Practical Aspects for Analog Compensators Design in Integrated DC–DC Converters

To guarantee the required performance and proper stability, a dc–dc regulator needs to be equipped with a tailored compensation network. A proportional-integral-derivative (PID) controller is typically employed and the required compensator transfer function is obtained from the study of the dc–dc converter frequency responses. Focusing on the widely adopted analog compensator, such required transfer function can be implemented mostly following two approaches. An implementation is based on an open-loop-amplifier (OLA), equipped with input and output filter networks, while another solution deploys a closed-loop-amplifier (CLA), locally closed in feedback by means of a filter network. This article presents a fair comparison between the two most common architectures of analog compensators for switched-inductor dc–dc converters. In the analyses, the trade-offs are detailed, starting from area, mismatch, system considerations, complexity, and limits, with the goal to empower the designer with a comprehensive breakdown. Although not providing disruptive innovations but retaining a tutorial flavor, this article aims to be a unified approach to the design of analog compensators for dc–dc converters.