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DRV8323R: DRV8323RS

user5182768
Prodigy 100 points
Part Number: DRV8323R
Other Parts Discussed in Thread: TIDA-01629

Hi,

I have my own design with the DRV8323RS see also previous case CS0271338.

I went to change the PCB, the question is do you have on this time a driver IC with the possibility bloking de motor. (so blocking the motor when stationary so that I don't need a magnetic brake)

 So I mean an IC with the same specifications as the DRV8323RS with the additional option of electrically blocking the motor.

Thanks and regards,

Leen

  • 0
    TI__Mastermind 21805 points

    Hello Leen,

    DRV8323RS does not have the capability to brake when it is powered OFF or in sleep mode. The device is shut down.

    DRV8323RS does provide the capability to brake the motor by commanding all of the low-side MOSFETs ON:

    • In 6x PWM, by turning all INHA low and all INLA high
    • In 3x PWM, by turning all INHA low and all INLA high
    • In 1x PWM, by pulling INLC or INHA low
    • Over SPI, by setting the BRAKE bit to 1 (addr 0x02, bit 1)

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    Prodigy 100 points

    Hi Matt,

    I know you can already turn the lower high, but that's not what I mean.

    I mean depending on the position HALL sensors are not driving but blocked.

    Depending on the current through the coils, you can adjust the holding torque, I know that the current should not be too large when the motor is standing still but check whether the coils do not get too hot.

    I hope you now understand what I mean.

    I've asked this question before the development would be looked at, hence the question is that already added in a new design.

    Thanks and regards,

    Leen

     P.S. as above you have an extra advantage if you use a BLDC motor instead of a brush dc motor.

  • 0 in reply to user5182768
    TI__Mastermind 21805 points

    Hi Leen,

    What you are describing is an active servo drive for holding position, not a braking scheme. Such a system needs to implement a rotor position monitor (typically a resolver or encoder) and a torque PI loop to control the motor current (torque) to ensure that the position is held accurately. For example, this reference design shows how to do a servo drive which can electrically hold a motor position against external force: TIDA-01629

    For a more low-resolution solution, you can interpret the hall signals and direct the DRV to "align" the rotor with the known position. You would be commanding the drive state which is directly in line with the hall state rather than the one that makes the motor commutate. However, without a more precise position sensor (encoder, resolver) it would not be possible to accurately tell how much current you need to hold the rotor in place. It would need to be open loop torque drive. You could have a different torque setting if the rotor is moved to the next hall state, but that is 60 electrical degrees of resolution and so it is very coarse.

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    TI__Mastermind 21805 points

    Hello Leen,

    Do you have any further questions?

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    TI__Mastermind 21805 points

    Hi Leen,

    I'll go ahead and close this thread. If you have further questions, please click the "Ask a related question: button at the top right of the window!

    Thanks,

    Matt