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DRV8231: DRV8231 circuit

Toby Schlank
Prodigy 10 points
Part Number: DRV8231

Hi,

We would to to use the DRV8231 to drive a brushed DC motor.

We need to be able to detect when the motor gets jammed (can't turn) so that the operator can be notified. The motor needs to cut out at about 1.7A.

The feedback from the driver passes through an opamp and is input to our microcontroller ADC. We can then take action. Our microcontroller ADC can handle 0-5V and 40mA max.

We've also added to LEDs which turn on when the motor turns on - a green LED for one direction and blue for reverse direction.

Referring to page 18 of the DRV8231 datasheet, please see attached image.

Does this look ok for our application?

Also, do we need to add a 600mOhm shunt resistor and if yes, in parallel with Rsense?

Appreciate any help.

Thanks

  • 0
    TI__Mastermind 37683 points

    Hello,

    Yes. the setup shown in the datasheet will work. Another option, if you wish to remove the opamp, is to use the DRV8231A which is the same as the DRV8231 but with a current mirror for current sensing. The analog output (IPROPI) will be within range of the ADC without the need of an external opamp. 

    This FAQ describes how to detect motor stall.

    Regards,

    Pablo Armet

  • 0 in reply to Pablo Armet
    Prodigy 10 points

    Hi Pablo,


    Thanks for your reply.

    We changed to DRV8231A. Please see attached, does it look right?

    Just to confirm, will our microcontroller's ADC conditions (0-5V input, maximum 40mA) condition still be ok with this setup?

    Thanks

  • 0 in reply to Toby Schlank
    TI__Mastermind 37683 points

    Hi Toby,

    The setup is good.

    Toby Schlank said:
    Just to confirm, will our microcontroller's ADC conditions (0-5V input, maximum 40mA) condition still be ok with this setup?

    The current from the IRROPI pin is in the µA range and the input to the ADC will be high-z so there is no risk of violating the 40mA spec of the ADC. There is also an internal clamp on IPROPI preventing it from going above 5V. If you are concern, a solution would be to all a limiting resistor between IPROPI and the ADC input.

    Regards,

    Pablo Armet