JPS5922283A - Method for testing magnetic bubble memory element - Google Patents

Abstract

PURPOSE:To guarantee operation from a disturbance magnetic field or the like, by providing a magnetic bubble memory element to which no regular disturbance is applied ordinally with a means to apply the disturbance selectively to a rotary magnetic field in testing of the operation of the magnetic bubble memory element. CONSTITUTION:A control part 1 controls a driving circuit 2 in accordance with a built in program to drive the magnetic bubble memory element 6 and execute the test of reading/writing operation. The control part 1 controls the on/off of oscillators 3x, 3y to oscillate asynchronous optional frequency with the frequency of rotary magnetic field HR driving current sent from a driving circuit 2 and superpose noise current of which amplitude is optionally set up by amplifiers 4x, 4y to driving current applied to coils 6x, 6y from the driving circuit 2 through modulation transformers 5x, 5y. If the control part 1 controls the on/off of optional one/both of oscillators 3x, 3y as required, driving current based on superposing or non-superposing is supplied selectively with optional period to coils 6x, 6y.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an improvement in a method for testing the operation of a magnetic bubble memory device.

(b) Background of the technology Bubble memory elements use binary information of 1.0 to determine the presence or absence of magnetic bubbles obtained by applying perpendicular bias magnetism to the surface of a magnetic thin film.
This is a nonvolatile serial magnetic memory element having a configuration in which a signal train generated by magnetic bubbles is shifted by applying a local gradient of a bias magnetic field to the signal train and transferred through a predetermined bubble transmission path.

(c) Conventional technology and problems Bubble memory elements have traditionally used garnet, a thin film with an axis of easy magnetization in the perpendicular direction, as a magnetic thin film, and a constant perpendicular magnetic field (bias magnetic field HB) obtained by a permanent magnet.
), T1 is obtained by placing it in contact with the magnetic thin film at each bit position, an in-plane rotating magnetic field is applied to a magnetic material such as a chevron or half-disk shape, for example, a permalloy thin piece, or a @-part magnetic field is obtained by applying current to a conductive pattern. By obtaining a local perpendicular magnetic field gradient, a large number of effective magnetic bubbles, for example ~10', in a magnetic thin film can be efficiently moved all at the same time, and the generation, disappearance, expansion, and division of magnetic bubbles can be selectively controlled to create a magnetic memory. do. Operation in a bubble memory element For example, the margin curve of the magnetic bubble memory element shown in Fig. 1 is a measurement of the operating region for the magnitude of the rotating magnetic field (HR) and the magnitude of the bias magnetic field (HB) in the operational characteristics of magnetic bubble movement. It is evaluated with an example. The inner region surrounded by the curve is the operating region under constant operating conditions, and even in the same bubble memory element, it changes depending on the temperature or HR frequency.

The margin curve indicating this operating region is the garnet substrate, magnetic thin film, magnetic thin piece, H
It differs slightly depending on the physical quantities and their error accumulation in B, HR, etc.

In the conventional bubble memory operation test, the magnitude of Hn and the magnitude of HB were measured, for example, in the central areas A, B, and C in Figure 1.

Is the performance confirmed by setting each condition point of D and performing certain memory write/read operations under each condition?Is there a guarantee of operation against disturbance magnetic fields, etc., especially against disturbances to rotating magnetic fields? There were some drawbacks that I hadn't thought about.

(d) Object of the Invention The object of the present invention is to have a means for selectively adding disturbance to a rotating magnetic field in an operation test of a magnetic bubble memory element, which has not been subjected to any disturbance in the conventional example; The purpose is to provide a method for guaranteeing operation against disturbance magnetic fields and the like.

