500 volt power supply...

https://www.papandayancargo.com/
https://www.papandayancargo.com/ekspedisi-surabaya-makassar/
https://www.papandayancargo.com/ekspedisi-surabaya-banjarmasin/
https://www.papandayancargo.com/ekspedisi-surabaya-balikpapan/
https://www.papandayancargo.com/ekspedisi-jakarta-ke-balikpapan/
https://www.papandayancargo.com/ekspedisi-jakarta-makassar/
https://www.papandayancargo.com/ekspedisi-jakarta-banjarmasin/
https://www.papandayancargo.com/ekspedisi-jakarta-ke-samarinda/
 
https://www.papandayancargo.com/
https://www.papandayancargo.com/ekspedisi-surabaya-makassar/
https://www.papandayancargo.com/ekspedisi-surabaya-banjarmasin/
https://www.papandayancargo.com/ekspedisi-surabaya-balikpapan/
https://www.papandayancargo.com/ekspedisi-jakarta-ke-balikpapan/
https://www.papandayancargo.com/ekspedisi-jakarta-makassar/
https://www.papandayancargo.com/ekspedisi-jakarta-banjarmasin/
https://www.papandayancargo.com/ekspedisi-jakarta-ke-samarinda/
 
On Sun, 1 Oct 2023 21:27:52 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Friday, September 29, 2023 at 12:07:37?PM UTC-7, John Larkin wrote:
On Fri, 29 Sep 2023 01:53:09 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Thursday, September 28, 2023 at 7:09:27?PM UTC-7, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund
klaus.k...@gmail.com> wrote:

I am driving a UV lamp, so I need to deliver a pulse. Possible with a multiplier, but doesn\'t make it easier
No, the C-W multiplier isn\'t good for pulsing. Ixys has a 4700 volt
mosfet. A C-W multiplier could make the HV.

Maybe use a Marx generator? With medium-high voltage mos or SiC fets?

Not usually a great idea; at HV, the best switch is photo-SCR.

Should work, but might be too slow for some applications. It is a nice
idea to make high-current HV pulses. Six of these maybe:

https://www.digikey.com/en/products/detail/vishay-semiconductor-opto-division/VOT8125AB-V/9843471

Ick; triacs, not SCRs, and you\'d have to wire-connect those input pins... I was
thinking more of fibers to a receiver with phototransistor, use PNP and NPN phototransistor to
make an SCR, bias it with a 9V battery at each node, so a single lamp flash can light
up all the nodes at once. That 9V pulse, of course, just goes to the gate of a REAL SCR.

This one seems thrifty, and does over a kilovolt

https://www.digikey.com/en/products/detail/vishay-general-semiconductor-diodes-division/VS-25TTS16SLHM3/9467407

The real advantage, though, of photoSCR is in the turnon dI/dt limit; it doesn\'t have any,
because it turns on full-area when lit. That takes more light than you\'d likely push through a fiber, however.
150 A/us is the limit you get for your $2.86
Click to expand...

Fiber would be great for a giant, megavolt, megabuck, gigawatt-scale
Marx, but not what I\'d want to put on a PC board.

A flashlamp wouldn\'t couple much light into a glass fiber. It might
work into the dreadful plastic audio stuff.
 
On Sun, 1 Oct 2023 19:57:13 -0700 (PDT), John Smiht
<utube.jocjo@xoxy.net> wrote:

On Sunday, October 1, 2023 at 9:08:19?AM UTC-5, John Larkin wrote:
On Sun, 01 Oct 2023 05:31:31 GMT, Jan Panteltje <al...@comet.invalid
wrote:
On a sunny day (Sat, 30 Sep 2023 12:10:06 -0700) it happened John Larkin
j...@997arbor.com> wrote in <2grghi1vnnsmrkbcl...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

OK, this has become sort of a background hobby, waiting on the
customer to get serious.

https://www.dropbox.com/scl/fi/60nb1pcrnl17c07tk8xeu/T875_HV_9.jpg?rlkey=9uv466edcuvddmjldgepcyi0u&raw=1

All the caps are a part that we have, 100nF 630 volts 1812. Of course
the capacitance plummets as voltage goes up, so the Spice values have
to be adjusted appropriately. C is only 20nF at 500 volts.

That much really? Th big caps I use do not change at all I think?
I measured one.

https://www.dropbox.com/scl/fi/zrrount2a5s7k5bmqh4bu/C-V.jpg?rlkey=3so16njq8md4ccnm610a8mf49&raw=1

John, I have worked quite extensively with CW multipliers. Both series and parallel ones.
The nice thing about series multipliers is that the capacitors will see no more than the p-p input voltage.
So I don\'t think you high voltage ones except to use them at a lower voltage to improve capacitance.
Parallel multipliers are more efficient but do require the higher voltage ( at least on the final stage).

Good luck with your project and please post its progress here.Thanks.
Click to expand...

Right, my caps lose most of their capacitance if I use them in
parallel mode. 5 or 6 caps in parallel work OK for the final 500 volt
filter to ground.

My experience with surface-mount film caps has been bad.

The Pockels Cell will work in switch mode, so sees zero volts or Vpi
(500) volts, and in both cases it\'s operating on the flat part of the
sine-squared curve, so ripple doesn\'t much matter. The light is
blowing up things anyhow.

I hope the customer gets serious and I get to actually build this one.

The power supply part is no big secret so I\'ll post any ideas or
actual progress. I do find it helpful to discuss this sort of thing.
 
On Monday, October 2, 2023 at 10:01:16 AM UTC-5, John Larkin wrote:
On Sun, 1 Oct 2023 19:57:13 -0700 (PDT), John Smiht
utube...@xoxy.net> wrote:
On Sunday, October 1, 2023 at 9:08:19?AM UTC-5, John Larkin wrote:
On Sun, 01 Oct 2023 05:31:31 GMT, Jan Panteltje <al...@comet.invalid
wrote:
On a sunny day (Sat, 30 Sep 2023 12:10:06 -0700) it happened John Larkin
j...@997arbor.com> wrote in <2grghi1vnnsmrkbcl...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

OK, this has become sort of a background hobby, waiting on the
customer to get serious.

https://www.dropbox.com/scl/fi/60nb1pcrnl17c07tk8xeu/T875_HV_9.jpg?rlkey=9uv466edcuvddmjldgepcyi0u&raw=1

All the caps are a part that we have, 100nF 630 volts 1812. Of course
the capacitance plummets as voltage goes up, so the Spice values have
to be adjusted appropriately. C is only 20nF at 500 volts.

That much really? Th big caps I use do not change at all I think?
I measured one.

https://www.dropbox.com/scl/fi/zrrount2a5s7k5bmqh4bu/C-V.jpg?rlkey=3so16njq8md4ccnm610a8mf49&raw=1

John, I have worked quite extensively with CW multipliers. Both series and parallel ones.
The nice thing about series multipliers is that the capacitors will see no more than the p-p input voltage.
So I don\'t think you high voltage ones except to use them at a lower voltage to improve capacitance.
Parallel multipliers are more efficient but do require the higher voltage ( at least on the final stage).

