This block diagram represents a typical single phase, wide range input AC/DC SMPS. It consists of 5 main power function blocks and 2 control function blocks. The EMI (Electro-Magnetic Interference) filter prevents switching noises from injecting back onto the AC line. The AC voltage is converted through the full-bridge rectifier. The rectified, half sine-wave, quasi-dc voltage is regulated via a PFC (Power Factor Correction) boost converter to a steady DC voltage ranging from 385V to 410V.