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Original question:

DRV8301-hc-evm revision D (CC2803X IDO DIM REV 1.3)

DRV8301 PWR_PAD bad connection with GND

Chen Jiao
Intellectual 810 points
Other Parts Discussed in Thread: DRV8301

Hi team,

We find some DRV8301 broken in W phase, which cause BST_C or GH_C resistance abnormal.

As it is soled manually, could you please confirm, if PWR_PAD is not in good connection with GND, could it cause the damage?

Thanks a lot.

  • 0
    TI__Guru 65250 points

    Chen,

    We cannot confirm that it would cause damage but by best practice we highly recommend connecting the PWR_PAD to the system GND.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    TI__Intellectual 810 points

    Hi Adam,

    Thanks for the reply.

    Could you please help confirm the below items to help us find the broken reason?

    1. Could you please confirm DRV8301 is proper to be used in 48V battery system?

    DRV8301 is powered by 48V battery, the max voltage could be 54V. And when motor stops, PVDD could be much higher.

    We have some concern about it and are grabbing the over-voltage waveform.

    2. Could you please tell what issue could bring if GVDD voltage drop too large?

    We found GVDD voltage drop 1.68V from around 11V under no-load condition. When rotating the motor, the drop should be higher. I am not sure if it is the reason of broken.

    Thanks.

  • 0 in reply to Chen Jiao
    TI__Guru 65250 points

    Chen,

    Usually we recommend about 1.5x or 2x voltage headroom between the voltage applied and the device abs max. This would mean that ~44V is the maximum voltage we would recommend for this device.

    We have several devices designed for 48V battery systems, I can recommend some of these if you would like.

    GVDD should not drop this low, we would need to check why GVDD is dropping so low.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    TI__Intellectual 810 points

    Hi Adam,

    Now we need another short circuit test, short U to V or the other phase wire. Could you please confirm if DRV8301 can protect under this situation?

    Details as below:

    Startup with U to V shorting, we found DRV8301 explode, but MOS is ok.

    For circuit setting, 50% duty cycle is set during start up. and MCU can monitor DRV8301 fault pin, once fault occurs, it would reset DRV8301. 

    Thanks a lot.

  • 0 in reply to Chen Jiao
    TI__Mastermind 18900 points

    Hello Chen,

    Let me get back to you tomorrow, 12/15/20.

    Best,

    -Cole

  • 0 in reply to Chen Jiao
    TI__Mastermind 18900 points

    Hello Chen,

    The DRV8301 might able to protect the MOSFET (because of VDS monitoring), but the increased current flow, as the result of bypassing the motor, would result in a large voltage spike that would couple into the gate pins and eventually lead to damage on the gate pins or GVDD pin before the gate driver pins can be turned off (as a result of the fault). Have you verified damage on the gate driver pins or GVDD after the DRV exploded? 

    Best,

    -Cole