Prediction of Conducted Emissions from Various DC-DC Converters by Using Two-Port Noise-Source Equivalent-Circuit Model

To predict conducted emissions from a DC-DC converter, we previously proposed a two-port (input and output ports) noise-source equivalent-circuit model, a black-box model, that focuses only on the behavior of the conducted emissions in differential mode. While developing the model, a Si-MOSFET buck converter was used for model validation. The advantage of a black-box model is that it can be easily applied to various types of converters. In this study, we verified our model by applying it to a Si-MOSFET boost converter and GaN-HEMT buck converter. The important features of our model for measurement-based parameter identification are enabling high signal-to-noise ratio measurement on the basis of the waveform-decomposition method we previously proposed and noise-level reduction at higher frequencies due to switching fluctuation. We found that the spectra predicted using our model are in good agreement with the measured spectra with switching fluctuation in terms of both the input and output ports independently of the converter type.