50 W Four-Output Internal Power Supply for Set Top Box

This reference document describes a built-and-tested GreenPoint solution for a 40 W (40 W nominal power, 50 W peak power) set-top box (STB) power supply, built around ON Semiconductor's NCP1308 current-mode controller. The paper presents the results of various secondary rectification and regulation techniques that were used to find the highest practical efficiency scheme for the power supply.