JPS6260757B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble memory transfer method that performs a transfer operation while preventing an increase in the lower limit of a bias margin.

Magnetic bubble memory (hereinafter abbreviated as bubble memory)
Creates a bubble generation circuit using conductive material (conductor pattern) on a garnet-type magnetic crystal, and a transfer circuit, a detection circuit, etc. using high permeability magnetic material (magnetic pattern), and then creates a circuit perpendicular to the magnetic crystal. This is a memory that writes and reads information by driving a cylindrical bubble magnetic domain held by a bias magnetic field applied to the crystal plane along a transfer circuit by a rotating magnetic field applied parallel to the crystal plane.

The bubble magnetic domain used as the storage medium of the bubble memory can only exist stably under a constant bias magnetic field. In other words, magnetic garnet-type crystals are magnetized with uniaxial anisotropy perpendicular to the crystal plane, and the directions of magnetization are opposite to each other, with alternating magnetic domains in opposite directions existing in a striped shape. There is.

Now, when a bias magnetic field is applied perpendicular to the crystal plane, the area of the magnetic domain in the opposite direction to the magnetic field decreases in proportion to the magnetic field value, and under an appropriate bias magnetic field it exists for the first time as a cylindrical bubble domain.

Therefore, if the bias magnetic field increases further, the bubble domain collapses and becomes a single domain with only the same magnetization direction, while if the bias magnetic field decreases, it forms striped magnetic domains again. Put it away.

In this way, bubble magnetic domains can exist only in the bias magnetic field region between the collapse magnetic field and the stripe magnetic field, and bubbles are generated, transferred, detected, etc. in this magnetic field region. It is being said.

In a bubble memory circuit, the operating margin differs depending on the circuit used, such as the transfer circuit and the gate circuit, and the minimum value of this operating margin is considered the overall margin of the memory chip. The operating margin is narrower than that.

The reason for this is that the gate circuit generates a magnetic field by applying a pulse current to the conductor pattern formed under the magnetic pattern, and the interaction between this magnetic field and the induced magnetic field generated on the magnetic pattern by the driving magnetic field (rotating magnetic field) However, due to manufacturing variations, the mutual position of the conductor pattern and the magnetic pattern formed on it may deviate from the designed value, or there may be a large deviation on the magnetic pattern. If there is a step, the operating margin becomes even narrower.

The present invention solves these problems by using a bubble transfer method and realizes a gate circuit with a wide operating margin.The present invention will be described below with reference to the drawings while comparing an embodiment and a conventional example.

FIG. 1 is a schematic diagram of a bubble memory having a conventional block-replicate-measure-minor-loop type transfer circuit, in which the circuit configuration is extracted and illustrated.

This transfer circuit has first and second write major lines 1 and 2 each consisting of a plurality of magnetic pattern arrays.
and the first and second readout major lines 7 and 8.
The upper and lower major lines 1, 2, 7, and 8 are connected to the minor loops 4 on the same plane through insulators and through transfer gates 3 and 9, which are composed of conductor patterns located in the lower layer. are doing.

Further, the first and second write major lines 1 and 2 are provided with bubble generators 5 and 6, and bubble signals generated by the bubble generators are transferred and written into the minor loop 4 by the action of the transfer gate 3.

On the other hand, the first and second readout major lines 7 and 8
By the action of the transfer gate 9, the bubble information stored in each minor loop 4 is read out to each readout major line, and after being detected by the detectors 10 and 11, it is swept out from the memory area and erased. .

Now, in this block replicate transfer method with the main/minor loop configuration, the bubble signal corresponding to the information is generated by the generator (in this case, 5,
6) and is transferred along the major line (1, 2 in this case) by the driving magnetic field, and one is placed at the position corresponding to each minor loop (4 in this case) connected to every other bit of the transfer pattern that makes up the major line. Every time the information is aligned, it is transferred to each minor loop by the action of the transfer gate (3 in this case) and circulated within the minor loop by the driving magnetic field. This is information writing.

In this block repeat transfer method, the bubble operation is the same, but the circuit configuration is divided into even-numbered blocks and odd-numbered blocks.
The feature is that the bubble signal is written and read separately into even and odd columns.

That is, in FIG. 1, the block consisting of the first write and read lines 5, 7 and the minor loop 4 is an even block, and the block consisting of the second write and read lines 6, 8 and the minor loop 4 is an odd block. In this method, identical bubble signals are created in generators 5 and 6 and transferred to major lines 1 and 2, and in even blocks, when the even columns of the signal come to opposite positions of the minor loop 4, and in odd blocks, When an odd numbered column comes to a position opposite to the minor loop 4, the transfer gate 3 causes the odd numbered column to be transferred to the opposing minor loop.

