IGBT fault current limiting circuit

Circuits are proposed which, by limiting the fault current magnitude, extends the short-circuit withstand time of high-efficiency (high-gain) IGBTs (insulated-gate bipolar transistors). Limiting of the fault current magnitude also results in reduced turn-off voltage transients, a desirable byproduct, especially for higher current modules. Moreover, the adverse Miller effect is counterbalanced to a great degree. If the fault current is of the short transient type, the circuit restores normal operation, a desirable feature for noise-prone systems. The circuit does not require an external DC supply to operate. This feature combined with the simplicity of the circuit, renders it feasible for insertion in IGBT modules or connection as an interface between the gate driver and module