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drv8432 VREG still problems

ALbert Tello
Intellectual 735 points
Other Parts Discussed in Thread: DRV8412

I upload a code in my private conversations VREG PROBLEMS

VREG still going down when a software is running Step by Step.

 Albert Post

  • 0
    Intellectual 735 points

    FIRST QUESTION

    Could you tell me what happen with drv8432 in th following stage:

     RESET_AB= RESET_CD= 3.3V  ;

    M3=M2=M1=0;

    CASE A:

    PWMA=PWMB=3.3V;

    PWMC=PWMD=3.3V

    CASE B:

    PWMA=PWMB=0;

    PWMC=PWMD=0

    SECOND QUESTION

    If  in  the initialization process can happen this can damage VREG  ?

    Albert Tello

  • 0 in reply to ALbert Tello
    TI__Guru** 114905 points

    Hi Albert,

    This scenario should not cause any problems.

    When RESET_AB and RESET_CD are 3.3 and M3=M2=M1=0, the device should be enabled in 2FB or 4 HB mode with CBC limit.

    Then when PWMA/B/C/D = 3.3V all outputs should go to PVDD.

    When PWMA/B/C/D = 0, all outputs should go to 0V.

    This should not damage VREG.

  • 0 in reply to Rick Duncan
    TI__Mastermind 20985 points

    Albert,

    It's not clear why VREG is getting damaged.  How do you know that it is?  Does the system stop working, and then you noticed VREG doesn't equal 3.3V?

    Check if the microcontroller is enabling a pull-up for OTW# and FAULT#.  The DRV8412 has internal pull-ups to VREG, and another pull-up to a higher voltage could cause damage.

    Also, try measuring the VREG capacitor voltage during operation.  If GND bounces, that could cause lots of transient current from VREG, or violate the VREG absolute max voltage.

    Best regards,
    RE