Patent ID: 7550929

Claim:
A power system for driving plural lamps, comprising: a transformer circuit for transforming a voltage level of an input alternating current (AC) signal, the transformer circuit having a first output end for outputting a first AC signal and a second output end for outputting a second AC signal, wherein the first AC signal and the second AC signal are opposite in phase; a filter and steady-flow circuit having a first plurality of filter and steady-flow units connected to the first output end for suppressing harmonic signals of the first AC signal and outputting a plurality of third AC signals, wherein each of the first plurality of filter and steady-flow units comprises an inductor and a capacitor; and a light source having a first plurality of lamps, each of the first plurality of lamps having one end connected to a respective one of the first plurality of filter and steady-flow units so as to be driven by a respective one of the plurality of third AC signals; wherein the inductor of the each of the first plurality of filter and steady-flow units is coupled between the first output end and respective one of the first plurality of lamps of the light source, and the capacitor of the each of the first plurality of filter and steady-flow units has one end coupled between the inductor and the lamp and another end grounded; wherein impedance associated with each of the inductors of the first plurality of filter and steady-flow units is substantially the same, and impedance associated with each of the capacitors of the first plurality of filter and steady-flow units is substantially the same, for making the plurality of third AC signals flowing through the first plurality of lamps substantially the same and for minimizing influence impedance of the first plurality of lamps on plurality of third AC signals.