| 摘要 |
PROBLEM TO BE SOLVED: To maximum power factor by feeding back a high-frequency voltage taken in by utilizing a lamp to the output terminal of a rectifier circuit, coupling a high-frequency filter at the pre-stage of the rectification circuit in advance for matching to a power factor improving feedback circuit for high-frequency switching and adjusting a phase difference. SOLUTION: A high-frequency filter 30 is connected next to a noise elimination circuit 20. A capacitor 33 of the high-frequency filter 30 not only plays a roles of the high-frequency filter but also a role for adjusting a power factor phase angle. A rectifier circuit 40 is provided at the later stage of the high-frequency filter 30. An input AC current in converted to a DC current for a lamp 70 and for a power factor improving feedback circuit 50. The anode of a diode 51 is connected to the lamp 70. A vibration circuit 60 is connected to both terminals of a capacitor 53 of the feedback circuit 50. The vibration circuit 60 consists of transistors 61 and 62 and flywheel diodes 63 and 64 and a high frequency is fed back to the output terminal of the rectification circuit 40 via the lamp 70. |
