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DRV8718-Q1: PWM frequency& duty cycle accuracy through HBx_CTRL SPI control register

Part Number: DRV8718-Q1

Dear expert,

What is accuracy of PWM frequency& duty cycle if with HBx_CTRL SPI control register?

  • Hi,

    DRV8718 has Direct PWM mode which is set by HBxCTRL. However DRV8718-Q1 does not have PWM generator, PWM signal should be provided by externally. Therefore, DRV8718-Q1 does not have the accuracy for frequency and duty cycle.

    regards

    Shinya Morita

  • Shinya,

    If DRV8718 doesn't have internal PWM generator, how to understand below comment? Thanks

    "The DRV8718-Q1 PWM inputs pins (IN1, IN2. IN3, IN4) can be used to set the PWM frequency and duty
    cycle for the assigned outputs. If higher frequency or precise duty cycle PWM control is not required, the eight
    half-bridge gate drivers can also be controlled directly through the HBx_CTRL SPI control register."

  • Hi Ryan,

    Your are referring 8.3.3.1.1 DRV8718-Q1 Half bridge control. This sentence means customer can control output via HBxCTRL SPI register. MCU can send 01b to driver Low and send 10b to drive High. So MCU keep sending these command continuously to make PWM. As a result MCU can control DRV to have PWM output, however it could be slower and not accurate frequency and duty cycle. 

    regards

    Shinya Morita

  • Shinya,

    Great thanks.