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Original question:

DRV8428: DRV8428 EVM : sin wave performance.

DRV8428: EVM : Sin waveform

Shunsuke Nagata
Genius 13050 points
Part Number: DRV8428

Hi,

This is requirement which is continued from e2e.ti.com/.../3583042

Customer evaluates the sin wave with changing DECAY/TOFF. It looks like the wave with 249kohm is closest to pure sin wave. But it still has flat at zero cross. Is it best performance? Or is there another idea / method to provide pure sin wave?

-> Below are waveforms when DECAY/TOFF value change

249k ohms: 

100k ohms:

44.2k ohms : 

14.7k ohms:

Hi -Z :

DVDD : 

Regards,
Nagata.

  • 0
    TI__Guru 56650 points

    Nagata-san,

    Thank you for providing more test data. I would think if the incremental current of each step is still below 1mA (the 1mA could be much smaller than the current sense circuit's resolution), the flat current at zero cross will keep there.

    Can you change the micro-stepping setting to 1/64 or 1/32, 1/16? By this test, we may find out the current sense circuit's resolution near the zero current.