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DRV8424: ISOLATION FOR DRV8424

Guru Hegde
Prodigy 60 points
Part Number: DRV8424

Hello Team,

We are using DRV8424PWPR part in our design. We have two GNDs in our system. One is power GND and the other is digital GND. We have used the power GND for all the high current applications. We want to isolate the Power GND from digital GND in DRV8424PWPR. The main reason for the two GNDs is to isolate the noise from the motor. Could you please suggest how we can implement the isolation between the power GND and the digital GND in DRV8424PWPR? If we want to use two different GNDs, where should we connect the PAD of DRV8424PWPR. Please suggest your inputs. Also attached the PDF of the schematics.MOTOR_DRIVER TI.pdf

  • 0
    TI__Mastermind 37683 points

    Hello Guru,

    Thank for your question. We'll get back to you with a reply shortly.

    Regards,

    Pablo Armet

  • 0
    Genius 5040 points
    Guru Hegde said:
    The main reason for the two GNDs is to isolate the noise from the motor.

    Isolate the noise from the motor to what? For the DRV8424 chip, GND and PGND pins should be connected to the Thermal Pad GND. So the DRV chip should only have one common ground which to be connected to the system ground at the star point, where other system ground (analog system or other MCU system)  all connected together at this single star point.

    No good reason to divide the GND and PGND into 2 sections at the DRV chip.

    Brian

  • 0 in reply to Brian Dang
    TI__Mastermind 37683 points

    Hello Guru,

    As Brian explained, it is better to have a common GND as opposed to split GND at the driver. Generally split GND is used when you wish to redirect high noise from sensitive components on your board. An example might be splitting your digital GND with Power GND to prevent damage to the digital components.

    Regards,

    Pablo Armet