POWER SWITCH CIRCUIT

摘要

PURPOSE:To obtain a power switch circuit which shows a prescribed function at 50Hz and 60Hz respectively, by integrating one of clock signals with different means of different time constants and applying the integrated signal to a comparator to apply the 3rd clock signal regardless of the frequency of the AC voltage. CONSTITUTION:An SCR switch and a mechanical switch R are connected in parallel between an input terminal I connected to an AC voltage source 2 and an output terminal O connected with a load. A power detecting circuit 58 which feeds the output of a comparator 50 is set between the terminals I and O. FFU1 and U2 are energized by an output signals CLK1 and CLK2 supplied from a comparator 26 and an inverter 40 respectively. The output of the comparator 50 is applied to the FFU1 and U2 respectively, and at the same time a control signal is applied to the FFU1 and U2 from a processor 28. The SCR switch is closed in response to the control signal, and then the switch R is closed. Then the switch R is opened in response to the control signal in order to cut off the SCR switch from the terminals I and O, and then the switch SCR is opened.