| 摘要 |
PURPOSE:To improve the efficiency of a motor by switching a transistor which supplies a drive current to a DC motor, varying a period that the current flows and controlling the speed of the motor, thereby reducing the power loss. CONSTITUTION:A reference signal (a) and a signal (b) are inputted from an FG signal generator 8 to a phase comparator 1 which has R-S flip-flop, thereby producing a sawtooth signal (d) through an integrator 2. On the other hand, the FC signal (b) is applied to a f/V converter 4 to produce a speed voltage signal (f), both signals are synthesized to be applied to a comparator 9 together with a reference voltage, thereby outputting a control signal i. Thus, a transistor 6 which is connected in series with a DC motor 7 is controlled, thereby controlling the rotation of the motor 7. Accordingly, the transistor 6 is switched ON or OFF in the switching state, thereby varying the period that the current flows. Accordingly, the loss of the transistor 6 can be reduced, thereby improving the efficiency. |
