This digest proposes a low Common-Mode (CM) noise Full-Bridge (FB) LLC resonant converter with the Split Primary Winding Transformer (SPWT) configuration. The transformer primary winding is split into two windings and the resonant tank is connected between these two windings. With a symmetrical winding structure, the CM noise current generated in the transformer can be canceled completely. A 360W FB LLC prototype is built to verify the feasibility and validity of the proposed methods. The CM noise is reduced by around 11 dB (a reduction of around 4 times) below 5 MHz.
