| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection circuit which certainly protects a lamp driving device even when an output terminal of a high voltage side and an output terminal of a low voltage side of a transformer circuit are short-circuited, and the lamp driving device having the protection circuit. SOLUTION: The protection circuit has a detection circuit 403 which detects a voltage from an electric current flowing between an high-voltage side output terminal T1 and a low-voltage side output terminal T2 of a transformer circuit 20 that supplies the current from the high voltage side output terminal T2 to a lamp 30 in which a discharge medium is filled inside and electrodes are formed on the both end external face, and, when the current flows between the both output terminals, outputs a detection voltage in which the detected voltage is stepped down to a prescribed permitted voltage or lower, and when the current does not flow between the both output terminals, outputs a detection voltage equivalent to zero, and a control circuit 402 which controls the current to be supplied to the lamp 30 according to the value of detection voltage output. A lamp driving device having the protection circuit is provided. COPYRIGHT: (C)2009,JPO&INPIT |
