0-30v power supply problem

Thread Starter


Joined Jan 1, 2016
I'm testing 0-30v power supply based on this circuit


I'm using it without transformer and feed supply voltage from my bench supply to circuit. Because i can get only positive voltage from bench power supply I use 555 negative voltage generator to to get negative voltage to op-amps. When I try to use same power supply to circuit and negative voltage generator nothing works. I set bench power suplly current limit to low 0,05A value and current limits comes on immediatly when i connect wires.

But when i use separete battery to power up negative voltage generator everything works. Maybe it's some stupid mistake i'm making. Is it even possible to use bench power supply to get +15 and -15v using negative voltage generator? Drawing attached to post which explains my wiring connections.