Patent ID: 8427071

Claim:
A light emitting diode (LED) driving device comprising: an LED circuit having an input side for receiving a driving current corresponding to an AC input voltage from an external power source when the magnitude of a driving voltage across said input side is greater than a predetermined value; and a clamp circuit coupled between said input side of said LED circuit and the external power source, said clamp circuit permitting the driving current to pass through for clamping the magnitude of the driving current to a predetermined current level and for clamping the magnitude of the driving voltage to a predetermined voltage level wherein said clamp circuit includes: a first diode having an anode adapted to be coupled to the power source, and a cathode; a first transistor having a first end coupled to said cathode of said first diode, a second end, and a control end coupled to said input side of said LED circuit; a first current limiting unit coupled between said second end and said control end of said first transistor; a second diode having an anode coupled to said input side of said LED circuit, and a cathode; a second transistor having a first end coupled to said cathode of said second diode, a second end, and a control end adapted to be coupled to the power source; and a second current limiting unit coupled between said second end and said control end of said second transistor.