DRV8871EVM: Noisy negative cycle

Vincent Lynch

Part Number: DRV8871EVM

Hello,

I am trying to get the DRV8871EVM to work in my application. I am pulsing IN1 200us followed by IN2 200us from a 3.3V MCU. VM is set to 15V. I am using a scope across a load connected to OUT1 and OUT2. I am having clean positive cycle but during negative cycle, it is quite noisy. Can you advise please?

Below is the waveform from the scope:

Thank you.

over 2 years ago

0 Pablo Armet over 2 years ago

TI__Mastermind 37683 points

Hi Vincent,

Can you clarify how you are connecting the MCU to the EVM? I'm assumming you are using an external MCU for the IN1 and IN2 signals?

Regards,

Pablo Armet

0 Vincent Lynch over 2 years ago in reply to Pablo Armet

Intellectual 290 points

Hi Pablo,

Yes, we use an external MCU which has 2 outputs going into IN1 and IN2. The MCU GND is also connected to the GND of the EVM

0 Pablo Armet over 2 years ago in reply to Vincent Lynch

TI__Mastermind 37683 points

Vincent,

Thanks for the clarification. Are you connecting the IN1 and IN2 from the MCU to pin 2 of J5 and J6? Did you also removed the jumper between pin 2 of J5 and J6? same with J3 and J4?

Regards,

Pablo Armet

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

TI__Mastermind 37683 points

Hi Vincent,

Any updates? Has the issue been resolved?

I will close this thread if no help is needed but you can reply if further support is required.

Regards,

Pablo Armet

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DRV8871EVM: Noisy negative cycle