Design of a novel fault-tolerant voter circuit for TMR implementation to improve reliability in digital circuits

Due to the shrinking of feature size and significant reduction in noise margins, nanoscale circuits have become more susceptible to manufacturing defects, interference from radiation and noise-related transient faults. Many of these faults are not permanent in nature but their occurrence can result in malfunctioning of circuits, either due to complexity of digital circuits or due to interaction with software. A fault-tolerant scheme such as triple-modular redundancy (TMR) is being implemented increasingly in digital systems. One of the drawbacks of this scheme is that the reliability of the voter circuit is assumed to be very high, which may not be true. Most of the implementation of digital circuits is in the form of integrated circuit; so all the circuit elements are fabricated with same technology and hence reliability of all the components is usually same. In this paper we are presenting a novel fault-tolerant voter circuit which itself can tolerate a fault and give error free output by improving the overall system's reliability. (C) 2009 Elsevier Ltd. All rights reserved.