Good luck with your project and please post its progress here.Thanks.
Right, my caps lose most of their capacitance if I use them in
parallel mode. 5 or 6 caps in parallel work OK for the final 500 volt
filter to ground.

My experience with surface-mount film caps has been bad.

The Pockels Cell will work in switch mode, so sees zero volts or Vpi
(500) volts, and in both cases it\'s operating on the flat part of the
sine-squared curve, so ripple doesn\'t much matter. The light is
blowing up things anyhow.

I hope the customer gets serious and I get to actually build this one.

The power supply part is no big secret so I\'ll post any ideas or
actual progress. I do find it helpful to discuss this sort of thing.
Click to expand...

Of course you do. So do the rest of us who are interested in electronics.
Like you, I do hope your customer comes forth with what you need to continue.
I would love to see your progress in your project if it comes to be.
Thanks John.
John
 
On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund
klaus.kragelund@gmail.com> wrote:

On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus
Kragelund <klaus.k...@gmail.com> wrote in
903144ac-6642-4a3f...@googlegroups.com>:

On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin
j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:

On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin
j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

Since I couldn\'t find a suitable flyback transformer, and I only need
500 volts at 10 mA, a flyback/C-W multiplier makes sense.

https://www.dropbox.com/scl/fi/aquzpawfn8mfmfsnx70ra/T875_HV_6.jpg?rlkey=vfs9pexa0rgyxpo7pg1grqlb7&dl=0

Do you still need C11 R8 in that circuit?

It doesn\'t need them to work, but there is a big high-Q ring when the
fet turns off, and the RC damps it. It would reduce radiated EMI. And
it speeds up the simulation some.

Did you scope that?

All Spice now. I\'ll build it when the customer gets serious.

There is a load of capacitance hanging from the MOSFET drain in that flyback multiplier ciruit
I would expect it to damp RF oscillations but could be wrong...
HV diodes have capacitance too..

The real circuit will have a lot of inductances too, what with those
long strings of parts. It needs to be built and tested. Dremeled, to
start.

Here\'s an old auto-flyback C-W miltiplier prototype. I think that was
1400 volts. Worked fine.

https://www.dropbox.com/s/yd19osiwz1z74s4/HV_Proto_2.JPG?rsw=1
Yea,
I did a PMT supply this way:
http://panteltje.nl/pub/PMT_HV_supply_with_regulator_img_3175.jpg
http://panteltje.nl/pub/PMT_HV_supply_componet_side_img_3180.jpg
http://panteltje.nl/pub/PMT_regulated_power_supply_diagram_img_3182.jpg

It has been in use now for many years, sits with PMT in the cardboard tube on the right, runs on batteries:
http://panteltje.nl/pub/gamma_soectrometer_IMG_4505.JPG

Of course that is very low power, but for a bit more power, and using a real TV muliplier:
https://panteltje.nl/panteltje/pic/sc_pic/

No dremeling, boards are OK when they work..

And old TV circuits.. if you want a few kV there was / is? plenty stuff to be found on ebay.
For my case, I am working on a 5W 24V to 4.5kV converter. Right now looking to use a flyback topology, with possibly usage of
CCFL transformer bobbins.

I am thinking about staggering the windings on 2 transformers, so the voltage across the windings will be lower, but still the
individual transformer needs to handle 4.5kV insulation (functional, not safety)

Due to the limiting power, it could also be tempting to use the capacitive doublers as listed elsewhere in the thread

My worry goes beyond the design, also about corona effects, which comes into play at +kV voltages. Potting is surely needed.

For a HV transformer, old TV transformers (from the CRT times) may perhaps be an option:
https://www.google.com/search?client=firefox-b-e&q=ebay+horizonatl+TV+output+transformer
4.5 kV diodes were used for focus in color TV sets...


For a flyback, my rule of thumb (I do not use El Tea Spice), is 1 V per turn for DC input.
So 24 turns primary for 24 V DC supply.
The flyback voltage is (70/12) * 24 = 140V positive pulse if positive DC supply.
To get a 4.5 kV pulse you would then wind 4500 / 140 is about 32, multiplied by 24 makes 768 turns.
This for an EI core running at about 15 kHz (math comes from building TV output stages).
768 turns is not a big deal..
Spreading the turns over a segmented coil former is a good idea.
If you want to use a voltage multiplier then less turns are needed, use a TV multiplier, those are \'potted\'
The 70/12 factor depends on the PWM on/off ratio of the drive you feed into the switch transistor.
I use Microchip PICs for that, it has a PWM unit., hardware comparators that can directly stop the PWM drive
for cycle by cycle current limiting, and ADCs to measure voltage and currents.
Maybe an old TV horizontal output transformer with build in rectifier / multiplier would do.
https://www.ebay.com/b/flyback-transformer/bn_7024744628
to adapt use 15 kHz and add 24 turns to the core primary?
...
:)

Maybe like this?
https://www.ebay.com/p/1692562663?iid=374326473542
plenty space for 24 turns thick wire, its a 30 kV DC out, so use less PWM ... or more primary turns
or whatever you can find... on ebay.

High turns ratios can have two problems: voltage breakdown in the
insulation, and winding capacitance limiting the flyback ratio. That\'s
where a C-W diode multiplier helps.

I am driving a UV lamp, so I need to deliver a pulse. Possible with a multiplier, but doesn\'t make it easier

No, the C-W multiplier isn\'t good for pulsing. Ixys has a 4700 volt
mosfet. A C-W multiplier could make the HV.

Maybe use a Marx generator? With medium-high voltage mos or SiC fets?

Some of the Zetex app notes, for their avalanche transistors, use a
Marx-type circuit. Charge the caps in parallel and discharge them in
series. You only have to trigger one in the string.

What sort of speed and current do you need?
Click to expand...
I will generate a single pulse, about 5us long, shaped like a half wave
sinusoid, at 100kHz repetition frequency. That\'s why I was looking at
flyback, since I can control the voltage delivered simply by adjusting
the primary peak current. Power seems to be less than 5W, at 4.5kV peak,
duty of let\'s say 25%. probably below 10mA
 
On 2023-09-24, John Larkin <jl@997arbor.com> wrote:
I started simulating with a single 1:5 transformer, but couldn\'t find
one for sale.
Click to expand...

I have successfully used power-over-ethernet transformers (Pulse PA1137) for
a 12V -> 200V nixie supply. Not sure how they handle 500V.

PA1137 is 1:8, PA1138 is 1:3.43

cu
Michael
--
Some people have no respect of age unless it is bottled.
 
