12.1 Introduction

In this chapter, the need for voltage regulation is examined. The different schemes for achieving voltage regulation and the typical ICs used are presented. By the end of this chapter, you should be able to use standard voltage regulator devices in your work and understand the advantages and disadvantages of the various types.

Generally, voltage regulators are used to keep power supply potentials constant in spite of changes in load current or source voltage. Without regulation, some circuits may be damaged by the fluctuations present in the power supply voltage. Even if devices are not damaged, the fluctuations may degrade circuit performance.

Two general forms are presented, the linear regulator and the switching regulator. Both forms have distinct advantages and drawbacks. The trick is to figure out which form works best in a given situation. Due to their wide use in modern power supply design, many regulators have achieved high levels of internal sophistication and robust performance. Often, the inclusion of voltage regulator ICs is a very straightforward – almost cookbook – affair.

The chapter concludes with a discussion of heat sink theory and application. As regulators are called upon to dissipate a bit of power, attention to thermal considerations is an important part of the design process.