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  • TI Thinks Resolved

DRV8312: driver output voltage is shorted with GND

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Replies: 5

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Part Number: DRV8312

Hello Support,

DRV8312 Driver IC used to derive 3-phase BLDC motor, When motor not connected to the driver we have observed 10V on each phase(A, B, C ) the  After using few days one of the driver phase(B) gone bad. Now we have measured the voltage on each phase, on A and C phase voltage is 10V and on C Phase voltage is 2.5V.

We have seen this issue very frequently in our design, Can anyone explain what could be the reason for failure.

Driver operating voltages:

VDD1-12V

PVDD-24V.

Thank you,

Rehaman.

  • Rehaman,

    Thanks for posting on the Motor Drives Forum.

    Have you checked the OUT_X pins with a scope near the DRV to see if the ABS MAX of the DRV is being violated? My estimation is that without the motor you have overshoot and undershoot on the Output lines which is killing the driver eventually.

    Are you using your own board or an EVM?

    Regards,

    -Adam

  • In reply to Adam Sidelsky:

    Rehaman,

    Could you tell us your switching frequency and BST cap value?

    Regards,

    -Adam

  • In reply to Adam Sidelsky:

    Hello Adam,

    We are using Hall sensor based BLDC motor. If motor not connected to the driver(DRV8312) , MCU will drive the reset signal low.

    BST cap value-100nF

    BST switching frequency-20KHz.

    Thank you,

    Rehaman.

  • In reply to Rehaman Tulugu:

    Hello Adam,

    We are suspecting the failure of bootstrap diode. Could you please share your thoughts.

    Thank you,

    Rehaman.

  • In reply to Rehaman Tulugu:

    Rehaman,

    It is possible that the BST could be damaged. If this is the case I would expect to see a BST_UVP, are you seeing any faults?

    Regards,

    -Adam

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