High power op amp (Or something similar)

Discussion in 'Power Electronics' started by TheFallen018, Jul 12, 2018.

  1. TheFallen018

    Thread Starter New Member

    Jul 12, 2018
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    0
    Hey, I'm currently a first year EEE student. I don't have a lot of experience under my belt, but I'm curious to try and make some of my own circuits at home in order to build an intuition that I might find hard to develop otherwise.

    At the moment one of my projects it to try to make a DC to AC inverter. I think I can figure out how to produce the sine wave voltage, but I also want the ability to deliver a large number of amps at a hundred volts or more.

    I've just been toying with the idea so far, and I was hoping that I could use something like an op amp for this. If I could achieve the desired AC pattern in a circuit with minimal current flowing through it, I thought I might be able to run it through an op amp, drawing current from the power rails. However, the op amps I've dealt with have nowhere near the ability to pass the amount of power I want. (Around a kW of power)

    Is there something that could achieve this without too much hassle?

    Thanks
     
  2. dl324

    AAC Fanatic!

    Mar 30, 2015
    7,450
    1,767
    Welcome to AAC!
    There are no high power opamps.
    There is no simple way to boost the output of an opamp to the kW range. Study the datasheets and application notes for opamp boosters.

    Here are a couple to start with:
    http://www.ti.com/lit/an/snoa600b/snoa600b.pdf
    http://www.analog.com/media/en/technical-documentation/application-notes/an18f.pdf
     
  3. crutschow

    Expert

    Mar 14, 2008
    20,265
    5,738
    There are some "high power" op amps that have output current and voltage higher than typical devices but still nowhere near what you want.
    And note that the power dissipated in a linear amp to deliver such voltage and current is at least 20% (maximum efficiency of a class B amplifier stage is 78.5%) of the power you are outputting, so will be very inefficient and require a huge heatsink.

    For that kind of power, inverters typically use PWM to generate the sinewave so that the output transistors are acting as switches and thus only dissipate a small amount of power.

    A lower power circuit might be more appropriate for your first project. ;)
     
    TheFallen018 likes this.
  4. ian field

    AAC Fanatic!

    Oct 27, 2012
    6,252
    1,131
    There are a few high voltage op-amps - but I doubt they go that high.

    ST do an L272 that can handle 1A output, but only standard type voltage.

    NS did various buffers, like TO3 can but more pins - still won't do it.

    A few manufacturers have published reference designs for audio PAs - the op-amp has its output tied to 1/2 voltage, the op-amp supply pins are fed via resistors, the voltage developed across those drive B/E junctions of power transistors. Study of those reference designs might get you there...……..eventually.
     
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