| 摘要 |
PROBLEM TO BE SOLVED: To increase detection accuracy by a rotation detecting means to make a correct rotation of a motor by reducing the current generated through power generation to reduce electromagnetic noise at least, while the rotation of the motor is detected by the rotation detecting means. SOLUTION: A resistance value switching circuit 101 is connected between a rectifying circuit 47 and a high capacity secondary power supply (large capacitance capacitor 48). The resistance value switching circuit 101 is controlled by a control signal SH output from a time counting control circuit 102. While a pulse for detecting the rotation is detected by a rotation detector circuit 106, the resistance value of a charging line is increased by the resistance value switching circuit 101 so as to reduce the charge current, and thereby to reduce electromagnetic noise generated by a power generation section A and reduce the noise overlaid on the pulse for detecting rotation. |
