Fault tolerant circuits for highly reliable systems

Transient effects such as cosmic rays and device degradation due to aging may lead catastrophic failure in many applications. Redundancy-based techniques have been widely used to implement fault-tolerant system. N-tuple modular redundancy (NMR) systems, in particular, are all based on the majority voting. The voter unit, therefore, becomes a reliability bottleneck. In this paper, we advocate a circuit-level voting mechanism to design a highlily reliable system. When applied to the logic gates, analog components and on-chip interconnects, we can completely eliminate the centralized voter unit and push the redundancy to the circuit level. Our strategy achieves high reliability that is vital for mission critical systems for which high reliability and/or long lifetime is expected. Experimental results are reported to prove the concept, clarify the design procedure and measure the system's reliability.