DRV8846: abnormal phase current

Ruixin Feng

Part Number: DRV8846

Hi team,

Customer use DRV8846 to drive stepper motor with below configuration: 1/16 Microstepping, AutoTune mode，full-scale current is 160mA；The current waveform as below. Could you pls help to analyze why in red block the current has some abnormal waveform?

Thanks!

Rayna

over 2 years ago

0 Tilden Chen over 2 years ago

TI__Expert 4886 points

Hello Rayna,

Today is a US holiday, we'll get back to you on July 5th.

0 Ryan Kehr over 2 years ago in reply to Tilden Chen

TI__Guru 54695 points

Rayna,

Can you please share a schematic if customer board? Is nFAULT going low at any time? What is the RPM of the motor? Does waveform look normal at lower speeds?

Regards,

Ryan

0 Jacob Thompson over 2 years ago

TI__Mastermind 21480 points

Hey Rayna,

That is interesting, I need a few more details in order to help with this:

Can you provide a circuit diagram or schematic? Or is it from the EVM?
Could you get a scope that that also includes a phase voltage for the motor and maybe the phase current?
It could also be useful to have the state of the nFault pin to see if the chip is sensing a fault for some reason.
What is VM?

And like Ryan said, what RPM does this occur at.

Regards,

Jacob T.

0 Jacob Thompson over 1 year ago in reply to Jacob Thompson

TI__Mastermind 21480 points

Hey Rayna, any update on this?

Cheers,

Jacob Thompson

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DRV8846: abnormal phase current