A multi-position magnetic core driver using electron-beam switched P-N junctions

A matrix of back biased p-n junction diodes, irradiated, one at a time, by a 10-30 KV electron beam can be used as a high-speed, high-current, multiposition driver. The operating characteristics of this device can be made to be compatible with its use as a decoder and driver in an ultra-fast, magnetic-core, memory system. The diodes, switched by the electron beam, can be designed to have better elctrical charactristics than the conventional common-emitter transistor switch circuits. For a given current density, the transistor switching speed is limited by discharge of the base-collector capacity and charge neutralization of the excess minority carriers in the base. Because the electron beam creates hole-electron pairs in the diode, the excess minority carriers are automatically neutralized and it is this characteristic that allows the diode design to give either higher back voltage, or faster rise time characteristics. In this paper, simple design procedures, for diodes to operate in the 5-50 nsec range and with 1 amp output will be presented. Experimental results, obtained with diffused silicon junctions, will be discussed.