Patent ID: 7122988

Claim:
A rotation driving apparatus having a motor at least rotating at a high speed and a low speed, a torque generating circuit for generating a torque of the motor by a supply voltage from a power source, a motor control circuit for controlling rotation of the motor, a rotation detector for detecting a rotating speed of the motor and transmitting a detection signal to the motor control circuit and controller for delivering the rotating speed of the motor and a number of revolutions thereof to and from the motor control circuit, wherein the torque generating circuit includes a voltage detector for detecting a level of the supply voltage and a period of voltage drop, the voltage detector transmitting a voltage-drop information to the controller, the controller memorizes power-recovery information including a voltage drop and a period thereof under an instantaneous blackout recoverable within a predetermined period, and rotation-control pattern information of the motor corresponding to the power-recovery information, in advance, and the controller controls rotation of the motor upon comparing the voltage-drop information, the power-recovery information, and the rotation-control pattern information of the motor with each other, the rotation-control pattern information of the motor has ranges of an accelerating rotation, a constant high-speed rotation and a decelerating rotation, such that when the voltage detector detects a voltage drop during the accelerating rotation of the motor, the controller outputs control signals for: decelerating rotation of the motor; next rotating the motor at a constant speed; and after the power recovery, accelerating rotation of the motor.