Reduction of Common Mode Conducted EMI in GaN-Based Two-Switch Flyback Converters Using the Delay Compensation Technique

Common mode conducted EMI is a critical issue in power switching converters, particularly in automotive applications. Symmetrical topologies like two-switch flyback are effective in reducing EMI, but the delay between high-side and low-side switches can worsen the delivered EMI. This work investigates the use of the delay compensation technique in a GaN-based two-switch flyback converter. The study addresses both impedance balancing and delay effects on conducted EMI. Simulation results confirm a 25 dB reduction at 200 kHz with both delay compensation and impedance balancing compared to a traditional flyback converter.