| 摘要 |
PURPOSE:To ensure starting without fail regardless of the switch time by providing the load starting transistor Tr, capacitor C, the parallel circuit of the high resistances and the discharging resistance each to the rectifying circuit. CONSTITUTION:The parallel circuit of C10 and high resistance 12 is connected to the output of rectifying circuit 3, and starting Tr4 conducts with the charging current of C10 with make of power switch 2. And Zener diode 9 conducts when the charging of C10 proceeds to make controlling Tr6 conduct as well as to turn off Tr4. This rectifying circuit features a switching type constant voltage circuit consisting of oscillation circuit 14, comparator circuit 22 and voltage control circuit 35 and protects Tr25 with the voltage drop caused by resistance 39 in case load 32 is short-circuited. When the load is made normal and switch 2 is made again after opening once, the charging of C10 is discharged by resistance 40 connected to C10 and Tr4. Thus, the starting current of Tr4 is supplied to actuate the starting circuit regardless of the switch time duration of the power source. |
