IGBT ghost failures in boost topology circuits explained through third quadrant operation

Faster IGBTs are being applied increasingly in boost topology circuits such as the boost power factor correction (PFC) and flyback power converter circuits. Unfortunately, field application of IGBTs in these circuits has resulted in unexplained IGBT failures. These random failures may result from IGBT third-quadrant reverse-avalanche operation. Analysis has confirmed that many continuous current mode (CCM) circuits operate in this mode transiently. The effects of this operation may have a cumulative destructive effect on the IGBT. This effect and the physical causes of the failures are explained through circuit simulation, experimentation and scanning electron microscope (SEM) analysis. Circuit designer guidance is provided.