I. Introduction
Almost all modern digital systems are supplied with power through dc–dc converters because high-performance CMOS devices are optimized to specific supply voltage ranges. DC–DC converters are generally classified into two types, namely: 1) linear voltage regulators and 2) switching voltage regulators, according to the circuit implementation. However, nontrivial power dissipation is unavoidable in both types of voltage conversion and directly affects battery life. Fig. 1 shows the path of current flow through a dc–dc converter from a battery. It is reported that there is always a nontrivial power loss in the converter, the amount of which is 10% to 40% of the total energy consumed in the system.
Typical current flow path. Nontrivial power loss in the dc–dc converter results in a short battery life despite low power dissipation of the digital system.