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DRV8718-Q1: DRVOFF pin function

Shawn_Wang
Expert 3811 points
Part Number: DRV8718-Q1

Hi team

My customer is designing the DRV8718 circuit and wants to know when and under what condition to control the DRVOFF pin to shut down the output drivers? 

Thank you in advance.

  • 0
    TI__Expert 3811 points

    Hi team

    Could you also give more explanation on the function of the BRAKE pin? My customer is using DRV8718 to control the motor for the car door, and they want to know if the powered off braking feature is enabled, is okay to close the door?

    "Enabling the external low-side MOSFETs allows the device to actively brake a motor connected to the external half-bridges by shorting the back emf across the motor terminals. This can help prevent reverse driving of the motor by an external force from overcharging the system power supply by dissipating the energy in the low-side MOSFETs."

    It seems that this feature would brake the motor and hence the customer raise this question.

  • 0 in reply to Shawn_Wang
    TI__Guru 54795 points

    Shawn,

    DRVOFF is exactly that...it turns off the drivers (HIZ the outputs) while the rest of the driver stays enabled.  So, it can be used to quickly turn off and on the output drivers under different cases.

    Powered off braking can be used for the door closing application.  It is meant to control BEMF when the motor is operated by and external force...like a person closing the door manually.  

    https://www.ti.com/lit/an/slla527a/slla527a.pdf

    Regards,

    Ryan