| 摘要 |
A converter device is provided which has a power factor improving circuit that removes effects of noise superimposed on an AC power supply and reduces higher harmonics and improves the power factor. A power factor improving circuit ( 103 ) generally includes a voltage error amplifier ( 8 ), a current error amplifier ( 10 ), a comparator ( 11 ), a triangular wave oscillator ( 12 ), an output buffer ( 13 ), and a DC power supply (PS). A power factor improving unit ( 102 ) has a photocoupler ( 14 ) for detecting an output of an AC power supply ( 1 ) and a microcomputer ( 15 ), where the output (Vp) of the photocoupler ( 14 ) is given to the MCU of the microcomputer ( 15 ). A D/A converter ( 17 ) in the microcomputer ( 15 ) gives a converter output (DAO) to the power factor improving circuit ( 103 ) and the power factor improving circuit ( 103 ) gives a reference voltage (VREF) to the D/A converter ( 17 ).
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