Patent ID: 7697306

Claim:
A switching supply comprising: an input part; an output part; a first transformer having a first coil group; a second transformer having a second coil group; an inverter circuit connected between the input part and an input terminal of the first and second transformers; a rectifier smoothing circuit connected between the output part and an output terminal of the first and second transformers; a first coil pair having a primary side coil and a secondary side coil magnetically coupled; a second coil pair having a primary side coil and a secondary side coil magnetically coupled; a third coil pair having a primary side coil and a secondary side coil magnetically coupled; and a fourth coil pair having a primary side coil and a secondary side coil magnetically coupled; wherein the first coil group has the first and third coil pairs, the second coil group has the second and fourth coil pairs, the primary side coils included in the first and second coil pairs are mutually connected in series between an input terminal of the first transformer and an input terminal of the second transformer, the primary side coils included in the third and fourth coil pairs are mutually connected in series between an input terminal of the first transformer and an input terminal of the second transformer, the secondary side coils included in the first and third coil pairs are mutually connected in parallel to the output part, and the secondary side coils included in the second and fourth coil pairs are mutually connected in parallel to the output part.