Retiming-based logic synthesis for low-power

Power management has become a great concern in VLSI design in recent years. In this paper, we consider the logic level design technique for low power applications. We present a retiming-based optimization method, in which part of the circuit is selected and moved so that it produces logic signals one clock cycle before they are actually applied. If these values can solely determine the output logic level, then the other part of the circuit can be turned-off to save power. We explore acceptable retimed circuit structures, in which circuit function is not changed. An algorithm is proposed to select the optimal logic block to be retimed. We experiment the low-power circuit structure with some MCNC benchmark circuits, and results indicate an improvement over previous methods. Our method achieves a significant reduction in switching activity, and the reduction can be more than 70% in some case. The required area overhead is very small.