A Common Mode And Differential Mode Integrated EMI Filter And Planar Research

As the performance of the discrete EMI filter is badly affected by its high frequency parasitic parameter, the paper presents a new common and differential mode integrated EMI filter. The new EMI filter has high attenuation characteristics by the results of the oscilloscope. For the developing trend of short, small, light, and thin of the electronic device at the present time, planar integrated structure of EMI filter should be established. For the drawback of the traditional transmission line theory, the paper presents a new generalized transmission line structure. On the base of the generalized transmission line structure, the planar electromagnetic module of the differential mode and common and differential mode integrated EMI filter are established. In order to have higher attenuation and meet parameter range, the paper uses the connection of multi-L-C cells and multi-conductor L-C cells. The validity of the structure is verified by software emulation.