TABLE OF CONTENTS All electronic systems require power supplies to operate. This part of the system design is often overlooked. But, as discussed in the amplifier section on PSRR (power supply rejection ratio), the AC component of the power supply (noise) may add to the output of the amplifier. And the PSRR has a strong frequency dependence, falling as frequency increases. The supply voltage(s) must be kept as quiet as possible for optimum performance of high performance circuits. Local decoupling helps but it is not sufficient.
Power management broadly refers to the generation and control of regulated voltages required to operate an electronic system. It encompasses much more than just power supply design. Today's systems require power supply design be integrated with the system design in order to maintain high efficiency. In addition, distributed power supply systems require localized regulators at the PC board level, thereby requiring the design engineer to master at least the basics of both switching and linear regulators.
Integrated circuit (IC) components such as switching regulators, linear regulators, switched capacitor voltage converters, and voltage references are typical elements of power management.
Historically, the standard for supply voltages was 15 V. In recent years the trend is toward lower supply voltages. This is partially due to the processes used to manufacture integrated circuits. Circuit speeds have increased. One of the enabling technologies of this increase is the reduction of size of the transistors used in the process. These smaller feature sizes imply lower breakdown voltages, which, in...
