Bench Power Supply

With current protection and everything. I'd usually make it a little more efficient by using a few transformer windings and switching them with a relay but it works just as well. The LED constant current source makes it easier to work with different input voltages without having to switch between current limiting resistors. It'll come in handy if you want to add the trick with the winding switching. This is basically an op amp with voltage gain. The reference voltage is defined by the most left LED and is around 2V. The most upper voltage divider acts as a negative feedback from the output setting the voltage gain of the op amp to 16. The current limiting is set by the 250mOhm resistor which should be wirewound and is around 3A. You can increase it or decrease it by changing the value of the resistor. The power transistor is MJ2955 and it should definitely be mounted on a heatsink. Worst case scenario is that it diasipates 120W of power which is why I'd make the winding switching, then the worst case scenario is no more than 60W. The output ripple is less than 20mVpk-pk and it can probably be set even lower. The ripple rejection is then -47dB

published 9 years ago