A new primary side controlled high power factor single-stage flyback LED driver

A new primary side controlled high power factor single-stage flyback LED driver with self-adjusted current reference proposed in this paper. The self-adjusted current reference is realized by a negative feedback circuit to achieve output current regulation and suitable for discontinuous conduction mode (DCM) or boundary conduction mode (BCM). The output of the self-adjusted current reference is a half-sine waveform and followed by the primary current, hence high power factor can be achieved. A DCM single-stage flyback LED driver with self-adjusted current reference is analyzed in this paper and detailed design considerations are presented. Finally, a DCM laboratory prototype for LED driver with 360mA/25V output based on the theoretical analyses was built up. Experimental results show that good output current regulation and high PF can be achieved.