  This paper discusses a 100 W single stage Power Factor Correction (PFC)
flyback converter operating in boundary mode constant ON time methodology using
a synchronous MOS-FET rectifier on the secondary side to achieve higher
efficiency. Unlike conventional designs which use two stage approach such as
PFC plus a LLC resonant stage or a two stage PFC plus flyback, the proposed
design integrates the PFC and constant voltage regulation in a single stage
without compromising the efficiency of the converter. The proposed design is
advantageous as it has a lower component count. A design of 100 W flyback
operating from universal input AC line voltage is demonstrated in this paper.
The experimental results show that the power factor (PF) is greater than 0.92
and total harmonic distortion (iTHD) is less than 20% for a load varying from
25 % to 100 %. The experimental results show the advantages of a single stage
design.
