300V power supply.

$100 parts?  You've looked at Digikey for inverter transformers right? 
There are off the shelf 240-to-5V flyback transformers for $5.  Run that in 
reverse, no problemo!

How about CCFL transformers?  Lots of leakage, resonant secondary, easy to 
get high voltages from little input.

You didn't say how much current you need, but I guess it isn't much.

LT is literally in the business of one-chip solutions.  Why do you think 
their one-chip solutions cost so much per part? :-)

You can probably do the CCFL route with two transistors, self excited, but 
some protection features would be a welcome addition.

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: https://www.seventransistorlabs.com/

"George Herold" <gherold@teachspin.com> wrote in message 
news:cc578e03-72e3-42c4-9c3b-0aeba9b2c657@googlegroups.com...
> Hi all, So I'd like to make a 300 V supply. I don't really want to start 
> from
> the AC line.  So I've been looking for a DC-DC converter solution.
>
> I started here, (of course)
> http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf
> Figure 13 looked nice.  I then priced a pico 32195 transformer.
> ~$100!  Ouch! (maybe I can find a cheaper one.)
>
> I then was trolling Linear Tech/ Analog Dev.  What I mostly found was a
> line of Xenon lamp charges.
> LT3420
> LT3468
> LT3484
> LT3485
> LT3585
> LT3750
>
> I haven't delved into the spec sheets, but the LT3420 looks like
> it will work.
>
> Any advice on any of these parts or other ideas is welcome.
>
> Oh over the weekend I was thinking about making a C-W generator,
> (mostly because I always wanted to.)  I was going to make my own
> oscillator ~10-100 kHz, boost the voltage with a transformer
> and send it into a CW network. Sounds fun, but a lot of work.
>
> Oh finally I can buy DC-DC converters from pico electronics for
> ~$100.
> https://www.picoelectronics.com/high-voltage-low-power-dc-dc-converters
>
> TIA
> George H.
> 

On Monday, April 16, 2018 at 4:02:31 PM UTC-4, John Larkin wrote:
> On Mon, 16 Apr 2018 10:49:40 -0700 (PDT), George Herold
> <gherold@teachspin.com> wrote:
> 
> >Hi all, So I'd like to make a 300 V supply. I don't really want to start from 
> >the AC line.  So I've been looking for a DC-DC converter solution.
> >
> >I started here, (of course) 
> >http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf  
> >Figure 13 looked nice.  I then priced a pico 32195 transformer. 
> >~$100!  Ouch! (maybe I can find a cheaper one.)  
> 
> Pico is insane. I don't know why anybody buys their stuff.
> 
> How much current do you want? The lower section of this will do 300
> volts.
> 
> https://www.dropbox.com/s/e3n5af9sw1a1flh/28S840A_3.pdf?raw=1
Right I already copied that out and stuck it in my notebook. 
What's the voltage range of the LTC3803?  
(it says 36 to 72 on typ. circuit)  
What's the turns ratio on the transformer?  (12-14?) 

I'd be happier with some more packaged solution form LT.  
Flying into unknown territory is fun, but not time efficient. 

This is my second choice from LT/analog.
http://www.analog.com/media/en/technical-documentation/data-sheets/3750fa.pdf

George H.  
> 
> Just skip the C-W HV stuff.
> 
> You could also buy some cheap (like $4) DC/DC converter bricks and put
> the outputs in series. Stack them on top of whatever power rail you
> already have.
> 
> 
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> picosecond timing   precision measurement 
> 
> jlarkin att highlandtechnology dott com
> http://www.highlandtechnology.com

On 04/16/2018 04:17 PM, Winfield Hill wrote:
> bitrex wrote...
>>
>> I got some "X-ray vision" pics
> 
>   Whoa, how'd you take those pictures?

Just using the camera on my Moto e4 smartphone, with an app called 
"Magnifying Glass" or somesuch - blast the PCB at about 8 inches away 
with light from the white LED on the front, flip the palette on the 
image, zoom in a bit and if you hold the phone at the right angle and 
autofocus everything pops right out.

