Chapter 1. Power, Delivering Power, and Power Integrity

Power may be defined as the capacity to perform work, and is measured as the work done or energy transferred per unit of time. The greater the power, the greater the capacity to move something (against forces of attraction, repulsion, or friction) or to transfer energy (by raising the temperature of a substance, for example). With reference to electronic systems, and integrated circuits in particular, power is the presence of voltage, or electromotive force, and current, or the flow of charge. Power enables the performance of desired functions in the system and is delivered by devices that generate, store, or regulate electromotive force or flow of charge. Electronic circuits and systems consume this delivered power and convert it into other desired forms of energy or activity. The integrity of delivered power relates to its stability and invariability through variations in energy expenditure, in transfer elements, in the generating source, or in the surrounding environment. These aspects are expounded on in the following sections of this chapter, with a focus on integrated circuits and systems.