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DRV8432: The burning of DRV8432 PVDD Pin

Annie Liu
Genius 10295 points

Part Number: DRV8432

Hi Team,

Customer's problem is: when M1, 2, 3 are connected to GND and half bridge control is used, then use 24KR (adj) to connect load to a solenoid motor. The current is about 10A. But after the power switch (maximum current 13A) is powered on, the PVD pin of 8432 burns directly. The procedure is: firstly, OUTA and B output 50% duty cycle every 50ms; secondly, OUTC and OUTD output 50% duty cycle every 70ms.Is it because there is no dead zone between them at 350ms?

  • 0
    TI__Guru** 114905 points
    Hi Annie,

    There are several connections that should be addressed in the schematic.

    Assuming the outputs are to be connected in parallel as shown, please refer to Figure 15 in the datasheet for reference.

    1) The M3, M2, M1 pins should be set to 0, 1, 0 (1 PFB).
    2) The PWM1 signal should be connected to PWM_A pin. The PWM2 should be connected to the PWM_B pin. PWM_C and PWM_D should be connected to GND.
    3) The outputs should be configured as shown in Figure 15. The outputs should have a small ferrite bead before connecting them in parallel. This is described on page 13 of the datasheet, and section 9.4.5 of the datasheet.
    4) Each GVDD_x and VDD pin should have a local 1uF capacitor. If these are not present, please add them.
    5) There should be a bulk capacitor for all GVDD_x and VDD pins.
    6) There should be a bulk capacitor for all PVDD_x pins.
    7) There should be a local 0.1uF capacitor at each PVDD_x pin. If these are not present, please add them.
    8) Please note the section 7.3.2.1 if the PWM switching frequency is intended to be less than 10kHz.
  • 0 in reply to Rick Duncan
    TI__Genius 10295 points

    Hi Rick,

    The brushed DC motor has a rated current of 2.8A and a stalling current of 18A. Is it possible to drive if the DVR8432 is used?

    Thanks.

  • 0 in reply to Annie Liu
    TI__Guru** 114905 points

    Hi Annie,

    It may be possible. This depends on how long the motor will be stalled. If the stall last too long, the device could enter overtemperature shutdown.

    Has the customer considered using the DRV8701 as an alternative? Assuming the 45V limit is acceptable, the DRV8701 uses external FETs with much lower RDSon. This will reduce the heat, and potentially eliminate the need for a heatsink.

    The DRV8701EVM is available for experimentation.