DRV8711: Stepper Motor Driving - DRV8711 Direct PWM Method

sivasuryan.R

Part Number: DRV8711
Other Parts Discussed in Thread: DRV8842

We are going to control Stepper Motor using Direct PWM method in DRV8711. So, we need to set different current values in each coil. In datasheet, there is given single Torque register. How can I set different current (90 Deg phase shift) in both coils?

Regards

R.Sivasuryan

over 6 years ago

0 sivasuryan.R over 6 years ago

Intellectual 610 points

0 Rick Duncan over 6 years ago in reply to sivasuryan.R

TI__Guru** 114905 points

Hi R.Sivasuryan,

The device was intended to have the same full scale current in both coils.

If you want to adjust the current separately in the coils, there are two methods. Please note these may not be practical for your application.
1) Change the sense resistor as required
2) Switch to PWM mode, add an external current sense amplifier and control the current using the PWM inputs.

Other options include using a different device (s)
One DRV8881E has two VREF that allow you to control the current in the coils
Two DRV8842 have higher full scale current

0 sivasuryan.R over 6 years ago in reply to Rick Duncan

Intellectual 610 points

Hi Rick

In the functional block diagram, it is showing there are two Torque DACs. Can you let me know the number of Torque DAC in DRV8711 in PWM input mode for driving stepper motor.

Thanks and regards,

R.Sivasuryan

0 Rick Duncan over 6 years ago in reply to sivasuryan.R

TI__Guru** 114905 points

Hi R.Sivasuryan,

There are two Torque DACs as shown. Both are controlled using the TORQUE register.

In both stepper and PWM mode, the full scale current setting is the same in both windings. You can further control the current by using the two previous methods suggested.

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DRV8711: Stepper Motor Driving - DRV8711 Direct PWM Method