>> ... so you could probably do a "spin off" of the design if
>> you like using significantly smaller diodes/switch/xfrmr.
> 
>   Hey, lots of stuff for $7, with free shipping.  Not all
>   of the eBay sellers add the parts needed for a bipolar
>   output.   The transformer is the most valuable part.
> 
> 

The capacitors are a lil dodgy but other than that it seems well-made, 
layout and soldering looks the business, never had a problem with one of 
these modules

On Mon, 16 Apr 2018 13:30:05 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

>On Monday, April 16, 2018 at 4:02:31 PM UTC-4, John Larkin wrote:
>> On Mon, 16 Apr 2018 10:49:40 -0700 (PDT), George Herold
>> <gherold@teachspin.com> wrote:
>> 
>> >Hi all, So I'd like to make a 300 V supply. I don't really want to start from 
>> >the AC line.  So I've been looking for a DC-DC converter solution.
>> >
>> >I started here, (of course) 
>> >http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf  
>> >Figure 13 looked nice.  I then priced a pico 32195 transformer. 
>> >~$100!  Ouch! (maybe I can find a cheaper one.)  
>> 
>> Pico is insane. I don't know why anybody buys their stuff.
>> 
>> How much current do you want? The lower section of this will do 300
>> volts.
>> 
>> https://www.dropbox.com/s/e3n5af9sw1a1flh/28S840A_3.pdf?raw=1
>Right I already copied that out and stuck it in my notebook. 
>What's the voltage range of the LTC3803?  
>(it says 36 to 72 on typ. circuit)  

There's no limit. The internal supply is 9V, from a shunt regulator
inside the chip. Note that my 9 volt offpage connector is an output,
not an input. I use the 9V somewhere else. 

The fet has to be able to stand the flyback voltage. Best way to
determine that is to Spice it. I used an FDD7N20, rated 200 volts,
because we have it.


>What's the turns ratio on the transformer?  (12-14?) 


1:1. It's one of those dual-winding inductors.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Monday, April 16, 2018 at 6:24:20 PM UTC-4, John Larkin wrote:
> On Mon, 16 Apr 2018 13:30:05 -0700 (PDT), George Herold
> <gherold@teachspin.com> wrote:
> 
> >On Monday, April 16, 2018 at 4:02:31 PM UTC-4, John Larkin wrote:
> >> On Mon, 16 Apr 2018 10:49:40 -0700 (PDT), George Herold
> >> <gherold@teachspin.com> wrote:
> >> 
> >> >Hi all, So I'd like to make a 300 V supply. I don't really want to start from 
> >> >the AC line.  So I've been looking for a DC-DC converter solution.
> >> >
> >> >I started here, (of course) 
> >> >http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf  
> >> >Figure 13 looked nice.  I then priced a pico 32195 transformer. 
> >> >~$100!  Ouch! (maybe I can find a cheaper one.)  
> >> 
> >> Pico is insane. I don't know why anybody buys their stuff.
> >> 
> >> How much current do you want? The lower section of this will do 300
> >> volts.
> >> 
> >> https://www.dropbox.com/s/e3n5af9sw1a1flh/28S840A_3.pdf?raw=1
> >Right I already copied that out and stuck it in my notebook. 
> >What's the voltage range of the LTC3803?  
> >(it says 36 to 72 on typ. circuit)  
> 
> There's no limit. The internal supply is 9V, from a shunt regulator
> inside the chip. Note that my 9 volt offpage connector is an output,
> not an input. I use the 9V somewhere else. 
Oh, I was going to ask about that.  
> 
> The fet has to be able to stand the flyback voltage. Best way to
> determine that is to Spice it. I used an FDD7N20, rated 200 volts,
> because we have it.
Right thanks.  'true confessions'; I realized driving home tonight 
this was a flyback... Well... everyone mentioned it enough. :^)  
Anyhow, I'm home now with 'my' SMPS book "Fund. of power electronics",
R.W. Erickson.  And reading about flybacks.. basically, you can
analyze them as buck-boosts with a turns ratio. 

I think I see the Fet has to take a lot of voltage stress.  
An external fet may be be a good idea.  And there's lots of 
switching transients, if I care less about efficiency, can I slow 
down the edges with R's in the right place?       

> 
> 
> >What's the turns ratio on the transformer?  (12-14?) 
> 
> 
> 1:1. It's one of those dual-winding inductors.
Huh, OK... I'm going back to read about buck-boost.
It's all in the duty cycle then?  

George H. 
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> picosecond timing   precision measurement 
> 
> jlarkin att highlandtechnology dott com
> http://www.highlandtechnology.com

On 2018-04-16, George Herold <gherold@teachspin.com> wrote:

> I started here, (of course) 
> http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf  
> Figure 13 looked nice.  I then priced a pico 32195 transformer. 
> ~$100!  Ouch! (maybe I can find a cheaper one.)  

that should be possible PC powersupplies have one for stepping about 350V down to
5V at about 2-10W as do many wall-warts. these transformers can be run in reverse.

digikey has a bunch of transformwers for a few bucks each
https://www.digikey.com/products/en/inductors-coils-chokes/arrays-signal-transformers/73
dunno why they call them sifnal transformers. the parameters are series
and parallel incuctance, but if you havce a spice parameters for the part
you want you can probably find a close match using those numbers.

