基于PoF模型和FTA的电子装备故障模式分析

Failure Mode Analysis of Electronic Equipment Based on PoF Model and FTA

针对电子装备的测试性验证试验中,因电路集成度较高,故障模式可能由一个或多个失效机理引起,利用热失效分析等传统手段已无法有效对电子装备进行深层故障模式分析而导致试验样本可信度降低的问题,提出了基于失效物理(physics of failure,PoF)模型和故障树(fault tree analysis,FTA)相结合的改进故障模式分析方法。以某型电子装备电源模块中过压保护电路为实例,运用失效物理模型从器件级故障模式分析入手,计算出故障率和危害度,得到过压保护电路的FMECA结果,并以故障树分析方法为引导,根据底事件概率重要度与电子元器件危害度定义的相通性,分别将二者优先排序相互比较后验证FMECA结果的正确性,而后按照此类方法层层向上解析,最终得到电子装备正确性高的故障模式分析结果,有效提高了测试性验证试验样本的可信度。

In the testability verification test of electronic equipment,due to the high degree of circuit integration,the fault mode may be caused by one or more failure mechanisms,and traditional means such as thermal failure analysis can no longer effectively analyze the deep fault mode of electronic equipment,which leads to the reduction of the credibility of test samples.An improved fault mode analysis method based on the combination of failure physics and fault tree is proposed.Taking the overvoltage protection circuit in the power module of an electronic equipment as an example,the failure physics model is used to calculate the failure rate and criticality from the device level failure mode analysis,and the FMECA results of the overvoltage protection circuit are obtained.Guided by the fault tree analysis method,the FMECA results are verified by comparing the priority of the two according to the similarity between the definition of the probability importance of the bottom event and the criticality of the electronic components.According to this method,the fault mode analysis results of electronic equipment are finally obtained with high accuracy,which effectively improves the reliability of testability verification test samples.