Single Inductor, Tiny Buck-Boost Converter Provides 95% Efficiency in Lithium-Ion to 3.3V Applications

摘要

In portable applications powered by a single lithium-ion cell, the input voltage can typically change from 4.2V initially, down to 2.5V at end of life. It is a challenging task to provide a regulated voltage within the range of the battery. Until now, the most popular solution has been the SEPIC converter, but its mediocre efficiency and requirement of both a coupled inductor and a high current flyback capacitor make it a less than optimal solution. Another option is to cascade a Boost converter with either an LDO or a Buck converter, but the additional area and cost of the extra components, as well as low efficiency, are major drawbacks. Linear Technology's new LTC~(~R)3440 Buck-Boost converter provides the most compact solution with the highest efficiency, thereby reducing cost, increasing battery life and saving precious real estate.