> Oh over the weekend I was thinking about making a C-W generator,
> (mostly because I always wanted to.)  I was going to make my own
> oscillator ~10-100 kHz, boost the voltage with a transformer
> and send it into a CW network. Sounds fun, but a lot of work.  

Yeah, for C-W you need a symmetrical output like Baxandall, if you
just want to step up you can use a flyback converter which is simpler.

> Oh finally I can buy DC-DC converters from pico electronics for 
> ~$100.  
> https://www.picoelectronics.com/high-voltage-low-power-dc-dc-converters

Seems to spoil all the fun. I guess it depends whether you want to
learn or to do.


-- 
     &#1578;

On Tuesday, April 17, 2018 at 4:01:17 PM UTC+10, Jasen Betts wrote:
> On 2018-04-16, George Herold <gherold@teachspin.com> wrote:
> 
> > I started here, (of course) 
> > http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf  
> > Figure 13 looked nice.  I then priced a pico 32195 transformer. 
> > ~$100!  Ouch! (maybe I can find a cheaper one.)  
> 
> that should be possible PC powersupplies have one for stepping about 350V down to
> 5V at about 2-10W as do many wall-warts. these transformers can be run in reverse.
> 
> digikey has a bunch of transformwers for a few bucks each
> https://www.digikey.com/products/en/inductors-coils-chokes/arrays-signal-transformers/73
> dunno why they call them sifnal transformers. the parameters are series
> and parallel incuctance, but if you havce a spice parameters for the part
> you want you can probably find a close match using those numbers.
> 
> > Oh over the weekend I was thinking about making a C-W generator,
> > (mostly because I always wanted to.)  I was going to make my own
> > oscillator ~10-100 kHz, boost the voltage with a transformer
> > and send it into a CW network. Sounds fun, but a lot of work.  
> 
> Yeah, for C-W you need a symmetrical output like Baxandall, if you
> just want to step up you can use a flyback converter which is simpler.

The regular Baxandall circuit always produces a sine wave with a couple of percent of harmonic content. I've got a less efficient version - 50% rather than 95% - where the harmonic content can be a couple of orders of magnitude lower.

-- 
Bill Sloman, Sydney

On Tuesday, April 17, 2018 at 8:58:07 AM UTC-4, bill....@ieee.org wrote:
> On Tuesday, April 17, 2018 at 4:01:17 PM UTC+10, Jasen Betts wrote:
> > On 2018-04-16, George Herold <gherold@teachspin.com> wrote:
> > 
> > > I started here, (of course) 
> > > http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf  
> > > Figure 13 looked nice.  I then priced a pico 32195 transformer. 
> > > ~$100!  Ouch! (maybe I can find a cheaper one.)  
> > 
> > that should be possible PC powersupplies have one for stepping about 350V down to
> > 5V at about 2-10W as do many wall-warts. these transformers can be run in reverse.
> > 
> > digikey has a bunch of transformwers for a few bucks each
> > https://www.digikey.com/products/en/inductors-coils-chokes/arrays-signal-transformers/73
> > dunno why they call them sifnal transformers. the parameters are series
> > and parallel incuctance, but if you havce a spice parameters for the part
> > you want you can probably find a close match using those numbers.
> > 
> > > Oh over the weekend I was thinking about making a C-W generator,
> > > (mostly because I always wanted to.)  I was going to make my own
> > > oscillator ~10-100 kHz, boost the voltage with a transformer
> > > and send it into a CW network. Sounds fun, but a lot of work.  
> > 
> > Yeah, for C-W you need a symmetrical output like Baxandall, if you
> > just want to step up you can use a flyback converter which is simpler.
> 
> The regular Baxandall circuit always produces a sine wave with a couple of percent of harmonic content. I've got a less efficient version - 50% rather than 95% - where the harmonic content can be a couple of orders of magnitude lower.
> 
> -- 
> Bill Sloman, Sydney

Yeah I've mostly given up the C-W dream for now.  At ~300V it looks like 
a flyback is a cheaper/ easier option.  

George h. 

On Monday, April 16, 2018 at 4:23:55 PM UTC-4, Tim Williams wrote:
> $100 parts?  You've looked at Digikey for inverter transformers right? 
> There are off the shelf 240-to-5V flyback transformers for $5.  Run that in 
> reverse, no problemo!
Hi Tim, No I haven't looked for inverter transformers at DK.  
Do you know where they would be listed?  
I've looked through most of these,
https://www.digikey.com/products/en/transformers/11

and only found useful stuff in the SMPS category.  

