DRV8231: Output is different if the load is applied.

Hi Chase,

It could be possible the current decay method being used is not allowing enough time to dissipate from the load. It is suggested to switch between DRIVE and BRAKE (slow decay) for better efficiency. 

To switch between DRIVE and BRAKE the IN1 signal should remain high and a PWM signal should be applied to IN2. 

How are the input signals (IN1 and IN2) being applied?

For more please see Current Recirculation and Decay Modes (Rev. A).

Best,

David

Dear David,

I want to drive piezo actuator. 

I am trying to explain the state In1 and in2.  IN1 is PWM signal (PWM 50% 150Khz, 1.8V). IN2 is always in Low state.

Is it possible for Drv8231 to drive piezo actuator?  piezo actuator cap has about 4nF

Thanks,

Seungyoon

Hi Seungyoon,

By applying a PWM on IN1 and keeping IN2 at a low, you are switching between a DRIVE and COAST state. When switching this fast it is possible the current isn't decaying from the load properly. Try following the image from my last post with and apply the PWM on IN2 and hold IN1 high to switch between forward and brake (slow decay) states. 

Best,

David