MOTOR ROTATION CONTROL CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a motor rotation control circuit that reduces a jitter in a driving signal and noise.

SOLUTION: The motor rotation control circuit includes: a detection circuit that detects a timing of change of a rotation detection signal and generates a first timing signal having a period that is 1/2 the rotation period of a motor and a second timing signal having the same period as the rotation period; a first counter that performs counting operation using a clock and counts rotation periods; a second counter for setting the time during which no coil current is supplied; a period determination circuit that determines the rotation period of the motor based on a signal from the first counter; a digital integration circuit 16 that increments or decrements the second counter when the same determination is consecutively made by the period determination circuit; and a third counter loading a difference between the values on the first and second counters and performs down-counting in accordance with a clock signal. A current passes through the coil of the motor until the count value of the third counter becomes "0".

COPYRIGHT: (C)2010,JPO&INPIT