Gate turn-off thyristor (GTO)

Summary

A gate turn-off switch (GTO) is a four-layer p-n-p-n device similar in construction to an SCR. A GTO is triggered into conduction by applying a forward bias to its gate and turned off by the application of a reverse-gate bias. An SCR, on the other hand, is turned off primarily by reducing or reversing the anode current. A simplified two-dimensional model of the switching mechanism of a GTO is discussed. The model predicts the dependence of the storage time (plasma-pinching time) on the device turn-off gain, i.e., on the ratio of the anode current to the reverse-gate current. An expression for the maximum switchable current is also derived.