Motor control circuit

Claim 1

A motor control circuit for causing a motor to have a reduced stopping time comprising: means for supplying first and second rotational signals whose phase difference is proportional to the rotational speed of said motor; means for forming an inverted signal of said first rotational signal; means for supplying a signal to stop the motor; a first discrimination circuit for discriminating a rotational direction of the motor in response to said first and second rotational signals and for providing an output signal representative thereof; a second discrimination circuit for discriminating the rotational direction of the motor in response to said inverted signal and said second rotational signal for providing an output signal representative thereof; a motor drive circuit; rotational direction instruction means for controlling said motor drive circuit so that said motor is reversely rotated when said signal to stop said motor is supplied; a stop circuit for supplying a signal to said motor drive circuit to de-energize said motor, said stop circuit responsive to the output signals from said first and second discrimination circuits, which circuits, after said motor has been rotated reversely, detect a predetermined initial change of said first rotational signal and said inverted signal; and a hold circuit for resetting said first and second discrimination circuits by a stop signal provided by said stop circuit for holding the stopped state of the motor.

Claim 10

A method for reducing the time for a motor to come to a complete stop comprising: supplying a plurality of n rotational signals related to the rotational speed of a motor by the relative phase difference therebetween, the signals nominally being related by 360°/n; forming n-1 inverted signals from said n rotational signals; reversing the rotational direction of said motor in response to a signal to stop the motor; determining, from said n signals and n-1 inverted signals, a predetermined initial change of any of said n rotational signals and n-1 inverted signals following a reversal of said motor; de-energizing said motor upon determining said initial change; and positively holding the motor in a stopped state after said motor has come to a complete stop.

Claim 11

A method for reducing the time for a motor to come to a complete stop comprising: supplying a plurality of n rotational signals related to the rotational speed of a motor by the relative phase difference therebetween, the signals nominally being related by 360°/n; forming n-1 inverted signals from said n rotational signals; reversing the rotational direction of said motor in response to a signal to stop the motor; determining, from said n signals and n-1 inverted signals, a predetermined initial change of any of said n rotational signals and n-1 inverted signals following a reversal of said motor; de-energizing said motor upon determining said initial change; and positively holding the motor in a stopped state after said motor has come to a complete stop.