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund
<klauskvik@hotmail.com> wrote:

On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund
klaus.kragelund@gmail.com> wrote:

On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus
Kragelund <klaus.k...@gmail.com> wrote in
903144ac-6642-4a3f...@googlegroups.com>:

On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin
j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:

On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin
j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

Since I couldn\'t find a suitable flyback transformer, and I only need
500 volts at 10 mA, a flyback/C-W multiplier makes sense.

https://www.dropbox.com/scl/fi/aquzpawfn8mfmfsnx70ra/T875_HV_6.jpg?rlkey=vfs9pexa0rgyxpo7pg1grqlb7&dl=0

Do you still need C11 R8 in that circuit?

It doesn\'t need them to work, but there is a big high-Q ring when the
fet turns off, and the RC damps it. It would reduce radiated EMI. And
it speeds up the simulation some.

Did you scope that?

All Spice now. I\'ll build it when the customer gets serious.

There is a load of capacitance hanging from the MOSFET drain in that flyback multiplier ciruit
I would expect it to damp RF oscillations but could be wrong...
HV diodes have capacitance too..

The real circuit will have a lot of inductances too, what with those
long strings of parts. It needs to be built and tested. Dremeled, to
start.

Here\'s an old auto-flyback C-W miltiplier prototype. I think that was
1400 volts. Worked fine.

https://www.dropbox.com/s/yd19osiwz1z74s4/HV_Proto_2.JPG?rsw=1
Yea,
I did a PMT supply this way:
http://panteltje.nl/pub/PMT_HV_supply_with_regulator_img_3175.jpg
http://panteltje.nl/pub/PMT_HV_supply_componet_side_img_3180.jpg
http://panteltje.nl/pub/PMT_regulated_power_supply_diagram_img_3182.jpg

It has been in use now for many years, sits with PMT in the cardboard tube on the right, runs on batteries:
http://panteltje.nl/pub/gamma_soectrometer_IMG_4505.JPG

Of course that is very low power, but for a bit more power, and using a real TV muliplier:
https://panteltje.nl/panteltje/pic/sc_pic/

No dremeling, boards are OK when they work..

And old TV circuits.. if you want a few kV there was / is? plenty stuff to be found on ebay.
For my case, I am working on a 5W 24V to 4.5kV converter. Right now looking to use a flyback topology, with possibly usage of
CCFL transformer bobbins.

I am thinking about staggering the windings on 2 transformers, so the voltage across the windings will be lower, but still the
individual transformer needs to handle 4.5kV insulation (functional, not safety)

Due to the limiting power, it could also be tempting to use the capacitive doublers as listed elsewhere in the thread

My worry goes beyond the design, also about corona effects, which comes into play at +kV voltages. Potting is surely needed.

For a HV transformer, old TV transformers (from the CRT times) may perhaps be an option:
https://www.google.com/search?client=firefox-b-e&q=ebay+horizonatl+TV+output+transformer
4.5 kV diodes were used for focus in color TV sets...


For a flyback, my rule of thumb (I do not use El Tea Spice), is 1 V per turn for DC input.
So 24 turns primary for 24 V DC supply.
The flyback voltage is (70/12) * 24 = 140V positive pulse if positive DC supply.
To get a 4.5 kV pulse you would then wind 4500 / 140 is about 32, multiplied by 24 makes 768 turns.
This for an EI core running at about 15 kHz (math comes from building TV output stages).
768 turns is not a big deal..
Spreading the turns over a segmented coil former is a good idea.
If you want to use a voltage multiplier then less turns are needed, use a TV multiplier, those are \'potted\'
The 70/12 factor depends on the PWM on/off ratio of the drive you feed into the switch transistor.
I use Microchip PICs for that, it has a PWM unit., hardware comparators that can directly stop the PWM drive
for cycle by cycle current limiting, and ADCs to measure voltage and currents.
Maybe an old TV horizontal output transformer with build in rectifier / multiplier would do.
https://www.ebay.com/b/flyback-transformer/bn_7024744628
to adapt use 15 kHz and add 24 turns to the core primary?
...
:)

Maybe like this?
https://www.ebay.com/p/1692562663?iid=374326473542
plenty space for 24 turns thick wire, its a 30 kV DC out, so use less PWM ... or more primary turns
or whatever you can find... on ebay.

High turns ratios can have two problems: voltage breakdown in the
insulation, and winding capacitance limiting the flyback ratio. That\'s
where a C-W diode multiplier helps.

I am driving a UV lamp, so I need to deliver a pulse. Possible with a multiplier, but doesn\'t make it easier

No, the C-W multiplier isn\'t good for pulsing. Ixys has a 4700 volt
mosfet. A C-W multiplier could make the HV.

Maybe use a Marx generator? With medium-high voltage mos or SiC fets?

Some of the Zetex app notes, for their avalanche transistors, use a
Marx-type circuit. Charge the caps in parallel and discharge them in
series. You only have to trigger one in the string.

What sort of speed and current do you need?


I will generate a single pulse, about 5us long, shaped like a half wave
sinusoid, at 100kHz repetition frequency. That\'s why I was looking at
flyback, since I can control the voltage delivered simply by adjusting
the primary peak current. Power seems to be less than 5W, at 4.5kV peak,
duty of let\'s say 25%. probably below 10mA
Click to expand...

One can stuff a bunch of current into an inductor and then dump it
into a mostly-capacitive load. That can make a high-voltage half-sine.

This boosts 48 volts to 1400v at MHz pulse rates.

http://www.highlandtechnology.com/DSS/T850DS.shtml

by switching an inductor around. The energy is recovered and returned
to the 48v supply after each pulse, which keeps the power dissipation
under control.

https://www.dropbox.com/scl/fi/lkjg19hvcus9xz8aeecxy/T850_Rev_C.JPG?rlkey=0pitv0zdmb0x1tz0fkw0gj3ob&raw=1

The really tricky stuff is on the bottom of the board, dumping heat
into the water-cooled baseplate.

At 5 us, you could make a 4KV DC supply and switch that into your load
with a high-voltage mosfet. Brute force.
 
On 30-09-2023 21:10, John Larkin wrote:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <jl@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

OK, this has become sort of a background hobby, waiting on the
customer to get serious.

https://www.dropbox.com/scl/fi/60nb1pcrnl17c07tk8xeu/T875_HV_9.jpg?rlkey=9uv466edcuvddmjldgepcyi0u&raw=1

All the caps are a part that we have, 100nF 630 volts 1812. Of course
the capacitance plummets as voltage goes up, so the Spice values have
to be adjusted appropriately. C is only 20nF at 500 volts.

The RCD snubber is nice. It softens the rise at the fet drain and
dissipates less power than a simple RC that damps ringing about the
same.

Isn\'t the RCD clamp done wrong?
Click to expand...

