A novel passive integrated unit is proposed to increase the power density of the multi-channel series resonant converter (SRC) for light-emitting diode (LED) driver circuit. Such an integrated unit consists of one transformer, one resonant inductor, two resonant capacitors and two common-mode (CM) inductors using the flexible multi-layer foil (FMLF) integration technique to reduce the volumes of these passive components. The composition principle of the proposed integrated unit is introduced and the design procedure for the integrated unit is detailed. Finally, in order to demonstrate the feasibility of the proposed ideas, one simulation model based on Maxwell/Ansoft and one prototype of the integrated unit are built, respectively.