JPH0132598B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble memory device, and particularly to a configuration for removing electrostatic noise picked up by a detector terminal on an insulating substrate.

Generally, when a perpendicular magnetic field is applied to a magnetic thin film whose magnetic domains have a perpendicular magnetic easy axis, bubble domains with a diameter of several μm or less are formed at a certain magnetic field strength. Since this bubble domain can be freely moved within a magnetic thin film by a gradient magnetic field, it is used as a memory element in a magnetic bubble memory device. Such a magnetic bubble memory device has conventionally been constructed as shown in a perspective view of the inside of the device in FIG. 1 and a sectional side view of the device in FIG.

In FIGS. 1 and 2, a magnetic bubble memory chip 1 mounted on an insulating substrate 2 has patterns formed thereon for generating, transferring, detecting and erasing bubbles. Electrodes are connected to terminals 3 provided on an insulating substrate 2, respectively. Further, an X-direction coil 4 and a Y-direction coil 5 are provided to surround the chip 1 and provide a rotating/gradient magnetic field necessary for bubble transfer, and the chip 1 is located in the center of each of the coils 4 and 5. It is fitted onto the insulating substrate 2 in such a manner. Each terminal 3 of the insulating substrate 2 is connected to a plurality of external leads 7 penetrated through the side wall of a frame-shaped molded body 6, and then biases are applied to the vertical direction of the coils 4 and 5 to hold the bubbles. Permanent magnets 8 and 9 that apply a magnetic field and magnetic field shunt plates 10 and 11 are attached to the molded body 6, and the whole is inserted into a magnetic shield case 12 that also serves as a yoke.

In a magnetic bubble memory device having such a configuration,
As shown in FIG. 3, the valve detector formed on the chip 1 includes magnetic resistance elements R ₁ and R ₃ for valve detection and dummy resistance elements R ₂ and R ₄ , which constitute a bridge circuit _. Amplifier A was connected to the connection point with R ₂ and the connection point between elements R ₃ and R ₄ to detect the output thereof, while the other ends of the elements R ₁ and R ₃ having the same polarity were grounded. The device board 2 equipped with two valve detectors has a series of detection terminal groups 3-1 and 3-
The terminals of the same polarity (positive terminal or negative terminal) of the two terminals were connected to ground. However, the normal detection terminal arrangement has positive polarity and negative polarity alternately, and terminal groups 3-1 and 3 facing each other.
Since the polarity arrangement of terminals 3-2 is reversed, the innermost terminals 3' and 3'' of each terminal group 3-1 and 3-2 are arranged with different polarities. ′
Since terminal 3'' (or 3') is not grounded when terminal 3'' (or 3'') is grounded, the output signal from terminal 3'' (or 3') which is not grounded includes the current flowing through coils 4 and 5 ( The drawback is that noise components based on triangular wave currents are included.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, and the purpose of this invention is to connect the bubble transfer coils in the X-Y direction to the crossing area of the pair of external connection terminals connected to the bubble detector via printed wiring. This is achieved by providing a magnetic bubble memory device characterized in that the terminal connected to the nearest printed wiring is electrically grounded to reduce electrostatic induction noise to the detector.

Hereinafter, the present invention will be explained using the aforementioned drawings and additional drawings related to embodiments of the invention.

Terminal group 3-1 of a magnetic bubble memory device equivalent to that shown in Fig. 1 and with the same polarity arrangement as the conventional one.
and 3-2 are formed in the magnetic bubble memory chip 1 in the configuration device of the present invention in which the innermost terminals 3' and 3'' are arranged closer to the intersection area of the coils 4 and 5 than other terminals in the same group. One bubble detector has its minus side grounded, while the other bubble detector has its plus side grounded.In other words, one bubble detector connected to terminal group 3-1 is configured with , as shown in Fig. 3, the negative (or positive) polarity terminal 3' is connected to ground, whereas the terminal group 3
The other bubble detector connected to the terminal -2 has a bridge circuit consisting of bubble detection magnetoresistive elements R' ₁ and R' ₃ and dummy resistive elements R' ₂ and R' ₄ , as shown in Fig. 4. , the connection point between elements R′ ₁ and R′ ₂ and the connection point between elements R′ ₃ and R′ ₄
An amplifier A' is connected to the connection point with the amplifier A' so that its output can be detected, and the plus (or minus) polarity terminal 3'' is connected to ground.

