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DRV8251A: Snubber circuits with the DRV8251A

Karen Leonard
Prodigy 45 points
Part Number: DRV8251A
Other Parts Discussed in Thread: DRV8251EVM

Hello, I'm planning to use the DRV8251A to drive a BDC motor, replacing the DRV8432. On the previous version of the schematic (not my design)

it shows snubber circuits, with a note "No snubber or Schottky diode is required, but TI recommended to add it for our application". I was able to

use the DRV8251A eval board to drive the motor both forward and reverse. I see nothing in the DRV8251A datasheet about using snubbers,

and I had the impression from the datasheet that the current regulation feature and/or ramping the PWM input signal would alleviate high

current conditions due to inrush or stalls. 

Does TI recommend anything like a snubber with the newer devices?

Thanks very much,

Karen

  • +1
    TI__Mastermind 20580 points

    Hi Karen,

    No, the use of additional snubber circuits or Schottky diodes are "required" with use of our motor drivers. It is difficult to say without seeing the design, but it could have been recommended for many different reasons (reduction of EMI, help eliminate ringing during switching, etc.).

    Yes, the current regulation feature does the limit inrush and stall currents but will not prevent them completely. Separate internal circuitry (overcurrent protection, OCP) protects the device from inrush and stall currents that last long enough to damage the device. A blanking time is added in order to not trigger OCP during inrush current conditions. The OCP threshold should be set higher than the ITRIP threshold to protect against any high current transients or shorts.

    No snubber circuits or Schottky diodes are used in the DRV8251EVM.

    Best,

    David