Presentation Information
[B-4-29]Investigation of CMC Placement Conditions for Resonance Frequency Shifting Toward Signal Integrity in Branched Transmission Lines
〇Sayaka Sekiguchi1, Hiroya Ueyama1, Naoki Iida1, Yoshiki Kayano2, Fengchao Xiao2 (1. Murata Manufacturing Co., Ltd., 2. The University of Electro-Communications)
Keywords:
differential line,Branch Circuit,Common-Mode Choke,Resonance Frequency,open stub
In recent automotive networks, bus-type branch circuits that control multiple sensors and other devices from a main board are being considered. Since such branch circuits operate as open stubs, stub resonance can overlap with the signal frequency band, causing transmission loss to increase at specific frequency components and degrading signal quality. Furthermore, since common-mode chokes (CMC), which are used to reduce EMI, affect the resonance frequency of the lines, standards specify the inter-line capacitance. However, the impact of the CMC’s inter-line capacitance and placement on the resonance frequency has not been clarified. Therefore, in this study, we formulated the relationship between the inter-line capacitance and placement of the CMC and the resonance frequency, and investigated a method for shifting the resonance frequency toward higher frequencies by adjusting the CMC placement. The analytical and simulation results showed good agreement, confirming the effectiveness of the method for shifting the resonance frequency based on inter-line capacitance and placement.