Now, the inventors have found a large correlation between the arrangement of bubble signals and the operating margin in such a transfer-in operation.

FIG. 2 is a diagram showing the relationship between the bias margin and the drive magnetic field, with the bias magnetic field H _B on the vertical axis and the drive magnetic field _HD on the horizontal axis.

The solid line 12 in FIG. 2 indicates the lower limit of the operating margin when bubbles are present in each of the adjacent magnetic patterns, that is, when the bubble signal is, for example, 1111 when the bubble performs the transfer-in operation, and the dotted line 13 indicates the transfer-in operation. The solid line 14 is the lower limit of the operating margin when there is no bubble in the adjacent magnetic pattern, such as 1100, while the solid line 14 is the upper limit of the bias margin, which is approximately the same regardless of the presence or absence of a subsequent bubble. It can be seen from this that the operating margin is wider when bubbles exist in adjacent magnetic patterns.

FIG. 3 shows the relationship between the pulse current (transfer current) I flowing through the conductor pattern of the gate circuit and the operating margin, with the bias magnetic field H _B plotted on the vertical axis. In the figure, the solid line 15 indicates the lower limit of the operating margin when bubbles are present in the adjacent magnetic pattern when the bubble transfers in, and the dotted line 16 indicates the lower limit of the operating margin when there is no bubble, and as the pulse current value increases, The operating margin is reduced in both cases, but the reduction is less when a trailing valve is present.

FIG. 4 is an enlarged view of the transfer gate section to explain the reason for this. In the figure, a transfer path consisting of a transfer pattern 18, which is a half-disk type magnetic pattern, is provided on a conductive pattern 17 via an insulating layer on a magnetic garnet crystal, and the seven patterns at the bottom of the paper are major line patterns. The two patterns extending perpendicularly to the top of the page represent part of the minor loop.

Here, the bubble transfer direction is from the right to the left, and the pulse current is applied during the transfer operation when the rotational direction of the driving magnetic field is in the shaded area of circle 19 on the right in the figure below.

The transfer operation for the gate section on the left side of FIG. 4 will now be explained as follows.

When the driving magnetic field 19 is in the A direction and the bubble 20 is transferred to the right end of the transfer pattern 21, when a pulse current as indicated by the arrow is passed through the conductive pattern 17, the bias magnetic field is weakened by the local magnetic field generated thereby and is attracted and expanded. The bubble 22 has a driving magnetic field of B,
As it changes in the C direction, it moves to the left end of the bar-shaped pattern 23 and is thereafter transferred to the minor loop pattern 24 by the driving magnetic field.

This is normal operation of the transfer
If the transfer pattern 21 formed on the conductive pattern 17 has a step, and therefore the induced magnetic field by the drive magnetic field is weak, or if the two patterns are misaligned and the drive pattern is shifted to the left, the transfer pattern 21 The repelling magnetic field at the right end becomes weaker, which is further weakened by the attracting magnetic field caused by the transfer gate current, resulting in a malfunction in which the bubble 20 is trapped at the left or upper end of the conductive pattern 25. This corresponds to the fact that the larger the transfer current, the narrower the operating margin, as shown in FIG.

Even in such a case, if a bubble 26 exists in the transfer pattern 25 when the driving magnetic field is in the C direction, the bubble 22 is likely to move to the left end position of the bar pattern 23 due to the repulsion magnetic field of the bubble 26. In other words, it is shown that the gate operating margin is improved by using the magnetic field of the subsequent bubble, and this corresponds to the improvement at the lower limit side of the operating margin in FIGS. 2 and 3.

As described above, when a bubble signal is transferred to even-numbered blocks and odd-numbered blocks in the block repeat transfer circuit shown in Figure 1, the presence of a bubble following the bubble signal is essential for ensuring an operating margin. Although more advantageous, conventionally the bubble signal is directly transmitted to the first and second signals.
It was impossible to create this condition because the data was transferred to the major write lines 1 and 2 of .

The bubble transfer method according to the present invention has been made to solve this problem, and whereas conventionally the generators 5 and 6 of the even and odd blocks are formed by a common power source as shown in FIG. In the block repeat transfer configuration according to the invention, a generator and an auxiliary generator are provided for each even numbered and odd numbered blocks.

Figures 5 to 7 show circuit diagrams according to the present invention equipped with this, and compared to the conventional circuit, only the circuit of the generator to the measure line is different, and Figures 6 and 7 overlap. The description of the circuits below the read transfer gate is omitted.

