DRV8871: DRV8871 overshoot/undershoot

Ian Wang

Mastermind 29690 points

Part Number: DRV8871

Hi Sir,

DRV8871 EVM o/p current as below,

We measure current as below,

CH1:IN1

CH2:IN2

CH3: Motor o/p current

It looks some overshoot/undershoot on it, is make sense?

How to reduce these overshoot/undershoot?

Thanks Ian.

over 4 years ago

0 Pablo Armet over 4 years ago

TI__Mastermind 37683 points

Hi Ian,

Thank you for posting to the Motor Drives forum.

A common way to suppress against these spikes is to add a varistor or TVS diode across the outputs to suppress the high output voltage spikes.

0 Ian Wang over 4 years ago in reply to Pablo Armet

TI__Mastermind 29690 points

Hi Sir,

Pls advise where put TVS and what spec. is?

Thanks, Ian.

0 Pablo Armet over 4 years ago in reply to Ian Wang

TI__Mastermind 37683 points

Ian,

Looking at the current waveforms a bit closer, I think the spikes can be an artifact of the current probe used to measure the current. The current through an inductive load shouldn't change so suddenly as shown in the waveforms. Can you try measuring the output voltage at the terminal where the current probe is measuring the current. If there are no voltage spikes in the voltage, it can suggest that the current spikes are the artifact of the current probe.

0 Pablo Armet over 4 years ago in reply to Pablo Armet

TI__Mastermind 37683 points

Hi Ian,

We haven't heard back from you. We assume you resolved your issue and we will close this thread. I will close the thread for now but feel free to reply if you need further support. If the thread is locked, please ask a related question.

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DRV8871: DRV8871 overshoot/undershoot