MRÁZEK Vojtěch and VAŠÍČEK Zdeněk. Automatic Design of LowPower VLSI Circuits: Accurate and Approximate Multipliers. In: Proceedings of 13th IEEE/IFIP International Conference on Embedded and Ubiquitous Computing. Porto: Institute of Electrical and Electronics Engineers, 2015, pp. 106113. ISBN 9781467382991. Available from: http://dx.doi.org/10.1109/EUC.2015.20 
Publication language:  english 

Original title:  Automatic Design of LowPower VLSI Circuits: Accurate and Approximate Multipliers 

Title (cs):  Automatický návrh integrovaných obvodů s nízkým příkonem: přesné a aproximační násobičky 

Pages:  106113 

Proceedings:  Proceedings of 13th IEEE/IFIP International Conference on Embedded and Ubiquitous Computing 

Conference:  13th IEEE/IFIP International Conference on Embedded and Ubiquitous Computing 

Place:  Porto, PT 

Year:  2015 

URL:  http://dx.doi.org/10.1109/EUC.2015.20 

ISBN:  9781467382991 

Publisher:  Institute of Electrical and Electronics Engineers 

Files:  


Keywords 

Evolutionary optimization, transistor level, low power, approximate computing, multiplier 
Annotation 

In order to satisfy a constant need of reducing
energy consumption of electronic devices, the approximate computing
paradigm has been introduced in recent years. This
paradigm is based on the fact that there are applications that
are inherently capable of absorbing some errors in computation.
Multimedia signal processing represents a typical example that
allows for quality to be traded off for power.
Typically, the approximate circuits are designed at gate level.
This paper introduces an automatic design method that is able
to operate directly at transistor level which offers a great
potential for discovering novel implementations of approximate
circuits. The method combines a stochastic search algorithm with
transistorlevel circuit simulator and is able to handle the circuits
consisting of hundreds of transistors. The goal of the search
strategy is to improve the power consumption. To estimate power
consumption, an algorithm based on transistor switching activity
is proposed.
A design of 4bit multiplier was chosen as a case study.
Two scenarios were considered. Firstly, the proposed method
is applied to improve the power consumption of a common
4bit multiplier and a 4bit multiplier consisting of manually
designed 2bit multipliers. In both cases, approx. 3% power
reduction was achieved. Then, it is demonstrated that a noticeable
improvement can be obtained when the multipliers are designed
using a hybrid approach operating at transistor as well as gate
level. We discovered a novel implementation of an approximate
4bit multiplier which has approximately by 40% better powerdelay
product and exhibits 14% lower worstcase error compared
to the best known 4bit multiplier consisting of 2bit manually
optimized approximate multipliers 
BibTeX: 

@INPROCEEDINGS{
author = {Vojt{\v{e}}ch Mr{\'{a}}zek and Zden{\v{e}}k
Va{\v{s}}{\'{i}}{\v{c}}ek},
title = {Automatic Design of LowPower VLSI Circuits: Accurate and
Approximate Multipliers},
pages = {106113},
booktitle = {Proceedings of 13th IEEE/IFIP International Conference on
Embedded and Ubiquitous Computing},
year = {2015},
location = {Porto, PT},
publisher = {Institute of Electrical and Electronics Engineers},
ISBN = {9781467382991},
language = {english},
url = {http://www.fit.vutbr.cz/research/view_pub.php?id=10831}
} 