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CCS/DRV8323: Spark produced at the driver in 1xPWM mode.

XUANHAO ZHAO
Prodigy 30 points
Part Number: DRV8323


Tool/software: Code Composer Studio

Hello everyone.

I designed a brushless dc motor controller using DRV8323RS and the PCB was designed by myself. The mode of drv8323 was configurated in 1xPWM mode. When I turned on the switch to configure the register, it suddenly sparked. And then I found that INLC was connected to GND.( through a multimeter).

I really need your help to solve this problem.

Here if my  schematics.原理图.pdf

  • 0
    TI__Guru 65830 points
    Xuanhao,

    I think the device is likely damaged because the DMM was connected. Please replace the device and try again.

    Your schematic looks fine. The buck is configured to output 5.5V? Did you make sure to keep the input PWM off until you enabled the device and then checked if the supply current looks normal?

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 30 points

    Adam，

    Thanks very much for your help.

    I want to know the order  to energize these pins (ENABLE、INHx、INLx) in 1xPWM mode. Should I keep these pins low before configuring the registers?

    Regards,

    Xuanhao

  • 0 in reply to XUANHAO ZHAO
    TI__Guru 65830 points
    Xuanhao,

    Enable must be HIGH first, then configure registers, then any of the inputs.

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 30 points


    Adam,

    I'm sorry to tell you the problem still unsolved.

    Firstly,I set the ENABLE pin be high, configure registers, then set the INLC(BRAKE) pin high.

    The problem is when I set the INHA(PWM) pin high,the fault occurs . The VDS_HA bit、FAULT bit and  VDS_OCP bit of 0x01 register become 1.

    When I set the  INHA(PWM) pin low and turned the motor shaft, two of the three pins(MOTA, MOTB,MOTC) are high voltage, I think there must be something wrong.

    Look forward to your reply.

    Regards.

    -Xuanhao

  • 0 in reply to XUANHAO ZHAO
    TI__Guru 65830 points
    Xuanhao,

    The PWM input pin needs to be togged with a PWM signal, not only set HIGH. When checking for voltage on SHx, please check also the associated GHx. Likely you will find that GHx and SHx are the same voltage, meaning VGS of the high side FET is 0V and the FET is actually off. There is a small leakage path inside the DRV that allows the SHx to raise in voltage in the right conditions but once you start switching the motor, this will go away.

    The leakage path is only in the uA range.

    Regards,

    -Adam