| 摘要 |
PROBLEM TO BE SOLVED: To reduce the loss of a rectifying circuit on the secondary side of a DC-DC converter, equipped with a synchronous rectifying circuit in its secondary circuit, and to reduce the loss of a primary-side switching circuit of the DC-DC converter, equipped with a switching circuit of full-bridge method. SOLUTION: The DC-DC converter comprises, with a voltage conversion transformer (TS1) provided, a synchronous rectifying circuit (20) on its secondary side and a switching circuit (10) of full-bridge method on its primary side, and performs synchronous rectification control, in which the current path to a secondary-side coil is switched in synchronous with the switching operation on the primary side by switching transistors (M5 and M6). It detects the current flowing into a load on the secondary side or the current on the primary side, that changes in connection with the load current and an input voltage on the primary side, to dynamically control the off-timing of a synchronous rectification transistor on the secondary side, and also detects the current flowing into the input voltage on the primary side and into the load on the secondary side, to dynamically control the on-timing of a transistor of the switching circuit on the primary side. COPYRIGHT: (C)2004,JPO&NCIPI
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