Browse Prior Art Database

Bubble Domain Functional Memory

IP.com Disclosure Number: IPCOM000075975D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 58K

Publishing Venue

IBM

Related People

Lin, YS: AUTHOR [+2]

Abstract

Functional memories use associative arrays of three-state cells to perform basic logic functions. Use of these cells reduces the number of memory locations required for logic functions. The three distinct states of the cells are 1, 0, and "don't care".

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Bubble Domain Functional Memory

Functional memories use associative arrays of three-state cells to perform basic logic functions. Use of these cells reduces the number of memory locations required for logic functions. The three distinct states of the cells are 1, 0, and "don't care".

The basic operation of the functional memory is in two phases: SEARCH and READ/WRITE. During the SEARCH phase the truth table for a cell is shown in Fig. 1.

Fig. 2 shows a functional memory using bubble domain devices, and Fig. 3 shows the timing diagram for the functional memory of Fig. 1, and in particular for bit location 11. In Fig. 2. a conductor overlay pattern is located on the bubble domain sheet. This pattern comprises two orthogonal loop arrays.

The bit (interrogate) lines are arranged along rows. The word (match detection) lines are organized in pairs along columns. Each bit location comprises a loop in each conductor of corresponding word and bit lines. The loops are arranged along diagonals. For instance, bit "11", defined by the bit line 1 and word line 1, includes five loops: X(1A), X(1B), X(1C), Y(1A), and Y(1B). The bubble domain can be located at any one of the three positions within loops X(1A), X(1B) and X(1C). The three states 1, 0, and X are defined when the bubble is located at loops defined by X(1A), X(1C), and X(1B), respectively.

Initially, the bubble domains can be nucleated in any bit location simply by pulsing either lines X(A) and Y(A), lines X(C) and Y(B), or line B alone. During a "clear" operation, lines X(B) are energized with "full" current level to shift the bubble from position "1" or "0" to position "X". If the bubble is originally located at position "X", no "CLEAR" operation is requi...