adjustable bench power supply

[Daxxin]

Got new switching power supply with fixed 50v 20a output , planning to use this output to build adjustable power something like 0-40v and 10A
supply for my beginner lab , what problems i can have using that switching psu? any schematich to suggest?

[lapm]

Schematics, that's your first problem right there.. You should seriously first figure out how it works now. Then re-trace schematics of it and look up control chip. Se what that can do for you...

Designing good quality switching power supply with high amperage is difficult. Do you really need 0-40 Volts range? I do some electronics as hobby and so far have not had use for anything over 15 Volts.

Maybe you could keep this unit as is 50V/20amps and design add on unit you hook with cables that handles lower power functionality?

40 Volts at 10A is 400 Watts of power. Be extremely careful what ever you build. That sort of power can kill, cause fire's, make things explode, etc...

[Aodhan145]

Too complicated with that high voltage as the only voltage in you need a pre regulator. Try find a nice transformer with taps and then get a negative rail as well.