Switching regulated power supply using 110V (voltage double)/220V AC voltage input

The power circuit is as shown in the figure, and the input AC voltage is 110V or 220V. When the 110V AC voltage power supply changes in the range of 85~132V or the 220V AC voltage power supply changes in the range of 170~265V, Sv=±1%. When the load current variation range is 10% to 100%, Si=±5%. The output ripple voltage is ±50mV. S in the circuit is the ll0V/220V AC voltage selection switch, which can also be replaced by a jumper on the printed board. When S is closed, the ll0V AC voltage input is selected. At this time, the voltage doubler rectifier circuit is composed of the rectifier bridge BR and the resistor-capacitor components R1, C1, R2, and C2. When S is disconnected, 220V AC voltage input is selected. In order to improve the voltage stability at light load, resistor R4 is added to the output circuit, and the minimum load current set by it is 36mA.