Patent ID: 8692484

Claim:
An automatic light regulating power supply device, connected between an AC power supply and a light-emitting-diode (LED) light string, to drive said LED light string to emit light, comprising: a sensing-and-setting unit, for sensing an infrared signal, and generating a plurality of brightness selection signals; and a digital power control unit, in which is provided with an AC/DC conversion circuit, to convert the AC power supply into a DC power and output said DC power, said digital power control unit is connected to said sensing-and-setting unit, and regulates its output power based on the infrared signal sensed by said sensing-and-setting unit and said brightness selection signals, to vary illumination of said LED light string; wherein said sensing-and-setting unit includes: a light regulator, in which is provided with a signal processing unit, a signal detection unit, a digital control signal output unit, and a brightness-setting unit, wherein, said signal detection unit, said digital control signal output unit, and said brightness-setting unit are connected respectively to said signal processing unit, said brightness-setting unit generates said brightness selection signals, and each of said brightness selection signals corresponds to a delay time; and at least one infrared sensor, connected to said signal detection unit, so that said signal processing unit regulates the output power of said digital control signal output unit, based on sensing results of said infrared sensor and said delay time corresponding to said brightness selection signal, to vary illumination of said LED light string.