Fail-safe optically coupled logic networks

Claim 2

A fail-safe optically coupled logic network comprising: a source of gating signals; a source of control signals; a transistor having base, emitter, and collector electrodes, with the base electrode being connected to said source of control signals; a light-emitting diode having two terminals, with the first being connected to said source of gating signals and the second being connected to one of the emitter and collector electrodes of said transistor, said light-emitting diode emitting light in responSe to the provision of a gating signal to the first terminal thereof concurrent with a control signal being applied to the base electrode of said transistor; means responsive to said light-emitting diode emitting light for providing an output signal; and means responsive to the provision of said output signal for applying a latching signal to the first terminal of said lightemitting diode.

Claim 3

A fail-safe optically coupled logic network comprising: first and second transistors of opposite conductivity each having base, emitter, and collector electrodes, with one of the collector and emitter electrodes of said first transistor being connected to the like electrode of said second transistor; first and second light-emitting diodes each having anode and cathode electrodes, with the anode electrode of the first being connected to the cathode electrode of the second and the cathode electrode of the first being connected to the remaining one of the collector and emitter electrodes of said first transistor and the anode electrode of the second being connected to the remaining one of the collector and emitter electrodes of said second transistor; first and second signal input means for applying first and second signals to the base electrodes of said first and second transistors, respectively, for rendering them conductive; means for selectively applying a third signal of one of two values to the common connection of said first and second light emitting diodes, the first value being of the sense to render said first light-emitting diode conductive and said second light-emitting diode nonconductive, and the second value being of the sense to render said first light-emitting diode nonconductive and said second light-emitting diode conductive, said first light-emitting diode emitting light in response to the third signal being of the first value concurrent with said first transistor being conductive, and said second light-emitting diode emitting light in response to the third signal being of the second value concurrent with said second transistor being conductive; and light responsive means for providing an output signal in response to one of said first and second light emitting diodes emitting light.

Claim 4

A fail-safe optically coupled logic network comprising: first and second transistors of opposite conductivity each having base, emitter, and collector electrodes, with one of the collector and emitter electrodes of said first transistor being connected to the like electrode of said second transistor; first and second light-emitting diodes each having anode and cathode electrodes, with the anode electrode of the first being connected to the cathode electrode of the second and the cathode electrode of the first being connected to the remaining one of the collector and emitter electrodes of said first transistor and the anode electrode of the second being connected to the remaining one of the collector and emitter electrodes of said second transistor; first and second signal input means for applying first and second signals to the base electrodes of said first and second transistors, respectively, for rendering them conductive; means for selectively applying a third signal of one of two values to the common connection of said first and second light emitting diodes, the first value being of the sense to render said first light-emitting diode conductive and said second light-emitting diode nonconductive, and the second value being of the sense to render said first light-emitting diode nonconductive and said second light-emitting diode conductive, said first light-emitting diode emitting light in response to the third signal being of the first value concurrent with said first transistor being conductive, and said second light-emitting diode emitting light in response to the third signal being of the second value concurrent with said second transistor being conductive; and light responsive means for providing an output signal in response to one of said first and second light emitting diodes emitting light.

Claim 5

A fail-safe optically coupled logic network comprising: first and second switches each having a conduction path and a control terminal to which control signals are applied for closing said switches, with said switches having their respective conduction paths connected in series; first and second light-emitting diodes each having anode and cathode electrodes, with the anode electrode of the first being connected to the cathode electrode of the second and the cathode electrode of the first being connected to the conduction path of said first switch and the anode electrode of the second being connected to the conduction path of said second switch; first and second control signal input means for applying first and second control signals to the control terminals of said first and second switches, respectively, for closing same; means for selectively applying a third signal of one of two values to the common connection of said first and second light emitting diodes, the first value being of the sense to render said first light-emitting diode conductive and said second light emitting-diode nonconductive, and the second value being of the sense to render said first light-emitting diode nonconductive and said second light-emitting diode conductive, said first light-emitting diode emitting light in response to the third signal being of the first value concurrent with said first switch being closed, and said second light-emitting diode emitting light in response to the third signal being of the second value concurrent with said second switch being closed; and light responsive means for providing an output signal in response to one of said first and second light-emitting diodes emitting light.

Claim 6

A fail-safe optically coupled logic network comprising: first and second switches each having a conduction path and a control terminal to which control signals are applied for closing said switches, with said switches having their respective conduction paths connected in series; first and second light-emitting diodes each having anode and cathode electrodes, with the anode electrode of the first being connected to the cathode electrode of the second and the cathode electrode of the first being connected to the conduction path of said first switch and the anode electrode of the second being connected to the conduction path of said second switch; first and second control signal input means for applying first and second control signals to the control terminals of said first and second switches, respectively, for closing same; means for selectively applying a third signal of one of two values to the common connection of said first and second light emitting diodes, the first value being of the sense to render said first light-emitting diode conductive and said second light emitting-diode nonconductive, and the second value being of the sense to render said first light-emitting diode nonconductive and said second light-emitting diode conductive, said first light-emitting diode emitting light in response to the third signal being of the first value concurrent with said first switch being closed, and said second light-emitting diode emitting light in response to the third signal being of the second value concurrent with said second switch being closed; and light responsive means for providing an output signal in response to one of said first and second light-emitting diodes emitting light.

Claim 7

A fail-safe optically coupleD latching logic network comprising: a source of gating signals; a source of control signals; a switch having a conduction path and a control terminal to which said control signals are applied for closing said switch; a light-emitting diode having two terminals, with the first being connected to said source of gating signals and the second being connected to the conduction path of said switch, said light-emitting diode emitting light in response to the provision of a gating signal to the first terminal of said light emitting diode concurrent with said switch being closed; means responsive to said light-emitting diode emitting light for providing an output signal; and means responsive to the provision of said output signal for applying same to the first terminal of said light-emitting diode for maintaining said light-emitting diode in a light-emitting condition during the time said control signals are concurrently applied to the control terminal of said switch.

Claim 8

A fail-safe optically coupleD latching logic network comprising: a source of gating signals; a source of control signals; a switch having a conduction path and a control terminal to which said control signals are applied for closing said switch; a light-emitting diode having two terminals, with the first being connected to said source of gating signals and the second being connected to the conduction path of said switch, said light-emitting diode emitting light in response to the provision of a gating signal to the first terminal of said light emitting diode concurrent with said switch being closed; means responsive to said light-emitting diode emitting light for providing an output signal; and means responsive to the provision of said output signal for applying same to the first terminal of said light-emitting diode for maintaining said light-emitting diode in a light-emitting condition during the time said control signals are concurrently applied to the control terminal of said switch.