Patent attributes
A switching power supply unit is provided, in which input terminals of an AC voltage can be made common to output terminals of an AC voltage. A first switching circuit is provided between a winding of a transformer and a main battery. A second switching circuit is provided between another winding of the transformer and input/output terminals. A third switching circuit is provided between the second switching circuit and the input/output terminals. Each of the first to third switching circuits includes a bidirectional switch (configured of a pair of one switching element and one diode connected in parallel to each other). A circuit for outputting an AC output voltage can be common to a circuit for inputting an AC input voltage to charge the main battery.
