Energy-Efficient Subthreshold Processor Design
Top Cited Papers
- 28 April 2009
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Very Large Scale Integration (VLSI) Systems
- Vol. 17 (8), 1127-1137
- https://doi.org/10.1109/tvlsi.2008.2007564
Abstract
Subthreshold circuits have drawn a strong interest in recent ultralow power research. In this paper, we present a highly efficient subthreshold microprocessor targeting sensor application. It is optimized across different design stages including ISA definition, microarchitecture evaluation and circuit and implementation optimization. Our investigation concludes that microarchitectural decisions in the subthreshold regime differ significantly from that in conventional superthreshold mode. We propose a new general-purpose sensor processor architecture, which we call the Subliminal Processor. On the circuit side, subthreshold operation is known to exhibit an optimal energy point (Knin)- However, propagation delay also becomes more sensitive to process variation and can reduce the energy scaling gain. We conduct thorough analysis on how supply voltage and operating frequency impact energy efficiency in a statistical context. With careful library cell selection and robust static RAM design, the Subliminal Processor operates correctly down to 200 mV in a 0.13-mum technology, which is sufficiently low to operate at Vmin . Silicon measurements of the Subliminal Processor show a maximum energy efficiency of 2.6 pJ/instruction at 360 mV supply voltage and 833 kHz operating frequency. Finally, we examine the variation in frequency and Vmin across die to verify our analysis of adaptive tuning of the clock frequency and Vmin for optimal energy efficiency.Keywords
This publication has 24 references indexed in Scilit:
- An Optimal Supply Voltage Determiner Circuit for Minimum Energy OperationsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2007
- A 2.60pJ/Inst Subthreshold Sensor Processor for Optimal Energy EfficiencyPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2006
- Variation-Driven Device Sizing for Minimum Energy Sub-threshold CircuitsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2006
- Ultralow-voltage, minimum-energy CMOSIBM Journal of Research and Development, 2006
- Ultra-Dynamic Voltage Scaling (UDVS) Using Sub-Threshold Operation and Local Voltage DitheringIEEE Journal of Solid-State Circuits, 2005
- A 180mV FFT processor using subthreshold circuit techniquesPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2004
- Ultra-low-power DLMS adaptive filter for hearing aid applicationsIEEE Transactions on Very Large Scale Integration (VLSI) Systems, 2003
- A 175-MV multiply-accumulate unit using an adaptive supply voltage and body bias architectureIEEE Journal of Solid-State Circuits, 2002
- Robust subthreshold logic for ultra-low power operationIEEE Transactions on Very Large Scale Integration (VLSI) Systems, 2001
- TEA, a tiny encryption algorithmLecture Notes in Computer Science, 1995