Chapter 2 Converter Topologies and Fundamentals To build a solid understanding of the capacitive conversion technique, this chapter introduces the fundamental characteristics of capacitive DC–DC converters in Sect. 2.1. Section 2.2 discusses three different analysis techniques: Charge Flow Analysis, Charge Balance Analysis and Branch Analysis. These complementary techniques have their specific merit in the development of the state-of-the-art capaci- tive DC–DC converter modeling techniques (Chap. 3) and are used for analyzing capacitive DC–DC converters. Charge Flow Analysis demonstrates an intuitive method to determine the VCR of capacitive converters. Charge Balance Analysis builds a bridge between the conventional switched-capacitor analysis and the analysis of capacitive DC–DC converters. Branch Analysis presents a generalized technique to analyze and to qualify the topology performance. Next the converter taxonomy is discussed in Sect. 2.3 and finally the analysis techniques are demonstrated for a selection of capacitive DC–DC converter topologies in Sect. 2.4. 2.1 Characteristics DC–DC conversion by means of capacitors differs fundamentally from an inductive DC–DC converter. The most notable difference is that lossless conversion can only be achieved at infinitely high switching frequencies or by a converter with an infinitely large amount of capacitance. In practice a properly designed capacitive DC–DC converter faces only a small efficiency penalty for violating these requirements. To make this more tangible, this section offers a first look into the principles and the operation of a primitive capacitive DC–DC converter. 2.1.1 DC–DC Converter Structure A capacitive DC–DC converter consists of the two parts in Fig. 2.1: the conversion block and the control block. The conversion block is the heart of the converter and T. Van Breussegem and M. Steyaert, CMOS Integrated Capacitive DC–DC Converters, 39 Analog Circuits and Signal Processing, DOI: 10.1007/978-1-4614-4280-6_2, © Springer Science+Business Media New York 2013