Today solid state lighting is one of the most rapidly growing industries. Unfortunately light-emitting diodes require additional electronics (ballasts, drivers) for proper operation with conventional energy sources. Therefore this paper summarizes the previous studies of LED luminous flux regulation techniques, as well as extends previous studies of current fed (CF) converters. Requirements for the switch mode constant current source are discussed in this paper. Two suitable circuits as well as control algorithm are considered here. PSIM models of the converter were created and the operation with CF converters was approved. The considerations regarding the practical implementation are given in the end of this paper.