A brief comparison of two-phase and NOR-based four-phase pipelined asynchronous systems

Two-phase micro-pipeline asynchronous modules show faster performance than common four-phase control systems, but the conventional systems with multi-port modules normally suffer from long signal paths on stacked C-elements. NOR-based control schemes provide an alternative solution to problems such as propagation delay. This paper compares modified versions of these two popular pipelined systems. HSPICE simulation results show the two-phase pipelined system is still a reliable solution with a limited number of inputs even when the theoretically lower control overhead is disregarded. A power reduction of over 27% and a propagation improvement of more than 11% were achieved by replacing some decision circuits with modified C-elements.