Licentia Patent-Verwaltungs Gmbh

Erich Bachle

Bernhard Rall

Dietrich Hoppner

Hermann Clauss

Helmut Kliem

Rudolf Schehrer

Electronic switch for use as a crosspoint in switching networks of space-division telephone exchanges where it is connected to function as an open circuit stable negative resistance provding ON-attenuation compensated signal transmission, the switch being constituted by a circuit arrangement which lends itself to monolithic integration and which, when switched off, prevents undersirable attenuation of crosspoints connected to the same row or column of the switching system.

Attenuation-free electronic switch

A monolithic integrated semiconductor circuit including a plurality of low on-state resistance vertical bipolar switching transistors for connecting a series of input lines, as desired, to one or more output lines wherein each of said switching transistors comprises a substrate region of a first type of conductivity having a first layer thereon of the second type of conductivity, a second layer on the first layer and of the second type of conductivity but with a lower doping than the first layer, a third layer of the first type of conductivity in the second layer, a fourth layer of the second type of conductivity in the third layer, a tank like structure formed from the first layer and a region encircling the second third and fourth layers and of the second type of conductivity, a first frame like region of the second type of conductivity encircling the tank like structure, a second frame like region encircling the first frame like region and being of the first type of conductivity and in contact with the substrate region, and connections for the tank like structure, the substrate region and the third and fourth layers.

Monolithic integrated semiconductor circuit

In an electronic switching device for use as the switching component of a switching network in a telephone central office, the device being composed of a switching transistor connected in series in the signal conduction path for switched signals and a controllable impedance connected in a shunt branch, the switching transistor, in its conductive state, having a low series resistance and an associated high shunt resistance, and, in its blocking state, having a high series resistance and an associated low shunt resistance, the shunt branch is composed of a control transistor having a control voltage applied to its base, having its collector connected to the base of the switching transistor, and having its emitter connected to the switching transistor through a resistor to constitute a feedback path for the switching transistor, a voltage-dependent resistor connected to the base of the switching transistor, and suitable sources of operation voltages, the voltages and characteristics of the voltage-dependent resistor being selected to be such that when the switching transistor is conductive, the control transistor operates conductively in its active region and the voltage-dependent resistor presents a high resistance and when the switching transistor is blocking the control transistor is also blocking and the voltage-dependent resistor has a low resistance and supplies to the base of the switching transistor a voltage which maintains the switching transistor blocking.

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Ulm, Donau, Germany

Erich Bachle