| 摘要 |
PROBLEM TO BE SOLVED: To provide a zero-cross point detection apparatus and method of counter-electromotive force in motor drive circuit, capable of exactly detecting a zero-cross point of a counter-electromotive force.SOLUTION: The zero-cross point detection method of counter-electromotive force in motor drive circuit includes: a step for a duty calculator to calculate a duty ratio of a PWM signal generated by a PWM generator; a step for a duty inverter to output an inverted signal or a non-inverted signal to an input pulse according to the calculated duty ratio; and a step for an electromotive force detector to detect a counter-electromotive force from a motor on the basis of an output signal from the duty inverter and to detect a zero-cross point. |
