| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect fault in each of two or more loads such as fluorescent lamps. <P>SOLUTION: A switching circuit includes a plurality of transistors connected to a primary winding of a transformer, and an input voltage and a ground voltage are alternately applied to the primary winding depending on ON/OFF of each of the transistors. A plurality of ballast capacitors C1<SB>1</SB>to C1<SB>n</SB>are provided for each of a plurality of fluorescent lamps 210, and each having one end commonly connected to a secondary winding of the transformer and the other end connected to each of the fluorescent lamps 210. Each of first capacitors C2 and each of second capacitors C3 are connected across each of connection points N3 between each of the monitoring fluorescent lamps 210 and each of the ballast capacitors C1, and each of grounding terminals, in order and in series. A fault determinating section 34 compares a voltage of each of connection points N4 between each of the first capacitors C2 and each of the second capacitors C3, with a predetermined threshold voltage. <P>COPYRIGHT: (C)2010,JPO&INPIT |
