JPS6048836B2 - Magnetic bubble memory module for high speed drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heat dissipation in magnetic bubble memory modules for high speed operation.

In order to realize high-speed drive of magnetic bubble memory, it is necessary to develop a module (a part that generates the rotating magnetic field and bias magnetic field necessary for the chip) that can operate at high speed in parallel with the development of a high-speed chip. .

Among these, the biggest problem with modules is the rise in chip temperature due to heat generated by the rotating magnetic field generating coil. This temperature rise narrows the bias margin width in which the chip can operate, making the chip operation unstable. Increasing the frequency of the rotating magnetic field for high-speed drive increases coil loss, making this problem even more severe. Therefore, in order to suppress the temperature rise of the chip within the module, it is important to reduce the loss of the coil and to design the radiation of the module. FIG. 1 shows a schematic configuration of a typical conventional high-speed drive magnetic bubble memory module.

In the figure, an inner coil 2 and an outer coil 3 are arranged orthogonally surrounding a substrate 1 on which a magnetic bubble memory chip is mounted. A rotating magnetic field parallel to the surface of the magnetic bubble chip mounted on the substrate 1 is generated by passing sinusoidal currents having a phase difference of 900 degrees to each other through the inner coil 2 and the outer coil 3. On the other hand, a bias magnetic field perpendicular to the surface of the magnetic bubble chip is applied by magnetic shunt plates 5, 5 made of ferrite or the like that are magnetically coupled to the permanent magnets 4, 4. Furthermore, although not shown, magnetic shunt plates 5, 5
A radiation plate is attached to the outside of the unit via a magnetic shield plate. In a magnetic bubble memory module having such a configuration, when a sinusoidal current is passed through the inner and outer coils 2 and 3, the inner and outer coils 2 and 3 are caused by the loss resistance of the coils.
3 has a fever.

The amount of heat generated is proportional to the loss resistance and proportional to the square of the coil current. Also, as the rotating magnetic field frequency increases, the loss resistance of the coil increases due to high frequency loss, and as a result,
The amount of heat generated increases. Therefore, 5 mounted on board 1
The temperature of the chip also increases accordingly. For example, the rotating magnetic field frequency is 500KH2) the rotating magnetic field amplitude is 50KH2)
In the case of Oersted, the total power consumption of the inner and outer coils 2 and 3 is approximately 25W, and the temperature rise of the chip is approximately 25W.
It becomes 40℃. This range of temperatures occurs depending on whether one set of coils 2 and 3 or multiple sets of coils 2 and 3 are included in one module. Therefore, the temperature of the chip is the sum of the temperature generated by the outer coils 2 and 3 and the environmental temperature placed in the module. Normally, this environmental temperature ranges from 0 to +50°C.
On the other hand, the operating temperature range of a magnetic bubble memory chip is limited to 0 to 70°C due to its temperature characteristics.

Therefore, the above-described magnetic bubble memory module has a drawback in that its operating environment temperature range is extremely limited, and an improvement is desired. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic bubble memory module for high-speed operation that eliminates the above-mentioned drawbacks. In order to achieve the above object, the present invention focuses on heat transfer in the space surrounded by the inner coil, magnetic field shunt plate, and permanent magnet, and creates a space that has good thermal conductivity and high electrical resistance. It is characterized by the provision of a thermal layer.

By configuring the magnetic bubble memory module in this way, the heat generated in the inner and outer coils is not only transmitted to the magnetic shunt plate via the outer coil, but also transferred to the magnetic shunt plate or permanent magnet via the inner coil. Therefore, efficient heat transfer is possible.

Therefore, the temperature difference between the temperature of the inner and outer coils and the surface temperature of the magnetic shunt plate or permanent magnet becomes very small.
The effect is that the operating environment temperature range is expanded. Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 is a schematic diagram of a magnetic bubble memory module for high-speed driving according to the present invention. In FIG. 5, the same parts as in FIG. 1 are designated by the same numbers, and only the structural differences will be described in detail.
Portions 6, 6 surrounded by the inner coil 2, magnetic field shunt plates 5, 5, and permanent magnets 4, 4 that formed a space in FIG.
' is replaced with heat transfer layers 7, 7' having high electrical resistance and good thermal conductivity as shown in FIG. As a result, the thermal resistance has become extremely small, and the heat that was previously confined in the spaces 6, 6' can be efficiently transferred to the magnetic field shunt plates 5, 5 or the permanent magnets 4.
, 4. The heat transfer layers 7, 7' are required not only to have good thermal conductivity, but also to have low thin current loss due to the high frequency rotating magnetic field. Therefore,
Metal is not suitable as the material, and suitable materials include a boron nitride molded plate, a silicon single crystal plate, and the like. In particular, a sintered body of boron nitride (BN) has characteristics such as having the second best thermal conductivity after Beryllium and being easy to process. When a BN plate is used as the heat transfer layer 7, 7', the conventional thermal resistance can be reduced by about 50%, calculated from its thermal conductivity, etc.
can be reduced. Actual experimental results show that the chip temperature rise when driving at 300 KHz with a conventional module is 2.
What was heated at 1°C can be heated to 500°C with the module according to the present invention.
The chip temperature rise during KHz driving is 15° C., and the heat transfer effect is extremely large.

Further, the heat transfer layers 7, 7' are plate-shaped, and the magnetic shunt plates 5, 5 and the permanent magnets 4, 4 in contact therewith are also plate-shaped.

Therefore, unless precision machining is applied to each contact surface, there will always be a slight gap. This gap acts as a large resistance to heat transfer. The same can be said of the contact surfaces between the inner coil 2 and the heat transfer layers 7, 7' whose surfaces are hardened with resin or the like. In order to reduce the thermal resistance on this contact surface, a thermally conductive grease containing a large amount of boron nitride (BN) powder is prepared and applied to the contact surface. Since the adhesion of the contact surface was improved using a grease with low thermal resistance, heat transfer was improved. As mentioned above, by providing a heat transfer layer such as a boron nitride plate or a silicon single crystal plate in the space inside the module, the heat generated by the rotating magnetic field generating coil consisting of the inner and outer coils can be efficiently demagnetized. It becomes possible to transmit the information to the plate and the permanent magnet, and as a result, the temperature rise of the magnetic bubble chip can be suppressed, and therefore, the operating environment temperature range of the magnetic bubble memory module for high-speed driving is expanded.

This widens the range of applications of magnetic bubble memory and makes it industrially useful.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional magnetic bubble memory module for high-speed drive, and FIG. 2 is a schematic configuration diagram of a magnetic bubble memory module for high-speed drive according to the present invention. ...Board, 2 ...Inner coil, 3 ・
...Outer carp...Permanent magnet, 5...
...Magnetic adjustment plate, 6,6'...Space, 7,7'...
...Heat transfer layer.

Claims (1)

[Claims] 1. A heat transfer device formed of at least one of a boron nitride forming plate and a silicon single crystal plate in a space surrounded by a rotating magnetic field generating inner coil, a magnetic shunt plate, and a permanent magnet. A magnetic bubble memory module for high-speed driving characterized by having layers. 2. Claim 1, characterized in that the heat transfer layer has grease containing boron nitride powder interposed on the surface in contact with the rotating magnetic field generating inner coil, the magnetic shunt plate, or the permanent magnet. The described magnetic bubble memory module for high-speed driving.