| 摘要 |
PROBLEM TO BE SOLVED: To sustain the accuracy of rotational speed and rotational position over a wide speed range by setting the initial phase reference of rotational phase at the time of edge of an FG signal arriving immediately after starting the rotational phase control thereby stabilizing the phase error signal. SOLUTION: A rotational speed control circuit 5 comprising a speed control circuit 10 for comparing an FG signal with a reference speed signal through a comparator 11 to produce a speed error signal, and a phase control circuit 13 for comparing the FG signal with a reference phase signal through a comparator 13 to produce a phase error signal is further provided with a phase reference setting circuit 20. At the time of starting a motor, rotational speed is increased in speed control mode up to a reference rotational speed and when a transition is made to speed & phase control mode in order to rotate the motor at a constant speed, the edge time of FG signal immediately after the switching point of time is matched with the timing of reference phase signal. According to the circuit, stabilized speed phase control can be performed with high accuracy. |
