High-throughput asynchronous datapath with software-controlled voltage scaling

Adaptive control of the power supply is one of the most effective variables to achieve energy-efficient computation. In this paper, we describe the development of a high-performance asynchronous micropipelined datapath that provides robust interfaces across voltage domains, performing appropriate voltage level conversions and operating between stages with fanout-of-four delays differing by almost two orders of magnitude. With software-specified throughput requirements, the power supply of the datapath is scaled from 2.5 V to 650 mV using an on-chip dc-dc conversion system. Because of the asynchronous design style, the processor operates continuously during the voltage scaling transitions.