JPS592285A - Driving system of magnetic bubble memory - Google Patents

Abstract

PURPOSE:To ensure selective control of bubbles by means of a common control conductor, by forming >=2 kinds of transmission lines of different levels of reluctance force to one magnetic bubble chip and actuating selectively the magnetic bubbles of the transmission lines. CONSTITUTION:As shown in the figure, the right half of minor loops m1-mn are set at normal reluctance force Hc I along with the left half set at higher reluctance force HcII respectively (Hc I <HcII). The number of bits can be changed per one page in response to applications by changing the level of the driving magnetic field. For instance, if a large capacity memory is used, the driving magnetic field is reduced to use only the right half region of small reluctance force in case only half or so of the capacity is used. Then the driving magnetic field is increased when the memory capacity is insufficient. At the same time, the left half minor loop is also driven. Thus it is possible to use all minor loops.

Description

[Detailed description of the invention] (a) Technical field of the invention The present invention relates to a method for driving a magnetic bubble memory.

(bl Prior Art and Its Problems Figure 1 is a diagram showing the circuit configuration of a conventional magnetic bubble memory, in which both ends of the minor loops m1 to mn-1 are connected to major lines M1 and M2 via gates. These minor lubes mI to m n-+ have gate control conductors C1l and CI2 in common.

Another minor loop mn is the minor loop m1~m
This is an auxiliary loop that records defective loops in n-1, and although it is connected to the aforementioned major lines Ml and M2, the conductors C21 and C22 for gate control are independent, making it difficult to use memory. At the start, only this auxiliary loop mn is read out and the states in the minor loops m1 to mn-1 are checked, and then information is written to the minor loops m1 to mn-+. Note that G is a bubble generator and D is a detector.

Figure 2 shows a magnetic bubble (hereinafter abbreviated as "bubble").
This figure shows a cross-sectional view of a pattern for transferring and controlling GGG, in which a control conductor is placed on a bubble material 2 made of a magnetic thin film created on the surface of a GGG single crystal 1 via an insulating layer 3. 4, an insulating spacer 5, a permalloy pattern 6, and a protective film 7 are formed. The propagation paths of the minor loops m1 to mn-1, the auxiliary loop mn, the major lines M1, M2, etc. are a series of permalloy patterns 6! It is composed of an n-shaped pattern, and the conductor portions such as the conductors CILC12, C21, and C22 of the game I-, the bubble generator, and the replicator are patterned by the conductor 4 into shapes according to their respective functions.

In this way, the auxiliary loop mn becomes the minor loop m1 again when the magnetic bubble memory starts to be used or when the power is cut off all at once.
It is used only when checking the status in ~mrl-1. Even if the frequency of use is low, the gates controlled by the conductors C2] and C22 must be independently provided and controlled independently, which increases power consumption and complicates the peripheral circuitry.

(C.1 Object of the Invention The object of the present invention is to solve such problems in the conventional magnetic bubble memory and to enable bubbles to be selectively controlled by a common control conductor.

FD1 Structure of the Invention In order to achieve this object, the present invention forms at least two types of propagation paths with different anti-mt forces in one magnetic hub, and changes the strength of the in-plane driving magnetic field according to the respective coercive forces. A configuration is adopted in which the magnetic bubbles in the propagation path are selectively operated by changing the height.

TE+ Embodiments of the Invention Next, examples will be used to explain how the driving method of the magnetic bubble memory according to the present invention is actually implemented. FIG. 3 shows a first embodiment of the present invention, in which the major line M
+ , , M2 is commonly connected to the minor loop m1 to lTln-1 and the boot (auxiliary) minor loop mn, as in FIG. 1, but in the case of the present invention, the data 1- Control conductors are also common as shown by CI and C2. Therefore, gate control is performed for all minor loops m1 to mn-, including the auxiliary minor loop mn.
+, mn can be performed all at once. However, if all the minor loops are simply controlled in common, the information on the auxiliary loop mn will also be read out when reading out the information on the minor loop ml''-mn-1, so do the following: The auxiliary loop mn is not read out except when necessary.

FIG. 4 shows an enlarged pattern of the gate portion between the minor loops m1 to mn-+ and the auxiliary minor loop mn and the conductor 02 for gate control. Permalloy patterns P+, Pz, etc. are formed above the gate control conductor Cz via the second spacer 5 explained in the figure. Further, PM is a transfer pattern forming the major line M1, P m n is a transfer pattern forming the auxiliary minor loop, Pmn-+, Pmn-z
... is a transfer pattern that constitutes a minor loop.

Among these transfer patterns, the permalloy pattern without diagonal lines is exactly the same as the conventional transfer pattern and has a coercive force of Hcl, but the transfer pattern with diagonal lines is the same as the other pattern with diagonal lines. The coercive force 1 (c is thicker and becomes Hc ■ (Hcl <
1 (cll). In the embodiment, the auxiliary minor loop mn
The coercive force of HclI is 5-100e.

The coercive force 11cl of the minor loop mn-1 was set at 1 to 20e.

