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DRV8881: microstepping methods, DAC on Vref or PWM as TIDA-00641?

Part Number: DRV8881

Hi all, 

Could you please give me some comments or tips about the microstepping methods, DAC on Vref or PWM as TIDA-00641?

In my case, the IC would be using is the drv8881P which has the Vref range from 0.3V ~ 3V, I believe the range should be sufficient for the microstepping, by the may, the c2000 has a 12bit build in DAC, in this case, will be DAC to Vref method a better choice?

is there a performance difference between DAC to Vref and PWM method?

what will be the analog bandwidth of Vref input usually, If we use the DAC to Vref to regulate the current?  I did not found any parameters for this in datasheets. 

  • Hai,

    PWM needs a filter to get a DC value. The filter time constant limits the microstepping current changing rate.

    I think the current change bandwidth is limited by the motor inductance. The VREF is analog circuit and he bandwidth should be quicker than DAC bandwidth.