Driving device for ultrasonic wave motor
AssigneeNikon Corporation
InventorRyoichi Suganuma
Life of this patent
Estimating the term…
Abstract
A driving device for an ultrasonic wave motor has a limit detecting circuit for that the drive voltage for the ultrasonic wave motor has reached a limit, and, in response, a drive voltage limiting circuit controls the drive voltage so as not to go beyond the limit value. Such control is conducted on the voltage or frequency of a signal for driving the ultrasonic wave motor. In another aspect of the invention, a drive state detecting circuit detects the drive state of the ultrasonic wave motor, and a drive frequency (or voltage) setting circuit controls the frequency (or voltage) of a signal for driving the ultrasonic wave motor so as to attain the maximum efficiency in the motor, based on the output of the drive state detecting circuit.
Claims4
A device for driving an ultrasonic wave motor, comprising:
- a drive frequency setting circuit for setting the frequency of a drive signal for said ultrasonic wave motor, said drive frequency setting circuit having a reference signal generating circuit for generating a reference signal corresponding to a frequency maximizing the torque at the starting of said motor;
- a phase shifting circuit for generating cyclic signals with a mutual phase difference, based on the output of said drive frequency setting circuit;
- a drive voltage setting circuit for transforming said cyclic signals from said phase shifting circuit into voltages for driving said ultrasonic wave motor;
- and
- a drive state detecting circuit for detecting the drive state of said ultrasonic wave motor and producing a drive state detecting signal on the basis of the detected drive state, said drive frequency setting circuit setting the drive signal frequency at a frequency corresponding to said reference signal on the basis of said reference signal and said drive state detecting signal.
A device for driving an ultrasonic wave motor, comprising:
- a drive frequency setting circuit for setting the frequency of a drive signal for said ultrasonic wave motor;
- a phase shifting circuit for generating cyclic signals with a mutual phase difference, based on the output of said drive frequency setting circuit;
- a drive voltage setting circuit for transforming said cyclic signals from said phase shifting circuit into voltages for driving said ultrasonic wave motor, said drive voltage setting circuit having a reference signal generating circuit for generating a reference signal corresponding to a voltage magnitude maximizing the torque at the starting of said motor;
- and
- a drive state detecting circuit for detecting the drive state of said ultrasonic wave motor and producing a drive state detecting signal on the basis of the detected drive state, said drive voltage setting circuit setting the drive voltage at a voltage magnitude corresponding to said reference signal on the basis of said reference signal and said drive state detecting signal.
Dependencies are inferred from the claim text.