CCS/DRV2625: Actuator whose resistance value decreases at resonance frequency

Thank you for reading my mail!

Resistance is  usually 100k-ohm and 10k-ohm at the resonance frequency.

Don't you see how to find the resonance frequency where the resistance value is high?

Can it be changed by setting?

I might not be completely understanding your questions.
The auto-resonance tracking drives the actuator and reads back its back-EMF to identify its resonance frequency, where the back-EMF is stronger.
If open-loop mode is used (no auto-resonance) then you can set the driving frequency through register settings, however this will not be updated during device operation as it is in open-loop mode.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

Thank you for your answer!

How does DRV2625 measure the back-EMF?

As shown in the DRV2625 documentation and block diagram, back-EMF is measured by some internal circuitry on the OUT+/OUT- pins. How this is measured is part of the device design and cannot be disclosed.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

Thank you for your answer!

The acutaor used is piezoceramic.

Therefore, back-EMF is not generated.

In this case, Can't DRV2625 know the resonance frequency?

(Piezoceramic resistor becomes the lowest at the resonace frequency )

If the device is not able to sense the back-EMF then it would most likely not be able to identify the resonance frequency.

DRV2625 is meant to be used with ERM and LRA actuators.
We have some products specifically for piezo actuators: www.ti.com/.../products.html

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators