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DRV8323: Overheat while operating without load

Duc Dang
Prodigy 40 points
Part Number: DRV8323
Other Parts Discussed in Thread: CSD19532KTT

Hi, I had a fatal problem with DRV8323 driver. I applied 10kHz PWM (open-loop) pulse with 50% duty cycle to each phase. The operation reach to approximate 200mA. After 3 minutes operating without load, the DRV8323 explored. 
I retry with another DRV8323 but only after 1 minute, the temperature of it reach to over 50 celcius degree.

The MOSFET I used is csd19532ktt with 44nC gate charge. 

The attached file is my schematic. 

Please help me, thanks a lot.

BLDC Driver.pdf

  • 0
    TI__Guru** 114905 points
    Hi Duc,

    What are your register settings?

    Please try operating the device at 10 to 12V if possible.
    Observe the operation of the device and power supply current.
    If it appears normal, raise the voltage 3 to 4V and measure again.
    Look for differences on the inputs and outputs.
    Continue until you see differences.
  • 0 in reply to Rick Duncan
    Prodigy 40 points
    I did it, but the power supply current at 12V is still pretty high, at 150mA.
    When I raised the supply voltage to 14V, DRV8323 became hotter. :(
    The output signal was always good with any input voltage (8-24V). The problem is operation current is too high.
    This driver IC uses SPI communication to set the the peak source gate current but I didn't config anything, is this the key of this problem?
    Sorry for my bad English.
  • 0 in reply to Duc Dang
    TI__Guru** 114905 points
    Hi Duc,

    Which inputs are being PWM'ed?

    What current do you observe @ 12V? when:
    1) the device is powered but not enabled
    2) the device is powered and enabled, but no PWM inputs
    3) the device is powered, enabled with one inputs PWM'ing
    4) the device is powered, enabled with two inputs PWM'ing
    5) the device is powered, enabled with three inputs PWM'ing


    Please provide a scope capture of low side gate PWM'ing @12V?

    By default, the highest IDRIVE settings are used. Lowering the IDRIVE settings may help.
  • 0 in reply to Rick Duncan
    Prodigy 40 points

    Hi,

    I succeed to change the IDRIVE setting to the lowest value (0h00). The current decreased from 198mA to 100mA (Voltage supply is 24V), but the DRV8323 was still hot.

    1. The current when I turn off the enable pin is nearly 40mA.

    2,3,4 and 5: when I supplied the 50% duty cycle PWM pulse to each phase sequently, the current increased linearly.

    Here is the picture of Vgs of low side Mosfet with 50% duty cycle of 10kHz PWM, IDRIVE  = 0h33.

    Do I miss to config something? 

    .

    Thanks a lot.

  • 0 in reply to Duc Dang
    TI__Guru** 114905 points
    Hi Duc,

    With the ENABLE pin low, the DRV8323 should consume <100uA (Ivmq). Please determine if the remaining 40mA is consumed elsewhere in the system.

    When the ENABLE pin is high and no inputs the DRV8323 current should increase to 10 to 12mA @ 12V (Ivm).
    If the current increases more than 12mA, please measure the regulator outputs and look for shorts between pins.
  • 0 in reply to Rick Duncan
    Prodigy 40 points

    Hi, 
    I resolved my problem. The reason is from my MCU, i resoldered it and the working current while I supplied 50% duty cycles 10kHz PWM pulse descreased from 100mA to only 46mA ( When the ENABLE pin high with no PWM duty cycles, the current was 40mA)
    Thanks a lot from your help.

    Have a nice day.