I’m reading the user guide for a Microchip reference design of a 300W AC/DC converter. Section 1.2 starts with these requirements:
A conventional SMPS must implement PFC if it draws more than 75 watts from the AC Mains. The PFC circuitry draws input current in phase with the input voltage, and the Total Harmonic Distortion (THD) of the input current should be less than 5% at full load. [emphasis by me]
What drives these requirements (in addition to efficiency)? Are these requirements driven by a standard or a regulation? If so, what's the driver behind the regulation?
Any insight or reference is appreciated!