| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an LED lighting fixture which, when an abnormal rise of temperature is detected, can maintain minimum illuminance in an abnormal environment without stopping electrical conduction to the LED, thereby preventing the user from feeling uneasy. <P>SOLUTION: The LED lighting fixture includes: an output current limiting circuit 92 which, by using output from a DC converter circuit 91, drives an LED unit 47 with constant current during normal time, or limits current flowing to the LED unit 47 at abnormal time; an ambient temperature detection circuit 93 which detects the ambient temperature; and a feedback circuit 94 which feeds a detection signal from the ambient temperature detection circuit 93 back to the DC converter circuit 91. In an abnormal case when an abnormal rise of the ambient temperature is detected by the ambient temperature detection circuit 93, the feedback circuit 94 feeds the detection signal back to the DC converter circuit 91, so that the output current from the output current limiting circuit 92 is limited and the minimum illuminance of the LED 42 of the LED unit 47 is maintained without stopping electric conduction to the LED 42. <P>COPYRIGHT: (C)2013,JPO&INPIT |
