Patent ID: 8213188

Claim:
A bidirectional DC-DC converter which converts a voltage between a high voltage side and a low voltage side, the converter comprising: a first transformer which includes a first primary side winding and a first secondary side winding, the first secondary side winding including a first winding and a second winding which are divided at a first midpoint; a second transformer which includes a second primary side winding and a second secondary side winding, the second primary side winding being connected in series to the first primary side winding, and the second secondary side winding being connected in parallel to the first secondary winding and including a third winding and a fourth winding which are divided at a second midpoint; a first switch which is inserted between a positive terminal at the high voltage side and a junction point of one end of the first primary side winding and one end of the second primary side winding; a second switch which is inserted between the junction point and a negative terminal at the high voltage side; a third switch which is inserted between an other end of the first primary side winding and the positive terminal at the high voltage side; a fourth switch which is inserted between the other end of the first primary side winding and the negative terminal at the high voltage side; a fifth switch which is inserted between an other end of the second primary side winding and the positive terminal at the high voltage side; a sixth switch which is inserted between the other end of the second primary side winding and the negative terminal at the high voltage side; a seventh switch which is inserted between a terminal of the first secondary winding at a side of the first winding and a positive terminal at the low voltage side; an eighth switch which is inserted between a terminal of the first secondary winding at a side of the second winding and the positive terminal at the low voltage side; a ninth switch which is inserted between a terminal of the second secondary winding at a side of the third winding and the positive terminal at the low voltage side; and a tenth switch which is inserted between a terminal of the second secondary winding at a side of the fourth winding and the positive terminal at the low voltage side, the first midpoint and the second midpoint being connected to the negative terminal at the low voltage side, and the seventh switch, the eighth switch, the ninth switch and the tenth switch respectively connecting the first terminal, the second terminal, the third terminal and the fourth terminal of the secondary winding to the positive terminal at the low voltage side.