV gate drives... Conceptualizing the electronics is relatively simple, the hard part is armor plating it against the real world, the mains are really harsh. Then if the transient protection overreacts in the wrong way, you can
https://www.emc-directory.com/community/what-is-a-power-line-transientThe CPC1540GS is claimed to be self-protecting, and it is to maybe 40
volts. It's about 25 ohms on and leaks picoamps off. It makes a nice
signal switch or mux.
It was an Ixys part but seems to be made now by someone else, so may
not be a good choice for new designs. The basic idea, a
current-limiting thermal-limiting SSR, is great.
Klaus Kragelund <klaus.kragelund@gmail.com> wrote:
On Friday, 10 November 2023 at 17:24:08 UTC+1, Phil Hobbs wrote:
John Larkin <j...@997PotHill.com> wrote:Sounds very interesting. Do you have a link to a schematics?
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>>>There’s the common-gate FET trick, where you use a small extra FET, with >>> its source connected to the transformer and its gate and drain to the main >>> FET’s source and gate, respectively, with a small storage cap.
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
(The other end of the transformer goes to the main FET’s source as usual. ) >>>
Using NFETs, a positive edge conducts via the body diode, turning the main >>> FET on, and a negative one conducts via transistor action, turning it off. >>> It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
I did it for a customer gig a couple of years ago, but they went away
before it got built.
(It was a large semiconductor equipment company.)
On Friday, 10 November 2023 at 17:24:08 UTC+1, Phil Hobbs wrote:
John Larkin <j...@997PotHill.com> wrote:Sounds very interesting. Do you have a link to a schematics?
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:There’s the common-gate FET trick, where you use a small extra FET, with >> its source connected to the transformer and its gate and drain to the main >> FET’s source and gate, respectively, with a small storage cap.
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >> FET on, and a negative one conducts via transistor action, turning it off. >> It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 17:24:08 UTC+1, Phil Hobbs wrote:
John Larkin <j...@997PotHill.com> wrote:Sounds very interesting. Do you have a link to a schematics?
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>>There’s the common-gate FET trick, where you use a small extra FET, with
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >>> a fet through a transformer, but nothing reasonable works.
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
I did it for a customer gig a couple of years ago, but they went away
before it got built.
(It was a large semiconductor equipment company.)
søndag den 12. november 2023 kl. 00.40.06 UTC+1 skrev Phil Hobbs:
Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 17:24:08 UTC+1, Phil Hobbs wrote:I did it for a customer gig a couple of years ago, but they went away
John Larkin <j...@997PotHill.com> wrote:Sounds very interesting. Do you have a link to a schematics?
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>>>>There’s the common-gate FET trick, where you use a small extra FET, with >>>> its source connected to the transformer and its gate and drain to the main >>>> FET’s source and gate, respectively, with a small storage cap.
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>>>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >>>>> a fet through a transformer, but nothing reasonable works.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >>>> FET on, and a negative one conducts via transistor action, turning it off. >>>> It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
before it got built.
(It was a large semiconductor equipment company.)
this one from the old "Philips Power semiconductor applications"
https://imgur.com/a/E3DaFAO ?
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:disables the opto.
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the switch offloss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
Eventually most every clever circuit design gets pre-empted by some
cheap nasty little IC.
So we need to keep inventing ever-goofier circuits. I can do that.
On Friday, 10 November 2023 at 20:23:02 UTC+1, Fred Bloggs wrote:
On Friday, November 10, 2023 at 1:27:19 PM UTC-5, john larkin wrote:It needs to switch fast, since transient loss might be very large, and exceed transient thermal resistance constraints
On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil HobbsIf the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
<pcdhSpamM...@electrooptical.net> wrote:
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>>>>
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it >>>>>>> to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >>>>> a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with >>>> its source connected to the transformer and its gate and drain to the main >>>> FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main >>>> FET on, and a negative one conducts via transistor action, turning it off. >>>> It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct
tiny spikes at the leading and trailing edge of the pulse, and drive a
highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or
a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:disables the opto.
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the switch
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..Since you have that 230 VAC source, you could make a gate power supply
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Then use my should-be-famous totem-pole optocoupler, which has zero
static supply current.
Why two fets? Change the heater and run half-wave.
