Patent ID: 7895894

Claim:
A driver device that forms an oscillation loop with a vibrator and causes the vibrator to produce driving vibrations, the driver device comprising: a gain control amplifier that causes the vibrator to produce the driving vibrations by controlling an oscillation amplitude in the oscillation loop; a signal generation circuit that generates a signal having a given frequency in the oscillation startup state, and stops the signal generation in the steady oscillation state; and a modulation circuit that modulates the frequency of the signal generated by the signal generation circuit to a resonance frequency of the vibrator, the modulation circuit including a switch provided in the oscillation loop, the itch being turned ON/OFF based on the signal venerated by the signal generation circuit, a mixed signal having the same frequency as the ON/OFF frequency of the switch is generated in the oscillation loop, a signal component that is contained in the mixed signal and has a frequency that coincides with the resonance frequency of the vibrator is output from the vibrator, and the gain control amplifier amplifies the signal component output from the vibrator, the modulation circuit modulates the mixed signal using an output signal from the gain control amplifier, the driver device causing the vibrator to produce the driving vibrations using the signal modulated by the modulation circuit in the oscillation startup state, and then causing the vibrator to produce the driving vibrations by controlling the oscillation amplitude in the oscillation loop formed by the vibrator, the gain control amplifier and the switch being turned on in the steady oscillation state.