JPS6132751B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble memory device, particularly to a winding structure of a rotating magnetic field generating coil.

Generally, a magnetic bubble memory device includes a magnetic bubble memory chip consisting of a magnetic thin film and a pattern of a soft ferromagnetic thin film formed on the magnetic thin film, and lead wires for signal propagation between the chip and an external circuit. It mainly consists of a coil block that applies a horizontal rotating magnetic field to the chip, and a magnet block that applies a bias magnetic field perpendicular to the chip, and generates magnetic bubbles in the pattern of the soft ferromagnetic thin film. , transfer and division to write, store and read desired information.

FIGS. 1a and 1b are a fragmentary plan view of a main part of an example of a conventional magnetic bubble memory device, and a sectional view thereof taken along line A-A'. In the figure, reference numeral 1 denotes an insulating substrate made of ceramic or the like, and a magnetic bubble memory chip 2 is embedded and fixed approximately in the center of the insulating substrate 1. From this magnetic bubble memory chip 2, output signal wirings 3a, 3b, 3c, and 3d are formed so as to be left and right symmetrical, and output terminals 4a, 3d provided at the end of the insulating substrate 1, 4b, 4c, 4d
are connected to each. In addition, the insulating substrate 1 on which the magnetic bubble memory chip 2 is mounted has an X coil 5a wound in the X-axis direction and a Y coil 5b wound orthogonally in the Y-axis direction on its outer circumferential side. A rotating magnetic field is supplied to the memory chip 2.

In the magnetic bubble memory device configured in this way, a minute magnetic bubble detection signal detected by the magnetic bubble detector in the magnetic bubble memory chip 2 is transmitted through the output signal wirings 3a, 3b, 3c,
3d and its output terminals 4a, 4b, 4c, 4d
The magnetic bubble memory output signal is supplied to an external differential amplifier (not shown) and amplified via the detection signal, and a magnetic bubble memory output signal of a predetermined level is obtained by the difference signal between the detection signals.

However, in the magnetic bubble memory device with the above configuration, the magnetic bubble memory chip 2
The X coil 5a and the Y coil 5b, which supply a rotating magnetic field to the magnetic field, are formed in a flat shape with a single layer of conductive wire, as shown in a perspective view in FIG. 2a. Therefore, its equivalent circuit consists of an inductance L and a resistance R, as shown in FIG. 2b. Here, the current I required to obtain the magnetic field strength H _R required at the center of the X coil 5a and Y coil 5b is the number of turns per unit length of the coil (n=N/l, N: the number of turns per unit length of the coil). Since it is inversely proportional to the winding (l: length of the coil), I=K ₁ H _R /n (1) (K ₁ : constant). Also, since the inductance L of the coil is proportional to n ² , L=K ₂ n ² (2) (K ₂ : constant). In order to reduce the power consumed by these X coil 5a and Y coil 5b, the number of turns n is usually increased and the current I is decreased, but in this case, the voltage V _L across the coils is V _L = ωLI = K ₁・K ₂・ω・n・H _R ………(3) (Q=ωL/R≫1) Therefore, when the winding n is increased, the voltage across the coil V _L is proportional to it. growing. In the vicinity of such X coil 5a and Y coil 5b,
Output signal wirings 3a to 3d are arranged, and since the minute detection signals detected by the magnetic bubble memory chip 2 are propagated on the output signal wirings 3a to 3d, the output signal wirings 3a to 3d are ~3d
Capacitive coupling noise generated by capacitive coupling with the X coil 5a and Y coil 5b is superimposed on the above, and when the detection signal is amplified by a differential amplifier (not shown), the difference in the capacitive coupling noise (unbalanced component) is ) is amplified, resulting in a decrease in the S/N ratio of the magnetic bubble output signal. Also, if the voltage V _L across the X coil 5a and Y coil 5b is high,
The transistors for driving both coils and their electric components are required to have high voltage resistance, which has disadvantages such as high cost.

Therefore, an object of the present invention was to improve the above-mentioned drawbacks, and to reduce the capacitive coupling noise by lowering the voltage across the rotating magnetic field generating coil without increasing the power consumption of the coil. It is an object of the present invention to provide a magnetic bubble memory device which is low in cost by reducing the withstand voltage of the coil driving transistor.

