Study Of The Electro-Magnetic Interference In High-Frequency Switching-Mode Power Supply

The rapid development of microelectronics requires miniaturization and compact components or systems. In these systems, more and more switching-mode power supply (SMPS) are used to improve the performance of the system. However, the electron-magnetic interference (EMI) in the system can result in deterioration of the performance. This dissertation focus on the analysis of the EMI mechanism and EMI measurement methodology as well as the EMI suppression.Based on the analysis of EMI mechanism, this dissertation gives a detailed description of the soft-switch operation, the filter design, and printed-circuit-board (PCB) design. Some misunderstandings about the system setup are corrected as well.In addition, the equipment specifications and the methods for the measurement of EMI are provided. These include the interference source, the transfer response and the sensitivity of the sensor, etc.Finally, simulations and experiments are performed, and the results are compared. These results indicate that the method sued in this dissertation are excellent in reducing EMI for high-frequency switching power supply.