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DRV8242H-Q1EVM: question about reverse and forward in PWM mode

Jay wang
Expert 3581 points
Part Number: DRV8242H-Q1EVM


hi expert

i saw the following words in our datasheet. whether do we identify reverse direction or forward direction? we only mention "one direction" and "other direction"

image.png

thanks

  • 0
    TI__Mastermind 26740 points

    Hi Jay.

    We typically recommend using high side recirculation so IPROPI will always be outputting the current, so in my explanation the input in that is not provided a PWM signal will be held low. 

    For current to flow from OUT1 to OUT2 (forward), EN/IN1 should be PWMed and PH/IN2 should be low.

    For current to flow from OUT2 to OUT1 (reverse), EN/IN1 should be low and PH/IN2 should be PWMed.

    Regards,

    Joshua

  • 0 in reply to Joshua Horlander Cruz
    TI__Expert 3581 points

    hi Joshua

    from my understanding, if designer want to implement high side recirculation, the HS FET of OUT1 should be on and LS FET of OUT1 should be off, and HS FET of OUT2 should be on and LS FET of OUT2 should be off. how to implement this logic at the same time?

    i cannot find suitable control logic during PWM mode

  • 0 in reply to Jay wang
    TI__Mastermind 26740 points

    Hi Jay,

    This is correct, for High Side recirculation both HS FETs are on. To enable both OUTx HS FETs, both EN/IN1 and PH/IN2 = 0b. From this brake state, applying a PWM signal to EN/IN1 will cause OUT2 to switch from HS on to LS on causing the current to current to flow from OUT1 to OUT2. If instead the PWM signal is applied on to PH/IN2, OUT2 will switch from HS on to LS on and the current will flow from For current to flow from OUT2 to OUT1.

    both forward, reverse, and both HS-FETs on are covered by the 3 highlighted rows in the table below.

    Regards,

    Joshua