DRV8825: Recommended circuits for EMC

Cherry Zhou

Part Number: DRV8825

Hi Team,

Using the circuit diagram in the DRV8825 specification sheet, the motor can run with radiation causing the FCC to fail. With the other conditions unchanged, the FCC can be passed by unplugging the motor cable.

Would it be possible to share some recommended EMC circuits and improvements?

Working voltage is 12V, 32 microsteps, IFS = 1A, decay mode, mixed decay.

Could you please help check this case? Thanks.

Best Regards,

Cherry

over 2 years ago

0 Pablo Armet over 2 years ago

TI__Mastermind 37683 points

Hi Cherry,

Most of the RF noise is in the lower frequency band. This is caused mainly by the PWM switching at the output side. That's why disconnecting the motor completely eliminates the EMI noise.

My recommendation is to make sure all critical high di/dt loops are minimized on your PCB. The bigger loops behave as antennas and radiated the noise.

Another suggestion is adding a differential filter (PI filter or multi-stage LC low pass filters) by the power input.

This document provides useful guidelines for minimizing EMC. If needed, I can review the schematic or layout and provide feedback.

Regards,

Pablo

0 Cherry Zhou over 2 years ago in reply to Pablo Armet

TI__Mastermind 22235 points

Hi Pablo,

Thank you for the support.

Pablo Armet said:
This document provides useful guidelines for minimizing EMC.

Could you help share this document?

Thanks and regards,

Cherry

+1 Pablo Armet over 2 years ago in reply to Cherry Zhou

TI__Mastermind 37683 points

Cherry,

https://www.ti.com/lit/ml/slyp697/

-Pablp

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DRV8825: Recommended circuits for EMC