Hi, can someone please answer this simple question:

Can I boost the voltage of a signal with an op-amp, to a level greater than the op-amp is being supplied with?

E.g. If I want to boost a 15V signal to 30V, and my op-amp is running from a 20v supply, will my output be limited to 20V?

Thanks for your help!

 

Generally, the output of an opamp is limited to somewhat less than the voltage on the power rails. Opamps with "rail to rail" outputs will come very close to the rails; traditional BJT outputs will have significantly less.

 

ah, ok, thanks for confiming that.

 

If you have a second, higher source of power, you can then boost the opamp's output with a transistor to get higher power levels than the opamp can handle...don't know if that is useful for you or not...

 

If you require a low current at the boosted voltage you can use capacitors to boost the voltage like in voltage doublers.