| 摘要 |
PURPOSE:To facilitate quick start of speed control and locking the revolution of a motor at a required value regardless of timing when the revolution of the motor reaches a reference revolution by a method wherein a motor speed detecting circuit which detects that the motor speed reaches a target value and outputs a control start signal only once at the time of first detection is provided. CONSTITUTION:The frequency and phase of a position detection signal Si shaped by a pulse shaping circuit 6 are compared with the frequency and phase of a speed detection reference pulse signal SOO from a speed detection reference pulse generating circuit 11 by a motor speed detecting circuit 7 and, when the angular frequency OMEGAi or the position detection signal Si exceeds the angular frequency OMEGAOO of the signal SOO, the motor speed detecting circuit 7 detects that the motor speed reaches a target value and outputs a control start signal SS only once at the time of this first detection. Then, the OR of the position detection signal Si and the control start signal SS whose timing is shifted from the position detection signal Si by a pulse delay circuit 8 is obtained by a synthesizing circuit 9 and the synthesizing circuit 9 generates a speed position detection signal SA and supplies it to a phase frequency comparator 2. |
