A Complete Synthesis Method for Block-Level Relaxation in Self-Timed Datapaths

Abstract

Self-timed circuits present an attractive solution to the problem of process variation. However, implementing self-timed combinational logic can be complex and expensive. This paper presents a complete synthesis flow that generates self-timed combinational networks from conventional Boolean networks. The Boolean network is partitioned into small function blocks which are then synthesised using self-timed techniques. The procedure employs relaxation optimisations to distribute the overheads associated with self-timed networks between function-blocks. Relaxation is incorporated into the function block synthesis procedures, meaning the optimisations can be applied at a much finer granularity than previously possible. The new techniques are demonstrated on a range of benchmarks showing average reduction of 5% in area, 26% in latency and 48% in energy over gate-level relaxation techniques and 17% in area, 8% in latency and 20% in energy consumption over other block-level relaxation techniques.