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DRV10974: UVW operation in PWM=LOW

David Park
Expert 5400 points
Part Number: DRV10974

Hi,

There is U output in PWM=Low.

Could you let me know it is normal operation?

  • 0
    TI__Mastermind 24405 points

    Hi David,

    We will get back to you by end of the day.

    Regards,

    Vishnu

  • 0 in reply to Vishnu Balaraj
    TI__Mastermind 24405 points

    Hi David,

    The device should be in low power mode if the input PWM voltage is less than 0.6V and the PWM turn-off/low time is less than 25 ms. In low power mode, motor should be stationary and there should not be any switching happening in the inverter. Can you make sure there is no positive offset voltage in the PWM pin? The reason why I ask this is because when the analog voltage on the PWM pin is above zero-speed analog voltage then the device exits low power mode and we can see some switching happening in the inverter. Also, can you pull the PWM pin to GND and check the phase U voltage? Ideally, you shouldn't see any switching when PWM is pulled low. 

    Regards,

    Vishnu.

  • 0 in reply to Vishnu Balaraj
    TI__Expert 5400 points

    Hi Vishnu,

    There was some issue and it's closed. Thanks.

    U to V resistance is 0.7Ohm.

    In the datasheet, recommended range is 1Ohm to 20Ohm.

    For supporting this motor, what is tuning factor?

    Thanks.

  • 0 in reply to David Park
    TI__Mastermind 24405 points

    Hi David,

    Since the motor resistance is out of range, we may not be able to tune the motor up to the rated speed. I highly recommend to refer to the tuning guide to tune the motor. This tuning guide has quick tuning and comprehensive tuning methods. The goal of quick tuning is to get the motor running quickly by inferring usable resistor values for the current (CS pin), lead time (ADV pin), and acceleration profile (RMP pin). The comprehensive tuning section covers the methodology for tuning each resistor value experimentally.

    Regards,

    Vishnu