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DRV8833: About the output terminal of DRV8833

Goto Satoru
Prodigy 60 points
Part Number: DRV8833

Hello.

Could you ask us a question about the Motor Driver IC (DRV8833)?

As we evaluate the motor driver IC, the connection terminals with the motor (AOUT and / AOUT2) are applied to the back electromotive power by about -1V when the motor is stopped.

So, could you tell us about the following two points?

1.Is the reverse electromotive power suppressed to -1.0V because the protection function etc. are working inside the motor driver IC?

2.How many V does the connection terminals with the motor (AOUT1 and AOUT2) withstand back electromotive power up to V?

Above, thank you.

  • 0
    TI__Mastermind 37683 points

    Hi Gotou Satoru,

    Goto Satoru said:
    As we evaluate the motor driver IC, the connection terminals with the motor (AOUT and / AOUT2) are applied to the back electromotive power by about -1V when the motor is stopped.

    I'm assuming you are forcing the motor to behave as a generator (driver outputs are HIGH-Z). If so, then the current path will look like (2) in the image below. However, since the FETs are disabled, the current will flow through the body diodes up to VM. There will be a plus and minus Vd (internal diode forward voltage) added to the output voltage. I think the -1V you are measuring is this diode forward diode.

    Please correct me if my understanding is not correct.

    Goto Satoru said:
    How many V does the connection terminals with the motor (AOUT1 and AOUT2) withstand back electromotive power up to V?

    The recommended voltage rating for both OUTx terminals is -Vd (min) to VM+Vd(max); where Vd is the FET body diode forward bias.

    Let me know if you need further assistance.

  • 0 in reply to Pablo Armet
    Prodigy 60 points

    Thank you for answering.

     

    Let me ask you an additional two question.

    ・What is the voltage range of Vd (forward bias of FET body diode)?

    ・Is the role of this diode to release the back EMF? If not, please tell me the original role.

    I checked it in the data sheet, but I don't know, so please let me know.

    Thank you.

  • 0 in reply to Goto Satoru
    TI__Mastermind 37683 points

    Goto,

    The Vd is around 1V typical but there is some variation due to external factors such as temperature, etc.

    The role of the body diodes is to provide a current path when the H-bridge is in coast mode (all FETs High-Z).