Digital Combination of Buck and Boost Converters to Control a Positive Buck-Boost Converter

A high efficiency control strategy for operating a buck-boost switching regulator is presented in this paper. The sophisticated control technique can regulate an output voltage for an input voltage, which is higher, lower, or the same as the output voltage. There are several existing solutions to these problems, but all have their disadvantages. The technique introduced here is unique of its kind from the point of view of ripple content in the output voltage and the reliability of the control strategy. The main objective of this work is to have a positive buck-boost regulator that automatically transits from one mode to the other. The method introduced in this paper is a combination of buck, boost, and buck-boost modes. Basic analytical studies have been made and are presented. An average expression for the output voltage has been derived. Finally, the simulation results have been added to support the proposed theory.