DC-DC converter-aware power management for low-power embedded systems

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 DC_DVS technique for dc-dc converter-aware energy-minimal DVS. 2) DC_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 DC-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., DC-lp, based on DC_DVS and DC-CONF, which addresses dc-dc converter configuration and DVS simultaneously. Experimental results show that DC-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-de converters.