Scalable mean voting mechanism for fault tolerant analog circuits

Redundancy techniques, such as N-tuple modular redundancy has been widely used to improve the reliability of digital circuits. Unfortunately nothing substantial has been done for the analog and mixed signal systems. In this paper, we propose a redundancy based fault-tolerant methodology to design a highly reliable analog systems. The key contribution of our work is an innovative analog mean voter. This mean voter is a low power, small area, very high bandwidth and linearly scalable voting circuit. Unlike digital voter which works with odd N in an NMR, for analog circuits the mean analog voter works for both odd and even N and hence reduces the area and power further. For the proof of concept, we designed two fault tolerant circuits i.e. a low pass anti-aliasing analog filter and a flash ADC. Experimental results are reported to verify the concepts and measure the system's reliability when single upset transient may occur.