Patent ID: 8773045

Claim:
A light emitting diode (LED) driving device for driving an LED module, said LED driving device comprising: a direct current (DC) to DC converter module including a full-bridge switching circuit for receiving a first DC electric power and for converting the first DC electric power into a first alternating current (AC) electric power, a resonant circuit electrically connected to said full-bridge switching circuit for receiving the first AC electric power and for filtering out high frequency harmonic components of the first AC electric power to output a second AC electric power, a rectifier circuit electrically connected to said resonant circuit for receiving the second AC electric power and for converting the second AC electric power to output a second DC electric power, and a first control circuit electrically connected to said full-bridge switching circuit and said rectifier circuit for receiving the second DC electric power from said rectifier circuit, for modulating a voltage of the second DC electric power, and for controlling switching operation of said full-bridge switching circuit according to the voltage thus modulated, such that said rectifier circuit outputs the second DC electric power with a predetermined voltage value; and a driving module including a buck converter circuit electrically connected to said rectifier circuit for receiving the second DC electric power therefrom and operable to buck convert the second DC electric power into a third DC electric power to be provided to the LED module for driving the LED module, and a second control circuit electrically connected to said buck converter circuit and disposed to receive a square wave signal alternating between two logic levels, said second control circuit being operable to output a control signal to be received by said buck converter circuit when the square wave signal is at one of the logic levels, said buck converter circuit being operable to modulate pulse width of the third DC electric power according to the control signal so as to output a current flowing through the LED module with a predetermined current value.