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# 3 3 Bubble Logic Circuits

IP.com Disclosure Number: IPCOM000082729D
Original Publication Date: 1975-Jan-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 39K

IBM

## Related People

Lin, YS: AUTHOR [+3]

## Abstract

High-density disk patterns for bubble propagation increase bubble memory cell density by significant factors and can be used for logic circuits.

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3 3 Bubble Logic Circuits

High-density disk patterns for bubble propagation increase bubble memory cell density by significant factors and can be used for logic circuits.

Fig. 1 shows a first logic circuit having three inputs x, y, and z and three outputs Fa, Fb, and Fc. Magnetic bubble domains representing signals x, y, and z travel from left to right along the three channels formed by semicircular disk patterns, which can be comprised of permalloy. As the bubble domains from the top two channels x and y come to position I, bubble domain interaction occurs. If there is a bubble in either one of the top two channels x or y, the bubble will propagate along the middle channel due to the small gap in the permalloy pattern in the top channel.

If both channels x and y have bubbles in them, then both Fa and Fb will have bubble outputs, because the third channel z is purposely set far away. Therefore, the logical functions are Fa = x.y and Fb = x+y. Here, the dot indicates the AND function while the plus sign indicates the OR function. Since the third channel z is set far away, the third output function Fc = z.

A second embodiment is shown in Fig. 2, where all three channels x, y, and z are comprised of disk patterns which are brought together at position I. Similarly to the situation in the first embodiment, the

(Image Omitted)

output functions are Fa = xy + yz + zx, Fb = x + y + z, and Fc = xy + yz + zx, where + indicates the exclusive OR function.

As an alternative w...