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DRV8840: question about nFAULT pin

TS Yang
Genius 4800 points
Part Number: DRV8840


Hi,

I have a question about using the DRV8840.

I am planning to use the TI's motor driver DRV8840 and I am debugging it because there is a problem that the motor stops while driving the DC motor on certain machines.

The DRV8840 nFAULT pin on my board is connected as a floating state.

When I connect a pull-up resistor to the nFAULT pin to check the status of the FAULT pin (open drain output), it will not reproduce the symptom of the motor stop.

So I ask you to check whether the nFAULT pin should be left floating.

thanks,

TS

  • 0
    TI__Guru** 114905 points
    Hi TS,

    Does the firmware monitor the nFAULT pin, and take action if the nFAULT pin is low. Does the mcu have an internal pullup? Is there noise on the pin?

    The nFAULT pin is an open drain pin that indicates a problem with the device. Leaving it floating should have no effect on device operation.

    It is recommended to connect and monitor the nFAULT pin. If nFAULT is not monitored, the outputs could be disabled and the system would not be aware of this.