(e) Structure of the Invention The object of the present invention is to provide a memory operation test device for a magnetic bubble memory element, which is a means for writing/reading data into a magnetic bubble memory element, and a means for writing/reading data into a magnetic bubble memory element, by superimposing the driving currents of the X and Y coils to provide a rotating magnetic field to drive the magnetic bubble memory element. A magnetic bubble memory element, comprising means for superimposing a noise current having an arbitrary frequency and amplitude asynchronously with each other on the 6th current, and means for controlling on/off of either or both of the X and Y coils for the superimposition operation. During operation tests, asynchronous noise was superimposed on either or both of the X and Y rotating magnetic fields.

This can be achieved by providing a method for testing a magnetic bubble memory device characterized by selecting non-overlapping and performing a write/read test.

(f) Embodiment of the Invention An embodiment of the invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a test method for a magnetic bubble memory device according to an embodiment of the present invention, and FIG. 3 shows a rotating magnetic field of an X coil or a Y coil. An example of a waveform when noise iii is superimposed on the drive current is shown.

In the figure, 1 is a control unit, 2 is a rotating magnetic field (I(R) drive circuit +3X-7 is an oscillator +4X+, y is an amplifier, and 5x.

ytf modulation transformer, 6 is a magnetic bubble memory element, and 6x, 'J is a rotating magnetic field drive coil. Figure, □-- Although not shown, HB necessary for the configuration of the magnetic puzzle memory element
Permanent magnets and other elements and other direct and indirect peripheral circuits other than drive circuit 2 are normal data save/
shall be complete for read operation configuration. The control unit 1 controls the drive circuit 2 according to a stored program, drives the magnetic bubble memory element 6, and performs a write/read operation test. Oscillator 3 Xy 3' v amplifier 4x,
'l and the modulation transformers 5x and 7 are not used, it is the same as the conventional operation test, but in this case, the control part l is the oscillator 3x+7.
is controlled on/off to oscillate an arbitrary frequency asynchronous to the frequency of the HR drive current sent out from the drive circuit 2, and drive the noise current with an arbitrary amplitude in the amplifiers 4x, y through the modulation transformers 5x, y. Coil 6X from circuit 2
It is superimposed on the drive wJ current given to 17. Furthermore, control section 1
is selectively superimposed on the coils 6x and y at an arbitrary period by controlling on/off any one or both of the oscillators 3x and 7 as necessary.

A non-overlapping drive current is provided. Although FIG. 2 shows an unbalanced superimposition operation by the modulation transformers 5x and 7, it goes without saying that similar results can be obtained by using a balanced modulation system if necessary.

(g) Detailed Description of the Invention According to the present invention, in addition to controlling the rotating magnetic field drive circuit by the control unit, oscillation! A Noise current is selectively superimposed on one or both of the driving direct current of the rotating magnetic field drive coil under control (1) Since the bubble memory element is driven, the operation test against the disturbance magnetic field can be efficiently performed. can be done.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the margin curve of a magnetic bubble memory device according to a conventional example and an embodiment of the present invention, and FIG. 2 is a block diagram and a diagram showing a test method for a magnetic bubble memory device according to an embodiment of the present invention. FIG. 3 shows a noise-superimposed vibration current waveform diagram applied to the rotating magnetic field drive coil. In the figure, 1 is a control unit, and 2 is a rotating magnetic field drive circuit. 3x and y are a modulation transformer, 6 is a magnetic bubble memory element, and 6x and y are rotating magnetic field drive coils. Age 1 figure R Age 2 figure

Claims (1)

[Claims] In a memory operation test device for magnetic bubble memory elements,
means for writing/reading data to/from a magnetic bubble memory element;
Regarding the means and superimposition operation for superimposing a noise current of an arbitrary frequency and amplitude that is asynchronous with each other on the drive current of the X and Y coils that provide a rotating magnetic field, either one of the X and Y coils is not yet used. is equipped with a means for controlling both on and off, and selects whether or not asynchronous noise is superimposed on either or both of the X and Y rotating magnetic fields in the operation test of the magnetic bubble memory element, and performs a write/read test. A method for testing a magnetic bubble memory device, characterized in that: