A Comparison of TMR With Alternative Fault-Tolerant Design Techniques for FPGAs

With growing interest in the use of SRAM-based FPGAs in space and other radiation environments, there is a greater need for efficient and effective fault-tolerant design techniques specific to FPGAs. Triple-modular redundancy (TMR) is a common fault mitigation technique for FPGAs and has been successfully demonstrated by several organizations. This technique, however, requires significant hardware resources. This paper evaluates three additional mitigation techniques and compares them to TMR. These include quadded logic, state machine encoding, and temporal redundancy, all well-known techniques in custom circuit technologies. Each of these techniques are compared to TMR in both area cost and fault tolerance. The results from this paper suggest that none of these techniques provides greater reliability and often require more resources than TMR.