How about an opto-triac? The whole thing becomes two parts.
søndag den 12. november 2023 kl. 00.40.06 UTC+1 skrev Phil Hobbs:
Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 17:24:08 UTC+1, Phil Hobbs wrote:
John Larkin <j...@997PotHill.com> wrote:Sounds very interesting. Do you have a link to a schematics?
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:There’s the common-gate FET trick, where you use a small extra FET, with
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look
good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >>> a fet through a transformer, but nothing reasonable works.
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
I did it for a customer gig a couple of years ago, but they went away before it got built.
(It was a large semiconductor equipment company.)
this one from the old "Philips Power semiconductor applications"
https://imgur.com/a/E3DaFAO ?
On 11/11/2023 11:05 pm, Klaus Kragelund wrote:
On Friday, 10 November 2023 at 20:23:02 UTC+1, Fred Bloggs wrote:Why do you need to switch a heater fast? Those are fancy fets just for heater switching, triacs make better use of silicon?
On Friday, November 10, 2023 at 1:27:19 PM UTC-5, john larkin wrote: >>> On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil HobbsIt needs to switch fast, since transient loss might be very large, and exceed transient thermal resistance constraints
<pcdhSpamM...@electrooptical.net> wrote:If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look >>>>> good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >>>>> a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct >>> tiny spikes at the leading and trailing edge of the pulse, and drive a >>> highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or >>> a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:disables the opto.
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the switch
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..Since you have that 230 VAC source, you could make a gate power supply
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
On Sunday, 12 November 2023 at 11:55:48 UTC+1, piglet wrote:
On 11/11/2023 11:05 pm, Klaus Kragelund wrote:Due to the switching loss of the FET. I am looking into heavy snubber to avoid that.
On Friday, 10 November 2023 at 20:23:02 UTC+1, Fred Bloggs wrote:Why do you need to switch a heater fast? Those are fancy fets just for
On Friday, November 10, 2023 at 1:27:19 PM UTC-5, john larkin wrote: >>>>> On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil HobbsIt needs to switch fast, since transient loss might be very large, and exceed transient thermal resistance constraints
<pcdhSpamM...@electrooptical.net> wrote:If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote: >>>>>>>
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look >>>>>>> good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive >>>>>>> a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap.
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the
small tranny can drive a gate driver chip. The tranny can also conduct >>>>> tiny spikes at the leading and trailing edge of the pulse, and drive a >>>>> highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or >>>>> a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
heater switching, triacs make better use of silicon?
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:disables the opto.
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the switch
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..Since you have that 230 VAC source, you could make a gate power supply
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Then use my should-be-famous totem-pole optocoupler, which has zero
static supply current.
Why two fets? Change the heater and run half-wave.
How about an opto-triac? The whole thing becomes two parts.
On 12/11/2023 11:19 am, Klaus Kragelund wrote:
On Sunday, 12 November 2023 at 11:55:48 UTC+1, piglet wrote:Surprised you find it worthwhile, I estimate you'll see 2.2W in the two
On 11/11/2023 11:05 pm, Klaus Kragelund wrote:Due to the switching loss of the FET. I am looking into heavy snubber to avoid that.
On Friday, 10 November 2023 at 20:23:02 UTC+1, Fred Bloggs wrote:Why do you need to switch a heater fast? Those are fancy fets just for
On Friday, November 10, 2023 at 1:27:19 PM UTC-5, john larkin wrote: >>>>> On Fri, 10 Nov 2023 16:24:00 -0000 (UTC), Phil HobbsIt needs to switch fast, since transient loss might be very large, and exceed transient thermal resistance constraints
<pcdhSpamM...@electrooptical.net> wrote:If the application is for a MOSFET analog switch, switching speed is not of the essence, duty is very low.
John Larkin <j...@997PotHill.com> wrote:Clever.
On Fri, 10 Nov 2023 08:28:15 -0500, legg <le...@nospam.magma.ca> wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it
to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand. >>>>>>>>>
Anyone got a recommendation?
Cheers
Klaus
Suggest you nail down your requirements first:
Lpmin
Vtmin,
Rdcmax,
Isolation class,
prod test level.
Many techniques avoid the requirement of high Lp and Vt.
Be smart or pay.
RL
Volt-second saturation will exclude small parts that othewise look >>>>>>> good. Ditto leakage inductance.
