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DRV10970: Absolute Maximum Ratingsfor PWM Pin

Andre Burkard
Prodigy 20 points
Part Number: DRV10970

Hallo,

the datasheet state, that the Absolute Maximum Ratings for the PWM pin is VINT + 0.3V. My problem is, that if the PWM is off, the chip enters sleep and the VINT is therefore off. At the moment this prevents me from start the chip as I use a level shifter supplied by VINT.

In more details:

The DRV10970 is controlled by a microcontroller which reads the hall sensors, calculates a closed-loop controller and outputs a PWM signal. The DRV10970 has an power supply independent from the MCU.

Problem 1: I guess, that I can apply up a 3.3V signal to the PWM pin, even if VINT is down, is this correct?

Problem 2: The power supply of the DRV10970 can be absent while the MCU has power. From the Datasheet I understand, that I can apply the Hall sensor voltage even is the DRV10970 power (VCP) is down.

Problem 3: Can I apply a PWM signal if the DRV10970 power (VCP) is down? Has the PWM input clamp diodes an do I need to limit the input current in this case?

Thanks for your advice.

  • 0
    TI__Mastermind 23662 points

    Hi Andre Burkard,

    I will reply to you early next week.

    Thanks and Best Regards,

    Venkatadri S

  • +1 in reply to Venkatadri Shantaram84961
    TI__Mastermind 23662 points

    Hi Andre Burkard,

    I am yet to update on this, I am checking about the IO structure if it is inverter type (internally) then we can apply high on the pin without powering the DRV.

    If we don't see any current drawn from the PWM then, that pin is fine to power without powering the DRV.

    I will clarify next week on this.

    Thanks and Best Regards,

    Venkatadri S

  • 0 in reply to Venkatadri Shantaram84961
    TI__Mastermind 23662 points

    Hi Andre Burkard,

    Problem 1: I guess, that I can apply up a 3.3V signal to the PWM pin, even if VINT is down, is this correct?

    Yes, PWM pin wakes up device. VINT rises when PWM is applied to wake the device from sleep mode.

    Problem 2: The power supply of the DRV10970 can be absent while the MCU has power. From the Datasheet I understand, that I can apply the Hall sensor voltage even is the DRV10970 power (VCP) is down.

    Yes, HALL can be pulled from external supply when DRV10970 is powered down

    Problem 3: Can I apply a PWM signal if the DRV10970 power (VCP) is down? Has the PWM input clamp diodes an do I need to limit the input current in this case?

    Yes, PWM pin wakes up device. VINT rises when PWM is applied to wake the device from sleep mode.

    Thanks and Best Regards,

    Venkatadri S