Controller-based power management for low-power sequential circuits

Abstract

A low-overhead controller-based power management technique that re-specifies control signals to reconfigure existing multiplexer networks and functional units to minimize unnecessary activity. Though the control signals in an RT-level implementation are fully specified, they can be re-specified under certain states/conditions when the data path components that they control need not be active. Another aspect of this invention is an algorithm to perform power management through controller re-specification, that consist of constructing an activity graph for each data path component, identifying conditions under which the component need not be active, and re-labeling the activity graph resulting in re-specification of the corresponding control expressions. The algorithm avoids the above negative effects of controller re-specification. Experimental results demonstrate that (i) controller re-specification allows us to perform efficient power management and obtain large power savings for control-flow intensive designs, which pose several challenges to conventional power management techniques, and (ii) it is important to consider the various potential negative effects while performing controller re-specification in order to obtain maximal power savings.