| 摘要 |
PURPOSE:To make sensing of the inter-end voltage and sense a lamp device using a simple circuitry configuration, with which the condition with discharge lamp unmounted can be sensed individually for a plurality of discharge lamps and there is no need for provision of any high withstand voltage element to a lamp voltage sensing circuit. CONSTITUTION:One of the output terminals of an inverter 3 is connected with an intermediate tap of a balancer 5, and the two ends of this balancer 5 are connected with one-side ends of filaments 14, 17. Secondary windings 9, 10 of a filament transformer 7 are connected with these filaments 14, 17, respectively, through diodes 21, 22, and another secondary winding 11 is connected with other filaments 15, 18. One-side ends of the filaments 15, 18 are connected with the other output terminal of the inverter 3, and series circuitry of voltage dividing resistances 23-26 is connected between one-side ends of the filaments 14, 17 and the other output terminal of the inverter 3. At the connection points of these resistances, lamp mount sensing signals L1, L2 are taken out individually for a plurality of discharge lamps, and a sensing signal E of the lamp inter-end voltage is taken out from a rectifier circuit A. |
