| 摘要 |
PURPOSE:To make it possible to achieve multi-stage dimming of a fluorescent lamp easily by lighting the fluorescent lamp for the full lighting condition when a power switch is charged by means of a lighting starting stabilizing circuit so as to light the lamp stably if dimming is performed before charging the power switch. CONSTITUTION:For a fluorescent lamp lighting device of a separate excitation type, a dimming circuit 10 is provided including generation resistances R1, R2 for dimming connected in parallel with a generation resistance R0 of a control signal generating circuit 7 through switching elements Q3, Q4, a lighting starting stabilizing circuit 11, and a switch drive control circuit 12 for controlling operating and closing of the switching elements Q3, Q4 by opening/switching operation of manual dimming switches SW1, SW2, SW3. The lighting starting stabilizing circuit 11 makes the switching elements of the generating resistances for dimming connected in parallel with the generation resistance R0 of a constant resistance value of the control signal generating circuit 7 open so as to light a fluorescent lamp 4 in the full light condition constantly, so the fluorescent lamp 4 is lighted stably even at low temperatures. The fluorescent lamp can thus be lighted and dimmed in more stages. |