Winding capacitance, too. There are cases where I would love to drive
a fet through a transformer, but nothing reasonable works.
There’s the common-gate FET trick, where you use a small extra FET, with
its source connected to the transformer and its gate and drain to the main
FET’s source and gate, respectively, with a small storage cap. >>>>>>
(The other end of the transformer goes to the main FET’s source as usual. )
Using NFETs, a positive edge conducts via the body diode, turning the main
FET on, and a negative one conducts via transistor action, turning it off.
It doesn’t matter much what happens in between.
Really stretches out the ol’ voltseconds.
Cheers
Phil Hobbs
Given a floating power supply, a dc/dc converter or equivalent, the >>>>> small tranny can drive a gate driver chip. The tranny can also conduct >>>>> tiny spikes at the leading and trailing edge of the pulse, and drive a >>>>> highside flop or schmitt.
In my youth, I invented the dual optocoupler totem pole fet gate
driver. That needs a floating power supply, a dc/dc or a PV coupler or >>>>> a bootstrap supply or something. Slow but nice.
Nowadays a fast logic coupler can drive a fast gate driver chip.
heater switching, triacs make better use of silicon?
FETs versus 2.9W in a triac - which costs less and frees up PCB area you could use instead for heatsinking?
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:disables the opto.
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the switch
Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund ><klaus.kragelund@gmail.com> wrote:disables the opto.
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the switch
Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>disables the opto.
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund ><klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the
Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply >>> from that. The little capacitor-limited thing like people use to power >>> LEDs from the AC line.
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
You could do your entire isolated gate driver for about 17 cents.
søndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:disables the opto.
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller first
switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the
You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply >> >>> from that. The little capacitor-limited thing like people use to power >> >>> LEDs from the AC line.
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Version 4
SHEET 1 960 800
WIRE 64 -112 -64 -112
WIRE 272 -112 144 -112
WIRE 688 -112 272 -112
WIRE 272 -64 272 -112
WIRE -64 0 -64 -112
WIRE 688 64 688 -112
WIRE 272 96 272 16
WIRE -64 112 -64 64
WIRE -64 112 -160 112
WIRE 80 112 -64 112
WIRE -160 144 -160 112
WIRE -64 144 -64 112
WIRE 224 176 144 176
WIRE -64 208 -160 208
WIRE 176 208 -64 208
WIRE 272 208 272 192
WIRE 272 208 176 208
WIRE 272 224 272 208
WIRE 224 240 224 176
WIRE 272 384 272 320
WIRE 688 384 688 144
WIRE 688 384 272 384
WIRE -144 432 -560 432
WIRE 80 432 80 112
WIRE 80 432 48 432
WIRE 80 496 48 496
WIRE -304 528 -336 528
WIRE -144 528 -224 528
WIRE 80 576 80 496
WIRE 144 576 144 176
WIRE 144 576 80 576
WIRE -336 624 -336 528
WIRE -336 624 -416 624
WIRE -304 624 -336 624
WIRE -144 624 -224 624
WIRE 80 624 80 576
WIRE 80 624 48 624
WIRE -560 640 -560 432
WIRE -416 640 -416 624
WIRE 176 688 176 208
WIRE 176 688 48 688
WIRE -416 720 -560 720
WIRE -144 720 -416 720
FLAG -560 720 0
FLAG -64 208 0
SYMBOL nmos 224 96 R0
SYMATTR InstName M1
SYMATTR Value R6020PNJ
SYMBOL nmos 224 320 M180
SYMATTR InstName M2
SYMATTR Value R6020PNJ
SYMBOL res 256 -80 R0
SYMATTR InstName R1
SYMATTR Value 70
SYMBOL voltage 688 48 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value SINE(0 325 50 0 0 0)
SYMBOL diode -80 0 R0
SYMATTR InstName D1
SYMATTR Value MUR460
SYMBOL zener -144 208 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D2
SYMATTR Value BZX84C10L
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 160 -128 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 500k
SYMBOL cap -80 144 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL Optos\\4N25 -48 496 R0
SYMATTR InstName U1
SYMBOL Optos\\4N25 -48 688 R0
SYMATTR InstName U2
SYMBOL voltage -560 624 R0
WINDOW 3 -65 60 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 2
SYMBOL voltage -416 624 R0
WINDOW 3 -74 146 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(2 0 .1 1u 1u .1205 .3457)
SYMBOL res -208 512 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 100
SYMBOL res -208 608 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 100
TEXT -326 -184 Left 2 !.tran 2
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen ><langwadt@fonz.dk> wrote:first disables the opto.
søndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller
switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the
You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply >>> >>> from that. The little capacitor-limited thing like people use to power >>> >>> LEDs from the AC line.
