Study and Modelling of Optocouplers Ageing
Résumé
Optocoupler is a coupling component used commonly in feedback control loop circuits for power supply equipment. Its high failure risk causes in most cases the breakdown of the whole equipment. In this work, the wear-out process of this component is studied and a special attention to the most significant parameters variation is paid. Different types of accelerated endurance tests under high temperature; high current and other types are applied to some batches of optocoupler samples in order to determine the best fault signature of the components. An accurate analytical model for the ageing of optocouplers is proposed. This model is based on microscopic analysis of physical phenomena at the semiconductor part of the component. Finally, results obtained with the proposed model are compared to experimental results. Thus the model can bi used to optimize working conditions of optocouplers and improve their lifetime and as a result the reliability of the whole power supply.