Power optimization of combinational modules using self-timed precomputation

Abstract

Precomputation has recently been proposed as a very effective power management technique. Precomputation works by preventing some of the inputs from being loaded into the input registers, thus significantly reducing the switching activity in the circuit. In this paper we present a self-timed approach for the precomputation of combinational logic circuits. This technique allows for maximum power savings without the need of a clock signal. However we may incur in some delay penalty. We describe how to achieve significant power reductions without increasing the maximum delay, by choosing a judicious placement of the latches in the combinational logic circuit. Experimental results are presented for arithmetic modules, confirming that power dissipation can be greatly reduced with marginal increases in circuit area and almost zero delay increase.