Ultrasonic motor and control circuitry thereof

摘要

An ultrasonic motor has a piezoelectric element, a driver circuit for creating an excitation signal based on information about the excitation of the piezoelectric element, and a power supply for supplying a voltage to the driver circuit. This motor includes a voltage-adjusting circuit for adjusting the voltage supplied from the power supply to the driver circuit. The motor further includes a voltage comparison means for comparing the voltage detected by the voltage-detecting means with data about a preset voltage of the power supply and a circuit constant control means for controlling the voltage-adjusting circuit to optimize the voltage supplied to the driver circuit, for example, if the comparison made by the voltage-comparing means indicates that the detected voltage is not coincident with the data about the voltage of the power supply.