| 摘要 |
PROBLEM TO BE SOLVED: To add a function as an emergency lamp to a fluorescent lamp type LED illuminating device to enhance the safety at interruption of service.SOLUTION: An LED illuminating device attachable between a pair of sockets provided on a fluorescent lamp comprises: a first power supply circuit causing an LED to emit light by a DC power obtained by converting and rectifying an AC power supplied from the sockets; and a second power supply circuit causing the LED to emit light by an incorporated battery. An incorporated SW controller detects rapid reduction that a current value or a voltage value flowing in or applied to the illuminating device becomes substantially zero from a predetermined value Von at the illumination switch ON is generated in a predetermined time period T, and when the rapid reduction is generated twice or more in the predetermined time period (Fig. 5), determines that a normal lighting-off operation is performed and extinguishes the LED, and when the rapid reduction is generated only once in the predetermined time period (Fig. 6), determines that the interruption of service occurs and lightens the LED as an emergency lamp by using a battery by the second power supply circuit. |
