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DRV8303: Negative gate voltage during regeneration

Part Number: DRV8303

Hello to everyone,

I have a new issue with the above mentioned three phase driver.

I have an application where I use two legs of drv8303 to drive a reversible DC motor. In this application there's the real chance that this motor will be forced to move while the drive is turned off.  Here is what I see on the scope when I move the motor to a fraction of the nominal speed.

Green trace is HS_A

Yellow is GH_A

Pink is GH_A - HS_A

As you can see there's a negative VGH_DIF lower than the minimum absolute rating of the IC. And, of course, sometimes the IC is killed by this treatment.

I can't find any workaround, since it seems to me that vbus capacitors charging through the body diode of the high side mosfet is causing the presence of this voltage. Does it means i can't use DRV8303 in an application where i can expect some kind of regeneration into a turned off board?

10 Replies

  • Hi Simone,

    We will investigate and reply soon.

    Rick Duncan
    Motor Applications Team

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  • In reply to Rick Duncan:

    Hi Rick,

    did you find anything about this matter? Do you need further information?

  • In reply to Simone Freato:

    Hi Simone,

    Sorry for the delay, and thank you for reminding me. I have contacted the experts on this device. We should have a response in a couple of days.

    Rick Duncan
    Motor Applications Team

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  • In reply to Rick Duncan:

    Hi Simone,

    Can you clarify what HS_A and GH_A nets correspond to pins on the DRV8303?

    Phil Beard
    Motor Applications Team

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  • In reply to Phil Beard:

    I'm sorry, I was meaning SH_A and GH_A, pins 42 and 43.

  • In reply to Simone Freato:

    Hi Simone,

    Thank you for the information.

    This is most likely damaging a diode between the SH_A and GH_A pins inside of our part. Is is possible for you to disconnect the motor in your application from the mechanical system back driving it?

    When the motor is acting like a generator, there is not a lot we can do in our system to protect against this continued stress to our part except to electrically or mechanically disconnect the motor.

    Phil Beard
    Motor Applications Team

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  • In reply to Phil Beard:

    Hi Simone,

    Can you take a picture of the top of the device and send it to us? We'd like to make sure this isn't a change we made in silicon causing the part to be damaged.

    Phil Beard
    Motor Applications Team

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                  Please Click the Verify Answer button on this post if your question has been answered.  Thank you
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  • In reply to Phil Beard:

    Hi Phil,

    here you are a photo of the IC. Your hypothesis is supported by the fact that this is the first time we see a damage in this condition, we use DRV8301 and DRV8301 since 5 years now, and regeneration with a powered off inverter is quite common in our applications.

    Thanks for your support.

  • In reply to Simone Freato:

    Hi Simone,

    Thank you for the image. Please give me a couple days to close with our design team on whether this part is affected.

    Phil Beard
    Motor Applications Team

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                  Please Click the Verify Answer button on this post if your question has been answered.  Thank you
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  • In reply to Phil Beard:

    Hi Phil,

    have you got some news?