| 摘要 |
PROBLEM TO BE SOLVED: To provide a fluorescent lamp lighting device which can detect any failures such as a state of no emission at one side or both sides, a defective contact, and an unusual high voltage, preventing unusual generation of heat surely at the neighboring area of a filament or defective contact part. SOLUTION: A direct current blocking capacitor CS1 is installed serially between a current limiter choke coil and a fluorescent lamp FLR1 at the output of a high frequency inverter circuit. A disorder detecting and protecting circuit 16, monitoring the direct current superimposed high frequency voltage, is installed between both electrodes of the fluorescent lamp FLR1. The disorder detecting and protecting circuit 16 short-circuits both electrodes of the fluorescent lamp FLR1 when direct current superimposed high frequency voltage exceeds at least one of the threshold values for positive and negative polarity respectively. |
