| 摘要 |
PURPOSE: To quickly bring about a state rotating stably at a set speed by reducing the response lag as much as possible at the time of starting a motor even in the case of a constitution where a time constant circuit is connected between the I/O terminals of an operational amplifier circuit. CONSTITUTION: A motor 11 is driven through a drive circuit 12. Rotational speed of the motor 11 is detected through a rotary encoder 14 and delivered to an F/V converter 15. The F/V converter 15 delivers a voltage signal, corresponding to the rotational speed, to an operational amplifier 13 through a resistor 16. The operational amplifier 13 compares the input voltage with a reference voltage Vref and outputs a differential signal. A time constant circuit 20 comprising a capacitor 18 and a resistor 19 is connected between the I/O terminals of the operational amplifier 13 and made effective by means of an analog switch 21. Since the analog switch 21 is turned OFF by a motor ON signal Son, the capacitor 18 is discharged during the OFF interval and the motor 11 is controlled quickly to rotate stably at a set speed. |
