Voltage Regulator Help Required

[Leethal]

With help from Crutschow I was able to get this 30V regulator working. What do I need to do to limit the current to 6A? I feel I need to control the errror amplifier in some way but it is already performing the voltage regulator function so how do I add current regulation as well???

 

[chuckey]

Can't open your file, when unzipped is a .asc file which windows does not recognise.
The standard way would be to put a low value reistor in series with the main PSU output current circuit, so at the trip current , the voltage drop across it is .8V. This voltage is fed to the base emitter of a transistor which then turns on. Depending on the actual circuit you can use this transistor to divert current from the output of the error amp to earth, so the voltage drive to the series regulator falls, so the output voltage falls. You could hang this circuit in the positive output line and fool the error amplifiers input that the output voltage has gone high, so the error amp then reduces the drive to the series transistor. make sure the error amp input is down stream of the current sensing resistor.
Frank

 

[Leethal]

Thanks for the answer Frank. The .asc file is for LT Spice. I have also put a PDF of the circuit. I imagine I could use the voltage drop across the resistance of the Mosfet M1 amplified to do the function you mentioned although in this case I would have to lift the voltage to the gate to decrease VGS???