JPS6117064B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to bubble memory devices. Generally, a 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.
It mainly consists of lead wires for signal propagation between the chip and an external circuit, a coil block that applies a rotating magnetic field horizontal to the chip surface, and a magnet block that applies a bias magnetic field perpendicular to the chip. Desired information is written, stored, and read by generating, transferring, and dividing magnetic bubbles in the pattern of the soft ferromagnetic thin film.

FIG. 1 is a perspective view of essential parts of a conventional bubble memory device, particularly showing an example of the inside of a ceramic package constituting the bubble memory device. In the figure, reference numeral 1 denotes an insulating substrate made of ceramic or the like. A groove is formed in the center of the insulating substrate 1, and a bubble memory chip 2 is placed in the groove. Further, on the surface of the insulating substrate 1, a signal wiring 3 for transmitting and receiving minute input/output signals of the bubble memory chip 2 is formed, and a plurality of terminals 4 provided at the end of the insulating substrate 1 are formed.
are connected to each. In addition, as shown in a simplified perspective view in FIG. 2, the insulating substrate 1 in which the bubble memory chip 2, signal wiring 3, and terminal 4 are installed has an X coil 4a extending in the X-axis direction on its outer peripheral surface. , Y coils 4b are wound perpendicularly to each other in the Y-axis direction, and apply a rotating magnetic field to the bubble memory chip 2. A pair of plate-shaped magnets 6 are provided on the outer surfaces of the X coil 4a and Y coil 4b to uniformly apply a bias magnetic field to the bubble memory chip 2.
a, a pair of magnetic field shuffling plates 6b, etc. are arranged in a sandwich-like manner, and as shown in the perspective view of the main part in FIG. Device is configured.

Further, a bias magnetic field variable coil 6c is installed to measure the operating margin of the bubble memory device (generally, the bias magnetic field strength is used as a reference and various conditions are used as parameters), and a current is passed through the bias magnetic field variable coil 6c. This changes the bias magnetic field.

In the bubble memory device configured in this way, a minute signal detected by the bubble detector in the bubble memory chip 2 is supplied to an external differential amplifier (not shown) via the signal wiring 3 and the terminal 4, and is amplified. At the same time, a bubble memory output signal of a predetermined value is obtained by the difference signal between the detection signals.

In the bubble memory device having the above configuration, in order to prevent the influence of the external magnetic field on the internal bubble memory chip 2, a shielding case 7 is disposed on the outer peripheral surface of the bubble memory chip 2, thereby making the external magnetic field less susceptible to magnetization. ing.

The dimensions of the bubble memory chip are 6 x 6 x 0.4 mm, and the dimensions of the Y coil 5b to apply a uniform rotating magnetic field of ±2% to each part of this chip are 12 x 13 mm.
x3.5mm, and when this coil is manufactured by winding two layers of 0.2mmφ madanet wire, the inductance of the coil is 48μH and the required amplitude of the sine wave current is 0.4A. Generally, to send a sine wave current with a frequency of 100 to 200 KHz through a rotating magnetic field coil, the coil and capacitor are connected in series.
An LC series resonant drive circuit is used. At this time, the terminal voltage Vc generated at the terminals of the coil is expressed as Vc≈IωL(v), and the terminal voltage when driven at 160KHz is 19V. This value is extremely large compared to the bubble output voltage (4 mV), and it is necessary to take measures to prevent the terminal voltage of the coil from having an adverse effect on the bubble output voltage.

The terminal voltage of the coil is propagated to the shield case by the coupling capacitance C between the coils 5a, 5b and the shield case 7, resulting in capacitive coupling noise, and a similar phenomenon occurs between the shield case 7 and the output terminal 4. , the noise is superimposed on the output terminal 4, and this problem can be overcome by electrically connecting the shield case to the lead pin and grounding the lead pin.

Fig. 5 shows the pin arrangement of a conventional device. 5a and 5a' are lead pins for bubble output detection, 5b is a lead pin for grounding the shield case, 5b' is a non-contact empty pin, 5c,
5c' is the bias magnetic field variable coil terminal, 5d is X
Coil terminals 5d' are Y coil terminals, and 5e and 5e' are terminals for sending pulse current to each function within the chip. As explained above, the conventional device has 22 lead pins, and in particular, there is a 5b' non-contact pin, which is wasteful. Also, the pitch of the lead pin is
The disadvantage was that the device size was 2.54mm, making the device larger.

The present invention has been made to eliminate the above-mentioned drawbacks, and by making one lead pin of the variable bias magnetic field coil common to the lead pin for grounding the shield case, the number of non-contact lead pins is eliminated and the number of lead pins is reduced to 20. It is.

FIG. 7 is a simple explanatory diagram of a lead pin connection section according to the present invention, in which terminals 6c and 6d of a coil 6g are welded to lead pins 5b and 5c', respectively. Further, the lead pin 5c' to which one terminal 6d is connected and the shield case 6f are connected by welding via a wire 6e.

In order to change the bias magnetic field in the positive and negative directions, the lead pin 5c' is set to the ground potential, and the lead pin 5b is set to the ground potential.
It is possible to change it in the positive and negative directions by setting it to a positive or negative potential, and in either case, the above-mentioned noise does not occur because the shielding case is at the ground potential.

As explained above, according to the present invention, the number of conventional lead pins can be reduced by two, and the device can be made smaller.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the ceramic package, Figure 2
The figure shows a coil, FIG. 3 is an external view of the device, FIGS. 4 and 5 are schematic cross-sectional views of the device, FIG. 6 is a diagram showing the pin arrangement of a conventional device, and FIG. 7 is a connection diagram according to the present invention. FIG. 8 is a pin-out diagram of a device according to the invention. 5a... Lead pin, 5b... Shield case, 5c... Terminal, 5e... Chip, 6g... Coil, 6c... Terminal, 6a, 6b... Lead pin.

Claims (1)

[Claims] 1. A magnetic valve memory chip that stores information,
It comprises a bias coil for varying the bias magnetic field for the chip, a plurality of lead pins electrically connected to the chip, and a shield case for magnetically shielding the chip from the outside, A magnetic bubble memory device characterized in that one end of the bias coil and the shield case are commonly electrically connected to one of the plurality of lead pins.