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DRV8839: Parallel Use of Half H Bridges

Part Number: DRV8839

I have a requirement for a half H-Bridge. Can I connected the two Half H-Bridges in the DRV8839 in parallel to achieve lower effective series resistance? The dead time in the part is specified at 100 ns and delays are 120 ns maximum . Will there be any simultaneous conduction across the two Half H-Bridges? Another thing I would like to know is the effective time constant (or bandwidth) of the Over Current Protection. Will it react to a brief (20 ns) current spike, or will it filter it out?

Thanks,

Bret

  • Hi Bret,

    What are your voltage and current requirements? Do you need multiple half bridges in your system?
    Perhaps we can suggest an alternate part that fits your needs.
  • 9 Volts, 2 Amps ... this is a high volume one-time use, disposable device, so unit cost is a big factor. I was attracted to the DRV8839 because if I could parallel the half H-Bridges it will (just) meet my requirements at a very attractive unit cost.
  • Also, I need only one Half H-Bridge ... hence the idea of paralleling the pair to get lower effective total series resistance.
  • Hi Bret,

    Thanks for the additional information.

    To confirm, you want to:
    1) connect the two outputs in parallel
    2) set the two INx inputs to a logic zero (can float because of the internal pulldowns)
    3) connect the two ENx inputs together to enable and disable the two outputs in parallel
    4) Use the high side FET body diodes for current recirculation

    If all of these are correct, the DRV8839 looks like a good choice for you requirements.

    In the above scenario, there is no cross conduction because the high side FETs are not enabled.
    Overcurrent circuits typically have a deglitch circuit, which will ignore a 20ns pulse. I don't have the exact timing, but the deglitch circuit usually is ~1.5us.