EMI Noise Analysis Using Frequency Domain Simulation Considering Dynamic Semiconductor Characteristics in Flyback Converter Circuits

We propose a hybrid analysis method that uses a general SPICE simulator to perform high-speed and high-precision conduction noise analysis of flyback converter circuits. Time domain analysis, generally used for conducted noise analyses, is disadvantaged by its long analysis time. Frequency domain analysis, which requires a shorter analysis time, is also used for conducted noise analyses, but it struggles to reproduce the operating characteristics of semiconductors. The hybrid analysis method enables frequency domain analysis that considers semiconductor operating characteristics by using the results of a time domain analysis as a noise source. The results of our proposed hybrid analysis method matched the results of a time domain analysis across the entire analyzed bandwidth, from $1-100 \mathrm{MHz}$. The analysis time was about $1/10$ of that of the time domain analysis.