JPS5816266B2 - Jiki Bubble Youmenai Jikai Hatsuseiki - Google Patents

Description

[Detailed description of the invention] The present invention relates to an in-plane magnetic field generator for magnetic bubble chips.

The in-plane magnetic field generator moves magnetic bubbles along the permalloy thin film pattern arranged on the surface of the bubble chip,
It plays an important role in driving the in-plane magnetic field that accomplishes various information processing functions.

Conventionally, in-plane magnetic field driving has been performed by supplying sinusoidal currents with a phase difference of 90° to a pair of drive coils wound perpendicularly to the bubble chip.

At this time, the back electromotive force generated in the drive coil is proportional to the product of the inductance of the drive coil, the amplitude of the sine wave current, and the frequency.

Even if the in-plane magnetic field required by the chip is about 30 millimeters, when the frequency is IM-, the inductance is close to 100 μH, and the withstand voltage is 100 V to 150 Vi with an allowable current of 3 A.
This requires the use of expensive transistors.

: Therefore, in the conventional in-plane magnetic field generator, even if the volume of the bubble chip itself is very small, the drive coil/lz is wound thickly in consideration of taking out the terminal from the chip. The inductance of the drive coil becomes very large, which necessitates the use of expensive transistors that can withstand a large back electromotive force when driving a high-frequency in-plane magnetic field.

An object of the present invention is to provide an in-plane magnetic field generator in which the above-mentioned defects can be easily removed.

That is, in the present invention, a planar conductor is brought into close contact with the bubble chip, and the planar conductor is driven through a pulse transformer.

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

FIG. 1 is an explanatory diagram of a conventional nine-plane magnetic field generator.

In the figure, substrate 1 has bubble chips arranged.
A drive coil 2 in the X-axis direction and a drive coil 2' in the Y-axis direction are wound around the current supply circuits 3 and 3' that supply sinusoidal currents with a phase difference of 90 degrees to them, and a current switching circuit. 4 and 4' are connected.

Even on a substrate with four chips (6 x 6 mm) arranged, the volume of the drive coil 2 or 2' is 40 x 40 x 5 m considering terminal extraction and uniform magnetic field distribution generation.
It will be about m.

Therefore, when supplying an in-plane rotating magnetic field of 30 Oe and 200 KHz to the bubble chip, a transistor with a driving capacity of 3 amperes and 30 V is required.

To increase the frequency to I MHz, current supply circuit 3,3
A transistor with a voltage resistance of 150V and a tolerance of 3 amperes is required for the current switching circuit 4.4' and the current switching circuit 4.4', and since the driving capability required of the transistor is as high as 450 volt amperes, it is difficult to meet this requirement with commercially available transistors.

A possible reason for this is that the drive coils 2 and 2' in the conventional in-plane magnetic field generator drive a space much larger than the volume of the magnetic bubble chip 5 that truly requires a rotating magnetic field.

Therefore, in order to bring the drive space closer to the volume of the bubble chip 5, an idea arises to drive the rotating magnetic field by a flat conductor closely attached to the bubble chip 5, but in that case, it is necessary to supply a current of several tens of amperes to the flat conductor. It came with the challenge of becoming a

FIG. 2 is an explanatory diagram of one embodiment of the present invention.

In the figure, a flat conductor 12 is used instead of the drive coils 2, 2'.
and 12' are perpendicular to each other just above the bubble chip 15 with an insulating layer in between.

The flat conductors 12, 12' are the substrate 1 at ground potential.
Even if the bubble chips 15 are placed in close contact with the bubble chips 15 arranged on top of the bubble chips 15, the magnetic field it can create is as small as 1 oersted per ampere.

However, the inductance L and DC resistance γ of the flat conductor 12, 12' are much smaller than in the case of a conventional drive coil.

The thickness of the flat conductor 12.12' is 1 inch, the width is 51n1n,
40 balls long, 11 conductors and ground potential substrate
Assuming that the distance between the two is 2.5 Ω, L is approximately 25 nH97' is approximately 0.0002 Ω.

It is easy to drive because the load is very small. However, in order to provide an in-plane magnetic field of 30 oersted by the flat conductor 12, 12', a current drive of 30 amperes is required.

The back electromotive force when driven with a current of 30 amperes is as small as about 4.7 V, but no matter how small it is, the allowable current is 30 amperes.
Transistors larger than ampere cannot be easily used.

Therefore, in Figure 2, the transformer 1 for current step-up
6,16' are used.

If a transformer 16.16' with a turns ratio of 10:1 is used, the load on the flat conductor 12.12' seen from the primary side will increase 100 times, L will be 2.5 μH, and the DC resistance will be 0. 0
2 ohms, but the current driving into the primary of transformer 16.16' is reduced to 3 amps.

As a result, the back electromotive force on the primary side is IMF (also 4 at z).
It falls within about 7V.

Therefore, by using practical transistors, the current drive circuit 13
and 14.13' and 14' can be realized economically.

Furthermore, the driving ability required for the transistor is 47×3
= 141 volts/amperes, which is less than half of the conventional case.

: Terminals are taken out from each chip 15 using a flat conductor 12.
It is sufficient to start from the part without 12'.

Flat conductor 12.1 for easier terminal removal
It is also conceivable to provide a slit hole at 2'.

In addition, the flat conductors 12 and 12' are directly connected to the bubble chip 15.
may be deposited on top of.

As described above, according to the present invention, by increasing the frequency in a conventional in-plane magnetic field generator, defects that would require an unrealistically expensive transistor can be easily eliminated.

In the above explanation, the flat conductors 12 and 12' are wired so as to pass sequentially over the four chips 15, but they can be folded under each so as to sandwich all the chips 15 or only the permalloy thin film pattern. The above description is not intended to limit the scope of the invention in any way.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional in-plane magnetic field generator, and FIG. 2 is a detailed explanatory diagram of the present invention. In the figure, 1 and 11 are substrates, 2 and 2' are drive coils, 12 and 12' are flat conductors, 3, 3', and 1
3 and 13' are current supply circuits, 4 and 4' and 14 and 14
' is a current switching circuit, 5 and 15 are bubble chips, 16 and 1
6' is a transformer.

Claims (1)

[Claims] 1. A magnetic bubble surface including two φ flat conductors perpendicular to each other on the magnetic bubble chip, a transformer connected to the flat conductors, and a current drive circuit that selectively supplies alternating current to the one lance. Internal magnetic field generator.