Patent ID: 7091675

Claim:
A driving apparatus for cold cathode fluorescent lamps, comprising: a primary and at least a secondary driving circuits; a primary and at least a secondary light tubes; a primary and at least a secondary feedback circuits; and at least two photosensitive elements corresponding to the primary and said secondary light tubes, respectively; wherein the primary and said secondary driving circuits provide power to drive the primary and said secondary light tubes, respectively, photoelectric currents of said photosensitive elements alter according to the respective brightness of the primary and said secondary light tubes, the primary feedback circuit receives the photoelectric current of a single corresponding photosensitive element and provides an output signal to the primary driving circuit, and said secondary feedback circuit receives at least two photoelectric currents of said photosensitive elements and provides at least an output signal to said secondary driving circuit in order to keep the brightness of said secondary light tube the same as the brightness of the primary light tube.