JPS6315675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble storage element detector.

Typically, a magnetic bubble storage element includes a circuit that controls generation and erasure of magnetic bubbles, a circuit that stores magnetic bubbles, a circuit that replicates magnetic bubbles, and a detector that detects the presence of magnetic bubbles and extracts them as electrical signals. are doing.

In particular, as shown in FIG. 1, many magnetic bubble detectors have recently been used that utilize the magnetoresistive effect of soft magnetic materials such as permalloy.
In the figure, 1 is a chevron-shaped transfer path pattern made of permalloy or the like, 2 is a magnetic bubble detection line made of permalloy or the like, and 3 is a magnetic bubble injection part.

Figures 2a and b are principle diagrams showing the mechanism for transferring magnetic bubbles, and the magnetic bubbles are transferred from A to B to C.
It is transferred via the route →D→E. Note that this magnetic bubble is generated by the in-plane rotating magnetic field A→B→ shown in figure b.
It is transferred as it rotates clockwise from C to D to E. In this case, A to E in Figure 2a and A in Figure 2b
~E are synchronized, and as a result, the magnetic bubble follows the rotation of the in-plane rotating magnetic field and is transferred bit by bit. The magnetic bubbles transferred based on this principle are injected from the magnetic bubble injector 3 shown in FIG. Due to the sufficiently enlarged magnetic bubble, the magnetoresistive effect of the detection line 2 appears and is sensed as an electrical signal.

When detecting magnetic bubble signals, the following problems occur. That is, in the detection line 2, in addition to the leakage magnetic field of the magnetic bubble as a signal, it is necessary to eliminate the noise of the magnetic resistance change due to the in-plane rotating magnetic field as noise. As a measure against this noise cancellation, conventionally, as shown in Fig. 3, a transfer pattern (commonly called a dummy detector) without a magnetic bubble injector, that is, unrelated to the transfer of magnetic bubbles, is provided to connect the normal detection line 2. The dummy detection line 2a is connected to the same amplifier to eliminate common mode noise. In addition, in Figure 3, the first
Components that are the same as those in the figure are given the same reference numerals. FIG. 4 shows the configuration of the magnetic bubble detection circuit. In the figure, the detection line 2, dummy detection line 2a, and resistors 4 and 4a are connected to Wheatstone Bridge (Wheatstone Bridge).
bridge) connected. 5 is a differential amplifier, and +V is a power supply. The operation of this circuit is such that when a magnetic bubble enters the detection line 2 due to an in-plane rotating magnetic field, the electrical resistance of the detection line 2 changes due to the magnetic field created by the magnetic bubble, while the electrical resistance of the dummy detection line 2a remains unchanged. As a result, the bridge becomes unbalanced, and an input is input to the differential amplifier 5, which amplifies this and outputs a signal indicating the presence of a magnetic bubble.

Now, as is well known, the dummy detector (not shown, but actually a guardrail made of a well-known T-bar or the like is provided around the outer periphery of the dummy detector pattern to prevent magnetic bubbles from entering). As shown in Figure 3, it occupies a large area like a regular detector (by doing so, the magnetic environment is the same as that of a regular detector), which is a factor that inhibits the improvement of bit density per chip. It has become one of the

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel magnetic bubble detector that solves the above problems.

In order to achieve the above object, in the present invention, a transfer path substantially the same as the magnetic bubble transfer path pattern forming the first and second detectors is provided on the magnetic bubble entry path side in the pattern forming the dummy detector. It is characterized by the provision of a transfer path for eliminating magnetic bubbles formed by rotating the pattern by approximately 180 degrees.

