| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED lighting device capable of superposing communication signals in free and easy extraction on on-off pulses of PWM control, in case LEDs are put under luminance adjustment by the PWM control. SOLUTION: The communication signals including luminance information of the LEDs 1 sent from a lighting part 2 via a power source cable W to a lighting drive part 3 in superposition on the on-off pulses of the PWM control are taken out at off-pulse time of the PWM control, so that the communication signals can be precisely taken out as driving current is low at the LED lighting off time as compared with extraction at on-pulse time at the LED lighting time. Therefore, communication signals can be superposed in free and easy extraction on the on-off pulses of the PWM control in a simple structure, without taking trouble to separately add other cables. COPYRIGHT: (C)2010,JPO&INPIT
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