Patent ID: 7368850
Filing Date: 2008-05-06
Classification: H02N

Abstract:
1. A resonance control apparatus that drives a resonant device having a resonance characteristic, the resonant device functioning as a resonant sensor, the apparatus comprising: a reference signal generating section that generates a reference signal having a predetermined frequency in response to a voltage signal that is inputted into the reference signal generating section; a divider that divides the predetermined frequency of the reference signal generated by the reference signal generating section to output a signal having a given frequency; a phase reference forming section that delays a phase of the signal outputted from the divider for a predetermined interval; a voltage comparator that compares a voltage of the output signal from the resonant sensor with a predetermined voltage, the resonant sensor detecting the driving state of the resonant device in synchronization with the driving of the resonant device; a phase comparator that compares the phase of the signal outputted from the voltage comparator with the phase of the signal outputted from the phase reference forming section, and a duty control section that controls a duty ratio of the drive signal provided for the resonant device based on the reference signal outputted from the reference signal generating section, the duty control section being constructed to control the duty ratio of the drive signal substantially linearly in the range of either 10%-50% or 50%-90%.