Patent ID: 7446480

Claim:
An apparatus for switching a light source, comprising: a light sensor for sensing an ambient luminance and outputting a sensing signal to indicate whether the luminance is greater than a predetermined value; a decision device, comprising: a first direct current voltage source providing a first logic high voltage; an analog switch, coupled between the first direct current voltage source and an output end of the decision device for receiving the sensing signal and a switching signal, wherein the analog switch connects the first direct current voltage source and the output end when the luminance is greater than the predetermined value so that the decision device outputs the first logic high voltage as a lighting signal, and the analog switch connects the switching signal and the output end when the luminance is less than or equal to the predetermined value so that the decision device directly outputs the switching signal as the lighting signal; and a light source, coupled to the output end of the decision device, deciding whether or not to emit light according to the lighting signal.