JPS5831671B2 - magnetic bubble memory module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat dissipation method for a magnetic bubble memory module in which two sets of rotating magnetic field generating coils can be mounted and a magnetic circuit that applies a bias magnetic field to a chip is of a magnetic shield type.

To operate the magnetic bubble chip, 6 points perpendicular to the chip must be
It is necessary to apply a bias magnetic field of about 0 to 2000 e and a rotating magnetic field of about 20 to 600 e that rotates within the chip plane.

Among these, the rotating magnetic field is generated by passing a sine wave current or triangular wave current having a phase difference of 90 degrees between two coils 3 and 4 wound orthogonally to each other around one part of the substrate 2 on which the chip 1 is mounted. do.

(Fig. 1) On the other hand, the bias magnetic field is generated by the magnetization plates 5, 5' (flat plates such as tuyulite) above and below the coil, and by the permanent magnets 6, 6.
′ occurs.

(Fig. 2) When a sinusoidal current is passed through the coils 3 and 4, the coils generate heat due to the loss resistance of the coils.

The loss power at this time is P, and the coil current amplitude is ■L,
Assuming that the coil O loss resistance is RL, the heat generated by this loss increases the temperature of the coil.

Therefore, the temperature of the chip mounted in the coil also rises.

For example, consider a module in which two boards each having eight 9-square chips mounted thereon are mounted.

Table 1 shows the shape, inductance, loss resistance, and power consumption of the coils 3 and 4.

However, the operating frequency is 500KHz, and the rotating magnetic field amplitude is 4
Set to 00e.

In the magnet block shown in Fig. 1 in which a coil of this shape is mounted, the size of the magnetic shunt plates 5, 5' is 100 mm
The size is 50 mm x 2 mm, and the upper and lower heat dissipation fins have a size of ioo x 5 Q mm x 8, but have unevenness on the surface as shown in Fig. 2.

).

The total power consumption of this module is about 12W, and the temperature rise of the chip is about 20°C.

On the other hand, in order to reduce the influence of external magnetic fields on the bias magnetic field, it is necessary to use a shield type bias magnetic circuit as shown in FIG.

In this case, a bias magnetic circuit is constructed by three magnetic shunt plates 5, 5', 5" (the shape is the same as in Figure 2) and 4 permanent magnets 6, 6', 6", 6". do.

8 is a magnetic material for the seed (L/-) of the disturbance magnetic field; 5,
5v) Surrounds the magnetic field shunt plate.

(The thickness is about 2 mm) At this time, there are rotating magnetic field coils 3, 3', and 4 in two places, upper and lower.

4' can be implemented.

Therefore, twice as many chips can be mounted in one magnetic circuit as compared to the configuration shown in FIG.

The disadvantages of the magnetically shielded memory module shown in Figure 3 are:
The heat dissipation of the coil is poor.

Let's focus on coils 3 and 4 and compare them with the case in Figure 2.

In the case of FIG. 2, heat can be radiated from the radiation fins 7, 7' through the magnetic field shunt plates 5, 5'.

On the other hand, in the case of FIG. 3, the heat transmitted to the inner magnetism plate 5' is not easily drawn out.

Therefore, only the heat radiation effect from the magnetic field shunt plate 5 and the radiation fin 7 side can be expected.

Therefore, if the structure shown in FIG. 3 is adopted, the temperature rise of the chip for the same power consumption will be 2 to 3 times larger than that in the case shown in FIG. 2.

Therefore, the temperature rise of the chip, which was 12°C in the case of the module shown in FIG. 2, becomes approximately 30°C in the case of FIG. 3, assuming that only one set of coils is driven.

Moreover, in the case of FIG. 3, if two sets of coils are driven at the same time, the power consumption will be doubled and the temperature rise will further increase to 40 degrees Celsius or more.

(The shape of the coil is the same as that shown in Fig. 2.

) The object of the present invention is to improve the heat dissipation effect of the magnetically shielded magnetic bubble memory module as described above.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 FIG. 4 shows a first embodiment of the present invention.

In other words, divide the inner magnetic field shunt plate into two pieces, 5' and 5''',
A heat sink 9 (for example, an aluminum plate) is inserted between the two.

This plate is spread out on the outside of the module so that it has the planar shape shown in FIG.

When mounting chips and coils with the same dimensions as those shown in the button in Figure 2 and Table IVC, use the magnetic shunt plates 5, 5', 5", 5.
All ″′ have the same shape, and the size is 1007ItTL
x501rL7IL x 2 mountains.

The thickness of the heat dissipation plate 9 is, for example, 2im (0.5mπ~
The appropriate thickness is approximately 4m.

The planar shape is the same size as the magnetic shunt plate inside the module.
On the outside of the module, the shape has an area on both sides ranging from about the same area as the magnetic field shunt plate to 4 to 5 times the area.

With this structure, the heat generated by the coils 3 and 40 can be radiated not only from the radiation fins 7 through the magnetic shunt plate 5 and the shield case 8, but also from the heat sink 9 through the magnetic shunt plate 5'.

Similarly, the heat generated by the coils 3/ and 4/ is transferred to the magnetic shunt plate 5''
In addition to dissipating from the heat dissipating fins 7' through the shield case 8, it can also dissipate from the heat dissipating plate 9 through the magnetic field shunt plate 5''.

With such a structure, the heat dissipation effect is significantly improved.

In the case of Fig. 3, the temperature rise of the chip (when driving one set of O coils) was 30°C, but in Fig. 4 of the present invention, the temperature rise of the chip was 1
The temperature can be about 5°C.

