A system approach to energy management

The accumulation of popular features in portable products such as mobile handsets is driving battery life to unacceptably low levels. Substantial change will not come from incremental improvements in voltage regulator efficiency or battery chemistry, but rather from rethinking the paradigm of power consumption vs power delivery. This paper proposes that the delivery and consumption of power be considered a system, whereby power supply voltages are dynamically sized to the computational task of the moment. The closed-loop approach chosen is automatically adaptive to variations in the fabrication process and temperature resulting in optimal use of the limited energy within the battery. Test results reported on an embedded image processor reveal a 25% to 63% reduction in power at the 0.18 um process node relative to conventional power management approaches.