Research on SAT solver-based PFGA permanent failure fault tolerant technique

FPGA is a kind of semiconductor device and it could be damaged by extern high energy cosmic ray in space. The permanent failure of reconfigurable SRAM based FPGA can not be cleared. Therefore a multiple redundancy technique is adopted to enhance system's reliability. However, it doubles or even triples the hardware consumption of electronic system. In this paper a method for repairing FPGA's permanent failure is proposed, by using FPGA's own redundancy resource. This method transforms FPGA's inner model into a satisfiability problem (SAT) and solves it by a modified SAT solver. And then an alternative circuit with the function equivalent to original circuit on the damaged FPGA can be obtained. Compared with genetic algorithm, the new method requires less computational effort and smaller memory, is more suitable for space applications.