Patent ID: 8179075

Claim:
A motor driving integrated circuit comprising: a speed control circuit configured to control a rotation speed of a motor according to a speed control signal; a detecting circuit configured to detect whether the speed control signal indicates stop of rotation of the motor; a shut-off circuit configured to shut off power supply to a circuit included in the motor driving integrated circuit when the detecting circuit detects that the speed control signal indicates stop of rotation of the motor; a binarizing circuit configured to output a binary signal obtained by binarizing a signal having a frequency corresponding to rotation speed of the motor, the signal being obtained from the motor; an edge detecting circuit configured to detect an edge of the binary signal; and a counter configured to be reset according to the edge of the binary signal detected by the edge detecting circuit, wherein the shut-off circuit shuts off the power supply when the detecting circuit detects that the speed control signal indicates stop of rotation of the motor and the counter counts for a predetermined period longer than an interval between edges of the binary signal.