| 摘要 |
PROBLEM TO BE SOLVED: To obtain a simple synchronous rectifier circuit with its power loss reduced as much as possible. SOLUTION: The synchronous rectifier circuit comprises a MOS transistor 1 the section between the source and drain of which is connected with one of two input/output lines connecting input terminals a and b and output terminals c and d, a capacitor C1 one of the terminals of which is connected with the source-side line, a photocoupler 3 as a switching element that is turned on in one-side half-wave section between the input terminals a and b and off in the other-side half-wave section, a charging circuit that, when the photocoupler 3 is off, charges the capacitor C1 so that the other-side terminal is higher than the one-side terminal, and a discharging circuit that, when the photocoupler 3 is turned on, connects the other-side terminal of the capacitor C1 to the gate G of the MOS transistor 1 to turn on the MOS transistor 1. |
