A low frequency supercapacitor circulation technique to improve the efficiency of linear regulators based on LDO ICs

Abstract

Linear regulators have output specifications far superior to switch-mode techniques, except for the overall efficiency. This efficiency limitation can be overcome by applying a very low frequency supercapacitor circulation technique at the input side of a low dropout regulator IC. The technique was proven in 12V to 5 V versions, and, can be easily applied to other power supplies such as 5 to 3.3V or 5 to 1.5V versions required by various processors. The paper outlines the concepts and experimental results related to this technique. With the commercial LDO chips available with output current ratings up to 10A, and, thin profile supercapacitors available are with DC voltage ratings from 2.3V to 5.5V, the technique assists developing medium current linear regulators which could compete with present day switch-mode power supplies in efficiency and compactness, maintaining the superior output specifications of a linear regulator.