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DRV8320: 1xPMW mode

Hirotaka Matsumoto
Guru 27585 points
Part Number: DRV8320

Hi all

Would you mind if we ask DRV8320?

We would like to confirm 1xPMW mode.

In case of INLA=INHB=INLB=0(no hall sensor input), despite of PWM input, state is stop, right?
In other words, unless there is hall sensor inputs, there is no output. Is it correct?



Kind regards,

Hirotaka Matsumoto

  • 0
    TI__Mastermind 18900 points

    Hello Matsumoto-san,

    If there are no hall sensor outputs and no pull ups on the INx pins, yes, the internal pull downs will disable the gate driver and the motor should not commutate.

    Note, STOP doesn't actually forcibly stop the motor, the gate driver outputs are just disabled. To reiterate, when the gate drivers are disabled, the rotor is allowed to do whatever it wants. So if the rotor was already spinning and the hall sensors gave out to give a all 0's command, then the rotor would continue to spin and coast until friction caused the motor to stop some time later. We just know that the gates of the FETs will not be asserted.

    I also want to note that most hall sensors have pull up resistors on the outputs, as explained on the other post from you. As such, a case where all broken hall sensors are broken, leaving all 1's, will cause the align function. More realistically, one hall sensor might break, causing one of the hall states to be frozen in a high state, and the commutation table might be frozen to one of the 6 states above, which is just another form of the align function.  

    Best,

    -Cole