Bench Lab PSU 0-30V 0-5A

Okay, so I just finished a bench lab psu for myself using this https://s.click.aliexpress.com/e/NzZoArm and even though it works perfectly, a constant little voice in my head tells me, you can do it better 😁. First of all, the Chinese circuit uses a low level current sensing (which I definitely dislike) and TL071 IC's which work at 36V max. The Chinese circuit supplies them with -5Vss and +40Vcc which is unacceptable for me. Also the output of these op amps is not rail to rail and it can hardly drive my output at 30V/3A. Anyway this is what I came up with. The potentiometer on the right controls the output voltage and the potentiometer on the left sets the current limit. Still needs a few diodes and caps here and there, but in general it's good to go. I might give it a go in the future when the one I got now burns. The op amps should be ua741 (LM741). Rail to rail op amps would be best but I can't seem to find a rail to rail 36V op amp in a DIP package.

published 7 years ago