| 摘要 |
PROBLEM TO BE SOLVED: To perform effective rotary control by accurately detecting rotary speed and speed for each rotary direction of a brush-type DC motor with a configuration that is simple and does not occupy any space. SOLUTION: A DC motor 13 is provided with brushes BD2a and BD2b for detecting rotation. In a rotary detection signal that is obtained by them, noise is eliminated, and one corresponding to a rotary detection signal selection signal is selected and is given to a comparator 14. The comparator 14 compares a rotary detection signal with a comparison reference signal, and outputs a pulse train with a pulse period and pulse width corresponding to the rotary speed. A pulse interval measurement means 151 of a motor control circuit 15 measures the pulse interval of the output pulse of the comparator 14 and gives it to a rotary speed calculation means 152, and calculates the rotary speed of the motor based on the pulse interval. A speed-voltage conversion means 153 supplies a drive voltage for setting to a target rotary speed to an output variable power supply circuit 11 based on a rotary speed that is calculated by the rotary speed calculation means 152 and the target rotary speed.
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