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DRV8432: PWM for bidirectional?

Lam Dinh
Prodigy 20 points

Part Number: DRV8432

For Mode 4 of operation of the chip. How do I use PWM (with 100kHz frequency) to drive full bridge (out A & out B) in forward and reverse direction?

  • 0
    TI__Guru** 114905 points
    Hi Lam,

    For mode 4, 50% duty cycle as PWM_A sets the motor at stop. To achieve forward, increase the PWM_A duty cycle from 51 to 99.x%. For reverse, decrease the PWM_A duty cycle 49 to 0.x%.

    Duty cycles of 100% and 0% are not recommended. Instead it is recommended to pulse the output low for at least 50 ns per PWM cycle. Please see section 7.3.1.2 for details.

    In mode 4, one PWM signal controls one full bridge to relieve some I/O resource from MCU, that is, PWM_A
    controls half bridges A and B and PWM_C controls half bridges C and D. In this mode, the operation of half
    bridge B is complementary to half bridge A, and the operation of half bridge D is complementary to half bridge C.
    For example, when PWM_A is high, high side FET in half bridge A and low side FET in half bridge B will be on
    and low side FET in half bridge A and high side FET in half bridge B will be off. Since PWM_B and PWM_D pins
    are not used in this mode, it is recommended to connect them to ground.
  • 0 in reply to Rick Duncan
    Prodigy 20 points
    Thank you for your prompt response!