Title
Tapered-Vth Approach for Energy-Efficient CMOS Buffers
Abstract
In this paper, “tapered-Vth” buffers are explored as an approach to significantly improve the energy efficiency of traditional CMOS buffers. In this approach, the transistor threshold voltage is progressively increased throughout the buffer stages, in addition to the traditional transistor tapered sizing. Analysis shows that tapered-Vth buffers are able to significantly widen the range of energy-delay trade-offs achievable in real designs, thereby showing improved design flexibility compared to single-Vth buffers. In addition, tapered-Vth buffers are shown to offer an up to 3× energy reduction under a given performance constraint. A circuit-level optimization procedure including the leakage energy contribution is adopted to explore the entire energy-delay space, in contrast to previous analyses that targeted only a specific point. To this aim, an analytical framework to express the energy-delay trade-off of CMOS buffers is presented, based on the Logical Effort methodology. Simulations in a 45-nm CMOS technology are extensively performed to validate the approach in a case study (Word Lines buffers for memory arrays) and in a number of other design cases. Extensive simulations are performed to understand the limits of the proposed approach, as well as the impact of the activity rate, the supply voltage, and process variations.
Year
DOI
Venue
2011
10.1109/TCSI.2011.2157740
IEEE Trans. on Circuits and Systems
Keywords
Field
DocType
transistor tapered sizing,energy efficient,energy-delay trade-offs,size 45 nm,low leakage,digital circuits,buffer storage,memory arrays,logical effort methodology,cmos buffers,vlsi,tapered-vth buffers,low power,leakage energy contribution,supply voltage,activity rate,process variations,word lines buffers,energy efficiency,cmos memory circuits,transistor threshold voltage,cmos integrated circuits,optimization,threshold voltage,transistors,process variation,capacitance
Digital electronics,Efficient energy use,Voltage,Electronic engineering,CMOS,Logical effort,Transistor,Very-large-scale integration,Threshold voltage,Mathematics
Journal
Volume
Issue
ISSN
58
11
1549-8328
Citations 
PageRank 
References 
4
0.62
12
Authors
3
Name
Order
Citations
PageRank
Fabio Frustaci112917.55
Massimo Alioto270688.98
Pasquale Corsonello327838.06