Analysis of EMI characteristics of switched mode power supply and switching noise reduction methods Shin Hyo Sub Department of Semiconductor and Display Engineering Sungkyunkwan University

Analysis of EMI characteristics of switched mode power supply and switching noise reduction methods Shin Hyo Sub Department of Semiconductor and Display Engineering Sungkyunkwan University 

 This paper classifies sources of switching noise of switched mode power supply and methods to reduce the effect of them. In this study, conventional approach to apply auxiliary switch between switching node and output node is enhanced, by removing original rectifying circuit and by applying auxiliary switch between switching node and VSS node. When turn-on duration of the auxiliary switch was varied, small pulse width duration shows less noise reduction effect, on the other hand large pulse width duration shows more noise reduction effect. However power efficiency showed reverse trend with noise reduction effect, so there is a trade-off between noise reduction effect and power efficiency. The effect of adding RC and RL snubber in addition to the auxiliary switch was investigated. When RC snubber was added, switching node voltage showed maximum reduction. Conducted noise simulation with line impedance stabilization network also showed noticeable reduction of differential mode noise.
 Keywords: Switched mode power supply, EMI, Conducted noise, snubber, switching ringing noise.
LINK
https://www.mediafire.com/file/f00t9zi6xcxq4ng/ANALYSIS_OF_EMI_CHARACTERISTICS_OF_SWITCHED_MODE_POWER_SUPPLY.pdf/file