Investigation of Conducted EMI Emission and Mitigation Techniques in a USB-C Charger

Due to its universal compatibility and versatility, the USB-C charger has been widely used for consumer electronics including laptops, phones, drones and so on. The standardization has reduced the need for multiple adapters of different devices and contributed to reducing electronic waste. Pursuing for convenience, the compact size of USB-C chargers is desired. However, the power density and efficiency of USB-C chargers are limited by the bulky and large EMI filters due to the severe conducted electromagnetic interference (EMI). To mitigate EMI noise effectively, this paper starts with the conducted EMI models and discloses the mechanism of conducted EMI emissions of the USB-C charger. Meanwhile, mitigation techniques including EMI filters, advanced topologies, shielding techniques and control strategies, are reviewed and summarized.