| 摘要 |
PURPOSE: To prevent uncomfortable sounds by providing a deflecting switch, a means which generates a power-on/off control signal in response to a signal, and an oscillator which controls the power-on operation mode and the power-off operation mode. CONSTITUTION: A second control signal is applied to a control circuit 110 to control the free-running frequency of the oscillator in the control circuit 110 being in the middle of power-off operation. In the case of operation in the unlatch mode where an SCR switch 200 is turned on, an average current is increased to such value that it can sufficiently replenish all the electric charge of a filter capacitor in the control circuit 110, which is lost in the period starting with the end of the preceding trigger pulse, in each trigger pulse period with respect to the degree of conduction of the SCR switch 200. In the case of the power-off operation, the second control signal increases the duty cycle of a first control signal, thereby increasing the duty cycle of the SCR switch 200. |
