Research on Turn-on Delay Time tdon of the Multichip IGBT Module after Partial Chip Failure

Exploration of the measurable precursor parameters is crucial for monitoring potential defects or estimating aging of the multichip insulated gate bipolar transistor (IGBT) module. In this paper, the theoretic background of variation in the turn on delay time tdon after chip failure is explored. It starts out from parasitic parameters consisting in gate circuit and turn on characteristics of the multichip IGBT module. Subsequently the correlation between variation in the turn on delay time and chip failure is found out in a special time interval of the turn on transient. This discovery will give a precursor of the multichip IGBT module being about to wear out, which is of great value to avoid severe subsequent collateral damage and guarantee safety running. Eventually, results of the verification experiment show that the observed considerable variation in the turn on delay time tdon is a potential precursor parameter which can be used to detect chip failure presented inside those multichip IGBT modules.