I need to make a 24V to 500-1000V, 20W adjustable power supply for a pulser. It needs to be a floating or negative converter. My specs are: Input: 24-28V Output voltage: 500-1000V adjustable via control signal Output current: 10mA @ 500V (5W), 20mA @ 1000V (20W) I've been reading through threads on different HV designs. So far the only one I've come across that is isolated is Figure 50 of LT Application Note 29 (https://www.analog.com/media/en/technical-documentation/application-notes/an29f.pdf). It is specified for 1000V, 5W so not beefy enough. The transformer is also obsolete, but this comment mentions potential replacements. https://groups.google.com/d/msg/sci.electronics.design/F120QpxWWkc/74ljdPZ_BQAJ There's also this design (https://www.edn.com/1-kv-power-supply-produces-a-continuous-arc/) that is 1kV, 20W. I just don't know enough about making it adjustable and isolated. Thoughts on how to proceed?
24V to 500-1000V, 20W floating DC-DC converter
Started by ●July 21, 2020
Reply by ●July 21, 20202020-07-21
On Tue, 21 Jul 2020 15:51:44 -0700 (PDT), Matt B <matt.blessinger@gmail.com> wrote:>I need to make a 24V to 500-1000V, 20W adjustable power supply for a pulser. It needs to be a floating or negative converter. > >My specs are: >Input: 24-28V >Output voltage: 500-1000V adjustable via control signal >Output current: 10mA @ 500V (5W), 20mA @ 1000V (20W) > >I've been reading through threads on different HV designs. So far the only one I've come across that is isolated is Figure 50 of LT Application Note 29 (https://www.analog.com/media/en/technical-documentation/application-notes/an29f.pdf). It is specified for 1000V, 5W so not beefy enough. The transformer is also obsolete, but this comment mentions potential replacements. https://groups.google.com/d/msg/sci.electronics.design/F120QpxWWkc/74ljdPZ_BQAJ > >There's also this design (https://www.edn.com/1-kv-power-supply-produces-a-continuous-arc/) that is 1kV, 20W. I just don't know enough about making it adjustable and isolated. > >Thoughts on how to proceed?Take a look at these maybe: https://magnetic-components.mpsind.com/viewitems/flyback-transformers/p3800-series-isolated-flyback-transformers
Reply by ●July 22, 20202020-07-22
On 7/21/2020 7:01 PM, John Larkin wrote:> On Tue, 21 Jul 2020 15:51:44 -0700 (PDT), Matt B > <matt.blessinger@gmail.com> wrote: > >> I need to make a 24V to 500-1000V, 20W adjustable power supply for a pulser. It needs to be a floating or negative converter. >> >> My specs are: >> Input: 24-28V >> Output voltage: 500-1000V adjustable via control signal >> Output current: 10mA @ 500V (5W), 20mA @ 1000V (20W) >> >> I've been reading through threads on different HV designs. So far the only one I've come across that is isolated is Figure 50 of LT Application Note 29 (https://www.analog.com/media/en/technical-documentation/application-notes/an29f.pdf). It is specified for 1000V, 5W so not beefy enough. The transformer is also obsolete, but this comment mentions potential replacements. https://groups.google.com/d/msg/sci.electronics.design/F120QpxWWkc/74ljdPZ_BQAJ >> >> There's also this design (https://www.edn.com/1-kv-power-supply-produces-a-continuous-arc/) that is 1kV, 20W. I just don't know enough about making it adjustable and isolated. >> >> Thoughts on how to proceed? > > Take a look at these maybe: > > https://magnetic-components.mpsind.com/viewitems/flyback-transformers/p3800-series-isolated-flyback-transformers > > >Someday all the guys who show up every couple of months out of nowhere looking for plans on how to build their own handheld electric zapper-taser will come to terms with the fact that it's one of the more useless "weapons" for just about any purpose there is. Might as well put it in a heavy enclosure and then bop your enemy on the head with it.
Reply by ●July 22, 20202020-07-22
On Tuesday, July 21, 2020 at 6:02:06 PM UTC-5, John Larkin wrote:> > Take a look at these maybe: > > https://magnetic-components.mpsind.com/viewitems/flyback-transformers/p3800-series-isolated-flyback-transformersThanks! That's a good start for a replacement transformer.
