Abstract: A driving device for an oscillatory actuator in which a FLL (Frequency Locked Loop) is employed for detecting an electromotive force generated in a driving coil resulting from mechanical oscillation during a period in which no driving current is supplied to the oscillatory actuator, and for controlling an oscillation frequency on the basis of a relative time ratio between positive and negative polarities of the electromotive force to thereby pull a driving frequency into a neighborhood of a self-resonance frequency of the oscillatory actuator.
Type:
Grant
Filed:
November 13, 2002
Date of Patent:
October 26, 2004
Assignees:
Teikoku Tsushin Kogyo Co., Ltd., AC Technologies Co., Ltd.