Design and Implementation of Fully-Integrated Inductive DC-DC Converters in Standard CMOS pp 27-63 | Cite as

# Basic DC-DC Converter Theory

## Abstract

Several methods exist to achieve DC-DC voltage conversion. Each of these methods has its specific benefits and disadvantages, depending on a number of operating conditions and specifications. Examples of such specifications are the voltage conversion ratio range, the maximal output power, power conversion efficiency, number of components, power density, galvanic separation of in- and output, etc. In order for the designer to obtain a clear view of the DC-DC voltage conversion methods and their individual advantages and disadvantages, with respect to monolithic integration, the three fundamental methods are discussed in this chapter. The first and oldest method of performing DC-DC voltage conversion is by means of linear voltage converters (resistive dividers), which are explained in Sect. 2.1. The second method is by means of capacitor charge-pumps, as explained in Sect. 2.2. The latter two methods are explained more briefly as this work will mainly concentrate on inductive type DC-DC converters, which are discussed in Sect. 2.3. Power conversion efficiency is in most cases a primary specification for any given energy converter. Therefore, a formal method for the fair comparison of DC-DC step-down voltage converters, in terms of power conversion efficiency, is introduced in Sect. 2.4. This method is referred to as the Efficiency Enhancement Factor (EEF). The chapter is concluded in Sect. 2.5.

## Keywords

Voltage Source Power Conversion Efficiency Linear Series Boost Converter Voltage Converter## References

- [Bre08]T.V. Breussegem, M. Wens, E. Geukens, D. Geys, M. Steyaert, Area-Driven Optimization of Switched-Capacitor DC/DC Converters. IEEE Electron. Lett.
**44**(25), 1488–1490 (2008) CrossRefGoogle Scholar - [Bre09a]T.V. Breussegem, M. Steyaert, A 82% Efficiency 0.5% Ripple 16-Phase Fully Integrated Capacitive Voltage Doubler, in
*IEEE Proceedings of the 2009 Symposium on VLSI Circuits*, vol. 1, 2009, pp. 198–199 Google Scholar - [Bre09b]T.V. Breussegem, M. Wens, E. Geukend, D. Geys, M. Steyaert, A DMOS Integrated 320 mW Capacitive 12 V to 70 V DC/DC-Converter for Lidar Applications, in
*IEEE Energy Conversion Congress and Exposition*, vol. 1, 2009, pp. 3865–3869 CrossRefGoogle Scholar - [Eri04]R.W. Erickson, D. Maksimović,
*Fundamentals of Power Electronics*, 2nd edn. (Kluwer Academic, New York, 2004). First edition: 2001 Google Scholar - [Mak95]M.S. Makowski, D. Maksimovic, Performance Limits of Switched-Capacitor DC-DC Converters, in
*Proceedings of IEEE Power Electronics Specialists Conference*, 1995, pp. 1215–1221 Google Scholar - [Ram10]Y. Ramadass, A. Fayed, B. Haroun, A. Chandrakasan, A 0.16 mm
^{2}Completely On-Chip Switched-Capacitor DC-DC Converter Using Digital Capacitance Modulation for LDO Replacement in 45 nm CMOS, in*IEEE International Solid-State Circuits Conference Digest of Technical Papers*, 2010, pp. 208–209 Google Scholar - [Rin98]G.A. Rincon-Mora, P.E. Allen, A Low-Voltage, Low Quiescent Current, Low Drop-Out Regulator. IEEE J. Solid-State Circuits
**33**(1), 36–44 (1998) CrossRefGoogle Scholar - [Wen08a]M. Wens, M. Steyaert, A Fully-Integrated 0.18 μm CMOS DC-DC Step-Down Converter, Using a Bondwire Spiral Inductor, in
*IEEE Proceedings of the Custom Integrated Circuits Conference*, vol. 30, 2008, pp. 17–20 Google Scholar