FIG. 5 is a plan view showing the terminal arrangement of an insulating substrate according to another embodiment of the present invention. In the figure,
An insulating substrate 13 made of ceramic has ten terminals 14 formed integrally with a printed wiring pattern 15 for chip electrode connection on both left and right ends thereof, and bubble detection terminal groups _14-1 and _14-2. Those of the same polarity are arranged to face each other. When a magnetic bubble memory chip 16 having an electrode facing the pattern 15 is mounted and an X-direction coil 17 and a Y-direction coil 18 are fitted in the conventional manner, the bubble detection terminal 14 closest to the coil intersection area ' and 14'' are connected to the negative electrodes, which are the ground sides of the bubble detection resistive elements R ₁ and R ₃ (Fig. 3) of the two sets of bubble detectors formed on the chip 16, using the same conventional means (bonding wires). and printed wiring patterns).

In this way, in the present invention, in the intersection area of the bubble transfer coil of a pair of external connection terminals connected to both sides of each resistive element R ₁ or R ₃ (R ₁ ′ or R ₃ ′) in each bubble detector. Since the terminals 3' (or 14') and 3'' (or 14'') that are closest, that is, have a larger electrostatic coupling capacity with the coil crossing area, are electrically grounded, these terminals can be used for bubble detection. It will function both as an electrostatic shield. That is, most of the electrostatic induction noise is induced to the grounded terminal, and the occurrence of electrostatic induction noise in the bubble detection signal output from the far terminal is significantly reduced.

In addition, in the embodiment shown in FIG.
4' and 14'' have negative polarity, but the other may have positive polarity or either one may have positive polarity.Furthermore, as for the mounting chip 16, a conventional one may be used as is, but the chip electrode and the substrate 13 bonding wires for connecting with the conductor pattern, or for crossing the printed wiring pattern,
It is necessary to interpose an insulating layer at the intersection. Therefore, it is desirable to form an electrode array on the chip 16 in advance that corresponds to the terminal array on the substrate 13.

As explained above, according to the present invention, since the bubble detection terminal closest to the intersection area of the X-Y coil is grounded, electrostatic Since the terminal with the larger coupling capacitance is grounded, it significantly reduces electrostatic noise entering the bubble detection signal (about 1/10 to 1/10), making detection easier, and making it easier to detect the bubble. This has the practical effect of improving the reliability of the bubble memory device.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the basic internal configuration of a magnetic bubble memory device, FIG. 2 is a side sectional view of the device, FIG. 3 is a circuit connection diagram of a bubble detector, and FIG. 4 is an embodiment of the present invention. One bubble detector is connected to the third
FIG. 5 is a circuit connection diagram of the other bubble detector when the connections are configured as shown in the figure, and FIG. 5 is a plan view showing the terminal arrangement of an insulating substrate according to another embodiment of the present invention. In the figure, 1 and 16 are magnetic bubble memory chips, 2 and 13 are insulating substrates, and 3, 3', 3'',
14, 14', 14'' are terminals, 3-1, 3-2, 1
4-1, 14-2 are bubble detection terminals, 4, 5,
17 and 18 indicate bubble transfer coils.

Claims (1)

[Claims] 1. A magnetic bubble memory chip on which a bubble detector etc. are formed is mounted on an insulating substrate provided with a plurality of external connection terminals, and the chip is wound in the X-Y direction.2. In a magnetic bubble memory device in which a plurality of bubble transfer coils, the detector, etc. are conductively connected to the terminals, an X- A magnetic device characterized in that the terminal connected to the printed wiring closest to the intersection area of the bubble transfer coil in the Y direction is electrically grounded to reduce electrostatic induction noise to the detector. Bubble memory device.