| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve further energy saving of an LED bulb and long life of an LED element peripheral device. <P>SOLUTION: An LED bulb includes: a rectifier circuit 4 that rectifies an AC voltage to a DC voltage; an LED light source 20 that is constituted from a plurality of LED elements; a step-down chopper circuit that drives the LED light source 20; and a control circuit 8 that drives the step-down chopper circuit so that the power consumption of the LED light source 20 is increased according to an increase in ambient temperature. An LED power is reduced between the power activation and temperature saturation according to the temperature characteristics of the LED, and a predetermined brightness at the time of temperature saturation is maintained. An LED power control is performed using a thermistor or a thermostatic resistor having a resistance value varying according to temperature changes. <P>COPYRIGHT: (C)2013,JPO&INPIT |
