Energy-Delay Efficiency of VLSI Computations

In this paper we introduce an energy-delay efficiency metric that captures any trade-off between the energy and the delay of the computation. We apply this new concept to the parallel and sequential composition of circuits in general and in particular to circuits optimized through transistor sizing. We bound the delay and energy of the optimized circuit and we give necessary and sufficient conditions under which these bounds are reached. We also give necessary and sufficient conditions under which subcomponents of a design can be optimized independently so as to yield global optimum when recomposed. We demonstrate the utility of a minimum-energy function to capture high level compositional properties of circuits. The use of this minimum-energy function yields practical insight into ways of improving the overall energy-delay efficiency of circuits