| 摘要 |
PURPOSE:To provide a small-sized and low-cost ultrasonic motor diving circuit which produces enough mechanical output, without abnormal state occurring even when the power source voltage has changed largely. CONSTITUTION:An ultrasonic motor driving circuit, which drives an ultrasonic motor 10 where a piezoelectric element is arranged by applying AC signals being generated by switching inductive elements, using a DC power source 10 where the voltage changes within a predetermined range, is equipped with a DC voltage detecting circuit, which detects the voltage of the DC power source 7, and a memory 2, which has stored the pulse width of the switching pulses corresponding to this power source voltage. And, it possess a pulse width setting circuit 4, which sets the width of the switching pulses, a monitor means, which detects the drive condition of the ultrasonic motor 10, and a frequency control means 1, which controls the frequency of AC signals, based on the output of this monitor means. |
