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Radiated EMI study on super‐junction VDMOS in flyback power converters
Author(s) -
Cheng Weichang,
Xu Shen,
Sun Weifeng
Publication year - 2017
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.2313
Subject(s) - emi , electromagnetic interference , parasitic extraction , electrical engineering , electronic engineering , slew rate , parasitic capacitance , capacitance , converters , engineering , flyback transformer , conducted electromagnetic interference , transistor , physics , voltage , transformer , electrode , quantum mechanics
Summary Electronic products must satisfy radiated noise specifications. In this paper, the impact of the power devices structures on the radiated electromagnetic interference (EMI) is investigated. The key stages of turn‐on and turn‐off waveforms in a flyback power converter using super‐junction metal–oxide semiconductor field‐effect transistor (SJMOS) are first discussed. Then, the impacts of parasitic capacitances on fast slew‐rate edges and harmonics are proposed. According to the analysis, the parasitic capacitances are considered to be the decisive factors of radiated EMI in the SJMOS. Furthermore, the unique formation mechanism and characteristic of parasitic capacitances in SJMOS are discussed. Based on the analysis, three groups of SJMOS with grid gate structure are fabricated to adjust the parasitic capacitance and then to validate the theory. The radiated EMI performances of three SJMOS with different structural parameters are then tested and discussed. The theoretical analysis agrees with experimental results. As an important advantage, the structure presented in this paper is provided to adjust the parasitic capacitances purposely to achieve a better tradeoff between the efficiency and EMI performance. Copyright © 2017 John Wiley & Sons, Ltd.