Basic power supply design question

Steve · 2007-06-04T23:33:59+00:00

Let me start off by clarifying that I'm not a design engineer, so I'mjust seeking some help, and apologize in advance if I'm unclear. What I want to build is a regulated 0-30v 0-3a DC supply, adjustablecurrent and voltage. I want to build it for personal gratification, Iknow I could just purchase a HY3003, but what's the fun in that?Looking at the schematic on Bowden's Hobby Circuits, looks like this supply has no line regulation. Am I wrong? Ithink it has load regulation, as the input for the voltage portion isfed directly off the output, but there is no input reference. Pleasecorrect me where I am wrong, I'm sure I am.Looking at the LM317 datasheet, 17, they show a regulated adjustable voltage and current supply.But this will not go to 0 V, only to 1.2V. On page 16, they show thenegative supply to allow the output to adjust down to 0v, but how doyou incorporate this into the adjustable current schematic shown?Just bring the voltage adjust pot down to -1.2V? How will this affectthe rest of the circuit, specifically the current limiter? Am Imaking this too complicated?Thanks for your help, all thoghts appreciated.Steve

Jun 04, 2007 22 Replies

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Alex 19 years ago

BUT don't you forget ... you have to apply a small stable voltage at the input to get an output at a certain voltage... And a DC coupled amp will have a feedback to prevent DC on the output... Alex

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D from BC 19 years ago

{snip]

There's some nice Vref IC's available. That's the input signal..

huh?..lost me on that..

D from BC

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Marra 19 years ago

Circuits,

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Work it out for yourself, thats even more fun !

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