| 摘要 |
<P>PROBLEM TO BE SOLVED: To protect other LEDs when one of LEDs connected to a common constant current power supply circuit suffers open failure. <P>SOLUTION: An output constant current circuit 40 supplies constant current. An LED array 1a and an LED array 2a are connected to each other in series. An FET 1 is connected to the LED array 1a in parallel, and an FET 2 is connected to the LED array 2 in parallel. A protection circuit 80 outputs an abnormality detection signal when detecting an LED open failure of any one of the LED array 1a and the LED array 2a. A control circuit 60 receives the abnormality detection signal, and controls on the basis of the input abnormality detection signal to turn on the FET (FET 1 or FET 2) connected to the LED array for which the LED open failure is detected by the protection circuit 80. <P>COPYRIGHT: (C)2012,JPO&INPIT |
