Patent ID: 7972025

Claim:
A light emitting diode device, comprising: an illumination element comprising a plurality of light emitting diodes (LEDs); a solar cell unit for generating power; a rechargeable cell unit electrically connected to the solar cell unit for storing power generated by the solar cell unit and providing the stored power to the illumination element; a first DC/DC converter electrically connected to the solar cell unit and the rechargeable cell unit; a second DC/DC converter electrically connected to the illumination element and the rechargeable element; and a pulse width modulation (PWM) controller, wherein the solar cell unit is electrically connected to the rechargeable cell unit through the first DC/DC converter, and the rechargeable cell unit is electrically connected to the illumination element through the second DC/DC converter; wherein in a charge mode, the PWM controller receives a first feedback signal from the rechargeable battery unit, and provides a first output signal to the first DC/DC converter; and wherein in a discharge mode, the PWM controller receives a second feedback signal from the rechargeable battery unit, and provides a second output signal to the second DC/DC converter for controlling the brightness of the illumination element.