JPS5843833B2 - magnetic bubble storage device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic bubble storage devices, and more particularly to high storage density magnetic bubble storage devices.

Supported by the remarkable development of electronic technology including semiconductor integrated circuit technology, electronic computers are rapidly becoming smaller and changing at a faster rate.

Moreover, its reliability has been significantly improved by making the circuit elements solid-state.

Furthermore, as the use of electronic computers progresses, the storage capacity of storage devices continues to increase year by year, and there is a strong desire to reduce the unit cost and access time required for storage.

In order to reliably store and retain large amounts of information, a highly reliable non-volatile large-capacity memory device is necessary, but it is impossible to achieve this with volatile semiconductor memory, and even though non-volatile However, magnetic tape devices, magnetic disk devices, and the like have a fatal flaw in that they have moving parts, and it is difficult to say that these are memory devices that meet needs in terms of reliability.

Magnetic bubbles were invented in view of the above technical background.

When a bias magnetic field of an appropriate magnitude is applied perpendicularly to the surface of a magnetic thin plate such as garnet or orthoferrite having uniaxial magnetic anisotropy, a cylindrical magnetic domain, a so-called magnetic bubble, is generated.

A device that uses magnetic bubbles to store information, perform logical operations, etc. using magnetic bubbles must be nonvolatile, be an all-solid-state device, have a large capacity, and be relatively fast. For these reasons, its practical application is rapidly progressing in fields that take advantage of these characteristics.

This magnetic bubble utilization device requires various functions such as generating, transferring, dividing, enlarging, detecting, and erasing magnetic bubbles.

Furthermore, a bias magnetic field application means for stably existing magnetic bubbles within the magnetic thin plate, and a rotating magnetic field application means for moving the magnetic bubbles within the magnetic thin plate to the base of the magnetic material pattern formed on the magnetic thin plate. Requires.

FIG. 1 is a diagram for explaining a typical storage configuration of a magnetic bubble storage device.

In the figure, 1 is a magnetic bubble generator that generates magnetic bubbles in synchronization with the period of the rotating magnetic field, and 2 is a first information propagation path for guiding the magnetic bubble information generated by the magnetic bubble generator 1 to the information storage section. , 3 is an information storage path consisting of a loop-shaped transfer path and forming a characteristic information storage section.If the capacity of the entire chip is N bits, the number of information storage paths 3 is fi/2, and the bit capacity of each information storage path is 2/page. Consists of bits.

Reference numeral 4 designates a second information propagation path for guiding the magnetic bubble information read from each of the information storage paths 3 to the magnetic bubble detector 5.

Actually, in addition to this, there is a control conductor for controlling the transfer of magnetic bubble information between the first and second information propagation paths 2 and 4 and the information storage path 30, a replicator for duplicating magnetic bubble information, and a magnetic bubble erasing device. Although an eraser and the like are arranged, they are omitted in this figure.

FIG. 2a shows an enlarged view of the area indicated by the broken line in the figure.

In the figure, the same parts as in FIG. 8 is a bar pattern placed on the extension of the leg of pattern 7, and this pattern 8 is originally formed to be long in order to generate a strong magnetic pole at the head of pattern I. However, when the direction of the rotating magnetic field is toward the bottom of the paper, a strong magnetic pole is formed at the end of the leg, which absorbs the magnetic bubbles propagating through the surrounding transfer path pattern that constitutes the information storage path 3, causing malfunctions. In order to prevent this from happening, it is divided into parts and formed to weaken the influence of the end magnetic poles.

However, the operation margin of the transfer control circuit configured in this manner is still not sufficient.

In other words, as shown in the operating margin characteristic curve in the same figure, it is possible to secure a predetermined operating margin in the linear propagation path region, but in the circular propagation path region shown in FIG. As shown in the section, it is not possible to secure an operating margin on the low bias magnetic field side, resulting in a narrow operating margin as a whole.

In the figure, the horizontal axis is the driving magnetic field applied in the in-plane direction,
The vertical axis indicates the bias magnetic field applied perpendicularly to the plane.

Further, another known transfer control circuit is shown in FIG. 3a, which is an improved transfer control circuit shown in FIG. 2a to ensure an operating margin on the low bias magnetic field side.

In the illustrated transfer control circuit, a modified half-disc-type permalloy pattern is arranged in a region forming a part of a corner instead of a piffax-type permalloy pattern.