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>first disables the opto.
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen ><lang...@fonz.dk> wrote:
sřndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com> >>> wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote: >>> >>> >> On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller
switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the
You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us.. >>> >>> >Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
That needs to be Spiced. It gets a little weird when the fets are off.
It may need another resistor.
søndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:first disables the opto.
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote: >> >>> >>> >> On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller
switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then the
That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen <lang...@fonz.dk> wrote:first disables the opto.
søndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com> >> >>> wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote: >> >>> >>> On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the microcontroller
the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then
That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us.. >> >>> >>> >Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so >> >>> >the series resistor can be big. Actually, the series resistor would >> >>> >work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the groundThe source-source node basically floats when both fets are off...
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:microcontroller first disables the opto.
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
søndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com> >> >> >>> wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote: >> >> >>> >>> On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost, then
The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us.. >> >> >>> >>> >Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so >> >> >>> >the series resistor can be big. Actually, the series resistor would >> >> >>> >work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:microcontroller first disables the opto.
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen <lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
sřndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin: >> >> >>> On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund >> >> >>> >>> >> <klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost,
I just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highThe source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor. >> >> >>> >
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget. >> >> >
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto >> could fail.
Very nice solution, and a lot more clean than the transformer one I have been working on.how? C1 gets charged via D1 and Q2s body diodeYeah, OK, I guess it does work.
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen <lang...@fonz.dk> wrote:microcontroller first disables the opto.
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
sřndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com> >> >> wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen >> >> ><lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin: >> >> >>> On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand. >> >> >>> >>> >> >
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost,
Very nice solution, and a lot more clean than the transformer one I have been working on.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off. >> >> It may need another resistor.something like this?You could do your entire isolated gate driver for about 17 cents. >> >> >>Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear. >> >> >>> >After this coffee diffuses into my brain.
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget. >> >> >
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diodeYeah, OK, I guess it does work.
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:microcontroller first disables the opto.
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin: >> > >> >> >>> On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund >> > >> >> >>> >>> >> <klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost,
I just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor. >> > >> >> >>> >
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget. >> > >> >> >
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto >> > >> could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
Looks like the internet lost the Philips handbook...This one? https://assets.nexperia.com/documents/user-manual/Nexperia_document_book_MOSFETGaNFETApplicationHandbook_2020.pdf
On 2023-11-10 17:37, Fred Bloggs wrote:
Looks like the internet lost the Philips handbook...This one? https://assets.nexperia.com/documents/user-manual/Nexperia_document_book_MOSFETGaNFETApplicationHandbook_2020.pdf
mandag den 13. november 2023 kl. 12.55.53 UTC+1 skrev Arie de Muijnck:
On 2023-11-10 17:37, Fred Bloggs wrote:http://jfsimon.net/public/Power_Semiconductor_Applications_Philips.pdf ?
Looks like the internet lost the Philips handbook...This one? https://assets.nexperia.com/documents/user-manual/Nexperia_document_book_MOSFETGaNFETApplicationHandbook_2020.pdf
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:microcontroller first disables the opto.
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen >> > >> <lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin: >> > >> >> On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund >> > >> >> >>> >>> <klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar. >> > >> >> >>> >>> >> >
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost,
What sort of switching rates do you need? Entire cycles at 50 Hz? FastI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
PWM? The triac solution wouldn't switch fast, and a heater shouldn't
need a lot of switching.
You can vary the led drive, and the coupler CTRs, to control mosfet
edge rates. I think EMI was an issue for you so you may not want fast
edges.
To go faster, add a couple of transistors to drive the gate
capacitance harder. One PNP, one NPN, one cent each.
mandag den 13. november 2023 kl. 05.49.19 UTC+1 skrev John Larkin:microcontroller first disables the opto.
