Step-down-stress degradation modeling based on Gamma process

The high reliability and long life characteristics of electronic products result in long degradation test time and low efficiency. Traditional degradation test depends on priori information and statistical analysis method is complex. In view of those problems, an evaluation method of step-down stress accelerated degradation modeling based on Gamma process is proposed. Firstly, the degradation path is portrayed by a Gamma process. Then using the Gamma process characteristics and MCMC method, the parameters are evaluated. this method greatly simplifies the procedure of statistical analysis. Finally, the simulation of metallized film capacitors is provided, the assessment of step-down stress is compared with constant stress and step-up stress, the validity and the efficiency of the proposed method is presented.