| 摘要 |
PROBLEM TO BE SOLVED: To obtain an output voltage lower than an input voltage and having an improved power factor even if a power supply circuit does not use a DC-DC converter. SOLUTION: In the power supply circuit provided with an active smoothing filter between a rectifying circuit 2 and a load 3, a choke coil in the active smoothing filter is replaced with a primary coil L1 in a transformer 12, a secondary coil L2 in the transformer 12 is connected to a second rectifying circuit 11, and the load 3 is connected to the second rectifying circuit 11. The output voltage is lower than the input voltage in the second rectifying circuit connected to the secondary coil by changing a turn ratio of the primary and secondary coils L1, L2 in the transformer 12. Since a waveform of the output voltage becomes a sinusoidal wave by a switching operation, the power factor can be improved. COPYRIGHT: (C)2007,JPO&INPIT
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