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Single supply power op amp

Discussion in 'Electronic Design' started by Kenneth Warren, Nov 12, 2006.

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  1. I am having difficulty finding a power op amp with the following
    characteristics. Can anyone offer suggestions?

    _Single supply_ 12VDC operation, IOW no biasing network required.
    Frequency range DC to 1KHz
    Max current out 1A

    It is being used as a positioning coil driver. Other parameters are
    non-critical.

    Thank you for any help with a part number.

    Kenneth Warren
     
  2. PeteS

    PeteS Guest

    Any op amp rated for operation at (V+ - V-) <= 12V will operate on a
    single supply.

    You say you want to have no biasing network, but that's not what single
    supply operation implies. We always have to bias the inputs (except in
    certain circumstances on special devices that have the biasing
    internally). We even bias split supply devices - the fact that we might
    (we don't always) bias them at 0V doesn't mean we aren't biasing them ;)

    I will note that it seems you don't know a lot about the devices - if
    so, say so and we'll start from the beginning rather than assuming a
    basic understanding.

    What's the input signal range, output voltage range required, load
    impedance etc.?

    Cheers

    PeteS
     
  3. Kingcosmos

    Kingcosmos Guest

    Depending on the nature of your input signal, you may not require
    biasing to mid-supply. I cannot name an amplifier off the top of my
    head but Apex, Texas Instruments, and National have op-amps with high
    output current that are > 1A. BTW, 1A continuous output current?
     
  4. Ban

    Ban Guest

    Usually an opamp plus a power-darlington BJT or a Mosfet is used for this
    application. Since the current is only of one polarity, a very simple stage
    is needed. Maybe better would be a voltage controlled current source, easily
    implemented with a few components. The driving force of the coil is
    proportional to the current
    But you should have measured much more data of your linear motor, or given
    a link to a datasheet to get some better advice.
     
  5. Eeyore

    Eeyore Guest

    An automotive audio amplifier might be the ticket.

    Graham
     
  6. I think you might find something usable if you browse
    through the audio amplifier (speaker driver) chips, instead
    of opamps. There are even some class D (switching) drivers
    that might do the job with higher efficiency.
     
  7. Ross Herbert

    Ross Herbert Guest

    You might be able to use the old venerable LM12 which can operate
    single rail.

    http://www.national.com/pf/LM/LM12CL.html
     
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