| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge-lamp lighting device reduced in size, by lighting a burden on a capacitor for direct current blocking. SOLUTION: A fluorescent lamp FL is started up by producing resonance with a resonance inductor L2 and a resonance capacitor C4. When the fluorescent lamp FL is lit, a capacitor C6 for direct current blocking is charged and a lamp-lighting abnormality detection circuit 6 judges the lighting to be normal, causing a switching circuit 3 to output a normal voltage. When the fluorescent lamp FL comes to its life-ending stage and half-wave discharge takes place, the lamp-lighting abnormality detection circuit 6 detects it and outputs a safety signal to lower the voltage of the switching circuit 3. The resonance current is prevented from flowing through the capacitor C6 for direct current blocking by connecting the capacitor C6 for direct current blocking in parallal with the resonance capacitor C4, and thereby the capacitor C6 for direct current blocking can be made lower in cost and smaller in size. |
