This paper presented a novel control method to improve totem-pole bridgeless PFC efficiency: with a combination of a special switching frequency profile, a zero current detection method, and a PWM reset mechanism, let PFC operate at continuous conduction mode (CCM) at AC peak, and switch to triangular current mode (TCM) with zero voltage switching (ZVS) around AC zero-crossing area, the efficiency is greatly improved. In addition, a revised average current mode controller generates PWM for both CCM and TCM operation, resulting a smooth mode transition without any input current distortion.
