| 摘要 |
PROBLEM TO BE SOLVED: To reduce power loss, radiation noise, and manufacturing cost by achieving zero volt switching for which no high-precision dead band time control is required. SOLUTION: A switching power supply includes a primary resonance capacitor connected in parallel to a primary switching element or a primary winding of a transformer and a secondary resonance capacitor connected to a secondary winding or a secondary rectifier diode. It furthermore includes a secondary switching element connected to the secondary resonance capacitor and a secondary control means, which controls the ON/OFF of the secondary switching element according to a voltage across the secondary winding. In the entire fluctuation range of a voltage input at the primary side of the transformer, the capacity of the primary resonance capacitor and that of the secondary resonance capacitor are set such that a residual voltage of the primary switching element becomes approximately zero. COPYRIGHT: (C)2009,JPO&INPIT
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