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen >> >> > >> <lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin: >> >> > >> >> On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund >> >> > >> >> >>> >>> <klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar. >> >> > >> >> >>> >>> >> >
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost,
What sort of switching rates do you need? Entire cycles at 50 Hz? FastI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
PWM? The triac solution wouldn't switch fast, and a heater shouldn't
need a lot of switching.
I assume Klaus did the calculations and concluded that a slow turnon/turnoff at the wrong time would
exceed the maximum allowable peak dissipation in the FETs
You can vary the led drive, and the coupler CTRs, to control mosfet
edge rates. I think EMI was an issue for you so you may not want fast
edges.
To go faster, add a couple of transistors to drive the gate
capacitance harder. One PNP, one NPN, one cent each.
or splurge and spend 30 cent and get a real gatedriver and optocoupler in one, like for example TLP155
On Mon, 13 Nov 2023 09:10:07 -0800 (PST), Lasse Langwadt Christensen <lang...@fonz.dk> wrote:microcontroller first disables the opto.
mandag den 13. november 2023 kl. 05.49.19 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen >> >> > <lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin: >> >> > >> On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund >> >> > >> >> >>> ><klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
lost, then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is
What sort of switching rates do you need? Entire cycles at 50 Hz? FastI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off... >> >> > >> battling substrate diodes. So the power supply to the totem-pole optoThat needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
PWM? The triac solution wouldn't switch fast, and a heater shouldn't
need a lot of switching.
I assume Klaus did the calculations and concluded that a slow turnon/turnoff at the wrong time would
exceed the maximum allowable peak dissipation in the FETs
You can vary the led drive, and the coupler CTRs, to control mosfet
edge rates. I think EMI was an issue for you so you may not want fast
edges.
To go faster, add a couple of transistors to drive the gate
capacitance harder. One PNP, one NPN, one cent each.
or splurge and spend 30 cent and get a real gatedriver and optocoupler in one, like for example TLP155It needs a floating power supply.
I think there are gate drivers with isolated power too, TI maybe.
On Thursday, November 9, 2023 at 6:14:58?PM UTC-5, Klaus Kragelund wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
If you're looking for cheap, you can't beat capacitor coupling the gate drive. Phillips has a whole chapter in their MOSFET applications handbook on how to do this reliably-wasn't in the market for the technique at the time and skipped it.
\
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:microcontroller first disables the opto.
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen >> > >> <lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin: >> > >> >> On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund >> > >> >> >>> >>> <klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar. >> > >> >> >>> >>> >> >
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost,
What sort of switching rates do you need? Entire cycles at 50 Hz? FastI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
PWM? The triac solution wouldn't switch fast, and a heater shouldn't
need a lot of switching.
You can vary the led drive, and the coupler CTRs, to control mosfetThe problem we had was with Triac control, in which they used diac to control the gate, so it would have a nasty transient every 10ms, which resulted in large EMI-
edge rates. I think EMI was an issue for you so you may not want fast
edges.
To go faster, add a couple of transistors to drive the gateI have tried that, still not good enough. I will try to add a schmitt trigger to clean the signal up, so I can push a lot of current into the gates for fast switching and low loss.
capacitance harder. One PNP, one NPN, one cent each.
mandag den 13. november 2023 kl. 22.59.42 UTC+1 skrev john larkin:microcontroller first disables the opto.
On Mon, 13 Nov 2023 09:10:07 -0800 (PST), Lasse Langwadt Christensen <lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 05.49.19 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote: >> >> On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
lost, then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is
What sort of switching rates do you need? Entire cycles at 50 Hz? Fast >> PWM? The triac solution wouldn't switch fast, and a heater shouldn'tI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
need a lot of switching.
I assume Klaus did the calculations and concluded that a slow turnon/turnoff at the wrong time would
exceed the maximum allowable peak dissipation in the FETs
You can vary the led drive, and the coupler CTRs, to control mosfet
edge rates. I think EMI was an issue for you so you may not want fast >> edges.
To go faster, add a couple of transistors to drive the gate
capacitance harder. One PNP, one NPN, one cent each.
sure, it only replaces the dual opto with something with a more "beefy" driveor splurge and spend 30 cent and get a real gatedriver and optocoupler in one, like for example TLP155It needs a floating power supply.
