Low cost High Quality Bench Power Supply

A bench power supply. Unconditionally stable at 30V/2A. Incorporates a current limiter at 2.2A which will come in handy if a short circuit should occur at the output. The power supply is variable from 0-30V at 2A (60W). The 2 power transistors are 2n3055. Their driving transistor is TIP41 and all others are general purpose low power transistors of any kind. The 630mOhm resistor should be hand wound and its value is directly proportional to the maximum current limit. Right now it's 2.2A. At 200mOhm it should be a lot higher but then you should add a third 2N3055 to distribute the current so that you won't overtax the transistors. The 4.7k potentiometer varies the voltage roughly and the 680ohm resistor may be substituted with a 2.2k rheostat to act as a fine voltage control. Output ripple is less than 100uVpk-pk at 60W which is extremely stable but that's because i placed a constant current source to drive the zener diode so combining these two will absolutely stabilize the zener. The input ripples for instance are around 3.9Vpk-pk. I won't talk about efficiency since it's relative with linear regulators.

published 11 years ago