2 research outputs found
Approximate logic circuits: Theory and applications
CMOS technology scaling, the process of shrinking transistor dimensions based
on Moore's law, has been the thrust behind increasingly powerful integrated circuits
for over half a century. As dimensions are scaled to few tens of nanometers, process
and environmental variations can significantly alter transistor characteristics, thus
degrading reliability and reducing performance gains in CMOS designs with technology
scaling. Although design solutions proposed in recent years to improve reliability
of CMOS designs are power-efficient, the performance penalty associated with these
solutions further reduces performance gains with technology scaling, and hence these
solutions are not well-suited for high-performance designs.
This thesis proposes approximate logic circuits as a new logic synthesis paradigm
for reliable, high-performance computing systems. Given a specification, an approximate
logic circuit is functionally equivalent to the given specification for a "significant"
portion of the input space, but has a smaller delay and power as compared to a
circuit implementation of the original specification. This contributions of this thesis
include (i) a general theory of approximation and efficient algorithms for automated
synthesis of approximations for unrestricted random logic circuits, (ii) logic design solutions
based on approximate circuits to improve reliability of designs with negligible
performance penalty, and (iii) efficient decomposition algorithms based on approxiiii
mate circuits to improve performance of designs during logic synthesis. This thesis
concludes with other potential applications of approximate circuits and identifies. open
problems in logic decomposition and approximate circuit synthesis