A Closed-Loop EMI Regulated GaN Power Converter with 500MHz-Sampling-Bandwidth In-Situ EMI Sensing and 9kHz-Resolution Global Excess-Spectrum Modulation

When applying switching power converter in automotive electronics, electromagnetic interference (EMI) is a critical issue to be addressed for reliable and safe driving. This is especially important for high-frequency gallium-nitride (GaN) power system. Traditionally, passive filter and active control circuits are widely employed to suppress EMI and thus fulfill the EMI standards through in-house testing. However, the pre-defined testing conditions can be quite different from the applications, inducing safety risks. To solve this dilemma, risk-based EMI standards have been established to link the EMI assessment to real applications [1]. Meeting this trend, an adaptive spread-spectrum modulation (SSM) scheme was reported [2]. But it highly relies on an ideal model between EMI and power conditions. On the other hand, an active filter was constructed [3] to dynamically cancel EMI. However, its effectiveness is impacted by the limited bandwidth (BW). To overcome the above issues, this work proposes a wide-bandwidth closed-loop EMI regulation for GaN power converters.