GTO Like Thyristors Triggered in Impact-Ionization Wave Mode

GTO like thyristors, comprising of highly interdigitated gate and cathode structure, similarly to a GTO, are used at CERN as a main switching component of LHC Beam Dumping System (LBDS). These devices, the 5STH-20H450002 (4.5 kV, 80 kA, 18 kA/µs), were developed by ABB semiconductors. A novel principle of operation such as impact-ionization triggering can enhance dI/dt capability and reduce turn-on delay time. The aim of the work reported in this paper is study of triggering the GTO like thyristors in impact-ionization wave mode. An SOS generator providing a triggering pulse across the main thyristors' electrodes was used. A thyristor switching time of approximately 200 ps was observed. Maximum discharge parameters were obtained for two series connected thyristors at charging voltage of 10 kV, and capacitor stored energy of~300 J: peak current of 43 kA, dI/dt of 120 kA/µs, FWHM of 1.5 µs. The switching efficiency was up to 96%.