BRUSHLESS MOTOR DRIVE CIRCUIT AND MOTOR HAVING THE SAME

摘要

This brushless motor drive circuit comprises a deviation determining part that receives a PWM input signal used for instructing a control of the number of revolutions and that determines a deviation of the duty ratio of the PWM input signal from 50 percents; a determining part that determines a comparison result with the duty ratio of 50 percents established as a threshold value; and a PWM output circuit part that receives a PWM reference signal the duty ratio of which is 50 percents and that generates a PWM drive signal for a brushless motor in accordance with the deviation and comparison result. The PWM drive signal is generated by adding the deviation to the PWM reference signal when the duty ratio of the PWM input signal is equal to or greater than 50 percents or by subtracting the deviation from the PWM reference signal when the duty ratio of the PWM input signal is less than 50 percents.