| 摘要 |
PURPOSE:To obtain a motor control circuit which can actually decelerate a motor when the rotational speed of motor is lowered by reducing the width of reference pulse. CONSTITUTION:A time difference detecting section 4 detects time difference between a sensor signal FG proportional to the rotational speed of a motor 1 and a reference clock CK. When the time difference is higher than a predetermined value, a deceleration pulse forming section 5 provides a deceleration signal to an operational amplifier 6 and to a motor drive circuit 9. When the motor 1 is decelerated and the time difference becomes smaller than the predetermined value, input signal to the operational amplifier 6 is switched to the output of a phase comparator 2 and thereby a rotational speed proportional to the reference clock can be obtained regardless of the mechanical factors such as inertia of the motor. |
