Modeling and Analysis of Differential-Mode Noise in a USB-C Charger

In order to design a compact and effective elec-tromagnetic interference (EMI) filter for USB-C chargers, this paper proposes a new DM noise model based on common-mode (CM) and differential-mode (DM) electrical behaviors. The effects of X -capacitors and single-stage EMI filters are analyzed and discussed. Also, the formulas of insertion gain (IG) are derived to evaluate the performance of EMI filters. Finally, a 65W USB-C charger is developed to verify the effectiveness of the proposed DM model. Given by experimental results, the calculated attenuation values of intrinsic DM (IDM) noise are close to measured results, which provides a useful tool for the design of EMI filters.