DRIVING CIRCUIT DEVICE OF ULTRASONIC MOTOR

PROBLEM TO BE SOLVED: To solve the problem of a secondary side voltage fluctuation due to a pulse width and ET product of a primary side high frequency input voltage which cannot be controlled by a primary side control circuit in a driving circuit device of an ultrasonic motor.SOLUTION: The driving circuit device of an ultrasonic motor includes an oscillating circuit which generates a signal having a reference frequency exciting a piezoelectric vibrator, a driving signal generating circuit which modulates a pulse width by the signal having the reference frequency and a detection signal, a driver circuit, a switching circuit, and a leakage transformer which power-amplifies a primary side controlled input voltage. A resonance circuit is composed, on the secondary side, of a leakage inductor Lk and a damping capacitance Co of the piezoelectric vibrator to form a driving voltage output circuit which excites the piezoelectric vibrator.