Design and implementation of an isolated switched-mode power supply for led application

摘要

This paper describes the design and implementation of an isolated switched mode power supply(SMPS) for LED lighting application. The flyback converter is used for AC to DC conversion as well as DC to DC conversion providing galvanic isolation between input and output. Basically, flyback converter can be derived from buck-boost converter, in which the inductor split to form a transformer. The transformer with specified turns ratio steps up or down the input voltage with isolation. The energy transfer from primary to secondary is controlled using a switch connected to primary. The duty ratio of the switch decides the output level, which can be controlled using an isolated secondary feedback. In this paper, a flyback circuit is designed to obtain a pure DC voltage of 12V, 5A from 230V, 50Hz AC mains. The output current can be regulated to drive a 16W LED load.