Normally you do it like this:

https://www.ridleyengineering.com/images/SPM/11/article11_02.jpg
 
On Tue, 3 Oct 2023 14:45:43 +0200, Klaus Vestergaard Kragelund
<klauskvik@hotmail.com> wrote:

On 30-09-2023 21:10, John Larkin wrote:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <jl@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

OK, this has become sort of a background hobby, waiting on the
customer to get serious.

https://www.dropbox.com/scl/fi/60nb1pcrnl17c07tk8xeu/T875_HV_9.jpg?rlkey=9uv466edcuvddmjldgepcyi0u&raw=1

All the caps are a part that we have, 100nF 630 volts 1812. Of course
the capacitance plummets as voltage goes up, so the Spice values have
to be adjusted appropriately. C is only 20nF at 500 volts.

The RCD snubber is nice. It softens the rise at the fet drain and
dissipates less power than a simple RC that damps ringing about the
same.

Isn\'t the RCD clamp done wrong?

Normally you do it like this:

https://www.ridleyengineering.com/images/SPM/11/article11_02.jpg
Click to expand...

There are at least two topologies of an RCD clamp.

The one that you show doesn\'t damp high-frequency ringing after the
diode turns off. My diode multiplier chain actually clamps the fet
drain swing in both directions, so there is no voltage overload hazard
to the mosfet. All that\'s left is to damp the residual ringing to
reduce radiated EMI a bit.

A plain RC will damp the ringing but adding the diode reduces damper
power dissipation a little.
 
On 03-10-2023 14:37, John Larkin wrote:
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund
klauskvik@hotmail.com> wrote:

On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund
klaus.kragelund@gmail.com> wrote:

On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus
Kragelund <klaus.k...@gmail.com> wrote in
903144ac-6642-4a3f...@googlegroups.com>:

On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin
j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:

On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin
j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

Since I couldn\'t find a suitable flyback transformer, and I only need
500 volts at 10 mA, a flyback/C-W multiplier makes sense.

https://www.dropbox.com/scl/fi/aquzpawfn8mfmfsnx70ra/T875_HV_6.jpg?rlkey=vfs9pexa0rgyxpo7pg1grqlb7&dl=0

Do you still need C11 R8 in that circuit?

It doesn\'t need them to work, but there is a big high-Q ring when the
fet turns off, and the RC damps it. It would reduce radiated EMI. And
it speeds up the simulation some.

Did you scope that?

All Spice now. I\'ll build it when the customer gets serious.

There is a load of capacitance hanging from the MOSFET drain in that flyback multiplier ciruit
I would expect it to damp RF oscillations but could be wrong...
HV diodes have capacitance too..

The real circuit will have a lot of inductances too, what with those
long strings of parts. It needs to be built and tested. Dremeled, to
start.

Here\'s an old auto-flyback C-W miltiplier prototype. I think that was
1400 volts. Worked fine.

https://www.dropbox.com/s/yd19osiwz1z74s4/HV_Proto_2.JPG?rsw=1
Yea,
I did a PMT supply this way:
http://panteltje.nl/pub/PMT_HV_supply_with_regulator_img_3175.jpg
http://panteltje.nl/pub/PMT_HV_supply_componet_side_img_3180.jpg
http://panteltje.nl/pub/PMT_regulated_power_supply_diagram_img_3182.jpg

It has been in use now for many years, sits with PMT in the cardboard tube on the right, runs on batteries:
http://panteltje.nl/pub/gamma_soectrometer_IMG_4505.JPG

Of course that is very low power, but for a bit more power, and using a real TV muliplier:
https://panteltje.nl/panteltje/pic/sc_pic/

No dremeling, boards are OK when they work..

And old TV circuits.. if you want a few kV there was / is? plenty stuff to be found on ebay.
For my case, I am working on a 5W 24V to 4.5kV converter. Right now looking to use a flyback topology, with possibly usage of
CCFL transformer bobbins.

I am thinking about staggering the windings on 2 transformers, so the voltage across the windings will be lower, but still the
individual transformer needs to handle 4.5kV insulation (functional, not safety)

Due to the limiting power, it could also be tempting to use the capacitive doublers as listed elsewhere in the thread

My worry goes beyond the design, also about corona effects, which comes into play at +kV voltages. Potting is surely needed.

For a HV transformer, old TV transformers (from the CRT times) may perhaps be an option:
https://www.google.com/search?client=firefox-b-e&q=ebay+horizonatl+TV+output+transformer
4.5 kV diodes were used for focus in color TV sets...


For a flyback, my rule of thumb (I do not use El Tea Spice), is 1 V per turn for DC input.
So 24 turns primary for 24 V DC supply.
The flyback voltage is (70/12) * 24 = 140V positive pulse if positive DC supply.
To get a 4.5 kV pulse you would then wind 4500 / 140 is about 32, multiplied by 24 makes 768 turns.
This for an EI core running at about 15 kHz (math comes from building TV output stages).
768 turns is not a big deal..
Spreading the turns over a segmented coil former is a good idea.
If you want to use a voltage multiplier then less turns are needed, use a TV multiplier, those are \'potted\'
The 70/12 factor depends on the PWM on/off ratio of the drive you feed into the switch transistor.
I use Microchip PICs for that, it has a PWM unit., hardware comparators that can directly stop the PWM drive
for cycle by cycle current limiting, and ADCs to measure voltage and currents.
Maybe an old TV horizontal output transformer with build in rectifier / multiplier would do.
https://www.ebay.com/b/flyback-transformer/bn_7024744628
to adapt use 15 kHz and add 24 turns to the core primary?
...
:)

Maybe like this?
https://www.ebay.com/p/1692562663?iid=374326473542
plenty space for 24 turns thick wire, its a 30 kV DC out, so use less PWM ... or more primary turns
or whatever you can find... on ebay.

High turns ratios can have two problems: voltage breakdown in the
insulation, and winding capacitance limiting the flyback ratio. That\'s
where a C-W diode multiplier helps.

I am driving a UV lamp, so I need to deliver a pulse. Possible with a multiplier, but doesn\'t make it easier

No, the C-W multiplier isn\'t good for pulsing. Ixys has a 4700 volt
mosfet. A C-W multiplier could make the HV.

Maybe use a Marx generator? With medium-high voltage mos or SiC fets?

Some of the Zetex app notes, for their avalanche transistors, use a
Marx-type circuit. Charge the caps in parallel and discharge them in
series. You only have to trigger one in the string.

What sort of speed and current do you need?


I will generate a single pulse, about 5us long, shaped like a half wave
sinusoid, at 100kHz repetition frequency. That\'s why I was looking at
flyback, since I can control the voltage delivered simply by adjusting
the primary peak current. Power seems to be less than 5W, at 4.5kV peak,
duty of let\'s say 25%. probably below 10mA

One can stuff a bunch of current into an inductor and then dump it
into a mostly-capacitive load. That can make a high-voltage half-sine.

This boosts 48 volts to 1400v at MHz pulse rates.

http://www.highlandtechnology.com/DSS/T850DS.shtml

by switching an inductor around. The energy is recovered and returned
to the 48v supply after each pulse, which keeps the power dissipation
under control.

https://www.dropbox.com/scl/fi/lkjg19hvcus9xz8aeecxy/T850_Rev_C.JPG?rlkey=0pitv0zdmb0x1tz0fkw0gj3ob&raw=1

The really tricky stuff is on the bottom of the board, dumping heat
into the water-cooled baseplate.

