System partitioning to maximize sleep time

Partitioning of a system to maximize exploitable sleep time for low-power synthesis is discussed. The motivation is to deactivate the memory refresh circuitry, apply power down or disable the clock signals during the inactive periods of operation of circuit elements, and thus minimize the power consumption. Since it is impractical to have a separate set of control signals for each circuit element (otherwise, the control itself would consume a lot of power), it is advisable to partition a circuit based on the activity patterns of its elements so that the partitions can be switched into sleep mode for long periods of time. In this paper, we formulate this partitioning problem and show that it is NP-hard. We present Geo-Part, a geometric partitioning heuristic for this problem. An efficient implementation of Geo-Part using segment tree data structure is discussed. Experimental results are encouraging.