Browse Prior Art Database

Persistent Current Storage Cell

IP.com Disclosure Number: IPCOM000097696D
Original Publication Date: 1961-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 3 page(s) / 23K

Publishing Venue

IBM

Related People

Sanborn, JL: AUTHOR

Abstract

The circuit employs three cryotrons operable as a persistent current storage cell. The storage of a 1 or 0 is detected without employing a reset method.

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 56% of the total text.

Page 1 of 3

Persistent Current Storage Cell

The circuit employs three cryotrons operable as a persistent current storage cell. The storage of a 1 or 0 is detected without employing a reset method.

The circuit consists of a pair of parallel superconductive paths having unequal inductances L1 and L2. The magnitude of L1 is much greater than L2. When current I is applied, with both paths superconducting, the current divides in inverse proportion to the inductance in each path. That is, the major portion of the current flows through the path exhibiting inductance L2. The current I2 through path L2 is: I2 = I L1/(L1 + L2)

The current I1 through path L1 is:

I1 = I L2 / (L1 + L2)

The storage of a 1 is effected under control of a write current IW. The application of IW causes the gate conductor in series with path L2 to switch resistive. This shifts all of current I into path L1. Upon termination of current IW, path L2 again becomes superconducting but current I remains entirely in path L1. The removal of current I is next effective to establish a circulating persistent current about the superconducting loop formed by paths L1 and L2, indicating the storage of a 1. This current Ic circulates in a clockwise direction and has a magnitude: Ic = I L1 / (L1 + L2)

The storage of a 0 is effected, with currents 11 and 12 as defined above established, by not applying current IW. The subsequent removal of current I results in no circulating persistent current being established. The absence of the persistent current indicates the storage of a 0.

Readout is accomplished by applying currents I and IR. The storage of a 0 or 1 is effective to direct current IR to output lines 0 or 1, respect...