| 摘要 |
PURPOSE:To eliminate the stoppage of a motor due to the variation in a load and to shorten the rise time by obtaining a latch pulse on the basis of the output pulse of an oscillator when a speed detection pulse is not obtained. CONSTITUTION:A rotating speed detector 18 detects whether the rotating speed of a motor 1 is the prescribed value or lower on the basis of a speed detection pulse (a), and outputs a speed detection pulse (a) when the speed is the prescribed value or higher and an output pulse (f) of a frequency divider 17 to a delay circuit 13 when it is the prescribed value or lower. Thus, even if the pulse (a) is not obtained, a pulse is inputted to the delay circuit 13. Accordingly, each latch pulse is always obtained, an accumulation is executed, and a signal S4 is updated to raise the rotating speed of the motor 1 in a drive circuit 16. |
