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DRV8880: DRV8880

Karthik N V1
Prodigy 80 points
Part Number: DRV8880

Hi Team,

In the datasheet of DRV8880 for determining the step frequency following equation highlighted in the attachment below is given.

It is mentioned that at high speed motor will not spin, so need a clarification on this.

And also is there any relation with Full scale current of winding of stepper motor to find the Step frequency at higher RPM of motor?

And if there is a relation between Step Frequency and Full Scale Current of Stepper, kindly suggest for the same.

Warm Regards,

Karthik 

  • 0
    TI__Guru 56650 points

    Karthik,

    No simple equation to link IFS to step rate due to the motor winding's back EMF.

    Motor winding is an inductor with the back EMF.  The back EMF is related to the motor speed and motor design. The inductor's inductance and resistance are related to the motor design.

    When the high side FET is on to push the winding current goes higher, the winding current di/dt= (VM-Vbemf-I*R)/L. If assume the winding current is sine waveform, VM needs higher enough to overcome the Vbemf to support di/dt and reach IFS setting.