Block replicate magnetic bubble memory circuit for high speed data

Abstract

Magnetic bubble domain memory circuit in which magnetizable overlay patterns of magnetically soft material, e.g. permalloy, are provided as bubble propagation elements on a bubble-supporting magnetic layer to define major and minor bubble propagation paths. The major bubble propagation paths provide interchangeable bubble input and output sections, and the minor bubble propagation paths are in the form of closed storage loops providing a bubble storage section comprising first and second pairs of blocks. Bubble generators are provided for each of the blocks included in the first and second pairs thereof comprising the bubble storage section, along with first and second detectors and input/output tracks of bubble propagation elements associated with the respective pairs of blocks of storage loops. Swap transfer/replicate gates are disposed between the input/output tracks and each of the storage loops included in the blocks of storage loops. These gates are alternately operable in a swap transfer mode and a replicate mode so as to simultaneously transfer data as represented by magnetic bubbles and voids from the tracks to the storage loops and from the storage loops to the tracks when operated in a swap transfer mode, and to split respective magnetic bubbles incident thereon in a replicate mode to form a duplicate magnetic bubble in addition to the original magnetic bubble so as to preserve the data intact in the minor storage loop while delivering a bubble to a detector for readout. The first and second bubble detectors are 180.degree. out of phase with respect to each other and are operable during respective halfcycles of a bubble propagation cycle to sense the presence or absence of magnetic bubbles. Thus, respective data bits from different blocks are alternately sensed by the first and second bubble detectors in each bubble propagation cycle to provide a data readout rate twice the field rate.