DRV8332: GVDD to Gnd short

Peter Westlund

Part Number: DRV8332

We are using a DRV8332 for sinusoidal control of a BLDC motor.

The chip operates correctly for a while and then randomly fails; I measure a short between the GVDD pins and Gnd. I have replaced the chip twice so far, so I would like some assistance in determining what might be causing this problem.

PVDD is set to 37V

During typical operation the BLDC motor is drawing between 1-5 Amps of current.

Best Regards,

Peter

over 4 years ago

0 Adam Sidelsky over 4 years ago

TI__Guru 62730 points

Peter,

If you remove the chip from the board, can you check the impedance from each of the BST pins to GND please?

Regards,

-Adam

0 Peter Westlund over 4 years ago in reply to Adam Sidelsky

Prodigy 20 points

Adam,

I was able to measure the impedance from the BST pins of one chip, but a BST pin (BST_C) broke off of one chip, so I wasn't able to read all of the impedances.

The ones I could measure were as follows:

BST_A = 22.7Kohms, BST_B = 1.375Mohms, BST_C = high impedance
BST_A = 363Kohms, BST_B = 5ohms, BST_C = Broken (couldn't get a good reading)

Peter

0 Adam Sidelsky over 4 years ago in reply to Peter Westlund

TI__Guru 62730 points

Peter,

You may be having a GVDD/BST in-rush current issue. Could you try adding a 5 ohm resistor at each of the GVDD pins to limit the current? This resistor should be between each GVDD pin and it's corresponding 1uF bulk cap.

Regards,

-Adam

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DRV8332: GVDD to Gnd short