DC–DC Converter-Aware Power Management for Low-Power Embedded Systems

摘要

Most digital systems are equipped with dc–dc converters to supply various levels of voltages from batteries to logic devices. DC–DC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of dc–dc converters is changed by the output voltage level and the load current, most existing power management techniques simply ignore the efficiency variation of dc–dc converters. However, without a careful consideration of the efficiency variation of dc–dc converters, finding a true optimal power management will be impossible. In this paper, we solve the problem of energy minimization with the consideration of the characteristics of power consumption of dc–dc converters. Specifically, the contributions of our work are as follows: 1) We analyze the effects of the efficiency variation of dc–dc converters on a single-task execution in dynamic voltage scaling (DVS) scheme and propose the ${ssr DC}_{ssr DVS}$ technique for dc–dc converter-aware energy-minimal DVS. 2) ${ssr DC}_{ssr DVS}$ is then extended to embed an awareness of the characteristics of dc–dc converters in general DVS techniques for multiple tasks. 3) We go on to propose a technique called ${ssr DC}_{ssr CONF}$ for generating a dc–dc converter that is most energy efficient for a particular application. 4) We also present an integrated framework, i.e., ${ssr DC} hbox{-}{ssr lp}$, based on ${ssr DC}_{ssr DVS}$ and ${ssr DC}_{ssr CONF}$, which addresses dc–dc converter configuration and DVS simultaneously. Experimental results -show that ${ssr DC}hbox{-}{ssr lp}$ is able to save up to 24.8% of energy compared with previous power management schemes, which do not consider the efficiency variation of dc–dc converters.