| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of surely detecting an abnormality of a life of a lamp and performing a protective operation. SOLUTION: A light load state of an invertor circuit is detected from a control state of an active filter 2 to perform the protective operation. According to it, since a circuit load becomes small when non-lighting and weak discharge states caused by a phenomenon such as filament-breaking at the end of the life of the lamp occur, it becomes possible to surely detect the abnormality of the lamp life span by detecting the states. COPYRIGHT: (C)2004,JPO |
