An Experimental Review of Step-Down Converter Topologies with Wide Input Voltage Range for Modern Vehicle Low-Power Systems

This study explored wide input voltage range step-down converters, which are crucial for supplying low-voltage power to microcontrollers, communication modems, and other low-power electronic circuits in modern vehicles that feature a diverse range of battery voltages, from 12 V to 90 V. Specifically, it focuses on converters suitable for devices employing 2G to 5G communication modems that typically require a 4 V supply. This article conducted a review of existing step-down converter technologies, focusing on the comparative analysis of synchronous versus asynchronous switched-inductor converters. Experimental data on 14 different converters is presented, where theoretical efficiency predictions are compared with empirical measurements. Using the dataset of 326 points gathered through experimental evaluation enabled evaluation of the accuracy of the efficiency estimating mathematical model, which demonstrated 73% accuracy for input voltages ranging from 12 V to 90 V and output currents from 0.1 A to 2 A. Further analysis demonstrated that estimating power losses in milliwatts enhanced the model’s accuracy, as indicated by a 94% correlation between measured and calculated power losses and an 87% correlation of measured power losses with measured temperature. This study provides insights that will guide both the authors and readers in developing more efficient DC-DC step-down converters, optimized for modern automotive applications.