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DRV8703-Q1: charge-pump undervoltage

huan yin
Prodigy 70 points
Part Number: DRV8703-Q1

Hi Expert,

I have encountered a mistake：FAULT Status Register = 0x84(charge-pump undervoltage). I don't know how to correct it and I want to know some of the possibilities that led to it.( The input voltage is 12V.)

BR,

Huan Yin

  • 0
    TI__Genius 10295 points

    Hi Team,

    The following is additional information regarding customer issues:

    The input voltage is 12V, and the status of each register is:

    Write_MainControl_State2          0x101C   //  LOCK = 011 , IN1/PH = 1 , IN2/PH = 0 , CLR_FLT = 0  IN1 is enabled, IN2 is not enabled

    Write_IDRIVE_WDControl_State1     0x18C7   //  TDEAD = 11 , WD_EN = 0 , WD_DLY = 0 , IDRIVE = 111  Dead time 960ns, watchdog turned off

    Write_VDSControl_State1           0x207F   //  Turn off VDS current limiting

    Write_ConfigControl_State1        0x2803   //  Magnification = 80

    The input PWM frequency is 500HZ, and the duty cycle is 50%; the power supply current limit is 2A, and the normal operating current value during the previous debugging process was about 0.2A.

    Regards,

    Annie

  • +1 in reply to Annie Liu
    TI__Mastermind 21185 points

    Hi Annie,

    Was there any external load connected to the VCP pin? Were the capacitor values suggested used correctly?

    IDRIVE = b111 is the highest gate current drive setting which is usually not required. Please refer to page-50 section 8.2.2.2 IDRIVE Configuration to calculate the required IDRIVE setting for the FETs used by the customer. Usually it should be a much lower IDRIVE setting that will not be demanding on the VCP, CP output voltage specifically required for HS-FET drive.

    If the fault persists it would be useful to capture the VM voltage, VCP voltage when nFAULT going LOW with this fault. When does this fault happen? Detailed description of sequence of events that resulted with this fault will be helpful to debug. Thanks.

    Regards, Murugavel