JPS5824864B2 - Jiki Bubble Kiokusouuchino Bias Jikaisei Giyohoushiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling a bias magnetic field in a magnetic bubble storage device.

Conventionally, in a magnetic bubble storage device, a bias magnetic field is generated for a bubble storage element using the configuration shown in FIG. 1, and its intensity is adjusted.

That is, 2 and 2' in FIG. 1 are permanent magnets for generating a bias magnetic field, and the magnetic field generated by these permanent magnets becomes a parallel magnetic field 5 indicated by an arrow on the yoke plates 4 and 4', and is applied to the surface of the magnetic bubble memory element 10. Applied vertically.

Further, a spacer 3 is inserted between the permanent magnets 2, 2' and the yoke plate 40, and by changing the thickness of the spacer 3, the intensity of the bias magnetic field applied to the magnetic bubble memory element 1 is adjusted.

By the way, in addition to the bias magnetic field described above, a rotating magnetic field having a magnetic field direction parallel to the surface of the magnetic bubble memory element 10 is applied to the magnetic bubble memory device in order to drive the puzzle, and the device uses these rotating magnetic fields. It is possible to operate in the range of magnetic field strength and bias magnetic field strength.

This is shown in FIG. FIG. 2 shows the rotating magnetic field strength on the horizontal axis and the bias magnetic field strength on the vertical axis, where region 11 is operable and region 12 is inoperable.

In this figure, for example, if the rotating magnetic field strength HR is kept constant, the operable region of the bias magnetic field is between Ha and Hb.

When examining the locus of the bias magnetic field strength boundaries Ha and Hb corresponding to temperature changes, as shown in FIG. 3, the operable region 11 tends to decrease as the ambient temperature of the magnetic bubble storage element increases.

This characteristic is thought to be determined by the characteristics of magnetic garnet, which is a magnetic bubble medium.

From this, in order to maximize the operating margin of the magnetic bubble memory element, the bias magnetic field strength must be changed in accordance with the temperature to the same bias strength as the locus 13 at the center of the operable region.

As explained in Figure 1, in the past, a spacer was inserted between the permanent magnet for generating the bias magnetic field and the yoke plate, and by changing the thickness of the spacer, the gap between the magnet and the yoke plate was changed, and the strength of the bias magnetic field was changed. Ta.

However, with this method, fine adjustment is difficult, the uniform magnetic field range is relatively narrow compared to the size of the magnetic circuit, and adjusting the bias magnetic field changes the uniform magnetic field distribution. There are drawbacks such as difficulty in making arbitrary adjustments after assembly.

In order to eliminate the problem of slanting, the present invention uses an electromagnet instead of a fine adjustment spacer, detects the ambient temperature of the magnetic bubble element, controls the excitation current of the electromagnet, and thereby applies a bias to the magnetic bubble memory element. It is an object of the present invention to provide a bias magnetic field control system that is optimal for changing the strength of a magnetic field in accordance with temperature and expanding the operating margin range of a device in response to temperature changes.

FIG. 4 shows an embodiment of the present invention.

In the figure, the configuration of the magnetic bubble storage element 1, permanent magnets 2, 2' for generating a bias magnetic field, and yoke plates 4, 4' is as follows.
Although it is the same as the case shown in the figure, electromagnets 4L41' are attached to the yoke plates 4, 4' instead of spacers, and on the other hand, a temperature sensing element 42 such as a thermocouple is installed around the magnetic bubble memory element 1. It is located.

43 is a current supply circuit for providing an exciting current to the electromagnet 4L41'; 44 is a current supply circuit for amplifying the output voltage from the thermocouple 42;
This is a control circuit for controlling the output current of the current supply circuit 43 according to the ambient temperature of the magnetic bubble memory element 1.

The operation of FIG. 4 is as follows.

First, the ambient temperature of the magnetic bubble storage element 1 is detected by the thermocouple 42 .

Then, depending on this ambient temperature, the magnetic bubble memory element 1
The magnetic field strength of the electromagnets 41, 41' is controlled so that the bias magnetic field for the magnetic field strength becomes the same as the magnetic field strength locus 13 in FIG.

This corresponds to the output voltage detected by the thermocouple 42,
The control circuit 44 controls the current supply circuit 43 and the electromagnet 4L.
This is done by changing the excitation current of 41'.

Various configurations are possible for the control circuit 44, but in any case, it may be operated so that the bias magnetic field strength follows a trajectory on the center point of the operable region in accordance with the temperature.

In this way, in response to temperature changes, the bias magnetic field strength 5 will track the optimum value within the bias magnetic field operable region of the magnetic bubble storage device.

Note that the thermocouple 42 may be any other temperature sensing element.

In some cases, it is also possible to remove the permanent magnets 2, 2' and have the electromagnet 4L41' receive the entire bias magnetic field.

As explained above, according to the present invention, the ambient temperature of the magnetic bubble memory element is detected, and the strength of the auxiliary bias electromagnet for fine adjustment is controlled in accordance with the detected temperature to change the strength of the bias magnetic field. , the magnetic field strength is always maintained exactly near the center of the operable region of the bias magnetic field characteristics of the magnetic bubble memory element,
Since the bias magnetic field is made to respond immediately to changes in ambient temperature, there is an advantage that the influence of changes in the operating margin region due to the temperature characteristics of the bubble memory element can be eliminated.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a conventional example of a bias magnetic field control method in a magnetic bubble storage device, Fig. 2 is a diagram illustrating the operable region of a combination of a rotating magnetic field and a bias magnetic field, and Fig. 3 is a diagram showing the area around the magnetic bubble storage element. FIG. 4 is a diagram illustrating the operable range of combinations of temperature and bias magnetic field strength, and is a diagram illustrating an embodiment of the method of the present invention. 1... Magnetic bubble storage element, 2... Permanent magnet for generating bias magnetic field, 3... Spacer,
4,4'... Yoke plate, 5... Bias magnetic field, 4L41'... Electromagnet, 42...
... Temperature sensing element, 43 ... Current supply circuit, 44.
...Control circuit.

Claims (1)

[Claims] 1. A part or all of the bias magnetic field applied to the magnetic bubble storage element is received by an electromagnet, and a temperature sensing element is arranged around the magnetic bubble storage element, and the excitation current of the electromagnet is adjusted in response to the output of the temperature sensing element. A bias magnetic field control method for a magnetic bubble memory device, characterized in that the bias magnetic field is controlled in response to the ambient temperature of a magnetic bubble memory element by changing the temperature of the magnetic bubble memory element.