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Original question:

DRV8306: Basic operation

DRV8306: nFAULT

user5933712
Prodigy 90 points
Part Number: DRV8306

Regarding the DRV8306:

Gate Driver Fault is encountered as I speed up the motor.

My PCB has two channels, the first one works correctly, but second one doesn't.

I think there is little difference in patterns between them.

Actually, I cannot measure the signal when the GDF occured.

I just recognized the nFAULT was asserted.

But I thought the error was GDF, because it was latched until power on reset.

And the error was not UVLO and CPUV because VM and VCP  didn't get low level when nFault was asserted.

Would you please let me know how to check if GDF is encountered?

And please suggest how to fix it.

I'd appreciate your kind cooperation in advance.

Best and regards,

Sango 

  • 0
    TI__Guru 65170 points
    Sango,

    You will need to check all High side and Low side VGS differentially. if any of the High side or Low side has unexpected VGS then the GDF could be triggered.

    When you check any FET, the positive of the differential should be the gate, the negative is the associated source pin. If you see positive voltage spikes when the gate should be off, or negative spikes when the gate should be on then you may have a GDF,

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 90 points
    Adam,

    Thank you for your advice.
    I'll check it.

    Btw, I have a question about HNx again.
    Do I need buffer to drive HNx after divided by register(1/2 DVDD)?
    According to DRV8306EVM design, SN74CBT3244PW is used.
    I am not sure if I had better use the buffer like that.

    Please let me know your suggestion again.

    Best and regards,
    Sango
  • 0 in reply to user5933712
    TI__Guru 65170 points
    Sango,

    This is dependent on your hall sensor output and your design needs. The DRV8306 EVM and guide should have info that will help you decide.

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 90 points

    Dear Adam,

    I'm sorry for late reply.

    As you said, GDF occurred due to the spike noise of VGS.

    I installed the bypass capacitors between VM and GND of each Half bridge gate,

    from then, GDF has not occurred so far.

    Btw, would you please advise me when it comes to another topic?

    I'd like to implement the constant current(torque) control of motor even if the load changes.

    How can I do by this device?

    or is it unsuitable for this device(because this device has only 120deg drive)?

    I'd appreciate your suggestion.

    Best and Regards,

    Sango

  • 0 in reply to user5933712
    TI__Guru 65170 points

    Sango,

    This driver does not have torque management or feedback built in. You would need to use a newer device and implement the C2000 team code/MCU to do this.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 90 points

    Adam,

    Thanks for your kind reply.

    I understood.

    Best and regards,

    Sango