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DRV8885: Weird sound when motor stopped

Part Number: DRV8885

Hi team,

My customer will use DRV8885 and he provided a question.

When the motor comes to a stop, a weird sound is heard.

In this case, standby and enable are left active.

Above weird sound can be disappeared when current setting is changed to 50% from 75%(initial value).

If you know anything about this phenomena, could you please provide any comment?

If you need schematic/waveform, the customer will prepare them.

Thanks in advance for your support.

Best regards,

Shota Mago

  • Mago-san,

    "The weird sound can be disappeared when current setting is changed to 50% from 75%(initial value)."

    Does the load still apply to the motor even the motor stops? If the load still applies to the motor when the motor stops, we cannot reduce the current or torque to overcome the load torque.

  • Hi Wang-san

    Thanks for your quick reply.

    I checked that information to the customer.

    There is certain load even the motor stops although the load is smaller than when the motor is running.

    Have you ever heard this kind of phenomena before?

    If so, does this phenomena has a specific cause?

    Best regards,

    Shota Mago

  • Mago-san,

    I didn't hear this phenomena before. But, we can figure it out.

    "sound can be disappeared when current setting is changed to 50% from 75%(initial value)."

    According to this clue, we know the sound related to the current level. What decay mode do you use? Can you change to other decay mode?

  • Hi Wang-san

    Thank you for your support.

    The customer mentioned that changing decay mode also disappears the sound(I'm checking that which decay mode they tried.).

    Are stop condition and decay mode related?

    Best regards,

    Shota Mago

  • Mago-san,

    Yes. The decay mode can affect the winding current waveform.

    Higher percentage fast decay will bring down the winding current faster. That may cause the noise in this case.