(Frequency 5001Glz, rotating magnetic field amplitude 400e) When driving two sets of coils simultaneously, the temperature rise was about 45°C in the case of Fig. 3, but it was about 23°C in Fig. 4 of the present invention. Became.

In either case, the present invention has made it possible to reduce the temperature rise of the chip to about 1/2.

If the inner magnetic shunt plate is divided into two pieces, 5' and 5'', there are 4 permanent magnets 6.6'.

If the magnetization strengths of 6" and 6" differ, the magnetic potentials of the magnetic shunt plates 5 and 5" will differ.

On the other hand, the magnetic potentials of the magnetic shunt plates 5 and 5v are kept the same through the shield case 8.

Therefore, the chips mounted on coils 3 and 4, coil 3/,
The bias magnetic field will be different for the chip mounted in 4/.

However, magnets 6, 6'. Generally, this problem is not so serious because magnetization of the same strength can be achieved by magnetizing the magnets 6" and 6"' at the same time.

Example 2 FIG. 6 shows another embodiment.

In this case, heat radiating plates 10 and 10' having a thickness of about 0.5 mm to 1 mm are placed on the outer sides of the upper and lower magnetic field shunt plates 5, 5, respectively.

A shield case 8 comes in place of this heat sink.

In this case, the heat of the coils 3 and 4 is radiated from the heat sink 10 through the magnetic field shunt plate 5.

Also, coil 3'. 4' is radiated to the heat sink 10' through the magnetic field shunt plate 5''.

Compared to the conventional structure shown in FIG. 3, the thermal resistance of the heat sink 1 is reduced by the amount that the heat sink 1 does not pass through the shield case 8.

Therefore, the heat dissipation effect of the coil is improved, and the temperature rise of the chip can be reduced.

FIG. 7 shows a plan view of this structured O module.

The chip temperature rise in a module with this structure is as follows in Example 1.
This is almost the same as in the case of .

The temperature was 16° C. when driving one set of coils, and 24° C. when driving two sets of coils.

In this case as well, permanent magnets 6 and 6' are used to match the bias magnetic fields at the upper and lower chip mounting positions.

6" and 6" must be equally magnetized.

Embodiment 3 In order to match the bias magnetic fields at the upper and lower chip mounting positions in Embodiment IK, it is sufficient to do as shown in FIG. It is sufficient to replace it with the body 11 and make the magnetic potentials of the magnetic field shunt plates 5' and 5'' equal.

With this structure, even if the magnetization magnitudes of the permanent magnets 6.6', 6", and 6"' are different from each other, the values of the bias magnetic fields in the upper and lower chip mounting devices can be made the same.

It is sufficient that the area of the magnetic body 11 is 2 to 5 φ of the magnetic shunt plate 5.

Embodiment 4 In order to match the bias magnetic fields at the upper and lower chip mounting positions in Embodiment 2, as in Embodiment 4 shown in FIG. If a part of a certain heat dissipation plate 10, 10' is replaced with a magnetic material 12, 12', the magnetic potentials of the magnetic shunt plate 5 and the shield case 8, and the magnetic shunt plate 5" and the shield case 8; are made equal. good.

With this structure, the magnetic potentials of the upper and lower magnetic shunt plates 5, 5 are equal, so even if the magnetization levels of the permanent magnets 6, 6', 6", and 6"' are different from each other, the upper and lower magnetic fields are the same. The value of the bias magnetic field at the chip mounting position can be made the same.

Also in this case, the area of the magnetic bodies 12 and 12' is equal to the area of the magnetic shunt plate 5.
2 to 5% of the amount is sufficient.

In the above embodiments, it is possible to form a memory module having three heat dissipation plates using both the first embodiment and the second embodiment.

Moreover, by using both of them, it is possible to further enhance the heat dissipation effect.

It is also possible to use both the heat dissipation plates of Example 3 and Example 4.

In the case of Example 1 and Example 2 above, further Example 1
The 10th article compares the effects of using both 2 and 2 with the conventional example.
It is a diagram.

This figure shows the change in temperature of the chip over time for each case.

In the above explanation, we have described the case where two sets of rotating magnetic field generating coils are used, but this is not limited to two sets, and more than one set can be used if necessary. Of course there is.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a rotating magnetic field drive coil, substrate, and chip for magnetic bubble memory, Fig. 2 is a cross-sectional view of a magnetic bubble memory module, Fig. 3 is a cross-sectional view of a magnetic shield type magnetic bubble memory module, and Fig. 4 5 is a cross-sectional view of a magnetic bubble memory module including a heat dissipation plate according to Embodiment 1 of the present invention, FIG. 5 is a plan view of the magnetic bubble memory module according to Embodiment 1 of the present invention, and FIG. 6 is an embodiment of the present invention. According to 2,
A magnetic bubble memory module including two plates for heat dissipation, FIG. 7 is a plan view of Embodiment 2, FIG. 8 is a diagram explaining Embodiment 3, and FIG. 9 is a diagram illustrating Embodiment 4. FIG. 10 is Example 1
, 2 is a diagram showing the effects of .

Claims (1)

[Claims] 1. A bias magnetic field generating device including a plurality of rotating magnetic field generating coils for driving magnetic bubbles each having a magnetic bubble chip disposed therein, and a pair of magnetic shunt plates arranged sandwiching the rotating magnetic field generating coils. and a magnetic bubble memory module surrounded by a magnetic material for magnetic shielding, wherein a heat dissipation plate is provided on the outer surface of the pair of magnetic shunt plates, a part of which protrudes from the magnetic material for magnetic shielding. Magnetic bubble memory module featuring ヲ.