Design of integrated POL DC-DC converters based on two-stage architectures

Due to the functionality increase of modern battery-powered portable devices such as PDAs, smart phones, and notebooks etc., the battery life is an important issue. An efficient voltage regulator (VR) is a must if we need to extend the battery life. For this purpose, this paper discusses the employment of two-stage architecture on the design of point-of-load (POL) Dc-Dc converters. At first, the paper discusses the benefits of replacing the conventional one-stage buck converter by an integrated two-stage step-down converter. The design aspects of a two-stage 6V-to-1V converter are shown as an example to clarify the benefits of the design over one-stage approach. The results show that efficiency of two-stage converter is higher than the one-stage approach in addition to size and cost reduction. Then, the benefits of replacing boost converters by integrated two-stage step-up converters are discussed followed by a design example for two-stage step-up converter from 3.6V-to-12V. The results show that the two-stage approach increases the efficiency of the converter in addition to the benefits from stability point of view.