CHAPTER LIST

Chapter 2 presented circuits that convert AC to DC. The rectifier circuit provides an average voltage to a type of load that requires a direct current. After rectification, it is often necessary to provide more than one DC voltage to various devices or equipment. For example, a system might require 12 VDC for a motor, 5 VDC for logic circuitry, and possibly -12 VDC for a communications channel. One solution to this design problem is to provide three separate rectifier circuits, each with its own transformer with the proper turns ratio to provide the required DC level. This solution is applicable when separate isolated outputs are required. Often, however, the output potentials are with respect to one another and, in such a case, a multitapped transformer applies. In either case, the size, weight, and cost of the transformers may not provide an optimum design. Furthermore, the issue of regulation must be addressed.

The circuit technology that meets the design challenges of size, weight, and cost are DC-DC converters. These circuits take a DC voltage input and convert it to a higher or lower DC voltage output, or even a DC voltage output of opposite polarity than the input. Furthermore, these circuits provide regulation, as they keep the output...