IMPROVED BUS VOLTAGE AND FEATURES OPTIMIZE LED DRIVER FOR SCOREBOARDS AND BILLBOARDS

摘要

Those huge LED billboards and advertising signs at ballparks and on the sides of buildings traditionally run their many LED drivers from 5-V buses. Equally traditionally, they have been terrible heat generators, partly from losses in the controllers themselves, and partly frorr 5imple conductive losses in each rail due to the enormous amounts of current needed to support all the triple LEDs that constitute the LED video arrays.This interesting fact came up because I asked Tony Armstrong, director of prod-uct marketing at Linear Technology, about one of the specifications on Lin-ear's LT3746 (see the figure). Developed expressly for next-generation score-boards and signs, the chip integrates a 32-channel, 20-mA LED driver with a 55-V buck dc-dc controller.