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DRV8323: DRV8323 burning.

Siddharth Pathania
Prodigy 10 points
Part Number: DRV8323

We're running a DC motor through DRV8323 by applying a PWM with constant duty cycle with Vdc as 24V. 

I applied a constant duty cycle when no motor was connected to it's terminals and suddenly sparks came out and the chip burned. I've attached a photo of the burned chip. 

Can you please indicate what could be the reason for the chip's burning.

  • 0
    TI__Guru 63710 points

    Siddharth,

    Thanks for posting on the MD forum!

    Could you please share your schematic and layout with us?

    Also please share your SPI register settings.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 10 points

    Hi Adam,

    Following is my SPI register values. The rest are set as defaults.

    Motor_Drive.pdf

    This is the schematic and layout of the board.

    -Siddharth

  • 0 in reply to Siddharth Pathania1
    TI__Guru 63710 points

    Siddharth,

    What FET are you using?

    The gate current of 260mA/520mA is very high and may be too much for your FETs with no gate resistor unless you have very large QGD on your FETs.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 40 points

    Hi Adam,

    Siddharth is out of town for some time,We work in the same team.

    We are using IRFB3407ZPBF .

    Regarding the gate resistor, as mentioned in section 8.3.1 of Datasheet ,DRV has internal current control capabilities for the gate of MOSFET 

    Do we still need resistor on the gate of MOSFET?

    Let us know if any other details needs to be provided.

    Regards

    Pankaj

  • 0 in reply to Pankaj Krishnantrey
    TI__Guru 63710 points

    Pankaj,

    A gate resistor is not needed, but some customers still choose to use it. Your IDRIVE is too high which is causing this issue.

    Your FET has a small Qgd of 24nC. An IDRIVE current of 260mA/520mA will attempt to slew the SHx node at 92nS/46nS respectively. This is very quick and will likely cause overshoot/undershoot/oscillation on your gate and switch node.

    I would reduce your IDRIVE current to 60mA/120mA and see if the issue persists. This should correspond to a switch node rise/fall time of between 200nS and 400nS.

    Regards,

    -Adam