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Journal of Electrical and Computer Engineering
Volume 2011, Article ID 936712, 23 pages
Research Article

VLSI Implementation of a Distributed Algorithm for Fault-Tolerant Clock Generation

Embedded Computing Systems Group (E182/2), Technische Universität Wien, Treitlstraße 3, 1040 Vienna, Austria

Received 15 June 2011; Accepted 12 August 2011

Academic Editor: Jae-Yoon Sim

Copyright © 2011 Gottfried Fuchs and Andreas Steininger. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We present a novel approach for the on-chip generation of a fault-tolerant clock. Our method is based on the hardware implementation of a tick synchronization algorithm from the distributed systems community. We discuss the selection of an appropriate algorithm, present the refinement steps necessary to facilitate its efficient mapping to hardware, and elaborate on the key challenges we had to overcome in our actual ASIC implementation. Our measurement results confirm that the approach is indeed capable of creating a globally synchronized clock in a distributed fashion that is tolerant to a (configurable) number of arbitrary faults. This property facilitates eliminating the clock as a single point of failure. Our solution is based on purely asynchronous design, obviating the need for crystal oscillators. It is capable of adapting to parameter variations as well as changes in temperature and power supply–properties that are considered highly desirable for future technology nodes.