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Is there a way to implement a DC motor driver with the DR8701E as a PWM?

Electrical Guy

Hello,

In my company, I inherited a project using the DR8701E driving a DC motor with a simple motor ON and motor OFF function. We finally need to control the torque and speed of the motor therefore the system needs a PWM function. The DR8701P (which has the PWM function) would have been better to use but several of our products are already using the DR8701E. At that point, we don't want to change the hardware but only the software to update easily these products.


Do you think we can use the DR8701E with a PWM function by monitoring the EN and PH inputs as it was IN1 and IN2 of the DR8701P?

Or is there a way to use the DR8701E as a PWM motor driver?

I am pretty sure that it won't work as DR8701E and P don't have the same input control but I would need some confirmation.

Thank you.

  • 0
    TI__Guru** 114905 points
    Hi Electrical Guy,

    Welcome to the forum.

    Assuming you use brake mode when PWM'ing, the DRV8701E can be PWM'ed. The PWM function should be placed on the EN pin, and switches between forward/reverse and brake (slow decay).
  • 0 in reply to Rick Duncan

    Hi Rick,

    i will definitely test that!

    So what is the difference between the DR8701E and P if they can both do the same?

    Thank you!

  • 0 in reply to Electrical Guy
    TI__Guru** 114905 points

    Hi Electrical Guy,

    The DRV8701P has the ability to select either coast or brake mode when PWM'ing. Many motors uses brake mode to minimize current ripple. Some use coast mode, but this increases the current ripple.

    One benefit of using coast mode is the ability to measure the motor speed through the back emf. This is not available in brake mode.

    Please note the difference in Table 1 and Table 2 of the datasheet.