Need circuit idea for programmable P.S.

Thread Starter


Joined Oct 11, 2009
I would like to build a programmable power supply that can go from 0 to 600vdc. Don't need much current, maybe 10-20ma max. Voltage increment should be 1 to 5 volts. If such a PS could be controlled by a PIC, that would be great. The trick in my mind is the PS, not the PIC part. Any ideas or suggestions?


Joined Apr 24, 2011
Well, there are three basic choices:

Build a 600V supply and put an adjustable linear regulator past it. At 20 mA you're only burning off 12 watts there.

Build a switcher to boost whatever convenient voltage you have to that range.

Build a switcher followed by a programmable linear regulator. Best efficiency and still a clean output.

Even with 1V resolution you only have 600 steps so a PIC with a 10 bit A2D could measure it, not sure if that same resolution is acceptable for a PWM control output to run a switcher. If you bang thru Microchip to the schematic for the PicKit 2 they have a step up switcher in there controlled by the PIC. It's only 13 V or so output but has the basic scheme you need to use (L1 & Q4 in 2nd page).


Joined Feb 12, 2009
Use a switcher to get your 600V. There will be a resistive divider on the output that will feed back to the controller circuit to regulate the output voltage.

This derived voltage will be compared to a reference voltage.

Instead of using a fixed reference voltage, use a reference voltage generated by a DAC fed from a digital input.