DISCHARGE LAMP LIGHTING DEVICE

• Main Authors: YASHIRO YASUNORI, TAKAHASHI OSAMU
• Format: Patent
• Language: English
• Published: 06.10.2005
• Edition: 7
• Subjects: ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device for easily identifying a faulty discharge lamp, such as the last period of lifetime, and being stopped safely by operating a protective circuit. SOLUTION: The discharge lamp lighting device comprises a conversion circuit, such as an inverter circuit, for performing the conversion drive of a DC current supplied from a DC power supply 1 to a high-frequency current that is higher than a lighting frequency when the discharge lamps 7, 11 are lit normally or a frequency that is higher than the lighting frequency; a plurality of discharge lamp load circuits L100, L110 that perform the lighting control of a plurality of discharge lamps and are connected in parallel, where a circuit constant is set so that a normal discharge lamp continues to light and a faulty one lights off, in the case of drive at a frequency that is higher than the lighting frequency; a ± detection circuit D100 for detecting abnormal discharge, on the basis of voltage across the plurality of discharge lamps 7, 11; and a determination circuit, such as a holding circuit H100, for stopping after driving at a frequency that is higher than the lighting frequency for a prescribed amount of time, when the ± detection circuit 100 detects the abnormal discharge of at least one discharge lamp. COPYRIGHT: (C)2006,JPO&NCIPI