Patent ID: 7443368

Claim:
A circuit apparatus for driving a light emitting diode (LED) and being energized by a power source, comprising: a first transistor; a second transistor; a capacitor connected to a base of said first transistor and to a collector of said second transistor; a resistor connected to a contact point between said base of said first transistor and said capacitor and connected to said power source; an inductor for using said power source with a low supply voltage to generate a high negative pulse voltage on a contact point between said collector of said second transistor and said inductor connected to a power ground and said collector of said second transistor; an anode of said LED connected to said power source; a cathode of said LED connected to a contact point of said collector of said second transistor and said inductor; an emitter of said first transistor connected to said power ground; a collector of said first transistor connected to a base of said second transistor; a first end of said inductor connected to said collector of said second transistor, and a second end of said inductor connected to said power ground; and an emitter of said second transistor connected to said power source, wherein said negative pulse voltage formed on a contact point between said second transistor and said inductor has an absolute value higher than an activating voltage of said LED.