Novel design technique for reducing common-mode current on wire harness connected to ECUs

An approach for practical use of common-mode noise reduction technique for in-vehicle electronic equipment

“…Several studies on common-mode noise generation mechanism and its reduction method have been reported [1]- [3]. We have also studied an evaluation system comprised of ECU and wiring harnesses that are not connected directly to the ground plane, and reported that common-mode noise can be minimized by appropriately controlling the circuit pattern and component impedances [4].…”

Common Mode Voltage Evaluation for choosing Quiet MCU and Optimizing PCB Design: Electromagnetic Emissions Measurement for Integrated Circuits

“…Vss terminal was connected by one of the cable and the other cable connected Vcc terminal. By (2) For investigating Vcc and Vss fluctuation in phase, 180deg four port hybrid balun model HYB-3 (R&K) was applied as shown in Fig.9. This balun provides us Vector-sum of two 50ohm input signal in wide frequency range (5 to 1000MHz) with low insertion loss (about 4dB).…”

“…The amount of fluctuations is depending on the EMI characteristics of CPUs and the layout design of the PCB. A solution to minimize the common mode voltage for typical CPUs is the symmetrical design spending same areas for Vcc and Vss and another solutions are also available when satisfying the balancing condition [1][2] [3].…”

“…The relationship between the amount of the common mode current and the Vcc/Vss conductor area on ECU has been investigated in the previous studies [1][2] [3]. The key parameters (Fig.2) controlling the amount of common mode current on the supply lines are parasitic capacitances (Cv, Cg) and trace inductances (Lv, Lg) of supply line (Vcc/Vss) patterns on printed circuit boards (PCBs).…”