Efficiency enhanced linear DC-DC converter topology with integrated DC-UPS capability

Abstract

Uninterruptible power supply (UPS) systems are used to buffer against input energy source disconnections. In most UPS systems associated with an AC input energy source, an AC-DC converter feeds an energy storage system such as a battery bank or a supercapacitor bank together with a DC to AC conversion systems to buffer against AC input supply failures. If the critical load is fed by a DC source, DC-UPS designs are introduced with high efficiency, less complexity, low cost and smaller size. Supercapacitor assisted low dropout (SCALDO) regulator is a novel DC-DC converter developed to achieve high efficiency in a linear regulator approach using a supercapacitor as a series dropper element in the series path of a linear regulator such as a LDO. The DC-UPS capability is a novel feature which can be integrated into the SCALDO regulator simply by oversizing the supercapacitor without using any additional hardware. This paper describes the conceptual background followed by experimental results of the DC UPS capability integrated SCALDO regulator using 12-5 V prototype.