Patent ID: 7889520
Filing Date: 2011-02-15
Classification: H01F,H02M,Y02B

Abstract:
1. A DC-DC converter comprising: a first transformer provided with a first core having a gap, the first core being wound around with a first core primary winding and a first core secondary winding; a second transformer provided with a second core having a gap narrower than the gap of the first core or no gap, the second core being wound around with a second core primary winding and a second core secondary winding; a first switching element serially connected to the first core primary winding and the second core primary winding, the first switching element being set in conducting/non -conductive state in a predetermined period; a first rectifier element in which a first polarity terminal is connected to a first terminal of the first core secondary winding that generates an electromotive force of first polarity when the first switching element conducts, the first rectifier element being biased in a reverse bias condition; a second rectifier element in which the first polarity terminal is connected to a second terminal of the second core secondary winding that generates an electromotive force of second polarity when the first switching element conducts, the second rectifier element being biased in a forward bias condition; a secondary winding connection point to which a third terminal and a fourth terminal are connected, the third terminal being provided at an opposite side of the first terminal of the first core secondary winding and the fourth terminal being provided at an opposite side of the second terminal of the second core secondary winding; a connection point which connects the secondary polarity terminal of the first rectifier element and the second polarity terminal of the second rectifier element; a common current path in common with a current path which includes the first core secondary winding and the first rectifier element and a current path which includes the second core secondary winding and the second rectifier element, the common current path connecting the secondary winding connection point and the connection point; an output terminal provided on the common current path; and an output coil provided on the common current path.