| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting device of a discharge lamp by a high-frequency inverter, which can protect the lighting device for the discharge lamp when a filament of the discharge lamp is broken or the discharge lamp is not normally inserted into a socket, and prevent electrical shock upon exchange of the discharge lamp. SOLUTION: A resistor is connected between a DC power source and output of an inverter circuit and in parallel with a resonance capacitor and a capacitor for cutting a DC current to form a bias circuit which lets a DC bias current flow into each filament of a discharge lamp. A detecting circuit for detecting a value of the DC bias current passing through the bias circuit is provided. The lighting device has a circuit for stopping power to the inverter circuit when the value of the DC bias current detected is lower than prescribed. |