At 5 us, you could make a 4KV DC supply and switch that into your load
with a high-voltage mosfet. Brute force.
Click to expand...
Yes, that could also be an idea. Will have some losses though, since
it\'s switching into a capacitive load
 
On Wednesday, October 4, 2023 at 1:41:37 AM UTC+11, Klaus Vestergaard Kragelund wrote:
On 03-10-2023 14:37, John Larkin wrote:
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau...@hotmail.com> wrote:
On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus.k....@gmail.com> wrote:
On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus
Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>:
On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:
On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin
j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote:
Click to expand...

<snip>

> > One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine.

A transformer would work better - perhaps several of them in series.

Dump a bunch of current into the primaries in parallel - perhaps time shifted to allow the high voltage pulse to propagate through the series connected secondaries - and rely on the parallel capacitances of the secondaries to shape the pulse into a half-sine.

An inductor to store a load of energy has to be a lot bulkier than a transformer which just couples it into a high impedance load.

--
Bill Sloman, Sydney
 
On Tue, 3 Oct 2023 16:41:27 +0200, Klaus Vestergaard Kragelund
<klauskvik@hotmail.com> wrote:

On 03-10-2023 14:37, John Larkin wrote:
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund
klauskvik@hotmail.com> wrote:

On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund
klaus.kragelund@gmail.com> wrote:

On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus
Kragelund <klaus.k...@gmail.com> wrote in
903144ac-6642-4a3f...@googlegroups.com>:

On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin
j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:

On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin
j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

Since I couldn\'t find a suitable flyback transformer, and I only need
500 volts at 10 mA, a flyback/C-W multiplier makes sense.

https://www.dropbox.com/scl/fi/aquzpawfn8mfmfsnx70ra/T875_HV_6.jpg?rlkey=vfs9pexa0rgyxpo7pg1grqlb7&dl=0

Do you still need C11 R8 in that circuit?

It doesn\'t need them to work, but there is a big high-Q ring when the
fet turns off, and the RC damps it. It would reduce radiated EMI. And
it speeds up the simulation some.

Did you scope that?

All Spice now. I\'ll build it when the customer gets serious.

There is a load of capacitance hanging from the MOSFET drain in that flyback multiplier ciruit
I would expect it to damp RF oscillations but could be wrong...
HV diodes have capacitance too..

The real circuit will have a lot of inductances too, what with those
long strings of parts. It needs to be built and tested. Dremeled, to
start.

Here\'s an old auto-flyback C-W miltiplier prototype. I think that was
1400 volts. Worked fine.

https://www.dropbox.com/s/yd19osiwz1z74s4/HV_Proto_2.JPG?rsw=1
Yea,
I did a PMT supply this way:
http://panteltje.nl/pub/PMT_HV_supply_with_regulator_img_3175.jpg
http://panteltje.nl/pub/PMT_HV_supply_componet_side_img_3180.jpg
http://panteltje.nl/pub/PMT_regulated_power_supply_diagram_img_3182.jpg

It has been in use now for many years, sits with PMT in the cardboard tube on the right, runs on batteries:
http://panteltje.nl/pub/gamma_soectrometer_IMG_4505.JPG

Of course that is very low power, but for a bit more power, and using a real TV muliplier:
https://panteltje.nl/panteltje/pic/sc_pic/

No dremeling, boards are OK when they work..

And old TV circuits.. if you want a few kV there was / is? plenty stuff to be found on ebay.
For my case, I am working on a 5W 24V to 4.5kV converter. Right now looking to use a flyback topology, with possibly usage of
CCFL transformer bobbins.

I am thinking about staggering the windings on 2 transformers, so the voltage across the windings will be lower, but still the
individual transformer needs to handle 4.5kV insulation (functional, not safety)

Due to the limiting power, it could also be tempting to use the capacitive doublers as listed elsewhere in the thread

My worry goes beyond the design, also about corona effects, which comes into play at +kV voltages. Potting is surely needed.

For a HV transformer, old TV transformers (from the CRT times) may perhaps be an option:
https://www.google.com/search?client=firefox-b-e&q=ebay+horizonatl+TV+output+transformer
4.5 kV diodes were used for focus in color TV sets...


For a flyback, my rule of thumb (I do not use El Tea Spice), is 1 V per turn for DC input.
So 24 turns primary for 24 V DC supply.
The flyback voltage is (70/12) * 24 = 140V positive pulse if positive DC supply.
To get a 4.5 kV pulse you would then wind 4500 / 140 is about 32, multiplied by 24 makes 768 turns.
This for an EI core running at about 15 kHz (math comes from building TV output stages).
768 turns is not a big deal..
Spreading the turns over a segmented coil former is a good idea.
If you want to use a voltage multiplier then less turns are needed, use a TV multiplier, those are \'potted\'
The 70/12 factor depends on the PWM on/off ratio of the drive you feed into the switch transistor.
I use Microchip PICs for that, it has a PWM unit., hardware comparators that can directly stop the PWM drive
for cycle by cycle current limiting, and ADCs to measure voltage and currents.
Maybe an old TV horizontal output transformer with build in rectifier / multiplier would do.
https://www.ebay.com/b/flyback-transformer/bn_7024744628
to adapt use 15 kHz and add 24 turns to the core primary?
...
:)

Maybe like this?
https://www.ebay.com/p/1692562663?iid=374326473542
plenty space for 24 turns thick wire, its a 30 kV DC out, so use less PWM ... or more primary turns
or whatever you can find... on ebay.

High turns ratios can have two problems: voltage breakdown in the
insulation, and winding capacitance limiting the flyback ratio. That\'s
where a C-W diode multiplier helps.

I am driving a UV lamp, so I need to deliver a pulse. Possible with a multiplier, but doesn\'t make it easier

No, the C-W multiplier isn\'t good for pulsing. Ixys has a 4700 volt
mosfet. A C-W multiplier could make the HV.

Maybe use a Marx generator? With medium-high voltage mos or SiC fets?

Some of the Zetex app notes, for their avalanche transistors, use a
Marx-type circuit. Charge the caps in parallel and discharge them in
series. You only have to trigger one in the string.

What sort of speed and current do you need?


I will generate a single pulse, about 5us long, shaped like a half wave
sinusoid, at 100kHz repetition frequency. That\'s why I was looking at
flyback, since I can control the voltage delivered simply by adjusting
the primary peak current. Power seems to be less than 5W, at 4.5kV peak,
duty of let\'s say 25%. probably below 10mA

One can stuff a bunch of current into an inductor and then dump it
into a mostly-capacitive load. That can make a high-voltage half-sine.

