Boost PFC with 100-Hz switching frequency providing output voltage stabilization and compliance with EMC standards

Consumer and household applications require cheap ac/dc power supplies complying with EMC standards. Passive solutions are bulky and do not provide output voltage stabilization. Active solutions based on power-factor correctors (PFC’s) with high-frequency switching provide compactness and regulation capability, but are generally expensive due to the need for fast-recovery diodes and complex EMI filters. This paper describes a boost PFC in which the switch is turned on and off only twice per line period. This results in limited di/dt and dv/dt and switch losses, allows use of slow-recovery diodes, and avoids the need for heavy EMI filters. In addition, the output voltage can be stabilized in a broad load range by a simple control. The switching unit, including control and protection, can also be integrated in a simple smart-power IC for large-volume applications.