| 摘要 |
PROBLEM TO BE SOLVED: To easily detect a one-end insufficient connection state in an inverter circuit in which a lamp current path exists, even if one end of a filament terminal becomes insufficiently connected. SOLUTION: If a direct current component is detected at a first or a second direct current component detecting circuit respectively connected to filaments of a power supply side and a non-power supply side of a discharge lamp, oscillation of the inverter circuit is made to be stopped. A high resistor RO is connected in parallel to a capacitor CO for a direct component cut of the inverter circuit so that the direct current component will be detected by the first direct current component detecting circuit when the filament terminal of the power supply side is separated in lighting of the discharge lamp. A prescribed direct current bias circuit is connected to the filament terminal of the non-power supply side of the discharge lamp so that the direct current component will be detected by the second direct current component detecting circuit when the filament terminal of the non-power supply side is separated in the lighting of the discharge lamp. COPYRIGHT: (C)2004,JPO&NCIPI |
