| 摘要 |
PROBLEM TO BE SOLVED: To improve power factor by suppressing the generation of EMI noise and the peak value of an input AC current. SOLUTION: First and second primary coil winding circuits 11 and 12 are alteately switched according to a drive pulse outputted by a switching control circuit 3, thus outputting a secondary AC power induced at secondary coil windings 2A-N2 of a transformer 4 from output terminals 8A-8C after rectifying and smoothing the power. At the same time, the - terminal of a tertiary rectification circuit 6 for rectifying a tertiary AC power induced at a tertiary coil winding N3 is connected to the positive output terminal of the diode bridge 3 and + terminal is connected between a large-capacity capacitor C1 and its discharging diode D1 for constituting a series circuit, thus charging the capacitor C1 with the sum of the instantaneous value of the output voltage of a diode bridge 2 of and the output voltage of the tertiary rectification circuit 6 and expanding the conduction angle of input current. |
