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Original question:

DRV8428: Motor oscillation

DRV8428: DRV8428 EVM : sin wave performance.

Shunsuke Nagata
Genius 12240 points
Part Number: DRV8428

Hi,

My customer evaluates DRV8428 EVM. Unfortunately, the motor current wave form doesn't be pure sin wave as below: 
It looks like the flat is shown at zero cross point.

And Below is GUI setting:

Could you please give me advice how to set GUI to set pure sin wave in motor current?
Below are motor condition
- Terminal resistance : 6.2 ohm
-  Motor voltage : 6V

Regards,
Nagata.

  • 0
    TI__Guru 56650 points

    Shunsuke,

    With 1/256 uStep setting and 0.6V VREF (0.2A full scale current), each step current resolution is less than 1mA.

    1. Please check zero crossing region, does the output have the PWM signal? Does the internal FETs switch?

    2. Right now, Decay/TOFF is low. Can we change the Decay mode setting to Dynamic decay or Mixed decay?

  • 0 in reply to Wang5577
    TI__Guru 56650 points

    Nagata-san,

    Let me close this thread since we don't have an update in a week. You can reopen it by post your new inputs.