DC voltage boost with OP Amp

Discussion in 'General Electronics Chat' started by sleeper1987, Feb 19, 2009.

  1. sleeper1987

    Thread Starter New Member

    Feb 19, 2009
    3
    0
    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!
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    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.
     
  3. sleeper1987

    Thread Starter New Member

    Feb 19, 2009
    3
    0
    ah, ok, thanks for confiming that.
     
  4. Mike33

    AAC Fanatic!

    Feb 4, 2005
    349
    25
    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...
     
  5. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    If you require a low current at the boosted voltage you can use capacitors to boost the voltage like in voltage doublers.
     
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