This boosts 48 volts to 1400v at MHz pulse rates.

http://www.highlandtechnology.com/DSS/T850DS.shtml

by switching an inductor around. The energy is recovered and returned
to the 48v supply after each pulse, which keeps the power dissipation
under control.

https://www.dropbox.com/scl/fi/lkjg19hvcus9xz8aeecxy/T850_Rev_C.JPG?rlkey=0pitv0zdmb0x1tz0fkw0gj3ob&raw=1

The really tricky stuff is on the bottom of the board, dumping heat
into the water-cooled baseplate.

At 5 us, you could make a 4KV DC supply and switch that into your load
with a high-voltage mosfet. Brute force.

Yes, that could also be an idea. Will have some losses though, since
it\'s switching into a capacitive load
Click to expand...

Switching a DC supply into a capacitive load is inherently lossy, and
people usually discharge the cap and waste that energy, too.

So power dissipation is C*F*V^2. The inductor trick has, ideally, zero
power dissipation... it just sloshes energy around. That\'s how I got 4
MHz out of a tiny Pockels Cell driver.

If F is low, it wouldn\'t matter much.
 
On Wednesday, October 4, 2023 at 3:00:46 AM UTC+11, John Larkin wrote:
On Tue, 3 Oct 2023 16:41:27 +0200, Klaus Vestergaard Kragelund<klau...@hotmail.com> wrote:
On 03-10-2023 14:37, John Larkin wrote:
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau....@hotmail.com> wrote:
On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus.k....@gmail.com> wrote:
On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>:
On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin <j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:
On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet..invalid> wrote:
On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin <j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote:
Click to expand...

<snip>

I will generate a single pulse, about 5us long, shaped like a half wave sinusoid, at 100kHz repetition frequency. That\'s why I was looking at flyback, since I can control the voltage delivered simply by adjusting the primary peak current. Power seems to be less than 5W, at 4.5kV peak, duty of let\'s say 25%. probably below 10mA

One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine.

This boosts 48 volts to 1400v at MHz pulse rates.

http://www.highlandtechnology.com/DSS/T850DS.shtml

by switching an inductor around. The energy is recovered and returned to the 48v supply after each pulse, which keeps the power dissipation under control.

https://www.dropbox.com/scl/fi/lkjg19hvcus9xz8aeecxy/T850_Rev_C.JPG?rlkey=0pitv0zdmb0x1tz0fkw0gj3ob&raw=1

The really tricky stuff is on the bottom of the board, dumping heat into the water-cooled baseplate.

At 5 us, you could make a 4KV DC supply and switch that into your load with a high-voltage mosfet. Brute force.

Yes, that could also be an idea. Will have some losses though, since it\'s switching into a capacitive load.

Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too.
Click to expand...

It isn\'t, if the load hasn\'t got any resistance. Discharging the capacitor into a separate supply isn\'t clever.

> So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That\'s how I got 4 MHz out of a tiny Pockels Cell driver.

What on earth is \"F\"?

Klaus seems to want to charge a 10pF load to 2.5kV peak, as a half cycle of 100kHz, getting it from 0V up to 2.5kV and back to 0V over 5usec.

If he sets up a 0.25H transformer secondary and charges it up with 10mA for about 2usec waits a usec and then discharges it at 10mA for another 2usec, he\'d get close.

Figuring on a 16:1 step=up from about 100V, and 10V per turn, that would be a 160 turn secondary, which implies a core with an Al of 10uH per root turn, which is bit high.

Going to two transformers in series lets you drop the step-up to 8:1. Each secondary now needs to be O.125H which is an Al of 20uH. Three times more turns fixes that, but you are stuck with an 240 T secondary on each transformer and you don\'t want the parallel capacitance of the secondaries to get close to the 10pF in your load.

If you allow 20pF across each secondary - 10pF in parallel with the load your 0,25H tuning inductance has to drop to 0.18H which makes life easier.

--
Bill Sloman, Sydney

 
On Tue, 3 Oct 2023 14:45:43 +0200, Klaus Vestergaard Kragelund
<klauskvik@hotmail.com> wrote:

On 30-09-2023 21:10, John Larkin wrote:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <jl@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

OK, this has become sort of a background hobby, waiting on the
customer to get serious.

https://www.dropbox.com/scl/fi/60nb1pcrnl17c07tk8xeu/T875_HV_9.jpg?rlkey=9uv466edcuvddmjldgepcyi0u&raw=1

All the caps are a part that we have, 100nF 630 volts 1812. Of course
the capacitance plummets as voltage goes up, so the Spice values have
to be adjusted appropriately. C is only 20nF at 500 volts.

The RCD snubber is nice. It softens the rise at the fet drain and
dissipates less power than a simple RC that damps ringing about the
same.

Isn\'t the RCD clamp done wrong?

Normally you do it like this:

https://www.ridleyengineering.com/images/SPM/11/article11_02.jpg

It\'s actually a current snubber, not a voltage clamp.
Click to expand...

Conventionally, for uncomplicated function, it\'s applied across the
switch that is turning off. In Larkin\'s application, it will only
function as well as layout strays and supply line decoupling allow.

RL
 
On Tuesday, October 3, 2023 at 10:30:48 PM UTC-5, Anthony William Sloman wrote:
On Wednesday, October 4, 2023 at 3:00:46 AM UTC+11, John Larkin wrote:
On Tue, 3 Oct 2023 16:41:27 +0200, Klaus Vestergaard Kragelund<klau...@hotmail.com> wrote:
On 03-10-2023 14:37, John Larkin wrote:
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau....@hotmail.com> wrote:
On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus.k....@gmail.com> wrote:
On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>:
On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin <j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet..invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:
On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin <j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote:
snip
I will generate a single pulse, about 5us long, shaped like a half wave sinusoid, at 100kHz repetition frequency. That\'s why I was looking at flyback, since I can control the voltage delivered simply by adjusting the primary peak current. Power seems to be less than 5W, at 4.5kV peak, duty of let\'s say 25%. probably below 10mA

One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine.

This boosts 48 volts to 1400v at MHz pulse rates.

http://www.highlandtechnology.com/DSS/T850DS.shtml

by switching an inductor around. The energy is recovered and returned to the 48v supply after each pulse, which keeps the power dissipation under control.

https://www.dropbox.com/scl/fi/lkjg19hvcus9xz8aeecxy/T850_Rev_C.JPG?rlkey=0pitv0zdmb0x1tz0fkw0gj3ob&raw=1

The really tricky stuff is on the bottom of the board, dumping heat into the water-cooled baseplate.

At 5 us, you could make a 4KV DC supply and switch that into your load with a high-voltage mosfet. Brute force.

Yes, that could also be an idea. Will have some losses though, since it\'s switching into a capacitive load.

Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too.
It isn\'t, if the load hasn\'t got any resistance. Discharging the capacitor into a separate supply isn\'t clever.
So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That\'s how I got 4 MHz out of a tiny Pockels Cell driver.
What on earth is \"F\"?
Click to expand...

To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary.

Klaus seems to want to charge a 10pF load to 2.5kV peak, as a half cycle of 100kHz, getting it from 0V up to 2.5kV and back to 0V over 5usec.

