Patent ID: 8638045

Claim:
A LED lighting system comprising: a transformer comprising a primary winding and a secondary winding; a plurality of LED strings coupled to the secondary winding of the transformer; at least one switch coupled to at least one of the plurality of LED strings, wherein the plurality of LED strings comprises a first LED string and a second LED string and the at least one switch comprises a first switch coupled to the first LED string and a second switch coupled to the second LED string; and a controller coupled to the at least one switch and configured to control the operation of the at least one switch such that current flows through the plurality of LED strings in an alternating manner to meet a current ratio of the plurality of LED strings corresponding to a target color temperature, wherein the controller is configured such that the first switch is operated at a first duty cycle and the second switch is operated at a second duty cycle, wherein the first duty and the second duty cycle are complimentary, and wherein the controller is further configured to adjust the first duty cycle and the second duty cycle based on a change in the current through the transformer.