DRV8256: PWM control

Shuhei Goto

Part Number: DRV8256

Tool/software:

Hi team,

I have questions regarding DRV8256 as follows:
1. For PWM control, is it mandatory to use IN1/IN2 pins instead of EN/PH pins?
Would it not work properly if PWM is applied to the EN pin and direction is controlled by the PH pin?
2. If this is not supported, is there any plan in the roadmap to release devices that allow PWM control with EN/PH pins?
3. If it does work, when driving with EN/PH control, we believe the behavior may differ depending on the rotation direction — i.e., PWM drive may insert brake in one direction and open in the other.
Do we have any plan to release devices where the drive behavior is consistent regardless of rotation direction when using EN/PH control?

Best regards,
Goto

2 days ago

0 David Medis 2 days ago

TI__Mastermind 19860 points

Hi Goto-san,

The DRV8256 has two variants, the DRV8256E supports a PH/EN control interface and DRV8256P supports a PWM control interface. Pins 24 and 25 are both used as the inputs for either device.

If using the DRV8256E, a PWM signal on EN pin is fine. When EN is high the output voltage on OUT1 would be high and when EN is low both outputs go to a Hi-Z state while current is recirculated during a decay period. The current decay method is set by using the DECAY pin 21.

If using the DRV8256P, a PWM signal can be used on IN1 or IN2 to select either a high-side or low-side slow decay during current recirculation. The PWM interface on DRV8256P allows for more flexibility in terms of current recirculation and control.

(+) [FAQ] What interface (PH-EN or PWM) to use for controlling brushed DC motors - Motor drivers forum - Motor drivers - TI E2E support forums

Best,

David