车载转向灯模组三极管烧毁分析

Analysis of the Burnout of the Vehicle Turn Light Module Triode

某车载转向灯模组在售后行驶9 km后出现故障,模组上的三极管发生烧毁。首先,通过X-ray透视检查和开封观察发现三极管芯片发射极发生了过流烧毁;然后,从电路原理图分析发现正常情况下外部电学条件不可能引发三极管过流烧毁,因而结合失效三极管的烧毁形貌推断三极管本身存在缺陷;最后,对三极管物料进行破坏性分析,发现:三极管芯片存在键合弹坑损伤,导致发射极耐压不断下降和漏电流不断增大,从而引发了正常使用时发生过流烧毁。

A vehicle turn light module fails after driving 9 km after sales,and the triode on the module burns out.Firstly,through X-ray fluoroscopy and unpacking observation,it is found that the emitter of the triode chip is burnt due to overcurrent.Then,from the analysis of the circuit schematic diagram,it is found that under normal circumstances,external electrical conditions are unlikely to cause the triode to burn out due to overcurrent.Therefore,combined with the burnt morphology of the failed triode,it is inferred that the triode itself has defects.Finally,the destructive analysis of the triode material shows that the triode chip has bonding crater damage,which leads to the continuous decrease of the emitter withstand voltage and the continuous increase of leakage current,then leads to the overcurrent burnout of the triode during normal use.