The EMC Analyzing And Testing Of The Computer Switching Mode Power Supply

Modern electronic engineers must take into account the electromagnetic compatibility (EMC) of the electronic equipments, the predicting of EMC may solve the EMC problem before the products being made, It may save a mass of time and money. Switching Mode Power Supplies (SMPS) offer many advantages over linear regulators, such as high efficiency and relatively smaller size and lighting weight. However, SMPS operate at high switching frequencies, and the associated transient pulses are full of high frequency harmonics that may cause electromagnetic interference (EMI). First of all, the EMC theory is introduced. The operating mechanism of the switching mode power supply is analyzed in detail. Secondly, The EMC of PC Switching Mode Power Supply is Analyzed theoretically .the restraining measures also be discussed, the measures include reducing the interference energy of the interference source,destroying or weakening the path of interference noise spreading,shielding,and reasonable placing and routing et. Thirdly, a reasonable and effective research method to predict the PC SMPS radiated EMI by using the field analyzing is presented, and the EMC test of the PC SMPS was done for comparing with the result of prediction. Finally, the summary is made and main results are given.