Trading Accuracy for Power with a Configurable Approximate Adder

Toshinori SATO  Tongxin YANG  Tomoaki UKEZONO  

IEICE TRANSACTIONS on Electronics   Vol.E102-C   No.4   pp.260-268
Publication Date: 2019/04/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.2018CDP0001
Type of Manuscript: Special Section PAPER (Special Section on Solid-State Circuit Design — Architecture, Circuit, Device and Design Methodology)
approximate computing,  low-power circuit,  approximate adder,  

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Approximate computing is a promising paradigm to realize fast, small, and low power characteristics, which are essential for modern applications, such as Internet of Things (IoT) devices. This paper proposes the Carry-Predicting Adder (CPredA), an approximate adder that is scalable relative to accuracy and power consumption. The proposed CPredA improves the accuracy of a previously studied adder by performing carry prediction. Detailed simulations reveal that, compared to the existing approximate adder, accuracy is improved by approximately 50% with comparable energy efficiency. Two application-level evaluations demonstrate that the proposed approximate adder is sufficiently accurate for practical use.