Abstract
As non-isolated step-up and step-down DC−DC converters are at present widely used in various fields, this review will summarize and introduce non-isolated step-up and step-down DC−DC converters in various aspects. First of all, the origin and development of power electronics technology and the generation and principle of certain basic non-isolated step-up and step-down DC−DC converters are briefly stated. Subsequently, according to their different characteristics, including whether they are unidirectional or bidirectional, voltage-fed or current-fed, or hard-switching or soft-switching, the review will classify them and analyze their advantages and disadvantages. Meanwhile, in order to change the voltage gains of the DC−DC converters, different voltage change techniques are applied to them. The review will elaborate on the four technologies (switched capacitors, voltage multipliers, switched inductors and different ways of connecting), providing examples and analyzing the topologies in which they are applied, before summarizing the advantages and disadvantages of these techniques. Finally, this review will describe the specific applications of non-isolated step-up and step-down DC−DC converters and the reasons behind their ubiquity and popularity. Although the performances of current DC−DC converter topologies are good, there continues to be increasing demand, an updating of the topology structure, and improvements in terms of their performance. In the future, DC−DC converters will play a more important role in industrial production and people’s lives.