Browse Prior Art Database

Back-to-Back Bubble Memory Detector System

IP.com Disclosure Number: IPCOM000051351D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Braun, RJ: AUTHOR

Abstract

Magnetoresistive sensors are used to detect bubbles in magnetic domain chips. The sensors are associated with a magnetic bubble expander-detector circuit, which consists of a specific geometric pattern, e.g., chevrons, of magnetic material, that is positioned over the bubble-supporting material or layer of the chip. In certain systems, to mitigate the effects of noise, a pair of sensors are connected in a noise-cancellation bridge configuration. One sensor, referred to as the active sensor, does the actual detection of the bubble, and the other functions as a dummy sensor to effect the cancellation. Ideally, the two sensors are in close proximity and reside within the same or equivalent magnetic environment.

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Back-to-Back Bubble Memory Detector System

Magnetoresistive sensors are used to detect bubbles in magnetic domain chips. The sensors are associated with a magnetic bubble expander-detector circuit, which consists of a specific geometric pattern, e.g., chevrons, of magnetic material, that is positioned over the bubble-supporting material or layer of the chip. In certain systems, to mitigate the effects of noise, a pair of sensors are connected in a noise-cancellation bridge configuration. One sensor, referred to as the active sensor, does the actual detection of the bubble, and the other functions as a dummy sensor to effect the cancellation. Ideally, the two sensors are in close proximity and reside within the same or equivalent magnetic environment. Thus, for example, a dummy expansion pattern is located or associated with the dummy sensor that is substantially equivalent to the active detector expansion pattern associated with the active sensor. For low chip capacity requirements, such dual-sensor systems are satisfactory. However, with the advent of larger capacity chips where two or more detectors are needed, the chip real estate that would be required to support the additional dual, i.e. active-dummy, detector system now becomes excessive.

The present system overcomes this difficulty and yet maintains the design criteria of close proximity between the pair of sensors and of equivalent magnetic environment for the pair with a minimum usage of chip area. To do...