A Comparison of Spread Spectrum and Sigma Delta Modulations to Mitigate Conducted EMI in GaN-Based DC-DC Converters

GaN power transistors offer significant advantages with respect to Si ones, but introduce challenges in meeting EMC regulations due to their high switching frequencies. This paper compares two modulation schemes, Spread-Spectrum Modulation (SSM) and Sigma-Delta Modulation (Σ∆M), for reducing the conducted Electromagnetic Interference (EMI) delivered by GaN-based DC-DC converters. The study analyzes how these techniques impact converter performance and evaluates their effectiveness in reducing conducted EMI at low frequencies. The findings provide valuable insights for designers seeking the most effective strategy for EMI mitigation.