Rotation control apparatus for a motor

摘要

A rotation control apparatus for a motor comprises a motor for rotating or moving a recording medium, a circuit for generating first and second reference signals, a circuit for passing a signal which is obtained by comparing phases of the first reference signal and a synchronizing signal through a filter circuit thereof so as to produce a first error signal therefrom, a circuit for producing a second error signal which is obtained by comparing phases of the second reference signal and the rotation detection signal, and a control circuit for controlling first and second switching circuits. The control circuit supplies a specific signal having a level dependent on the level of the second error signal to a capacitor of the filter circuit through the second switching circuit and selectively passes the second error signal through the first switching circuit when the motor rotates at a rotational speed which is not near a steady state rotational speed. The control circuit blocks the supply of the specific signal to the capacitor by the first switching circuit and selectively passes the first error signal through the first switching circuit when the motor rotates at a rotational speed which is approximately equal to the steady state rotational speed.