| 摘要 |
PURPOSE:To prevent the erroneous function of a rotational position detecting circuit by providing an automatic phase regulating circuit for regulating the phase difference between two pulse signals, obtained in synchronism with the rotation of the rotor section of an electromagnetic rotating machine, more than a set value on the input side of the rotational position detecting circuit. CONSTITUTION:The rotational position detecting circuit for detecting the index position of an electromagnetic rotating machine such as a motor being employed in a floppy disc drive or the like detects phase difference between first and second pulse signals FG1, FG2 being obtained in synchronism with the rotation of the rotor section of the motor thus detecting a rotational position. The rotational position detecting circuit is provided, on the input side thereof, with an automatic regulating circuit for subjecting the output from a first phase difference detecting circuit 300a for detecting a minimum phase difference of FG1 pulse to FG2 pulse and the output from a second phase difference detecting circuit 300b for detecting a minimum phase difference of FG2 pulse to FG1 pulse to differential amplification through an amplifier 110 and outputting a differentially amplified signal. According to the constitution, the phase shift for timing regulation can be realized. |
