| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately detect wire disconnection of a filament or fall-off of a terminal when the power is supplied in a lighting device lighting and driving a discharge lamp having the filament and connected in series. <P>SOLUTION: A closed loop is formed by connecting terminals T3, T5 connected in series and other terminals T4, T6 with a condenser C1 and voltage from a DC power supply 12 is applied to the terminal on the side of the high-voltage discharge lamp La1 of the condenser C1 through a resistance R1 for enabling to detect the wire disconnection and the fall-off of the terminal. Providing two detection circuits 17, 18 for the detection, the voltage VK1 of the terminal on the side of the high-voltage discharge lamp La1 of the condenser C1 is taken out through a resistance R2 for applying to the first detection circuit 17. Voltage VK2 of a junction PB with the terminal on a low-voltage discharge lamp side La2 of the condenser C1 is taken out through a series circuit comprising a resistance R3 and a diode D1 for applying to a second detection circuit 18. Then, a controlling circuit 16 having a mask function of the detected result in a preheating/start-up mode determines. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