This pattern has a relatively long leg 7' bent towards the left side of the pattern, which creates a predetermined strong magnetic pole at the head of the pattern.

Compared to the Pifax-type pattern shown in Figure 2a, this type of pattern does not place unnecessary patterns in positions that are not originally transfer areas, so a relatively sufficient operating margin can be obtained, but the current phase margin It's bad.

That is, the phase margin width is very narrow, as shown in the figure.

In the figure, the horizontal axis represents the current phase, and the vertical axis represents the bias magnetic field.

As described above, it cannot be said that the conventionally known transfer control circuit has a sufficient operating margin.

Therefore, the present inventors have already proposed a transfer control circuit which eliminates these drawbacks and provides a sufficient operating margin in Japanese Patent Application No. 5265474.

A magnetic bubble storage device to which the transfer control circuit according to the present proposal is applied is shown in FIG. 4 below.

In the figure, the same parts as in FIG. 1 are given the same numbers.

Note that 31 indicates an improved information storage path.

As is clear from the figure, the most distinctive feature of this embodiment is that the information storage path 3' is meandered to ensure a large space for the transfer control circuit for one information storage path.

That is, by arranging transfer control circuits for each information storage path every 4 bits for the information propagation path 4 as shown in the figure,
By ensuring sufficient space for each transfer control circuit, the transfer control circuit placed at the corner of the information storage path shown in Figure 2a threatens the operation of magnetic bubbles propagating on the information storage path placed nearby. It solves problems such as.

The operation of the transfer control circuit of the embodiment shown in FIG. 4 is not directly related to the gist of the present invention and will not be described here, but if necessary, please refer to Japanese Patent Application No. 52-65474.

In the embodiment shown in FIG. 4, it is possible to secure a sufficient operating margin for each transfer control circuit by improving the information storage path, but this brings about a new problem.

That is, in the embodiment shown in FIG. 4, if the storage capacity N of the entire chip is the same as in the configuration shown in FIG. 1, the meandering information storage path 3' of the embodiment shown in FIG. is twice as long as the information storage path 302 in FIG. 1, that is, if the information storage path 3 in FIG. 1 is made up of 27 bits, that in FIG. 4 is made up of 4/N bits.

This means that the access time of FIG. 4 is twice as long as that of FIG. 1.

Furthermore, a serious drawback of the embodiment shown in FIG.
The magnetic bubbles that make up the above information string are arranged every three bits.

This means that if f is the driving frequency applied externally to drive the magnetic bubbles, then in the configuration shown in Figure 1, the magnetic bubbles are arranged every other bit, so the speed of information read out from the magnetic bubble detector is is f/2, whereas that of FIG. 4 is f/4, reducing the read speed.

The object of the present invention is to eliminate all of the above-mentioned drawbacks and to realize a novel magnetic bubble storage device in which a sufficient area for a transfer control circuit is secured without reducing the read speed.

An object of the present invention is to provide a plurality of information storage paths each including a loop-shaped transfer path having a bent portion at least partially bent inward, and a region adjacent to the loop-shaped transfer path opposite to the bent portion of the information storage path. An information propagation path is provided between the information storage path and the information propagation path, and the information storage path is configured with a transfer pattern period larger than the constituent pattern period; This can be achieved by using a magnetic bubble storage device that includes a transfer control circuit that controls bubble transfer.

The present invention will be explained below using the drawings.

FIG. 5 is a configuration diagram for explaining a magnetic bubble storage device according to the present invention.

The embodiment shown in the figure is basically the same in configuration as shown in FIGS. 1 and 4, but includes an information storage path 3I, an information propagation path 41, an information storage path 3', and an information propagation path 4'. The configuration differs from the previous configuration example in terms of mutual arrangement.

The information storage path 3' will be explained in detail in FIG. 6, which will be described later.
Each information storage path 3' is composed of 27□ pits having the same capacity as the information storage path 3 shown in FIG.
Like the information storage path 31 shown in the figure, it is constructed of a loop-shaped transfer path at least partially having an inward bend.

Further, the information propagation path 4' applied to the present invention is configured such that the transfer pattern period is twice the period of the transfer pattern constituting the information storage path 31, as will be described in detail in FIG.

A transfer control circuit disposed between each information storage path 3I and information propagation path 4' is provided for every other bit on the information propagation path 4'.

