High Voltage Power Supply

[alexo]

Could anybody recommend schematics for a high voltage variable power supply ? If possible for around 400V ( 600V a bonus ) and current limiting, short circuit protection. Min 100mA , more a bonus, again.

[Cerebus]

Do you mean a variable bench PSU or a PSU for inclusion inside some other piece of equipment?

[alexo]

Variable. Thanks.

[T3sl4co1l]

http://www.radiomuseum.org/r/eico_1030_regulated_power_supp.html?language_id=2

Tim

[fable]

Is 300v 50mA good enough?

[alexo]

Not really - I need around 80-85mA.

[mariush]

Here's a schematic for a 120v 1A power supply.  They're using 2SC2751 transistors, which go up to 500v.  I suppose you can put more in parallel and you can use several smaller transformers and maybe transformer taps to go up to 300v and let's say 100-200mA

They're using small transformer taps (about 30-40v AC per tap) to keep the wasted power in the transistors low at 1A , but if you're going to alter the design to work at only up to 100-200mA, you may be able to use common 115v -> 2x48v AC or 230v -> 4 x 48v AC secondary windings , or maybe use even 115v ac per winding , after all at 100mA in the worst case scenario (about 130-140v DC in, 1v at 100mA out you're going to dissipate about 15 watts, easily doable with 3-5 such transistors in parallel) 

[PointyOintment]

How about the Heathkit PS-3? Even if you can't find one, the schematic's available, so you could build something based on it.

[BravoV]

This circuit only max at 500V 10ma though, but I'm pretty sure some mod by expert (not me) can increase to your requirement may be ? 

Linky -> http://www.edn.com/design/power-management/4403836/Regulate-a-0-to-500V--10-mA-power-supply-in-a-different-way-

[BrianHG]

What's your budget, you can use an AC transformer + power opamp like the following:

http://www.digikey.com/product-detail/en/apex-microtechnology/PA15FL/598-1428-ND/1762090
450v, 200ma range.

http://www.digikey.com/product-detail/en/apex-microtechnology/PA95/598-1335-ND/1761959
900v, 100ma range. (Recommended if your source voltage is unregulated and above 350v, this gives you excellent clearance)

The rest shouldn't be too difficult except finding the right source power transformers, and additional circuitry if you want an adjustable current limiter.  A little more work is involved if you want a MCU digital interface, but this may make adjustable current limiting easier.