Abstract: 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.

Key words: FPGA, Fault tolerant, Permanent failure, Satisfiability problem (SAT), SAT solver