Reply by ●July 22, 20202020-07-22
On Tuesday, July 21, 2020 at 10:03:58 PM UTC-5, bitrex wrote:> On 7/21/2020 7:01 PM, John Larkin wrote: > > On Tue, 21 Jul 2020 15:51:44 -0700 (PDT), Matt B > > > > > >> I need to make a 24V to 500-1000V, 20W adjustable power supply for a pulser. It needs to be a floating or negative converter. > >> > >> My specs are: > >> Input: 24-28V > >> Output voltage: 500-1000V adjustable via control signal > >> Output current: 10mA @ 500V (5W), 20mA @ 1000V (20W) > >> > >> I've been reading through threads on different HV designs. So far the only one I've come across that is isolated is Figure 50 of LT Application Note 29 (https://www.analog.com/media/en/technical-documentation/application-notes/an29f.pdf). It is specified for 1000V, 5W so not beefy enough. The transformer is also obsolete, but this comment mentions potential replacements. https://groups.google.com/d/msg/sci.electronics.design/F120QpxWWkc/74ljdPZ_BQAJ > >> > >> There's also this design (https://www.edn.com/1-kv-power-supply-produces-a-continuous-arc/) that is 1kV, 20W. I just don't know enough about making it adjustable and isolated. > >> > >> Thoughts on how to proceed? > > > > Take a look at these maybe: > > > > https://magnetic-components.mpsind.com/viewitems/flyback-transformers/p3800-series-isolated-flyback-transformers > > > > > > > > Someday all the guys who show up every couple of months out of nowhere > looking for plans on how to build their own handheld electric > zapper-taser will come to terms with the fact that it's one of the more > useless "weapons" for just about any purpose there is. > > Might as well put it in a heavy enclosure and then bop your enemy on the > head with it.Sigh... it's for a piezo stack. I've seen you comment on other HV PSU threads. Do you have any insight for a good isolated design?
Reply by ●July 22, 20202020-07-22
On Tue, 21 Jul 2020 20:22:28 -0700 (PDT), Matt B <matt.blessinger@gmail.com> wrote:>On Tuesday, July 21, 2020 at 6:02:06 PM UTC-5, John Larkin wrote: >> >> Take a look at these maybe: >> >> https://magnetic-components.mpsind.com/viewitems/flyback-transformers/p3800-series-isolated-flyback-transformers > >Thanks! That's a good start for a replacement transformer.I you want to design the whole circuit, take a look at LT3803 and its app notes. It just always seems to work. Scribble some circuits and we can talk about them. LT Spice includes the 3803 too. It seems to work just like it simulates. -- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
Reply by ●July 22, 20202020-07-22
On Wednesday, July 22, 2020 at 8:51:49 AM UTC+10, Matt B wrote:> I need to make a 24V to 500-1000V, 20W adjustable power supply for a pulser. It needs to be a floating or negative converter. > > My specs are: > Input: 24-28V > Output voltage: 500-1000V adjustable via control signal > Output current: 10mA @ 500V (5W), 20mA @ 1000V (20W) > > I've been reading through threads on different HV designs. So far the only one I've come across that is isolated is Figure 50 of LT Application Note 29 (https://www.analog.com/media/en/technical-documentation/application-notes/an29f.pdf). It is specified for 1000V, 5W so not beefy enough. The transformer is also obsolete, but this comment mentions potential replacements. https://groups.google.com/d/msg/sci.electronics.design/F120QpxWWkc/74ljdPZ_BQAJ > > There's also this design (https://www.edn.com/1-kv-power-supply-produces-a-continuous-arc/) that is 1kV, 20W. I just don't know enough about making it adjustable and isolated. > > Thoughts on how to proceed?http://www.sophia-electronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm has a circuit for a high-voltage output inverter at the bottom of the page, which relies on pulse with modulation to adjust the output voltage. It's strictly an LTSpice simulation, the output voltage goes higher than you need, and the power levels are for biasing a photomultiplier tube and lower than you want. A bigger transformer, with room for thicker wire would fix most of that - you would also need a higher voltage MOSFET switch - 24V into the centre tap of a Baxanadall class oscillator produces a 75.4V peak half-sine across the MOSFET that is off, and the AP9465GEM is only good for 40V. The NXP BUK9Y72-80E might do. http://www.farnell.com/datasheets/1705544.pdf -- Bill Sloman, Sydney
Reply by ●July 22, 20202020-07-22