Therefore, the minor loop Pn-+ which is not shaded
, Pn-z, major line PM, etc., are able to transfer bubbles by applying an in-plane driving magnetic field of 11 dl, which is sufficiently larger than 1 cl of antimagnetic nozzle, as shown in Fig. It is possible to conduct gate control by applying current. However, the hatched transfer patterns P+ and P2 with large coercive force and the auxiliary minor lube pattern pmn are not sufficiently magnetized to transfer bubbles with the normal in-plane drive magnetic field Hd+. Therefore, the bubble is not transferred within the auxiliary minor lube P m n and is not replicated or transferred out in the gate pattern P1 even if the conductor C2 is energized.

In order to be able to drive with these hatched patterns with large coercive force, the in-plane drive magnetic field H must be larger than the energized in-plane drive magnetic field 0d■ and sufficiently larger than the anti-magnetic force 1clr.
Apply dII. In the example, the driving magnetic field 11dl is set to 5
0 to 600e, driving magnetic field 11dII to 65 to 750-
6=e, respectively. If we apply a sufficiently large in-plane driving magnetic field that can drive the bubble with the diagonally lined pattern with a large coercive force, the auxiliary minor loop P m r
The bubble circulates within +r, and when conductor C2 is energized, the bubble is replicated out at gate patterns P1 and P2.

In this case, other minor loops Pn-+, , Pn-r, etc. with appropriate sounds that are not shaded can also transfer bubbles, but as mentioned above, reading information from the auxiliary minor loops P m n is not possible using bubbles. This is not a problem since it is limited to when starting to use the memory or when starting to use a page after power is turned off. Especially when you first start using Bubble Memory,
Since no information is stored in the minor loops mn-+ and ml-2, only the map information of the minor loop stored in the auxiliary minor loop mn is read out, and there is no problem at all.

Write side major line M1 and auxiliary minor loop m
By applying a sufficiently large in-plane driving magnetic field to drive the auxiliary minor ruble rn11 during the interval T, the map information pass is transferred via the gate.
(or swap) in. Therefore, a conductor dedicated to the auxiliary loop is not required, and the gate configuration can be shared with the minor loop.

By changing the strength of the in-plane driving magnetic field in this way, the coercive force of some permalloy patterns can be reduced so that the minor loops mn-1, mn-2 and the auxiliary minor loop m1lljl can be selectively driven. Increasing the strength can be achieved by changing the substrate temperature during permalloy deposition or by changing the composition of the permalloy pattern by several percent. As a result of experiments, two types of coercive force were obtained by changing the substrate temperature during vapor deposition. First, the substrate temperature was set at 320'C, and the coercive force was set at 1 to 20e. At this time, in areas with large coercive force,
Permalloy and selectively etched chromium (Cr)
A metal mask was applied. Next, the previously vapor-deposited portion was reversely masked, and vapor deposition was performed in the same manner at a substrate temperature of 280 to 290° C., with a coercive force of 5 to 100 e. After this, a pattern was formed using an energizing photography technique. The composition of the permalloy pattern is also changed by masking the other pattern when vapor depositing one pattern and changing the composition of the evaporation source.

In FIG. 6, the right half of the minor lubes m1 to mn is set to the coercive force Hcl for energization, and the remaining left half is set to a strong coercive force to 1lclll, so that 1lcl < tlcll. The layer structure and driving conditions of the memory element are the same as in the first embodiment, and by changing the magnitude of the driving magnetic field, the number of bits per page can be changed depending on the application. For example, in the case of a large-capacity memory, while only about half of its capacity is being used, the driving magnetic field is reduced to use only the right half area where the coercive force is small, and when the memory capacity becomes insufficient, By increasing the drive field, the left half minor loop can also be driven to use the entire liner loop.

(F1 Effects of the invention As described above, according to the present invention, at least two types of propagation paths with different coercive forces are formed in one magnetic bubble chip, and in-plane driving is performed according to each coercive force =91) A configuration is adopted in which the magnetic bubbles in the propagation path are selectively operated by changing the strength of the magnetic field.

Therefore, in applications where bubbles in the propagation path are selectively activated, such as in frequently used minor loops and minor loops that are not used, or in bubble memory devices that are used with different numbers of pages, it is not possible to use a common gate. This method has unique effects such as reducing power consumption by reducing gate control conductors and simplifying peripheral circuits.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a conventional magnetic bubble memory, Fig. 2 is a cross-sectional view showing its pattern configuration, Fig. 3 is a diagram showing the circuit configuration of the first embodiment of the present invention, and Fig. 4 is its pattern configuration. FIG. 5 is a characteristic diagram showing the relationship between coercive force and driving magnetic field, and FIG. 6 is a diagram showing a second embodiment of the present invention. In the figure, M+, Mz are major line, ml,
ml "mn-1 is the minor loop, mn is the boot 10- (auxiliary) loop, C11, C12, C21, C22 are the conductors, Pmn is the auxiliary minor loop pattern, Pn-
1 and Pn-+ each indicate a minor loop pattern. Patent applicant Fujitsu Co., Ltd. Agent Patent attorney Minoru Aoyagi 11- Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] By forming at least two types of propagation paths with different coercive forces in one magnetic bubble chip and changing the strength of the in-plane driving magnetic field according to each coercive force, magnetic bubbles in the propagation paths can be selectively generated. A magnetic bubble memory drive system that is characterized by operating as follows.