Battery-Conscious Task Sequencing I ncl u d i n g Vo I tag e/C I oc k

Operation of battery-powered portable systems can no longer be sustained once a battery becomes discharged. Maximization of the battery lifetime is a difficult task due to nonlinearity of battery behavior that depends on the characteristics of the system load profile. We address the problem of task sequencing without and with voltageklock scaling that shapes the profile so that the battery lifetime is maximized. We developed an accurate analytical battery model and validated it with measurements taken on a real lithium-ion battery used in a pocket computer. We use the model as a basis for a unique battery-conscious cost function and utilize its properties to develop several novel algorithms, including insertion of recovery periods and voltage/clock scaling for delay slack distribution.