I think there are gate drivers with isolated power too, TI maybe.analog too, but afaict they something like 20x the price of one without isolated power
On Fri, 10 Nov 2023 08:37:45 -0800 (PST), Fred Bloggs <bloggs.fred...@gmail.com> wrote:You can use Y caps, then you just need to keep the capacitance below 1nF.
On Thursday, November 9, 2023 at 6:14:58?PM UTC-5, Klaus Kragelund wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
If you're looking for cheap, you can't beat capacitor coupling the gate drive. Phillips has a whole chapter in their MOSFET applications handbook on how to do this reliably-wasn't in the market for the technique at the time and skipped it.
\
One problem is achieving safe isolation from the 230 VAC power lines.
On Monday, 13 November 2023 at 05:49:19 UTC+1, John Larkin wrote:microcontroller first disables the opto.
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen >> >> > >> <lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin: >> >> > >> >> On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund >> >> > >> >> >>> >>> <klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar. >> >> > >> >> >>> >>> >> >
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is lost,
What sort of switching rates do you need? Entire cycles at 50 Hz? FastI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
PWM? The triac solution wouldn't switch fast, and a heater shouldn't
need a lot of switching.
Entire cycle, to reduce EMI. It will use something like 1s on, and 1s off, at least many periods between turn on and off.
The edge rate is not that critical, it controls the envelope fall rate, which is at a very high frequency. At 50Hz (1Hz in case of 50cycles on/off), the emission is the same.
What matters for the MOSFET case is transient dissipation, since that can easily result in very high transient temperature.
mandag den 13. november 2023 kl. 05.49.19 UTC+1 skrev John Larkin:microcontroller first disables the opto.
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen >> > <lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin: >> > >> On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund >> > >> >> >>> ><klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
lost, then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is
I assume Klaus did the calculations and concluded that a slow turnon/turnoff at the wrong time wouldWhat sort of switching rates do you need? Entire cycles at 50 Hz? Fast PWM? The triac solution wouldn't switch fast, and a heater shouldn'tI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off... >> > >> battling substrate diodes. So the power supply to the totem-pole optoThat needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
need a lot of switching.
exceed the maximum allowable peak dissipation in the FETs
You can vary the led drive, and the coupler CTRs, to control mosfet
edge rates. I think EMI was an issue for you so you may not want fast edges.
To go faster, add a couple of transistors to drive the gateor splurge and spend 30 cent and get a real gatedriver and optocoupler in one, like for example TLP155
capacitance harder. One PNP, one NPN, one cent each.
On Mon, 13 Nov 2023 15:29:43 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:microcontroller first disables the opto.
On Monday, 13 November 2023 at 05:49:19 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen >> >> > <lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin: >> >> > >> On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund >> >> > >> >> >>> ><klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
lost, then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is
What sort of switching rates do you need? Entire cycles at 50 Hz? FastI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off... >> >> > >> battling substrate diodes. So the power supply to the totem-pole optoThat needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
PWM? The triac solution wouldn't switch fast, and a heater shouldn't
need a lot of switching.
Entire cycle, to reduce EMI. It will use something like 1s on, and 1s off, at least many periods between turn on and off.
The edge rate is not that critical, it controls the envelope fall rate, which is at a very high frequency. At 50Hz (1Hz in case of 50cycles on/off), the emission is the same.Check the SOAR curves. A mosfet can dissipate a lot of power for a millisecond.
What matters for the MOSFET case is transient dissipation, since that can easily result in very high transient temperature.
Zero-cross switching solves the dynamic dissipation problem.
On Monday, 13 November 2023 at 18:10:12 UTC+1, Lasse Langwadt Christensen wrote:microcontroller first disables the opto.
mandag den 13. november 2023 kl. 05.49.19 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote: >> On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote:
On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin: >> > >> On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
lost, then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power is
I assume Klaus did the calculations and concluded that a slow turnon/turnoff at the wrong time wouldWhat sort of switching rates do you need? Entire cycles at 50 Hz? Fast PWM? The triac solution wouldn't switch fast, and a heater shouldn't need a lot of switching.I just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
exceed the maximum allowable peak dissipation in the FETs
You can vary the led drive, and the coupler CTRs, to control mosfet
edge rates. I think EMI was an issue for you so you may not want fast edges.
The TLP155 does not has UVLO protection AFAICS.To go faster, add a couple of transistors to drive the gateor splurge and spend 30 cent and get a real gatedriver and optocoupler in one, like for example TLP155
capacitance harder. One PNP, one NPN, one cent each.
