Patent ID: 8164271

Claim:
A uni-directional light emitting diode drive circuit in bi-directional power series resonance, comprising: first and second terminals for receiving power input bi-directional power from a bi-directional power source; a capacitive impedance component; an inductive impedance component that is connected to the capacitive impedance component at an intermediate connection node, the inductive impedance component and capacitive impedance component forming a series circuit that is connected between the first and second power input terminals and that is in series resonance status with the bi-directional power source; a rectifier device that is connected to the intermediate connection point and that provides DC power; and a uni-directional light emitting unit that is driven by the DC power, wherein the capacitive impedance component comprises at least one capacitor and the inductive impedance component comprises at least one inductor, wherein the bi-directional power is one of AC power with a constant or variable voltage and a constant or variable frequency, bi-directional square wave power with a constant or variable voltage and constant or variable frequency, and bi-directional pulse wave power with a constant or variable voltage and constant or variable frequency, wherein the rectifier device comprises at least one bridge rectifier or at least one half-wave rectifier, and wherein the light emitting unit comprises one of an LED, a plurality of LEDs connected in series, and a plurality of LEDs connected in parallel.