I am using DRV2667 to drive a disk piezo actuator with maximum of +- 100 V output range. We have another separate PCB with gyro, MCU and some other driver sitting on top of this piezo actuator. Of course the PCB and piezo actuator are insulated.
problem observed : when I drive the piezo actuator with a constant voltage(say 50V), I noticed my actuator is buzzing with high frequency(not the sound caused by the switching of the driver) and my gyro on the PCB is drifting a lot even through the platform is not rotating. This problem always exists no matter whether I am using the evaluation kit or my PCB board(with DRV2667 on it) to drive the piezo actuator. However, if I use the DC power supply equipment in our lab to direct drive it with same voltage, the buzzing and drift of gyro disappears.
Possible cause: I used oscilloscope to compare the voltage generated by the driver and our DC supply equipment and noticed the voltage generated by the driver has a large high frequency noise. And this noise level increases with the output voltage. Seems it has a frequency around 2.5 KHz which may corresponding to switching frequency. The noise of our DC supply equipment is significantly smaller. Thus we think the buzzing is caused by ripping in the output voltage and the gyro drift is due to the electromagnetic interference caused by the noise.
Questions: I am wondering if you have any suggestion about reducing the ripping in output voltage, such as changing inductor/capacitor values, adding filtering in the output voltage. What's the PWM switch frequency of the boost converter? Any suggestion about reducing the electromagnetic interference of this chip?
I also attached the schematic of our own driver board as a reference. Let me know if you need more information. Really appreciated. Thank you very much.