The power factor corrector (PFC) preregulator, located between the front-end rectifier bridge and the input filter capacitor of an offline converter, provides a quasi-sinusoidal current from the mains in phase with the line voltage. In such way, a high power factor (PF) value (>0.9) and low input current harmonic distortion (THD) value (<10%) are obtained. The boost topology, through its numerous advantages, is mainly used.
The block diagram will help you make the right choice from a wide range of recommended products.