Patent ID: 8362714
Filing Date: 2013-01-29
Classification: H05B,Y02B

Abstract:
1. An LED illumination system for emitting light with different light intensities at different times comprising: an LED lamp for illuminating an object; a control circuit comprising a timing unit, a control unit and a PWM signal generating unit, the timing unit dividing an operating period of the LED lamp into a plurality of time segments each being no less than one hour, and outputting a clock signal at a start of each of the time segments to the control unit, the control unit outputting different controlling signals corresponding to the clock signals to the PWM signal generating unit to cause the PWM signal generating unit to output different PWM signals which have different duty cycles at different time segments; and a constant current circuit electrically connecting the control circuit to the LED lamp, the constant current circuit outputting different electric currents to the LED lamp according to the PWM signals, to thereby control the LED lamp to emit light having different light intensities at the various time segments of the operating period.