Patent ID: 7880407

Claim:
A system for driving a plurality of cold-cathode fluorescent lamps, the system comprising: a subsystem configured to receive at least a DC voltage and generate a first AC voltage in response to at least the DC voltage; a power converter configured to receive the first AC voltage and convert the first AC voltage to at least a second AC voltage; and a plurality of current balancing devices; wherein the power converter and the plurality of current balancing devices are configured to be directly or indirectly coupled to a plurality of cold-cathode fluorescent lamps including N fluorescent lamps; wherein: the plurality of cold-cathode fluorescent lamps includes a 1 st fluorescent lamp, a 2 nd fluorescent lamp, . . . , a (j−1)th fluorescent lamp, a jth fluorescent lamp, a (j+1)th fluorescent lamp, . . . , an (n−1)th fluorescent lamp, and an nth fluorescent lamp; the 1 st fluorescent lamp, the 2 nd fluorescent lamp, . . . , the (j−1)th fluorescent lamp, the jth fluorescent lamp, the (j+1)th fluorescent lamp, . . . , the (n−1)th fluorescent lamp, and the nth fluorescent lamp are associated with a 1 st lamp current, a 2 nd lamp current, . . . , a (j−1)th lamp current, a jth lamp current, a (j+1)th lamp current, . . . , an (n−1)th lamp current, and an nth lamp current, respectively; n≧3; and 1<j<n; wherein: each of the plurality of current balancing devices is configured to receive two currents and balance the two currents; the plurality of current balancing devices are further configured to balance the 1 st lamp current and the 2 nd lamp current, . . . , the (j−1)th lamp current and the jth lamp current, the jth lamp current and the (j+1)th lamp current, . . . , the (n−1)th lamp current and the nth lamp current, and the nth lamp current and the 1 st lamp current, different pairs of currents being balanced by different current balancing devices; wherein: each of the plurality of current balancing devices includes a first winding and a second winding; the first winding is in series with one of the plurality of cold-cathode fluorescent lamps; and the second winding is in series with another one of the plurality of cold-cathode fluorescent lamps.