Patent ID: 8242713

Claim:
An LED illumination system for emitting light with different light intensities at different times, comprising: an LED lamp; a control circuit comprising a timing unit, a control unit, a PWM signal generating unit, and a micro-programmed control unit, the timing unit dividing an operating period of the LED lamp into a plurality of different time segments, and outputting a clock signal at a start of each of the different 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 the different time segments, the micro-programmed control unit located out of the LED lamp and setting a program therein to control the timing unit, the control unit and the PWM signal generating unit; 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 control the LED lamp to emit light having different light intensities at the different time segments of the operating period.