On the stability domain of a DC-DC buck converter with software control loop

Abstract

In recent years, there has been an increasing interest in developing software controlled DC-DC converters because of their fast configurability, e.g. for several supply and load values. This paper aims at exploring the stability of a DC-DC buck converter with a software control loop in the multidimensional space of control parameters. Once the stability domain is determined, it can be further used to search for the optimal parameter values for which the output voltage of the converter satisfies specific performance requirements. In this paper, we determine the stability domain by two approaches. First, we apply an analytical method that uses an analog-to-digital transform followed by the D-decomposition technique. Second, we apply a searching algorithm developed to efficiently characterize pass/fail behavior of electronic devices. The results obtained by the two methods are directly compared and discussed. The analytical approach is more conservative in determining the stability border, identifying a sub-domain of the real one. The search-based method proved to be more accurate in determining the stability border, at the cost of additional simulation runs.