This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8886AT: Does DRV8886AT support back EMF protection?

Part Number: DRV8886AT

Dear Expert,

As title, does DRV8886AT support back EMF protection?

I found  we have "7.3.4 Current Regulation" in datasheet which mentioned back EMF function, but we would like to double check this protection with you if we can support or not. 

Thanks!

Ben

  • Ben,

    Do you mean the VM will be raised by back EMF during decelerating and braking?
    Normally, VM should be protected by capacitors or Zener diodes.
  • Hi Wang,

    Did you have more detail information which is talking about " current regulation and back EMF"?
    Please share with us and we can pick up this knowledge. Thanks!

    Ben
  • Ben,

    In datasheet 7.3.4 Current Regulation:

    "The current through the motor windings is regulated by an adjustable, fixed-off-time PWM current-regulation

    circuit. When an H-bridge is enabled, current rises through the winding at a rate dependent on the DC voltage,

    inductance of the winding, and the magnitude of the back EMF present. When the current hits the current

    regulation threshold, the bridge enters a decay mode for a fixed 20 μs, period of time to decrease the current.

    After the off time expires, the bridge is re-enabled, starting another PWM cycle."

    I assume you question about "When an H-bridge is enabled, current rises through the winding at a rate dependent on the DC voltage,

    inductance of the winding, and the magnitude of the back EMF present."

    For an inductor, deltaV=L* deltaI/deltat.  Vvm-Vemf=deltaV. So, the timing of the winding current reaching the current limit threshould is depended on the back EMF voltage.