Optimizing Power and Throughput for M-Out-Of-N Encoded Asynchronous Circuits

Jun Xu1,  Ge Zhang2,  Weiwu Hu2
1Institute of Computing Technology, Chinese Academy of Sciences; Graduate Univiersity of Chinese Academy of Sciences, 2Institute of Computing Technology, Chinese Academy of Sciences; Loogson Technology Corporation Limited


The m-out-of-n encoded asynchronous circuits are able to implement the truly delay-insensitive circuit operations, but they suffer from higher power dissipation due to the large amount of logic cells. Besides, the throughput of the circuits is also worse than the synchronous counterparts since the four-cycle handshake protocol requires inserting a “NULL” token between two adjacent valid data transmissions. In this paper, we first propose a power gating technique to reduce the leakage power consumption in the idle phase, then figure out a replication method to improve the throughput at the cost of area increase. The evaluation results show that about 85% of leakage power reduction can be obtained when the power gating scheme is employed, and 62% of throughput improvement can be acquired nearly without additional power penalty when both proposals are integrated.