I have been looking at DGD1003, it has a UVLO of at least 8V, so fit's well. Less than 20cents
https://www.diodes.com/assets/Datasheets/DGD1003.pdf
On Fri, 10 Nov 2023 08:37:45 -0800 (PST), Fred Bloggs ><bloggs.fredbloggs.fred@gmail.com> wrote:
On Thursday, November 9, 2023 at 6:14:58?PM UTC-5, Klaus Kragelund wrote:
Hi
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
If you're looking for cheap, you can't beat capacitor coupling the gate drive. Phillips has a whole chapter in their MOSFET
applications handbook on how to do this reliably-wasn't in the market for the technique at the time and skipped it.
\
One problem is achieving safe isolation from the 230 VAC power lines.
tirsdag den 14. november 2023 kl. 01.05.11 UTC+1 skrev Klaus Kragelund:microcontroller first disables the opto.
On Monday, 13 November 2023 at 18:10:12 UTC+1, Lasse Langwadt Christensen wrote:
mandag den 13. november 2023 kl. 05.49.19 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote: >> On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote: >> > On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet?
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
STB43N60DM2
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
is lost, then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power
I assume Klaus did the calculations and concluded that a slow turnon/turnoff at the wrong time wouldWhat sort of switching rates do you need? Entire cycles at 50 Hz? Fast PWM? The triac solution wouldn't switch fast, and a heater shouldn't need a lot of switching.I just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
exceed the maximum allowable peak dissipation in the FETs
You can vary the led drive, and the coupler CTRs, to control mosfet edge rates. I think EMI was an issue for you so you may not want fast edges.
The TLP155 does not has UVLO protection AFAICS.To go faster, add a couple of transistors to drive the gate capacitance harder. One PNP, one NPN, one cent each.or splurge and spend 30 cent and get a real gatedriver and optocoupler in one, like for example TLP155
I have been looking at DGD1003, it has a UVLO of at least 8V, so fit's well. Less than 20cents
https://www.diodes.com/assets/Datasheets/DGD1003.pdfbut it doesn't have the opto isolation build in
On Tuesday, 14 November 2023 at 02:57:58 UTC+1, Lasse Langwadt Christensen wrote:microcontroller first disables the opto.
tirsdag den 14. november 2023 kl. 01.05.11 UTC+1 skrev Klaus Kragelund:
On Monday, 13 November 2023 at 18:10:12 UTC+1, Lasse Langwadt Christensen wrote:
mandag den 13. november 2023 kl. 05.49.19 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 17:52:25 -0800 (PST), Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Monday, 13 November 2023 at 02:37:13 UTC+1, Klaus Kragelund wrote:
On Monday, 13 November 2023 at 01:51:39 UTC+1, John Larkin wrote: >> > On Sun, 12 Nov 2023 15:54:43 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
mandag den 13. november 2023 kl. 00.32.30 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 13:53:18 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 21.59.15 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 11:55:40 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 11:00:03 -0800 (PST), Lasse Langwadt Christensen
<lang...@fonz.dk> wrote:
s?ndag den 12. november 2023 kl. 18.15.35 UTC+1 skrev John Larkin:
On Sun, 12 Nov 2023 07:44:41 -0800, John Larkin <j...@997PotHill.com>
wrote:
On Sun, 12 Nov 2023 03:29:02 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Sunday, 12 November 2023 at 01:02:21 UTC+1, John Larkin wrote:
On Sat, 11 Nov 2023 14:57:11 -0800 (PST), Klaus Kragelund
<klaus.k...@gmail.com> wrote:
On Friday, 10 November 2023 at 16:28:14 UTC+1, John Larkin wrote:
On Thu, 9 Nov 2023 15:14:53 -0800 (PST), Klaus KragelundSTB43N60DM2
<klaus.k...@gmail.com> wrote:
HiAre you driving the gate of a fet? What fet? >> > >> >> >>> >>> >
I am on the lookout for a cheap 1:1 pulse transformer. Will be using it to drive a MOSFET based Solid State Switch.
I know Larkin has used the DRQ127
https://www.digikey.dk/en/products/detail/eaton-electronics-division/DRQ127-1R5-R/667262
But, I am looking to see if I can find bottom dollar.
