Patent ID: 8558462

Claim:
A driving circuit for a plurality of cascade light emitting diodes, comprising: a power module providing a direct current voltage and a ground potential; a plurality of light emitting diode modules serially connected between the direct current voltage and the ground potential, with each light emitting diode module comprising a bypass circuit and a light emitting diode, wherein each bypass circuit comprises a first terminal, a second terminal, and a third terminal, with each light emitting diode connecting between the first terminal and the second terminal of the bypass circuit, respectively, and wherein the first terminal of each bypass circuit is connected to the direct current or the third terminal of an adjacent upstream bypass circuit; and a constant current component serially connected between the plurality of light emitting diode modules and the power module; wherein each bypass circuit respectively comprises: a first terminal, a second terminal, and a third terminal; a reference voltage source connected to the first terminal and the third terminal and producing a reference voltage; a current limiting transistor connected between the first terminal and second terminal and adjusting a bypass current passing through, an error amplifier having a positive terminal connected to the reference voltage source, a negative terminal connected to the second terminal of the bypass circuit, and an output terminal connected to a gate or a base of the current limiting transistor; and a sensing resistor connected to the second terminal and the third terminal.