| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED dimming apparatus which hardly generates noises even when an LED current is large, and which hardly causes irregularities in brightness even if dimming is intensified. SOLUTION: The LED dimming apparatus includes a current adjusting means (a constant current circuit 6) which variably controls a magnitude of a current flowing through an LED load 4, a switching means (a transistor Q1) which intermittently controls the current flowing through the LED load 4, and a dimming control means (a microcomputer 5) which receives a dimming signal outputted from a dimmer 1 to control the current adjusting means and the switching means. When the dimming signal outputted from the dimmer 1 is on a higher side of a predetermined brightness level, the dimming control means sets the current flowing through the LED load 4 to a continuous current, and dims the LED load 4 according to the magnitude of the flowing current. When the dimming signal outputted from the dimmer 1 is on a lower side of the predetermined brightness level, the dimming control means sets the current flowing through the LED load 4 to a pulsed current and dims the LED load 4 by varying a DUTY ratio of the pulsed waveform. COPYRIGHT: (C)2011,JPO&INPIT |