George H. 
> 
> How about CCFL transformers?  Lots of leakage, resonant secondary, easy to 
> get high voltages from little input.
> 
> You didn't say how much current you need, but I guess it isn't much.
> 
> LT is literally in the business of one-chip solutions.  Why do you think 
> their one-chip solutions cost so much per part? :-)
> 
> You can probably do the CCFL route with two transistors, self excited, but 
> some protection features would be a welcome addition.
> 
> Tim
> 
> -- 
> Seven Transistor Labs, LLC
> Electrical Engineering Consultation and Contract Design
> Website: https://www.seventransistorlabs.com/
> 
> "George Herold" <gherold@teachspin.com> wrote in message 
> news:cc578e03-72e3-42c4-9c3b-0aeba9b2c657@googlegroups.com...
> > Hi all, So I'd like to make a 300 V supply. I don't really want to start 
> > from
> > the AC line.  So I've been looking for a DC-DC converter solution.
> >
> > I started here, (of course)
> > http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf
> > Figure 13 looked nice.  I then priced a pico 32195 transformer.
> > ~$100!  Ouch! (maybe I can find a cheaper one.)
> >
> > I then was trolling Linear Tech/ Analog Dev.  What I mostly found was a
> > line of Xenon lamp charges.
> > LT3420
> > LT3468
> > LT3484
> > LT3485
> > LT3585
> > LT3750
> >
> > I haven't delved into the spec sheets, but the LT3420 looks like
> > it will work.
> >
> > Any advice on any of these parts or other ideas is welcome.
> >
> > Oh over the weekend I was thinking about making a C-W generator,
> > (mostly because I always wanted to.)  I was going to make my own
> > oscillator ~10-100 kHz, boost the voltage with a transformer
> > and send it into a CW network. Sounds fun, but a lot of work.
> >
> > Oh finally I can buy DC-DC converters from pico electronics for
> > ~$100.
> > https://www.picoelectronics.com/high-voltage-low-power-dc-dc-converters
> >
> > TIA
> > George H.
> >

On Tuesday, April 17, 2018 at 2:01:17 AM UTC-4, Jasen Betts wrote:
> On 2018-04-16, George Herold <gherold@teachspin.com> wrote:
> 
> > I started here, (of course) 
> > http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf  
> > Figure 13 looked nice.  I then priced a pico 32195 transformer. 
> > ~$100!  Ouch! (maybe I can find a cheaper one.)  
> 
> that should be possible PC powersupplies have one for stepping about 350V down to
> 5V at about 2-10W as do many wall-warts. these transformers can be run in reverse.
> 
> digikey has a bunch of transformwers for a few bucks each
> https://www.digikey.com/products/en/inductors-coils-chokes/arrays-signal-transformers/73
> dunno why they call them sifnal transformers. the parameters are series
> and parallel incuctance, but if you havce a spice parameters for the part
> you want you can probably find a close match using those numbers.

Thanks, I was looking through the DK site at transformers.... but I guess 
that is not what I want... well there are some here,
https://www.digikey.com/products/en/transformers/switching-converter-smps-transformers/168.  

I don't have any spice parameters.  I think today I'll fire up LTspice and 
see what I can make work... I have to do some calc's first.  
Say could I take one with six coils, (like this one.) 
https://www.digikey.com/product-detail/en/eaton/VP1-0190-R/513-1191-1-ND/754689
Put one on the input and wire up the other five in series as output 
to give me a 1:5 turns ratio?   

George H. 


> 
> > Oh over the weekend I was thinking about making a C-W generator,
> > (mostly because I always wanted to.)  I was going to make my own
> > oscillator ~10-100 kHz, boost the voltage with a transformer
> > and send it into a CW network. Sounds fun, but a lot of work.  
> 
> Yeah, for C-W you need a symmetrical output like Baxandall, if you
> just want to step up you can use a flyback converter which is simpler.
> 
> > Oh finally I can buy DC-DC converters from pico electronics for 
> > ~$100.  
> > https://www.picoelectronics.com/high-voltage-low-power-dc-dc-converters
> 
> Seems to spoil all the fun. I guess it depends whether you want to
> learn or to do.
Right that's always a trade off.  I got some cheap APD's from digikey in
yesterday.  Part of me wants to bias 'em up and see how bad the dark count 
rate is.  Or do I delve into flyback converters?  
There's never enough time in a day. :^)  

George H.   
> 
> 
> -- 
>      &#1578;