As the silicon-based power devices are gradually reaching their performance limits, new power transistors such as Silicon Carbide (SiC) and Gallium Nitride (GaN) FETs have been rapidly developed in recent years. GaN devices have been widely accepted by researchers for its higher speed and efficiency than silicon power devices. However, despite all its merits, the GaN device faces a more severe problem of electromagnetic interference (EMI) than the silicon device due to its high performance. Various control techniques of EMI have been studied so far and many of them require the evaluation of EMI. Research shows that the EMI level of switching converters is related to the switching node voltage. Therefore, sensing the switching node could provide a possible solution for the EMI control.
In this thesis, an EMI evaluation method is proposed. The approach is to evaluate the EMI by sensing the switching node voltage with a giga-sample per second (GS/s) analog-to-digital converter (ADC). In order to verify the feasibility of the proposed method, a synchronous DC-DC step down (buck) converter is built. Measurements are carried out in both time and frequency domain. Experimental results proved this evaluation idea is a possible solution for the EMI evaluation.
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Zhang, Chi, "Using GS/s ADC to Evaluate the EMI of GaN-based Power Devices" (2018). Electrical Engineering Theses and Dissertations. 19.