Actuator driver circuit with self-resonance tracking

A method of driving an actuator with a driver, comprising:

• detecting, with calibration circuitry, a phase of a voltage signal output by the driver;
• detecting, with the calibration circuitry, a phase of a current signal output by the driver;
• determining, with the calibration circuitry, a phase difference between the phase of the voltage signal and the phase of the current signal;
• adjusting, with the calibration circuitry, a frequency of an oscillating signal for the driver, based at least in part on the phase difference;
• and
• outputting, from the driver for driving the actuator, a driver signal having the adjusted frequency of the oscillating signal.

An apparatus for haptic feedback, comprising:

• means for driving an actuator;
• means for detecting a phase of a voltage signal output by the means for driving;
• means for detecting a phase of a current signal output by the means for driving;
• means for determining a phase difference between the phase of the voltage signal and the phase of the current signal;
• and
• means for adjusting a frequency of an oscillating signal for the means for driving, based at least in part on the phase difference, wherein the means for driving is configured to drive the actuator at the adjusted frequency of the oscillating signal.