| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect abnormality in LED lamps surely even when a plurality of LED lamps are turned on in series, based on which to control their output. <P>SOLUTION: When a voltage across an LED lamp 110B having a short-circuit fault therein drops, causing a second detection voltage VS2 to fall below a lower limit, a control unit 5 determines that the LED lamp 110B is defective and stops a power conversion unit 2. Similarly, when a voltage across an LED lamp 110A having a disconnection fault therein rises, causing a differential voltage between a first detection voltage VS1 and the second detection voltage VS2 to exceed an upper limit, the control unit 5 determines that the LED lamp 110A is defective and stops the power conversion unit 2. Therefore, even when plural LED lamps 110A and 110B are turned on in series, abnormality in the LED lamps 110A and 110B is detected surely, based on which their output can be controlled. <P>COPYRIGHT: (C)2012,JPO&INPIT |