On 7/21/2020 11:24 PM, Matt B wrote:> On Tuesday, July 21, 2020 at 10:03:58 PM UTC-5, bitrex wrote: >> On 7/21/2020 7:01 PM, John Larkin wrote: >>> On Tue, 21 Jul 2020 15:51:44 -0700 (PDT), Matt B >>> >>> >>>> I need to make a 24V to 500-1000V, 20W adjustable power supply for a pulser. It needs to be a floating or negative converter. >>>> >>>> My specs are: >>>> Input: 24-28V >>>> Output voltage: 500-1000V adjustable via control signal >>>> Output current: 10mA @ 500V (5W), 20mA @ 1000V (20W) >>>> >>>> I've been reading through threads on different HV designs. So far the only one I've come across that is isolated is Figure 50 of LT Application Note 29 (https://www.analog.com/media/en/technical-documentation/application-notes/an29f.pdf). It is specified for 1000V, 5W so not beefy enough. The transformer is also obsolete, but this comment mentions potential replacements. https://groups.google.com/d/msg/sci.electronics.design/F120QpxWWkc/74ljdPZ_BQAJ >>>> >>>> There's also this design (https://www.edn.com/1-kv-power-supply-produces-a-continuous-arc/) that is 1kV, 20W. I just don't know enough about making it adjustable and isolated. >>>> >>>> Thoughts on how to proceed? >>> >>> Take a look at these maybe: >>> >>> https://magnetic-components.mpsind.com/viewitems/flyback-transformers/p3800-series-isolated-flyback-transformers >>> >>> >>> >> >> Someday all the guys who show up every couple of months out of nowhere >> looking for plans on how to build their own handheld electric >> zapper-taser will come to terms with the fact that it's one of the more >> useless "weapons" for just about any purpose there is. >> >> Might as well put it in a heavy enclosure and then bop your enemy on the >> head with it. > > Sigh... it's for a piezo stack. I've seen you comment on other HV PSU threads. Do you have any insight for a good isolated design? >Yeah you make it adjustable and isolated more or less the same way you make any other flyback converter adjustable and isolated. You've designed and built a flyback before, right?
Reply by ●July 22, 20202020-07-22
Matt B <matt.blessinger@gmail.com> writes:> I need to make a 24V to 500-1000V, 20W adjustable power supply for a pulser. It needs to be a floating or negative converter. > > My specs are: > Input: 24-28V > Output voltage: 500-1000V adjustable via control signal > Output current: 10mA @ 500V (5W), 20mA @ 1000V (20W)If this is a one-off or a few pieces, how about Ultravolt 1C24-N20 ? We used that (actually positive version) to start a product line and later designed a custom one. In our case, we needed robust short circuit protection and cap charging, which required some knowledge in the flyback control loop - mostly reduced frequency for low end voltage. Other items to take care of were correct snubbering and resistor chains to deal with 1kV on SMD. And discharging on powerdown to avoid accidents! Transformer is a custom one with 4 HV sections and a 2-turn foil primary around them for down to 14V operation. Each HV section was rectified to a cap and the DC was in series. -- mikko
Reply by ●July 22, 20202020-07-22
On Tuesday, July 21, 2020 at 10:32:47 PM UTC-5, jla...@highlandsniptechnology.com wrote:> I you want to design the whole circuit, take a look at LT3803 and its > app notes. It just always seems to work. > > Scribble some circuits and we can talk about them. LT Spice includes > the 3803 too. It seems to work just like it simulates.I generally like to design or at least modify a current design so I understand what's going on. This is new territory for me, so I'll look into a start some simulations. Thanks for the tip on the LTC3803. On Tuesday, July 21, 2020 at 10:40:31 PM UTC-5, Bill Sloman wrote:> http://www.sophia-electronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm > > has a circuit for a high-voltage output inverter at the bottom of the page, which relies on pulse with modulation to adjust the output voltage. > > It's strictly an LTSpice simulation, the output voltage goes higher than you need, and the power levels are for biasing a photomultiplier tube and lower than you want. > > A bigger transformer, with room for thicker wire would fix most of that - you would also need a higher voltage MOSFET switch - 24V into the centre tap of a Baxanadall class oscillator produces a 75.4V peak half-sine across the MOSFET that is off, and the AP9465GEM is only good for 40V. > > The NXP BUK9Y72-80E might do. > > http://www.farnell.com/datasheets/1705544.pdfI'll simulate this one as well and read up on Baxandall oscillators more. Interesting that this design was never built; I'm sure I would find a way to produce some fireworks. On Wednesday, July 22, 2020 at 2:32:57 AM UTC-5, Mikko OH2HVJ wrote:> If this is a one-off or a few pieces, how about Ultravolt 1C24-N20 ? > We used that (actually positive version) to start a product line and later > designed a custom one. > > In our case, we needed robust short circuit protection and cap charging, > which required some knowledge in the flyback control loop - mostly > reduced frequency for low end voltage. Other items to take care of were > correct snubbering and resistor chains to deal with 1kV on SMD. And > discharging on powerdown to avoid accidents!It will only be a few pieces. The 1C24-N20 does fit the bill (excellent find btw), but space constraints may dictate I can't use it. I want to start with a custom board and then I can fall back on the Ultravolt if need be. I have ~5uF of HV capacitance and don't actually want fast cap charging, so the Ultravolt would be overkill in that sense.
