Circuits and methods for driving resonant actuators

摘要

The present disclosure includes circuits and methods for driving resonant actuators. In one embodiment, a drive signal is applied to an actuator during a portion of a plurality of half cycles of a period of the drive signal. The actuator has a resonant frequency and may vibrate in response to the drive signal. An induced voltage is generated on terminals of the actuator in response to the vibration. A detection circuit may detect when the induced voltage on the actuator crosses a threshold after the drive signal is turned off. The drive signal may be triggered based on when the induced voltage crosses the threshold to align a frequency and phase of the drive signal with the resonant frequency and a phase of the actuator.

主权项

1. A method comprising:
applying a drive signal to an actuator during at least a portion of a plurality of half cycles of a period of the drive signal, wherein the actuator has a resonant frequency; detecting when an induced voltage on the actuator crosses a threshold after the drive signal is turned off; triggering a drive clock signal in a clock generator circuit in response to the detecting; and triggering the drive signal in response to the drive clock signal to align a frequency and phase of the drive signal with the resonant frequency and a phase of the actuator, wherein a positive polarity drive signal is triggered by the drive clock signal a fixed time after a rising edge of the drive clock signal and a negative polarity drive signal is triggered by the drive clock signal a fixed time after a falling edge of the drive clock signal.