Simulation-Based Method for Synthesizing Soft Error Tolerant Combinational Circuits

Due to current technology scaling trends, digital designs are becoming more sensitive to radiation-induced particle hits resulting from radioactivity decay and cosmic rays. A low-energy particle can flip the output of a gate, resulting in a soft error if it propagates to a circuit output. Thus, soft error tolerance has become an important criterion in digital system design. In this work, we propose a simulation-based approach to reduce the soft error probability of circuit failure in combinational logic circuits. The proposed method is based on maximizing the probability of logical masking when a soft error occurs. This maximization is done by extracting sub-circuits from an original multi-level circuit, and then re-synthesizing each extracted sub-circuit to increase fault masking against a single fault. We present a two-level synthesis scheme to maximize soft error masking on each extracted sub-circuit. This scheme provides a heuristic that finds the best set of cubes to cover the input patterns of an extracted sub-circuit. A Fast Extraction (FX) algorithm is used to enhance the area overhead of synthesized two-level sub-circuits. Experimental results on some MCNC combinational benchmarks show that, on average, a probability of circuit failure reduction of 32% is achieved compared to the original circuit. The average area overhead is 40% of the original circuit.