If he sets up a 0.25H transformer secondary and charges it up with 10mA for about 2usec waits a usec and then discharges it at 10mA for another 2usec, he\'d get close.

Figuring on a 16:1 step=up from about 100V, and 10V per turn, that would be a 160 turn secondary, which implies a core with an Al of 10uH per root turn, which is bit high.

Going to two transformers in series lets you drop the step-up to 8:1. Each secondary now needs to be O.125H which is an Al of 20uH. Three times more turns fixes that, but you are stuck with an 240 T secondary on each transformer and you don\'t want the parallel capacitance of the secondaries to get close to the 10pF in your load.

If you allow 20pF across each secondary - 10pF in parallel with the load your 0,25H tuning inductance has to drop to 0.18H which makes life easier.

--
Bill Sloman, Sydney
Click to expand...
 
On Thursday, October 5, 2023 at 2:24:13 AM UTC+11, John Smiht wrote:
On Tuesday, October 3, 2023 at 10:30:48 PM UTC-5, Anthony William Sloman wrote:
On Wednesday, October 4, 2023 at 3:00:46 AM UTC+11, John Larkin wrote:
On Tue, 3 Oct 2023 16:41:27 +0200, Klaus Vestergaard Kragelund<klau....@hotmail.com> wrote:
On 03-10-2023 14:37, John Larkin wrote:
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau...@hotmail.com> wrote:
On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus..k...@gmail.com> wrote:
On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f....@googlegroups.com>:
On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin <j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:
On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin <j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote:
snip
I will generate a single pulse, about 5us long, shaped like a half wave sinusoid, at 100kHz repetition frequency. That\'s why I was looking at flyback, since I can control the voltage delivered simply by adjusting the primary peak current. Power seems to be less than 5W, at 4.5kV peak, duty of let\'s say 25%. probably below 10mA

One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine.

This boosts 48 volts to 1400v at MHz pulse rates.

http://www.highlandtechnology.com/DSS/T850DS.shtml

by switching an inductor around. The energy is recovered and returned to the 48v supply after each pulse, which keeps the power dissipation under control.

https://www.dropbox.com/scl/fi/lkjg19hvcus9xz8aeecxy/T850_Rev_C.JPG?rlkey=0pitv0zdmb0x1tz0fkw0gj3ob&raw=1

The really tricky stuff is on the bottom of the board, dumping heat into the water-cooled baseplate.

At 5 us, you could make a 4KV DC supply and switch that into your load with a high-voltage mosfet. Brute force.

Yes, that could also be an idea. Will have some losses though, since it\'s switching into a capacitive load.

Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too.
It isn\'t, if the load hasn\'t got any resistance. Discharging the capacitor into a separate supply isn\'t clever.
So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That\'s how I got 4 MHz out of a tiny Pockels Cell driver.

What on earth is \"F\"?

To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary.
Click to expand...

An engineer wouldn\'t capitalise it. And they\'d use radians per second - 2.pi.f - rather than frequency to get the numbers to come out right.

https://en.wikipedia.org/wiki/Radian_per_second

<snipped the bit an engineer might have found interesting>

--
Bill Sloman, Sydney
 
On 03-10-2023 16:59, Anthony William Sloman wrote:
On Wednesday, October 4, 2023 at 1:41:37 AM UTC+11, Klaus Vestergaard Kragelund wrote:
On 03-10-2023 14:37, John Larkin wrote:
On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau...@hotmail.com> wrote:
On 29-09-2023 04:09, John Larkin wrote:
On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus.k...@gmail.com> wrote:
On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus
Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>:
On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:
On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote:
On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin
j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:
On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote:

snip

One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine.

A transformer would work better - perhaps several of them in series.

Dump a bunch of current into the primaries in parallel - perhaps time shifted to allow the high voltage pulse to propagate through the series connected secondaries - and rely on the parallel capacitances of the secondaries to shape the pulse into a half-sine.
Click to expand...

That\'s what I was considering doing, but still the individual
transformer needs to be able to handle the 4.5kV isolation from winding
to winding.
 
On 29-09-2023 18:16, Lasse Langwadt Christensen wrote:
fredag den 29. september 2023 kl. 15.41.10 UTC+2 skrev Klaus Kragelund:
On Thursday, 28 September 2023 at 23:09:44 UTC+2, Lasse Langwadt Christensen wrote:
torsdag den 28. september 2023 kl. 22.58.46 UTC+2 skrev Klaus Kragelund:
On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote:
On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus
Kragelund <klaus.k...@gmail.com> wrote in
903144ac-6642-4a3f...@googlegroups.com>:

On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote:
On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>:
On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin
j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>:

On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin
j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

Since I couldn\'t find a suitable flyback transformer, and I only need
500 volts at 10 mA, a flyback/C-W multiplier makes sense.

https://www.dropbox.com/scl/fi/aquzpawfn8mfmfsnx70ra/T875_HV_6.jpg?rlkey=vfs9pexa0rgyxpo7pg1grqlb7&dl=0

Do you still need C11 R8 in that circuit?

It doesn\'t need them to work, but there is a big high-Q ring when the
fet turns off, and the RC damps it. It would reduce radiated EMI. And
it speeds up the simulation some.

Did you scope that?

All Spice now. I\'ll build it when the customer gets serious.

There is a load of capacitance hanging from the MOSFET drain in that flyback multiplier ciruit
I would expect it to damp RF oscillations but could be wrong...
HV diodes have capacitance too..

The real circuit will have a lot of inductances too, what with those
long strings of parts. It needs to be built and tested. Dremeled, to
start.

Here\'s an old auto-flyback C-W miltiplier prototype. I think that was
1400 volts. Worked fine.

https://www.dropbox.com/s/yd19osiwz1z74s4/HV_Proto_2.JPG?rsw=1
Yea,
I did a PMT supply this way:
http://panteltje.nl/pub/PMT_HV_supply_with_regulator_img_3175.jpg
http://panteltje.nl/pub/PMT_HV_supply_componet_side_img_3180.jpg
http://panteltje.nl/pub/PMT_regulated_power_supply_diagram_img_3182.jpg

It has been in use now for many years, sits with PMT in the cardboard tube on the right, runs on batteries:
http://panteltje.nl/pub/gamma_soectrometer_IMG_4505.JPG

Of course that is very low power, but for a bit more power, and using a real TV muliplier:
https://panteltje.nl/panteltje/pic/sc_pic/

No dremeling, boards are OK when they work..

And old TV circuits.. if you want a few kV there was / is? plenty stuff to be found on ebay.
For my case, I am working on a 5W 24V to 4.5kV converter. Right now looking to use a flyback topology, with possibly usage of
CCFL transformer bobbins.

