Electroplated planar transformers

Planar transformers are ideal for power electronic applications where high-density energy processing capabilities and low energy losses are required, however, ferrite core weight and volume are still an issue in some applications, e.g. very thin-profile boards and planar assemblies. In this paper, it is proposed a methodology to build the entire transformer using lithography and electroplating techniques, much alike the procedures employed in conventional printed circuit board (PCB) industry, with minor adjustment setups. The proposed technique is based on a thin layer of electroplated ferromagnetic material, such as Iron-Nickel, followed by the successive copper and tin electroplating, stripping and etching procedures. This methodology allows integrating magnetic structures within the PCB prior production, aiming the construction of transformers and magnetic sensors as well.