Research On The Filter Based On Impedance Characteristics Of Switching Power Supply Of Information Equipment

At present, we do not know the noise source internal impedance of noise sourcewhen we design domestic and foreign filter. We often set as a universal value (e.g.,50ohms) for designing the noise source impedance. For a generic filter designing, Thisdesign of filter have not a well effect. Therefore, this article focuses on the switchpower source internal resistance characteristics, The first analysis of the understandingof the basic working principle of switch power supply, From the basic circuit theory toanalyze the electromagnetic interference produced by switching power supplymechanism, And gave the simulation analysis; Secondly, combined with the switchingpower supply in common mode and differential mode current transmission path. Bytesting the means to understand and grasp the switching power supply ofcommon-mode and differential-mode internal impedance characteristics. Proposes touse the double current probe method and insertion loss method, switching powersupply for the differential mode and common mode impedance in the frequency bandof the10KHz-10MHz range test research; At the end of the switching power supplyimpedance test results with different impedance filter for GJB152A CE102test itemstest validation, In order to verify the above two methods of measuring resistance withthe correctness of the results. Getting the information equipment switching powersupply of differential mode and common mode impedance characteristics for thefollow-up of switching power supply based on EMI filter design with.