By configuring the dummy detector in this manner, the area required for conventional detection can be reduced by about 40%, and as a result, it can greatly contribute to improving the bit density per chip.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 5 is a diagram showing the overall configuration of a dummy detector according to the present invention. The figure shows only the dummy detector portion of the magnetic bubble detector constructed using the Chevron pattern. Reference numeral 6 denotes a detection line in which soft magnetic materials such as permalloy patterns are connected in series. 7 is a magnetic bubble transfer path, and 8 is a magnetic bubble elimination transfer path according to the present invention, which uses the same chevron pattern as the magnetic bubble transfer path 7. Since an in-plane rotating magnetic field as shown in FIG. 2b is applied, the magnetic bubble advances from the bottom to the top of the drawing. However, since the transfer path 8 for removing magnetic bubbles is rotated by 180 degrees with respect to the other regular magnetic bubble transfer path 7, magnetic bubbles cannot enter. That is, this transfer path 8 for removing magnetic bubbles plays the role of a guardrail (consisting of a T-bar pattern) for preventing the entry of magnetic bubbles surrounding the conventional dummy detector. Furthermore, it also plays the role of creating the same magnetic environment as a regular detector. Therefore, instead of using the traditional T-bar guardrail, we used the exact same chevron pattern and simply
Since it only rotates 180 degrees, it is much easier to create a magnetic environment compared to when using a guardrail.
This is because the magnetic environment is different between a dummy detector that uses mutually different patterns such as a T-bar pattern and a Chevron pattern close to each other, and a regular detector that consists only of a Chevron pattern. It is necessary to have the same configuration as a regular detector in order to match the magnetic environment, but if a guardrail is not used, the magnetic environment can be adjusted without having the same configuration. Therefore, the magnetic bubble transfer path 7 between the dummy detection line 6 and the magnetic bubble elimination transfer path 8
It becomes possible to reduce the number of columns. According to experimental results, it has been found that one or two rows is sufficient. Furthermore, it has been found that two rows of magnetic bubble elimination transfer paths 8 as shown in the figure is sufficient. However, although the magnetic bubble transfer path 7 on the upper side of the drawing of the dummy detection line 6 has the same number of rows as the conventional one, normally, after detecting a magnetic bubble, a magnetic bubble eraser (for example, permalloy) is used without reducing the size. bar, etc.), the number of rows of transfer paths for this purpose may be small. Therefore, the number of dummy detection lines 6 can also be reduced.

Therefore, according to the present invention, the number of columns of the magnetic bubble transfer path 7 between the dummy detection line 6 and the magnetic bubble elimination transfer path 8 in the pattern configuration of the dummy detector can be reduced, and the reduced number of columns can be reduced by the occupied area. Approximately 40
%. The area created by this reduction can be used for the memory circuit of the warped magnetic bubble, and as a result, it greatly contributes to improving the bit density per chip. Incidentally, since the dummy detector occupies approximately 10% of the effective area of the chip, the area allocated to the memory circuit is approximately 4% of the total area. This number may seem small at first glance, but it is an important number in order to realize recent high-density packaging.

In the above explanation, a basic chevron shape is used as the pattern used, but the same effect can be obtained by forming both the magnetic bubble transfer path 7 and the magnetic bubble elimination transfer path 8 in a T-bar pattern, or in other patterns with various modifications. Of course, it is effective.

As described above, according to the present invention, the magnetic environment of the dummy detector can be maintained similar to that of the regular detector, while the area occupied by the dummy detector can be significantly reduced compared to that of the regular detector. It has become possible to increase the storage capacity per chip, that is, to improve the bit density.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the magnetic bubble expansion detector, Figure 2
Figures a and b are diagrams explaining the transfer order of the Chevron type transfer pattern, Figure 3 is a pattern configuration diagram of a regular detector and a dummy detector, Figure 4 is a configuration diagram of a magnetic bubble detection circuit, and Figure 5 FIG. 2 is a pattern configuration diagram of a dummy detector according to the present invention. 6...Detection line, 7...Magnetic bubble transfer path, 8...Magnetic bubble elimination transfer path.

Claims (1)

[Scope of Claims] 1. A magnetic bubble detector including a first detector that magnifies and detects magnetic bubbles and a second detector that does not magnify and detect magnetic bubbles, wherein the second detector is located on the magnetic bubble entry road side. A transfer path for eliminating magnetic bubbles is provided, which is formed by rotating a transfer path pattern substantially the same as the magnetic bubble transfer path pattern constituting the first and second detectors by about 180 degrees. magnetic bubble detector.