| 摘要 |
PROBLEM TO BE SOLVED: To satisfactorily control a motor while an electromagnetic wave with an excessive peak at a particular frequency is not generated. SOLUTION: A CPU 31 controls a reference voltage generating circuit 41 according to the deviation of an actuator revolution of an electric motor 27 from a target revolution. A triangular wave generated by a triangular waveform generating circuit 43 is converted into a trapezoidal waveform signal limited by a reference signal Vref by a diode 42. The trapezoidal waveform signal is amplified by an amplifier circuit 45 and then supplied to a drive circuit 28 as a drive pulse. The gain of the amplifier circuit 45 is variably set as Vb/Vref according to the reference voltage Vref. With such a constitution, orthogonal angles of a rising waveform and falling waveform of the drive pulse are changed according to the value of the reference voltage Vref. |
