Adjustable High Voltage Power Supply - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 27th November 2011, 11:15 PM   #1
alfa88 is offline alfa88  United States
diyAudio Member
 
Join Date: Aug 2009
Location: Hawaii
Default Adjustable High Voltage Power Supply

Last month I fixed a guy's antique radio and was thoroughly intrigued by tube technology. In my stupidity, years ago, I traded a Heathkit HV power supply for a hard drive. I suppose because I didn't have the 'tube bug' back then.
I have a power transformer I pulled out of some old military equipment that has a 820Vct@100ma secondary, several 6.3 windings and a 5V winding. I'm hoping someone has some easy to build schematics where maybe I can turn that high voltage into a variable B+ and C power supply. I've seen several mosfet designs but they all seem to be fixed Voltage.

Last edited by alfa88; 27th November 2011 at 11:29 PM.
  Reply With Quote
Old 28th November 2011, 12:41 AM   #2
diyAudio Member
 
thaumaturge's Avatar
 
Join Date: Aug 2011
Location: Utah
Take a look at some commercial HV supply schematics. Should find some on the BAMA (boat anchor manual archive) site. HV supplies are rather tricky.
Doc
__________________
Ne timeas a facie mulierum ea ignorare
  Reply With Quote
Old 28th November 2011, 01:58 AM   #3
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
It seems like one of the high-output-voltage "booster" amplifiers could be used as a DC power supply, if it were DC coupled.

For example, there is a schematic for one in Figure 13 of AN18 at Linear Technology's site ( http://cds.linear.com/docs/Application%20Note/an18f.pdf ) that is a 1000V 15-Watt unipolar output stage that is powered by only a fixed +28V DC supply.

Control inputs of 0-10 Volts give outputs of 0-1000 Volts.

It would also work as a low-frequency AC supply or signal/function generator.

It seems to be artificailly limited to a slew rate of about 500 Volts per millisecond or a little more but that could be increased, at least a little bit.

There is a somewhat-similar schematic in Figure 10 of AN-272 from national.com ( http://www.national.com/an/AN/AN-272.pdf#page=1 ), that provides up to 1000V @ 300 mA output (300 Watts) and runs off of a +/-15V dual-polarity supply.

Cheers,

Tom Gootee

Last edited by gootee; 28th November 2011 at 02:23 AM.
  Reply With Quote
Old 28th November 2011, 02:34 AM   #4
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Bandwidth of that one from national.com in Figure 10 of AN-272 is similar to the one from linear.com, at 50 Hz. But if you need 500 kHz bandwidth, just look at the next one, in Figure 12, which goes to 350 V in one microsecond with the tubes shown but could be extended to several kilovolts by using different tubes and a higher-voltage fixed DC supply. However, as shown, it can only supply about 10 mA at 350 V.

Cheers,

Tom Gootee
  Reply With Quote
Old 28th November 2011, 09:43 PM   #5
diyAudio Member
 
thaumaturge's Avatar
 
Join Date: Aug 2011
Location: Utah
One trick I've seen used quite often on high voltage supplies is to feed the primary of the transformer with a variac for rough voltage out control. This reduces the differential voltage across the pass transistor. A pot mounted on the shaft of the variac sets drive voltage for course setting of base drive.
Doc
__________________
Ne timeas a facie mulierum ea ignorare
  Reply With Quote
Old 4th January 2012, 01:11 AM   #6
benc is offline benc  United Kingdom
diyAudio Member
 
Join Date: Apr 2010
Location: UK
I've used a LOPT (line output transformer) from a TV before to generate HT. You can pick these up new and cheap or raid some old TV's main board - basically they are flyback transformers.

Typically you will need to put an HT capacitor on the output as they tend to rely on the CRT's capacitance (which you won't have).

When i've done it in the past i've used a 555 timer to generate 15KHz low-duty cycle square wave (5-10%) to switch a fairly plain common-emitter power transistor, that sinks the primary to 0V. I' haven't bothered to regulate it and have varied the DC supply on one side of the primary to change the output V.
  Reply With Quote
Old 4th January 2012, 01:57 AM   #7
diyAudio Member
 
wrenchone's Avatar
 
Join Date: Feb 2004
Location: Silicon Valley
Why not just buy an electrophoresis power supply for the HV? The other voltages can be handled by standard bench supplies.
  Reply With Quote
Old 8th January 2012, 11:33 AM   #8
dangus is offline dangus  Canada
diyAudio Member
 
Join Date: May 2004
Location: Vancouver Island
This might be a place to use an SCR or TRIAC. I designed a high-power constant current supply once, long enough ago that now I can't remember which side of the transformer the TRIAC was on. The controller used PID (mostly I). Output didn't need to be very clean since it was driving an electrolytic cell, but I stuck a huge computer-grade surplus cap in there. With a high-voltage supply you can use inductors to smooth things out. Possibly a "capacitance multiplier" active filter.

Elektor (if I remember correctly) published a pre-regulator for high voltage supplies sometime in the '80s that used phase control, so as to limit the drop across a linear regulator. I may have a photocopy of that article still. I tried using it in a project once, but it didn't work right away so I put in a variac on the primary and a fullwave rectifier and filter caps on the secondary. As it turned out, that's all the customer actually wanted.

Perhaps an ATX power supply transformer (or two) driven backwards. For high power, use the power supply portion of a car amp.

Last edited by dangus; 8th January 2012 at 11:36 AM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Precision Adjustable Low Voltage DC Power Supply Stocker Equipment & Tools 0 19th December 2010 05:44 AM
high frequency high voltage power supply... moray james Planars & Exotics 6 23rd July 2008 07:57 PM
high voltage power supply leemajcool Power Supplies 3 5th August 2007 11:40 AM


New To Site? Need Help?

All times are GMT. The time now is 12:28 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2