Created by
Created March 08, 2013
Last modified March 28, 2013
Tags dc   hv   power-supply   regulate   supply   voltage  


Create HV Variable DC Supply using LM317.


Possible 1.2-81.2V Regulator design. Untested - brain melting ideas. R10 is designed to force U1 to regulate at a certain voltage to protect U2 from getting voltages out of spec and killing the circuit. The potentiometers would be dual gang.


R2 should be 1/2 R9 for proper operation. Probably.

See this version:

by adash
April 03, 2013

Thanks for the input Adash. I am not understanding why R2 should be 1/2 R9. When I tested this idea, I was getting over voltage problems on U1 because the span from input to output was greater than the rated 40V. R10 was thrown in the design to compensate for that and "balance" it out. I am interested in your idea if you wouldn't mind elaborating.

by hondabones
April 03, 2013


Love the schematic. :)

by hondabones
April 03, 2013

Hm, maybe I was wrong about that R2 and R9. And thanks for liking my schematic, but now I see I am missing some probably important capacitors across R8 and R11. Those should speed up the response of the regulators to changes in load current and improve stability with changing loads etc. Furthermore, if you really want that output swing, you should probably consider adding a switching regulator instead of the first 317. It will dramatically improve efficiency.

by adash
April 03, 2013

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