Design and experiment research of integrated EMI filter based on flexible multi-layer foils

A novel passive integration structure based on flexible multi-layer foils was proposed for EMI filter in switching-mode power supply. Common mode (CM) inductors and capacitors, differential mode (DM) inductors and capacitors were all integrated in a single unit. This passive integration applied flexible multi-layer foils (FML). Prototypes were implemented for an 1 kW switching power supply. The conductive EMI testing result was presented. The temperature rising and efficiency curves of the integrated EMI filter were also presented. In comparison with the discrete EMI filter, the prototype in this paper can reduce the volume by 32%.