Triac dimmer compatible switching mode power supply and the method thereof

摘要

A triac dimmer compatible switching mode power supply (20) used as a LED driver is disclosed. A PFC controller (250) instead of a Non-PFC controller and a bleeder dummy load is configured in the switching mode power supply. With the PFC controller (250), the current keeping the triac (210) in the on-state is supplied by the DC/DC converter (260) itself, and the LC resonance is avoided too, so there is no need to use any dummy load, the efficiency is improved.