SYNCHRONOUS RECTIFYING CIRCUIT, FORWARD CONVERTER PROVIDED WITH THE SAME AND SYNCHRONOUS RECTIFICATION METHOD

PROBLEM TO BE SOLVED: To surely prevent cross conduction such that a rectifying transistor and a commutating transistor become continuous simultaneously. SOLUTION: In a forward converter which obtains a DC output by connecting a primary winding L1 of a transformer T and a switching device Q0 in series between DC input terminals and rectifying and commutating an output generated by the secondary winding L2 of the transformer T, a rectifying transistor Q1 and a commutating transistor Q2 connected in series to the secondary winding L2 are turned off complimentarily, on the basis of a switching signal A and a positive pulse voltage B of the second winding L2. The conmutating transistor Q2 is turned off, being adjusted to the turn-on of the switching device Q0, and the rectifying transistor Q1 is turned on being adjusted to the rise of the positive pulse voltage B. On the other hand, the rectifying transistor Q1 is turned off being adjusted to the turn-off of the switching device Q0, and the commutating transistor Q2 is to be turned on being adjusted to the fall of the positive voltage B.