Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

  • State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 29 subscribers
  • Views 2391 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

DRV8703-Q1: active freewheeling

TI Joern
Prodigy 575 points
Part Number: DRV8703-Q1

Hello Team,

checking the DRV8703-Q1 does not show up any information about active freewheeling. Does this device support that feature?

I guess that this can only be implemented by using the independent PWM Control Interface (MODE = 1).

Are there any app notes regarding this topic available?

Best Regards

Joern

  • 0
    TI__Guru** 114905 points
    Hi Joern,

    Can you provide a diagram of the desired operation?
  • 0 in reply to Rick Duncan
    TI__Prodigy 575 points

    Hi Rick,

    Using PWM as control method, freewheeling is needed in my opinion needed during off time to pass the current through lowside mosfet that the magnetic field is reduced. The idea is to activate the fet to reduce the losses instead of using the body diode. I found here an example, but talking about BLDC only:

    Best Regards

    Joern

  • 0 in reply to TI Joern
    TI__Guru** 114905 points
    Hi Joern,

    Thanks for the clarification. The DRV8703-Q1 has two methods to recirculate current through the low side FETs for active freewheeling.

    1) Current Regulation can be automatically controlled by setting VREF and Rsense. Once the current trip point is reached the current is automatically recirculated through the low side FETs for a toff time set by the TOFF bits. See section 8.3.4 of the datasheet.

    2) Current Regulation can be manually controlled by using the SO output to change from Drive (forward or reverse) to Slow decay. The control inputs differ between PH/EN control and PWM control. For PH/EN control, the IN2/EN signal is PWM'ed. For PWM control, either IN1/PH or IN2/EN is PWM'ed depending on direction.