5V/800mA SMPS is an easy-to-use module, which uses minimal components to convert a 220V AC input to a 5V DC output. The module has an output current rating of 800mA. It is widely used in mobile chargers, audio/video players, and more.
The VIPER12A is a SMPS controller IC that consists of a PWM controller with a power MOSFET. It can take in AC voltage from 85V to 265V and convert to low level voltage like 5V with output current from 10mA to 200mA.