In order to achieve such an object, the magnetic bubble memory device according to the present invention has a rotating magnetic field generating coil formed by winding a plurality of integrated conducting wires. The magnetic bubble memory device according to the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a perspective view of essential parts showing an example of the magnetic bubble memory device according to the present invention, particularly an X coil and a Y coil for generating a rotating magnetic field. In the same figure, an X coil 6a and a Y coil 6b for generating a rotating magnetic field are formed by winding two integrated conductive wires of the same diameter closely in a flat shape corresponding to the cross-sectional shape of an insulating substrate 1 (not shown). has been configured.

In the magnetic bubble memory device configured in this way, the X coil 6a and Y coil 6b for generating a rotating magnetic field are formed by winding two conductive wires in parallel, so that the equivalent circuit of these coils is as follows. As shown in Figure 4a, the equivalent is a series circuit of inductance L ₁ and resistance R ₁ of one conductor, and a series circuit of inductance L ₂ and resistance R ² of another conductor connected in parallel. circuit, and its composite equivalent circuit is shown in Figure 4b, with the inductance
It becomes a series circuit of L′ and resistor R′. Now, in this equivalent circuit, the following conditions are obtained for the combined inductance L', combined resistance R', and current I'.

L'=L/4 ......(4) (L ₁ = L ₂ , Coupling constant K between coil L ₁ and coil L ₂ =
1) R'=R/4......(5) (R ₁ = R ₂ = R/2) I'=2・I......(6) Therefore, the power consumption P of the coil is P=I ′ ²・R′=4I ²・R/4=I ² R ………(7) Also, the voltage V _L across the coil is V _L = ω・L′・I′=ω・L/4・2I =ωLI/2...
...(8) (Q'=ω・L'/R'>>1), and the voltage across the coil can be reduced to 1/2 of the conventional voltage while keeping the power consumption constant. Therefore, the capacitive coupling noise due to the voltage across the coil can be suppressed to 1/2, and a coil driving transistor with a withstand voltage of 1/2 can be used.

In addition, in the above embodiment, the rotating magnetic field generating coil was explained in the case where two integrated conducting wires were wound, but the present invention is not limited to this. It goes without saying that the same or better effect as described above can be obtained even when the conductor is wound around the conductor.

As explained above, according to the magnetic bubble memory device according to the present invention, since the voltage across the rotating magnetic field generating coil can be reduced, capacitive coupling noise is significantly reduced and the S of the magnetic bubble memory output signal is reduced. /N ratio can be significantly improved. Further, it is possible to use transistors for driving the coil and electric components having a lower breakdown voltage than those of conventional ones, and there are excellent effects such as the ability to manufacture a magnetic bubble memory drive circuit at low cost.

[Brief explanation of the drawing]

Figures 1a and 1b are fragmented plan views of essential parts showing an example of a conventional magnetic bubble memory device, and a sectional view thereof taken along line A-A'; Figure 2a is a perspective view of essential parts of conventional X coils and Y coils; FIG. 2b is an equivalent circuit diagram of FIG. 2a, FIG. 3 is a magnetic bubble memory device according to the present invention,
Particularly, the main part perspective view showing an example of the X coil and the Y coil, and FIGS. 4a and 4b are equivalent circuits and composite equivalent circuits of FIG. 3. DESCRIPTION OF SYMBOLS 1...Insulating substrate, 2...Magnetic bubble memory chip, 3a-3d...Output signal wiring, 4a-4d...
...Output terminal, 5a...X coil, 5b...Y coil, 6a...X coil, 6b...Y coil.

Claims (1)

[Scope of Claims] 1 Comprising a magnetic bubble memory chip and at least first and second coils that apply a magnetic field to the chip, the first and second coils being arranged along a first coordinate axis. The first and second coils are electrically parallel to each other so as to apply a magnetic field in the same direction to the chip. A magnetic bubble memory device characterized in that the device is connected to a magnetic bubble memory device. 2. Comprising a magnetic bubble memory chip and X and Y coils that apply a rotating magnetic field to the chip,
The X coil has at least a first and a second coil, and the first and second coils are wound in the same direction along the first coordinate axis and are aligned in the first coordinate axis direction. The first and second coils are electrically connected in parallel so as to apply a magnetic field in the same direction to the chip, and the Y coil has at least a third and a fourth coil. The third and fourth coils are wound in the same rotation direction along a second coordinate axis perpendicular to the first coordinate axis, and are wound so as to be aligned in the second coordinate axis direction. and the third and fourth coils are electrically connected in parallel so as to apply magnetic fields in the same direction to the chip.