I am thinking about staggering the windings on 2 transformers, so the voltage across the windings will be lower, but still the
individual transformer needs to handle 4.5kV insulation (functional, not safety)

Due to the limiting power, it could also be tempting to use the capacitive doublers as listed elsewhere in the thread

My worry goes beyond the design, also about corona effects, which comes into play at +kV voltages. Potting is surely needed.

For a HV transformer, old TV transformers (from the CRT times) may perhaps be an option:
https://www.google.com/search?client=firefox-b-e&q=ebay+horizonatl+TV+output+transformer
4.5 kV diodes were used for focus in color TV sets...


For a flyback, my rule of thumb (I do not use El Tea Spice), is 1 V per turn for DC input.
So 24 turns primary for 24 V DC supply.
The flyback voltage is (70/12) * 24 = 140V positive pulse if positive DC supply.
To get a 4.5 kV pulse you would then wind 4500 / 140 is about 32, multiplied by 24 makes 768 turns.
This for an EI core running at about 15 kHz (math comes from building TV output stages).
768 turns is not a big deal..
Spreading the turns over a segmented coil former is a good idea.
If you want to use a voltage multiplier then less turns are needed, use a TV multiplier, those are \'potted\'
The 70/12 factor depends on the PWM on/off ratio of the drive you feed into the switch transistor.
I use Microchip PICs for that, it has a PWM unit., hardware comparators that can directly stop the PWM drive
for cycle by cycle current limiting, and ADCs to measure voltage and currents.
Maybe an old TV horizontal output transformer with build in rectifier / multiplier would do.
https://www.ebay.com/b/flyback-transformer/bn_7024744628
to adapt use 15 kHz and add 24 turns to the core primary?
...
:)

Maybe like this?
https://www.ebay.com/p/1692562663?iid=374326473542
plenty space for 24 turns thick wire, its a 30 kV DC out, so use less PWM ... or more primary turns
or whatever you can find... on ebay.

High turns ratios can have two problems: voltage breakdown in the
insulation, and winding capacitance limiting the flyback ratio. That\'s
where a C-W diode multiplier helps.
I am driving a UV lamp, so I need to deliver a pulse. Possible with a multiplier, but doesn\'t make it easier

Old TV flybacks were pie wound to help with both problems. That makes
a hand-wound transformer yet nastier; Sloman would love to (have
someone else) wind that.
Pie wound, so that\'s adding on layers instead of across the bobbin?

There are some cool old parts from CRT TVs but we wouldn\'t use Ebay
parts for production. Even ISDN transformers are hard to get these
days. And most of our boards have a component height limit below about
1\".
I agree, Ebay does not work for production items :)

I\'ve gravitated to the classic C-W layout with all series strings of
caps. That\'s driven by the poorly-or-never defined C/V behavior of
available ceramic caps, which encourages their use at a small fraction
of rated voltage.
In any case for the C-W multiplier to work properly, the charging of the caps needs to be kept low.

There are lots of cute flyback controller chips that do peak current
limiting control.

I am using a microcontroller. Microcontroller and kV design does not sound good, right?
I don\'t know how much voltage we dare generate on a regular PCB
without coating or potting. I\'m guessing that 1KV is safe and I know
that 7KV isn\'t.
Potting or conformal coating is probably needed to avoid carbonization of PCB surface.
how about something crazy, a car ignition coil? ratio about 1:100, isolation good for +20kV
coil-on-plug can be pretty small, if you need access to both ends of the secondary a dual output coil for wasted spark has that
These are used for old style flash:

https://www.aliexpress.us/item/32521417603.html?gatewayAdapt=4itemAdapt

coilcraft have some ccfl transformers, but the isolation rating is quite a bit lower than your 4.5kV

https://www.coilcraft.com/en-us/products/transformers/power-transformers/ccfl-transformers/fl/
Click to expand...

Maybe the isolation can be achieved by potting. That\'s a reasonable
cheap way to boost the isolation voltage.
 
On Sunday, 1 October 2023 at 18:07:40 UTC+2, Jan Panteltje wrote:
On a sunny day (Sun, 01 Oct 2023 07:08:02 -0700) it happened John Larkin
j...@997arbor.com> wrote in <4cuihitefaok29ca0...@4ax.com>:
On Sun, 01 Oct 2023 05:31:31 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sat, 30 Sep 2023 12:10:06 -0700) it happened John Larkin
j...@997arbor.com> wrote in <2grghi1vnnsmrkbcl...@4ax.com>:

On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com
wrote:


This is pleasingly weird.

https://www.dropbox.com/sh/sif3efs69dxe1mg/AACY0RJGXl4k8CVvauUbJtYFa?dl=0

Sort of a baseline-boosted multi-auto-transformer voltage-doubler
flyback.

What\'s strange is that adding the two snubbers increases the LT spice
sim speed radically, about 10:1.

OK, this has become sort of a background hobby, waiting on the
customer to get serious.

https://www.dropbox.com/scl/fi/60nb1pcrnl17c07tk8xeu/T875_HV_9.jpg?rlkey=9uv466edcuvddmjldgepcyi0u&raw=1

All the caps are a part that we have, 100nF 630 volts 1812. Of course
the capacitance plummets as voltage goes up, so the Spice values have
to be adjusted appropriately. C is only 20nF at 500 volts.

That much really? Th big caps I use do not change at all I think?

I measured one.

https://www.dropbox.com/scl/fi/zrrount2a5s7k5bmqh4bu/C-V.jpg?rlkey=3so16njq8md4ccnm610a8mf49&raw=1
That is realy awfull!
Tt will likely create more ripple and less output.
There are some big C0G caps around these days, but in this case I may
as well use the X7R in stock and let it do what it does.
If the output stays in spec OK...
It\'s fun to make an RC timing ramp from a Z5U or something. The
exponential curves UP.
You could use that for frequency modulation, sort of a very big varicap...
Not very linear...

The RCD snubber is nice. It softens the rise at the fet drain and
dissipates less power than a simple RC that damps ringing about the
same.

Nice, it delivers power back to the supply line :)

I didn\'t invent that, got that from a switcher textbook.

There are actually \"lossless\" snubbers that store the snub energy in
an inductor or a transformer and return it to the supply, but that\'s
overkill in a 5 watt supply.

The C-W multiplier actually clamps the mosfet drain to safe voltages;
an inductor doesn\'t have leakage inductance! (Or it has 100% leakage
inductance?) The snubber is there to damp the HF ringing and reduce
radiated EMI.
CRT TV horizontal output stages are interesting, also have a \'tuning capacitor\'
so the flyback is tuned to some harmonic (third harmonic Fred?) of the drive frequency,
I experimented with winding several transformers for TVs I build.

This goes a bit into that, so no snubbers needed.
http://www.broadcaststore.com/pdf/model/793699/TT207%20-%205080.pdf
tv_horizontal_output_stage_operating__TT207-5080.pdf
see figure 6:
--------- --------
| | | |
-- --- ---
.
/ \\
----------- ------------ flyback tuned
Click to expand...

Thanks for the link, that is a very informative document, from the good old days :)
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top