Analysis of a CMC (Common Mode Choke) Insertion Loss and Common Mode Current Characteristics in a Balanced Transmission Line with a CMC Inserted(Electromagnetic Compatibility(EMC))

概要

論文の詳細を見る
For common-mode noise current reduction, a CMC (Common Mode Choke) is widely used in signal transmission line circuits consisting of a ground and two conductors (a balanced transmission line). However, a common-mode noise current reduction characteristic is not clearly analyzed yet in the case that a CMC is inserted in a balanced transmission line. In this paper we propose the calculation method of CMC insertion losses and derive an equation to analyze the common-mode current characteristics of a balanced transmission line with a CMC inserted. The analyzed frequency range is from 100 kHz to 100 MHz. We conclude that in the frequency range up to 30 MHz: (1) the proposed insertion loss calculation method is useful for analyzing CMC insertion losses in differential-mode and in common-mode; (2) the derived circuit equation can be applied for analyzing the common-mode current characteristics of a balanced transmission line locally unbalanced with conditions of a CMC inserted; (3) the proposed calculation method may give the expected results that a CMC should be placed in a signal source side of an unbalanced point of a pair-cable for reduction of common-mode currents; and (4) if it is placed in a terminal (or load) side of an unbalanced point, there is no effect, or rather common-mode currents are increased by the insertion of a CMC.
社団法人電子情報通信学会の論文
2003-07-01