Research On Multi-frequency Scrubbing Technique For Single Event Upsets In SRAM-based FPGAs

Soft error in SRAM-based FPGA is one of the key factors affecting the reliability of space electronic system.In the radiation environment,SRAM configuration units in FPGA are prone to single event upsets(SEU),which results in the change of circuit structure and the error of circuit output.Therefore,soft error mitigation techniques for FPGA have important research significance and application value.As a common soft error mitigation technique,configuration scrubbing repairs soft error by repeatedly writing the correct configuration data into FPGA.But there is a common problem with the traditional configuration scrubbing technique,that is,all the configuration units are scrubbed at the same frequency,ignoring the criticality of each configuration unit.As a result,the scrubber cannot implement a targeted scrubbing,and there is room for improvement in scrubbing.To solve this problem,a new multi-frequency scrubbing technique based on configuration criticality is proposed.This technique regards the propagation time of soft error as the criticality.By adjusting the scrubbing frequency of configuration frames,it can change the time needed for the scrubber to detect soft error.In that case,soft error can be repaired before they are propagated to the output of the circuit.To improve the pertinence of scrubbing and effectively reduce the soft error of the circuit,this thesis designs a set of algorithm,process and hardware design for multi-frequency scrubbing technique.Firstly,the actual criticality of configuration units is obtained by fault injection experiment,then the optimal scrubbing frequency of each configuration frame is calculated through SEU quantitative analysis model,finally,the scrubbing hardware generates the optimal address sequence online,and realizes effective protection against soft error for different configuration frames.Based on this technique,this thesis takes Xilinx Kintex-7 FPGA as the target device to realize the multi-frequency scrubbing flow,algorithm and hardware.At the same time,a fault injection test platform is built to excute fault injection on open source IP cores,and the error rate under multifrequency scrubbing protection is evaluated.The experimental results show that the proposed multi-frequency scrubbing technique reduces the average soft error by 48% compared with the non-scrubbing protection,and improves the effect by 18% compared with the traditional uniformfrequency scrubbing technique.At the same time,the hardware resource overhead of the multi-frequency scrubber can be controlled within 1% of the total resources of the FPGA,and the purpose of improving the performance and reducing the error rate of the scrubber is realized under low overhead.