AN389自动线电压开关电路 AN389 APPLICATION NOTE AN AUTOMATIC LINE VOLTAGE SWITCHING CIRCUIT ABSTRACT The voltages found in line sockets around the world vary widely. Power supply designers have, most often, overcome this problem by the use of a doubler/bridge switch that can double the 120V nominal line and simply rectify the 240V nominal voltage. A two device solution (comprising an integrated circuit and a customized triac) that will adapt the power supply to various line voltages around the world is described in the following paper. This circuit replaces a manual switch and could also open special markets. Other advantages of this integrated circuit solution are……