The Bidirectional Phase Control Thyristor

Abstract

The operational principle and design aspects of the bidirectional phase control thyristor (BiPCT) are presented. The BiPCT has been invented with the intention to replace the existing bidirectional control thyristor (BCT) by bringing the advantage of increased surge current, reduced thermal resistance, and reduced processing complexity (cost). This has been achieved by the interdigitation of the anode and cathode regions of both antiparallel connected thyristors, which newly occupy the whole silicon wafer. This requires a new approach to device design, where the most demanding task consists in retaining the commutation turn-off capability and achieving the technology curve between the ON-state voltage VT and the recovery charge Qrr as close to the single phase control thyristor (PCT) as possible. As a prerequisite of reliable operation of the new device concept, short commutation turn-off time of the BiPCT is demonstrated.