In FIG. 5, the bubble signal generator 27 for even blocks and the generator 29 for odd blocks are independent of each other. generates an odd sequence of signals.

For example, when the bubble information is 1011, a bubble signal of 01 is generated from the generator 27 of an even numbered block, and a bubble signal of 11 is generated from the generator 29 of an odd numbered block. At the same time, the auxiliary generators 28 and 30 that are adjacent to each of the generators 27 and 29 exist with transfer patterns shifted by one bit from those of the generators 27 and 29, so in this example, the write major line 1 of the even block is
The signal transferred to write major line 2 of an odd block is 0011, or the signal transferred to write major line 2 of an odd block is 0011.
1111, and when a bubble is transferred, an auxiliary bubble exists following it to assist the gate function.

For the auxiliary bubble, after the bubble information is transferred to the minor loop, it is directly transferred to the major line and swept out to the guardrail.

Next, FIG. 6 shows a circuit in which the bubble signals generated by the bubble signal generator 31 for even blocks and the auxiliary generator are transferred to the major line by different transfer lines, and in this case, the bubble signals generated by the bubble signal generator 31 for even blocks and the auxiliary generator are transferred to the major line. The path is one pitch longer than the transfer path of generator 31. The same applies to the odd block generator 33 and the auxiliary generator 34.

The generation, transfer, and transfer operations of bubble information in FIG. 6 are exactly the same as in FIG. 5.

In FIG. 7, unlike the above two embodiments, the generator 35 for even blocks and the auxiliary generator 36 are independent, while the auxiliary generator 36 for even blocks and the auxiliary generator 38 for odd blocks are connected in series. Here, the generators 35, 37 and the auxiliary generator 36,
The transfer path is different from No. 38 by 1 bit as in the case of FIG.

In the case of the circuit shown in FIG. 7, bubbles are always generated from the auxiliary generators 36 and 38 regardless of whether bubbles are generated in the generators 35 and 37 for even and odd blocks.

For example, if the bubble information is 1011, the generators 35 to 01 of even blocks are also generated from the auxiliary generator 36.
11 is generated, and both are rearranged at the intersection point 39 of the median line to become 0111. Also, in the case of an odd block, it is rearranged in the same way to become 1111, and transferred from the major line to minor loop 4,
In this case, regardless of whether there is a bubble in the gate circuit or not, there is always a bubble at the next bit position, which helps the gate operation and after the transfer operation of the bubble signal, transfers the measure line and sweeps it to the outside. will be given out.

Although the explanation has been given by taking the block replicator transfer method as an example, the present invention is not necessarily limited to this.

The present invention focuses on the fact that in a gate circuit with a major-minor loop configuration, when a bubble exists in an adjacent transfer pattern when performing a transfer-in operation, the lower limit of the operating margin expands due to the repulsive magnetic field compared to when there is no bubble. By providing an auxiliary generator in addition to the conventional generator, bubbles can always exist in adjacent patterns when performing a transfer-in operation, thereby expanding the operating margin.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a circuit according to the conventional block repeat transfer system, Figure 2 is a diagram of the relationship between the bias magnetic field and drive magnetic field in the transfer gate circuit, and Figure 3 is the relationship between the bias magnetic field and the driving magnetic field in the same circuit. FIG. 4 is an explanatory diagram of the transfer-in operation, and FIGS. 5 to 7 are explanatory diagrams of an embodiment equipped with an auxiliary generator according to the present invention. In the figure, 1 and 2 are major lines, 3 and 9 are transfer gates, and 4 are minor loops 5 and 2.
7, 31, 35 are bubble generators for the first write major line; 6, 29, 33, 37 are bubble generators for the second write major line; 28, 3;
2 and 36 are auxiliary bubble generators for the first write major line; 30, 34, and 38 are auxiliary bubble generators for the second write major line.

Claims (1)

[Scope of Claims] 1. Bubble information written by a bubble generator is transferred through a major line (loop), and the bubble information is transferred from the major line to a minor loop via a transfer gate to store information. In the bubble memory, in addition to the bubble information, auxiliary bubbles located between the information bubbles are written in the major line, and when the information bubble is transferred, the information bubble is transferred with the help of the magnetic field of the adjacent auxiliary bubble. A bubble transfer method for a magnetic bubble memory characterized by ein. 2. The bubble transfer method for a magnetic bubble memory according to claim 1, wherein the auxiliary bubble is provided by an auxiliary bubble generator connected to the measure line in addition to the bubble generator.