| 摘要 |
PURPOSE: To improve an input distortion while restricting a rise of terminal voltage of a smoothening capacitor during light load to a power supply. CONSTITUTION: A rectifier RE is connected to an AC power supply Vs through a high frequency reverse current suppressing portion RR for checking a reverse flow of the high frequency to AC power supply side, and the output voltage of the rectifier RE is smoothened by a smoothening capacitor C1 . An inverter circuit INV is driven by a voltage at both the ends the smoothening capacitor C1 . A high frequency feedback portion FB feeds back part of the high frequency power of the inverter circuit INV between the high frequency reverse current suppressing portion RR and the rectifier RE and alternately repeats the state of absorbing a current from the AC power supply Vs in response to the polarity of the feedback high frequency and the state of charging the smoothening capacitor C1 through the rectifier RE. The feedback amount regulating portion CF turn on the switching element SW when the load becomes light and decreases the amount of feedback of the high frequency feedback portion FB. |
