CONTROL CIRCUIT FOR A BRUSHLESS DC MOTOR AND METHOD THEREFOR

摘要

PURPOSE: A control circuit for a brushless DC motor and a method thereof are provided to improve an effectiveness of the motor by controlling a rectifying time. CONSTITUTION: A current driving circuit(140) selectively drives the brushless DC motor(160) into a first polarity or a second polarity in response to a control signal. The current driving circuit senses the current through the brushless DC motor in order to supplying a current sensing signal. A current loop regulator(122) changes a duty cycle of the control signal in order to adjust the current in response to the current sensing signal. The current loop regulator adjusts the current using one current selected among a second current of an opposite polarity with the first current of a first current based on a state of a polarity signal. Rectifying loop regulators(124, 126) adjust a transition of the polarity signal in response to a comparison of a post-rectifying duty cycle value and a post-rectifying duty cycle value.