An Accurate Approach to Calculate and Measure Capacitor Voltage and Inductor Current Levels in Hybrid Converters

Abstract

Switched-capacitor based hybrid converters, stressed by accelerating current density demands, are generally operated with large ripples in flying capacitor voltages and inductor currents, especially at moderate to high load ranges. While the general analysis technique to use average voltage and current values gives close results in the light load range, it leads to inaccurate calculations and measurements, misinterpretations, and misaligned expectations of the converters’ operations in higher load ranges with large voltage and current ripples. In this work, after discussing the problems of the average value analysis, we show that instead of average values, median voltage and current values should be used for accurate calculations, measurements, and analysis of the converters. A modified volt-second balance method is also discussed to directly determine the median levels. Verification of the analyses is provided with simulations of a high current, moderately high voltage hybrid converter.