Threshold logic circuits utilizing series connected transistors and level shifting diodes

Claim 2

A threshold logic circuit comprising: a. means deriving a variable maximum permissible voltage level at a junction by individual switching of a plurality of seriesconnected transistors each having a discrete input; b. one or more series-connected diodes connected in shunt with the collector-emitter terminals of each transistor; c. a threshold level detector including a predetermined number of series-connected level-shifting diodes connected between said junction and the base of an output transistor; and d. means adjusting the number of series-connected diodes in shunt with the collector-emitter terminals to establish a maximum permissible voltage level at the junction just below the threshold level set by the level shifting diodes for any desired condition of the discrete inputs.

Claim 3

A threshold logic circuit comprising: a. a first string of series-connected diodes connected in series with a single impedance across a source of potential, said diodes being poled in a direction to permit forward current flow; b. means providing controlled shunting of said diodes in integrally numbered groups; including c. a plurality of transistors each having a base adapted to receive an individual input signal and having a collector-emitter path in shunt with one of said integrally numbered groups of diodes; d. an output transistor connected in the common emitter configuration; e. a second string of series-connected diodes connected between the junction formed by said impedance with said first string of diodes and the base of said output transistor, said second string of diodes being poled in a direction to conduct forward base current for the output transistor; and f. an output terminal connected to the collector of the output transistor.

Claim 4

A threshold logic circuit comprising: a. a first string of series-connected diodes connected in series with a single impedance across a source of potential, said diodes being poled in a direction to permit forward current flow; b. means providing controlled shunting of said diodes in integrally numbered groups; including c. a plurality of transistors each having a base adapted to receive an individual input signal and having a collector-emitter path in shunt with one of said integrally numbered groups of diodes; d. an output transistor connected in the common emitter configuration; e. a second string of series-connected diodes connected between the junction formed by said impedance with said first string of diodes and the base of said output transistor, said second string of diodes being poled in a direction to conduct forward base current for the output transistor; and f. an output terminal connected to the collector of the output transistor.

Claim 5

A threshold logic circuit comprising: a plurality of transistors of like polarity having their collector-emitter paths connected in mutual series and through a common impedance to a source of biasing potential; b. base electrodes for said transistors each adapted to receive an individual input signal to selectively permit or prevent conduction in each transistor; c. one or more series-connected diodes connected across the collector-emitter terminals of each transistor; d. a single output transistor having a base, a collector and an emitter; e. a plurality of series-connected diodes connected between said last-named base and through said common impedance to said source of biasing potential; f. an output terminal connected to said last-named collector; and g. a second impedance connected between said last-named collector and a source of biasing potential.

Claim 6

A threshold logic circuit comprising: a plurality of transistors of like polarity having their collector-emitter paths connected in mutual series and through a common impedance to a source of biasing potential; b. base electrodes for said transistors each adapted to receive an individual input signal to selectively permit or prevent conduction in each transistor; c. one or more series-connected diodes connected across the collector-emitter terminals of each transistor; d. a single output transistor having a base, a collector and an emitter; e. a plurality of series-connected diodes connected between said last-named base and through said common impedance to said source of biasing potential; f. an output terminal connected to said last-named collector; and g. a second impedance connected between said last-named collector and a source of biasing potential.

Claim 7

A threshold logic circuit comprising: a. a plurality of transistors of like polarity having their collector-emitter paths connected in series with each other between a junction and a point of reference potential; b. a first impedance connected between said junction and a source of biasing poteNtial; c. base electrodes for said transistors each adapted to receive an individual input signal to selectively permit or prevent conduction in each transistor; d. one or more series-connected diodes connected across the collector-emitter terminals of each transistor; e. a single output transistor having a base, a collector and an emitter; f. a plurality of series-connected diodes connected between said junction and said last-named base, said diodes being poled in a direction to conduct forward base current for said output transistor; g. an output terminal connected to said last-named collector; h. a second impedance connected between said last-named collector and a source of biasing potential; and i. means connecting said last-named emitter to said point of reference potential.

Claim 8

A threshold logic circuit comprising: a. a plurality of transistors of like polarity having their collector-emitter paths connected in series with each other between a junction and a point of reference potential; b. a first impedance connected between said junction and a source of biasing poteNtial; c. base electrodes for said transistors each adapted to receive an individual input signal to selectively permit or prevent conduction in each transistor; d. one or more series-connected diodes connected across the collector-emitter terminals of each transistor; e. a single output transistor having a base, a collector and an emitter; f. a plurality of series-connected diodes connected between said junction and said last-named base, said diodes being poled in a direction to conduct forward base current for said output transistor; g. an output terminal connected to said last-named collector; h. a second impedance connected between said last-named collector and a source of biasing potential; and i. means connecting said last-named emitter to said point of reference potential.

Claim 9

A threshold logic circuit as set forth in claim 4, wherein a different number of series diodes are connected across the collector-emitter terminals of the transistors to provide different weights to the inputs with respect to their effect on the threshold function.