Fault performance requirements of high voltage Mosfets and IGBTs

Modern field controlled devices (FCD) such as FETs and IGBTs are becoming readily available with the capability of switching high power (>1000 V and >100 A) at high speed <100 ns). The large majority of these devices are fully specified for their expected field of application,which is usually some form of switched mode power supply (SMPS) application at switching speeds of up to the 100 kHz region. Many of these devices work with loads that may produce fault transients, which could damage the load and or the SMPS system driving it. For most of these applications the rate of build up of the fault current/energy is such that the switching speed of the semiconductors can easily and predictably handle the fault condition. This is due largely to the inclusion of reactive elements such as inductor and/or transformers, which delay the build up of fault current to a rate that the FCD can be readily designed to handle.