Since the magnetic bubble storage device according to the present invention is constructed as described above, although the storage capacity of each information storage path 3' is a 2-babit configuration as in FIG. By bending the transfer path, sufficient space can be secured for the area, and even though adjacent transfer control circuits are placed the same distance apart from each other as in the configuration shown in Figure 4, By adopting the information propagation path 4' having a transfer pattern period of , the read speed can be made the same as that of the configuration shown in FIG.

The configuration example shown in the figure was devised on the premise that a magnetic bubble storage device with the same storage capacity would be constructed on a substantially square magnetic bubble chip, and therefore the configuration is divided into two groups as shown in the figure. and arranged in parallel.

Another feature of this embodiment is that the magnetic bubble detectors 5 of each storage configuration divided into two groups are arranged close to each other.

That is, when using a plurality of detectors, it is advantageous to make the external conditions of each detector, such as the crystal region, drive magnetic field, and bias magnetic field values the same, when considering noise/signal characteristics and the like.

The read and write operations are no different from the conventional configuration, but in particular, when reading, each set of information strings is detected by the detector 5 every other bit, so if the drive frequency is f, the read speed is is f/2+f/2=f, and the magnetic bubble information can be read out at the same period as the driving frequency as a whole.

FIG. 6a is an example of an actual pattern showing the structure shown in FIG. 5, particularly the broken line area, enlarged.

In the figure, 3' is an information storage path composed of a modified half-disk pattern made of permalloy, and 4' is composed of a modified half-disk pattern also made of permalloy and having a period twice the transfer pattern period of the information storage path 3'. The information propagation path 6 is a conductor pattern made of gold or the like formed in the layer below the pearloy patterns 3' and 4'.
The hairpin loop of the conductor pattern 6 and the Piffax pattern forming part of the information storage path 31 constitute a transfer leg circuit.

As is clear from the figure, the area of each transfer control circuit corresponding to each information storage path 3'' is much expanded compared to that shown in FIG.

Therefore, the lower end of the pattern 7, in particular, does not have an adverse effect on the magnetic bubbles propagating on the adjacent patterns constituting the information storage path.

This is also clear from the graph shown in FIG.

In other words, as can be seen from the operating margin characteristic curve of the magnetic bubble storage device according to this embodiment shown in the same figure, the operating margin of the circular propagation path including the transfer control circuit is guaranteed to be approximately the same as that of the linear propagation path. There is.

Further, the current phase margin of this embodiment is also sufficiently wide as is clear from the graph shown in FIG.

The horizontal and vertical axes in both graphs correspond to the horizontal and vertical axes shown in FIGS. 2b and 3, respectively.

As explained above, according to the present invention, it is possible to realize a magnetic bubble storage device in which a sufficient area for the transfer control circuit is secured without reducing the read speed.

In particular, as the density of magnetic bubbles increases and the diameter of magnetic bubbles becomes smaller in the future, the area of the transfer control circuit can be expanded, which means that the magnetic field generated by the conductor pattern can be applied more strongly and effectively to the magnetic bubbles. This means that the effect is enormous.

In the above-described embodiment, a modified half-disk pattern was used as the actual driving pattern, but the present invention is not limited to this, and T
It is also possible to apply a bar pattern, a chevron pattern, a continuous disk pattern, etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining a typical storage configuration of a conventionally known magnetic bubble storage device, FIGS. 2 and 3 are graphs showing a specific example of a transfer control circuit and its merge/characteristic curve, FIG. 4 is a storage configuration diagram of a magnetic bubble storage device already proposed by the applicant, FIG. 5 is a storage configuration diagram of a magnetic bubble storage device according to the present invention, and FIG. 6 is an enlarged view of the broken line area in FIG. 5. This is an example of a specific pattern. In the figure, 1 is a magnetic bubble generator, 2, 4' is an information propagation path, 3' is an information storage path, and 5 is a magnetic bubble detector.

Claims (1)

[Scope of Claims] 1. A plurality of information storage paths consisting of loop-shaped transfer paths each having a bent portion at least partially bent inward, and a region of the loop-shaped transfer path opposite to the bent portion of the information storage path. an information propagation path that is provided in close proximity and has a transfer pattern period larger than the transfer pattern period that constitutes the information storage path; and an information storage path and an information propagation path that are provided between the information storage path and the information propagation path. 1. A magnetic bubble storage device comprising a transfer control circuit for controlling transfer of magnetic bubbles between the memory devices. 2. A magnetic bubble storage device according to claim 1, wherein the information storage path is 2/2 bits (N is the capacity of the entire chip).