Driving multiple mosfets

Discussion in 'Power Electronics' started by kevinjones, Feb 2, 2017.

  1. kevinjones

    Thread Starter New Member

    Feb 2, 2017
    2
    0
    Hello,

    I have a PV charge controller which drives 4 50A mosfets to supply current to charge batteries in a small power station. I wish to modify it to handle larger current, by increasing the number of mosfets to 16.

    Currently, the 4 mosfets are driven by a single emitter-follower circuit, through 10K resistors, one connected to each mosfet gate. eg, the emitter of the driver transistor is connected to 4 10k resistors, each resistor being connected to the gate of each mosfet.

    My question is, can I simply connect the gates of the additional mosfets in the same way, to the same emitter-follower driver? So then I would have a single emitter-follow output connected to 16 10k resistors, each one connected to the gate of a mosfet. Or will I need to add additional emitter-follower driver circuits? It would seem to me that additional drivers should not be necessary, since the gate impedance of the mosfets are extremely high.

    Also, I am curious what the purpose of the 10k resistors are.

    (cross-posted on Electronics Point Forum)
     
  2. MrChips

    Moderator

    Oct 2, 2009
    16,737
    5,132
    Adding additional MOSFETs will be fine.

    The 10kΩ resistor limits the current between the controller and the MOSFET and therefore provides a bit of protection to the controller in the event of a catastrophic failure of the MOSFET.
     
  3. kevinjones

    Thread Starter New Member

    Feb 2, 2017
    2
    0
    Great, thank you very much.

    Kevin
     
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