We discuss the design of energy-efficient pipelines for asynchronous VLSI architectures. To maximize throughput in asynchronous pipelines it is often necessary to insert buffer stages, increasing the energy overhead. Instead of optimizing pipelines for minimum energy or maximum throughput, we consider a joint energy-time metric of the form � �,where�is the energy per operation and � is the time per operation. We show that pipelines optimized for the � � energy-time metric may need fewer buffer stages and we give bounds when such stages can be removed. We present several common asynchronous pipeline structures and their energy-time optimized solutions. 1.

Thermal management is becoming increasingly important in circuit designs with high power density. Circuits that overheat beyond specified operating conditions may suffer timing failures, or become damaged for various reasons, including thermal runaway. Traditional power management in synchronous systems often involves transitions to different system states or modes, typically involving changes in clock frequencies or voltage levels. However, the self-timed nature of asynchronous circuits allows delays to vary continuously during operation, enabling stall-free performance-throttling. We present a novel application of a thermally sensitive circuit to automatically regulate the performance and power consumption of asynchronous circuits, with minimal implementation overhead. 1

Abstract We discuss the design of energy-efficient pipelines for asynchronous VLSI architectures. To maximize throughput in asyn-chronous pipelines it is often necessary to insert buffer stages, increasing the energy overhead. Instead of optimizing pipelines for minimum energy or maximum throughput, we consider a joint energy-time metric of the form Eo/ ff, where E is the energyper operation and o / is the time per operation. We show that pipelines optimized for the Eo/ ff energy-time metric may need fewer buffer stages and we give bounds when such stages can be removed. We present several common asynchronous pipelinestructures and their energy-time optimized solutions.

Thermal management is becoming increasingly important in circuit designs with high power density. Circuits that overheat beyond specified operating conditions may suffer timing failures, or become damaged for various reasons, including thermal runaway. We present a novel application of a thermally sensitive circuit to automatically regulate the performance and power consumption of asynchronous circuits, with minimal implementation overhead, and free of interruption of operation. 1