Browse Prior Art Database

El GaAs Majority Logic and Multivibrator Circuit

IP.com Disclosure Number: IPCOM000095968D
Original Publication Date: 1964-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Brayton, R: AUTHOR [+3]

Abstract

The four light emitting and light responsive Gallium Arsenide (GaAs) diodes 1, 2, 3 and 4 are connected to operate as a multivibrator. Diodes 1, 4 and diodes 2, 3 are positioned to communicate optically. Diodes 1, 2 and diodes 3, 4 are connected in parallel. External light sources, not shown, are provided to energize diodes 3 and 4.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

El GaAs Majority Logic and Multivibrator Circuit

The four light emitting and light responsive Gallium Arsenide (GaAs) diodes 1, 2, 3 and 4 are connected to operate as a multivibrator. Diodes 1, 4 and diodes 2, 3 are positioned to communicate optically. Diodes 1, 2 and diodes 3, 4 are connected in parallel. External light sources, not shown, are provided to energize diodes 3 and 4.

Assuming diodes 1 and 4 to be in their light emitting or conducting state and diodes 2 and 3 to be in their non-light emitting or nonconducting state, the respective states of diode conduction can be reversed. Irradiating diode 3 causes it to conduct which reduces the current in parallel-connected diode 4 such that it is biased to its off state. Diode 1 then switches into its off state, which is aided by diode 2 being turned on from the light generated by diode 3. Similarly, the circuit can be returned to its initial condition by removing the external light source from diode 3 and irradiating diode 4.

The state of the bistable multivibrator is determined by optically sampling the light emitted from either diodes 1, 2 or diodes 3, 4. The multivibrator can be made free-running by optically connecting diodes 2 and 4 and diodes 1 and 3 and then providing external irradiation to energize the circuit to any of the four diodes.

Majority logic functions are performed with light responsive and emitting GaAs diodes in the following manner. In a typical application diode 4 is so biased that it req...