mosfets gate-to-source and gate-to-drain?

Discussion in 'General Electronics Chat' started by Kardo22, Oct 22, 2015.

  1. Kardo22

    Thread Starter New Member

    Mar 12, 2014
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    0
    Hi,
    I'm not very familiar with power electronics and I was wondering what the part in my picture does. It part of a charging circuit but I can't figure out why the mosfets are used differently. Sorry but I can't share more of the circuit.
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
    3,250
    626
    Without more of the circuitry, it's difficult to determine why the MOSFETs are connected in a mirror image. If consider the polarity of the body diodes, which aren't shown in your schematic fragment, it might make sense.
     
  3. dl324

    Distinguished Member

    Mar 30, 2015
    3,250
    626
    Here is the schematic redrawn with a component that shows the body diodes (which are incorrectly drawn as zeners, but that's what my editor had; it's really just a silicon diode).
    bodyDiodes.jpg
    Having both MOSFETs on at the same time might make sense in the larger context but, in this fragment, it doesn't... If they're both on all the time, you don't need them and could replace them with a wire.
     
  4. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    Looks like a fancy OR gate to me.
     
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