I probably wont go to LCSC, so would prefer a known brand.
Anyone got a recommendation?
Cheers
Klaus
I did a change to the design, since the 1:10 transformer was bugging me, so used a old fashion CD4093 from 15V supply, to make an isolated supply with a 1:1 transformer.
Then an opto to contol the MOSFETs. Emitter followers to lower the impedance driving the gate, since the turn on/turn off losses needs to be kept low due to transient thermal resistance.
Schematics, first draft:
www.electronicsdesign.dk/tmp/ssr.pdf
Some comments:
UVLO is handled by the microcontroller in that the PSU starts when power is applied, but the microcontroller is not allowed to turn the FET on until we are sure the PSU is active (milliseconds). Likewise, during shutdown the
is lost, then the switch off loss is also zero, but we could have a situation with low mains voltage and we need to take actions accordingly.
We need to have UVLO detection on the 15V power supply for the self-running oscillator, in case of a brown-out – lower voltage of the 15V node, the opto needs to be turned off before voltage sags deeper. Normally, if power
I assume Klaus did the calculations and concluded that a slow turnon/turnoff at the wrong time wouldWhat sort of switching rates do you need? Entire cycles at 50 Hz? FastI just simulated Lasses solution. C1 needs to be 1uF due to charge transfer, otherwise the switching losses are too highVery nice solution, and a lot more clean than the transformer one I have been working on.Yeah, OK, I guess it does work.The source-source node basically floats when both fets are off...That needs to be Spiced. It gets a little weird when the fets are off.You could do your entire isolated gate driver for about 17 cents.Actually the capacitive couplers are not very good when it comes to surges/transients on the mains line, so need to add impedance to reduce peak currents in the circuit.Since you have that 230 VAC source, you could make a gate power supply
MOSFET selected is STB43N60DM2, 100mohm/D2PAK, about 40K/W with current layout.
At 100mohm/3.7A, loss is 1.3W. 600V device to have 60% derating from peak of 360V.
275V varistor SIOV1 is placed across drain/drain of MOSFETs. We might be able to use lower voltage rated MOSFETs due to thje varistor.
MOSFETs are avalanche rated for 800mJ.
K = 0.015 for less than 10us switching time. Estimated for 1us..
Rth = 40K/W. Transient Rth = 0.6K/W
from that. The little capacitor-limited thing like people use to power
LEDs from the AC line.
Sure, the LED night-light circuits include a series resistor.
The totem-pole opto gate driver needs about zero supply current, so
the series resistor can be big. Actually, the series resistor would
work without a series cap. I can sketch it if it's not all clear.
After this coffee diffuses into my brain.
something like this?
Close. I was thinking
https://www.dropbox.com/scl/fi/ee9cpnt16nyxotka4zgkw/Isol_Gate_Driver_1.jpg?rlkey=v2o44hxa52eraurnuqpohmcp0&raw=1
One could add a zener somewhere without blowing the 17 cent budget.
It may need another resistor.
it should work, either way is a bit weird to look at in simulation if you don't make the fet sources the ground
battling substrate diodes. So the power supply to the totem-pole opto
could fail.
how? C1 gets charged via D1 and Q2s body diode
Only worry is noise coupling into the gates, from transients. But that can be remedied by adding a capacitance to the gates of Q1 and Q2. Will slow switching times a little, but more robust.
PWM? The triac solution wouldn't switch fast, and a heater shouldn't need a lot of switching.
exceed the maximum allowable peak dissipation in the FETs
You can vary the led drive, and the coupler CTRs, to control mosfet edge rates. I think EMI was an issue for you so you may not want fast
edges.
The TLP155 does not has UVLO protection AFAICS.To go faster, add a couple of transistors to drive the gate capacitance harder. One PNP, one NPN, one cent each.or splurge and spend 30 cent and get a real gatedriver and optocoupler in one, like for example TLP155
I have been looking at DGD1003, it has a UVLO of at least 8V, so fit's well. Less than 20cents
I will only use it to drive the FETs, to make sure I have sufficient gate current.https://www.diodes.com/assets/Datasheets/DGD1003.pdfbut it doesn't have the opto isolation build in
Come to think about it, why not just use a high-side gatedriver, with a circuit to supply the HS supply? Then the circuit simplifies to just a gatedriver and the FETs....
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