Browse Prior Art Database

Three Dimensional Memory

IP.com Disclosure Number: IPCOM000098947D
Original Publication Date: 1962-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Flaherty, RJ: AUTHOR

Abstract

The three-dimensional memory array (upper left) uses three mutually aiding excitations to write information into a core. It uses only two aiding excitations to read information out.

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Three Dimensional Memory

The three-dimensional memory array (upper left) uses three mutually aiding excitations to write information into a core. It uses only two aiding excitations to read information out.

The wiring arrangement is such that each bit plane includes X windings coupling the rows of cores, Y windings coupling the columns, a Z winding coupling all cores in the plane. A sense winding (not shown) also couples all cores in the plane. The X and Y windings have drivers capable of supplying currents of two different magnitudes, At read time, the X and Y drivers supply normal half-select currents. Thus, the core in each plane at the intersection of the activated X and Y lines is read. At write time, the X and Y drivers produce currents of lesser magnitude so that the core at the intersection of the activated lines is not switched. It is only brought to the knee of its hysteresis loop (upper right). If a 1 is to be written in the selected core of a given plane, the Z winding is activated with current of the same sense and magnitude as the X and Y write current. This carries the core past the knee of its loop and switches it toward the opposite state. The combined effect of the Z drive and either the X or Y drive alone is insufficient to switch any nonselected core.

Because of the relatively low driving force applied to a core during write time, it is advantageous to extend the duration of the write pulses (lower right). This insures that substantial flux sw...