The dV / dt capability of field-controlled thyristors

A detailed analysis of the capability of field-controlled thyristors is presented. It is demonstrated for the first time that induced turn-on can occur in these devices due to gate debiasing as a result of capacitive gate current flow if a large series gate resistance is present in the circuit. A theoretical analysis of the capability is presented based upon this mechanism which predicts that the capability will decrease inversely with increasing gate series resistance at low values and become independent of the gate series resistance at very high values. The quantitative calculations of the capability that have been made by using this theory are in very good agreement with measurements taken on asymmetrical field-controlled thyristors fabricated from wafers of various thickness. The results obtained in this study allow the conclusion that the capability of field-controlled thyristors are superior to that of conventional thyristors.