RESONANT FREQUENCY SEARCH FOR RESONANT ACTUATORS

The embodiments described herein relate to an improved system and algorithm for searching for a resonant frequency of a resonant actuator where the error between the drive frequency of the LRA and the resonant frequency of the LRA is large. In one embodiment, the drive frequency of a resonant actuator is set to an initial drive frequency, which is applied to the LRA. An induced voltage on the resonant actuator crosses can then be detected crossing a threshold voltage after the drive signal is turned off. If crossing the threshold voltage is not detected, the system is configured to sweep through a plurality of drive frequencies until the induced voltage on the resonant actuator is detected crossing the threshold voltage. This can be accomplished by repeatedly adjusting the drive frequency by a predefined incremental frequency ΔF and determining when the induced voltage on the LRA crosses the threshold voltage.