JPS5841590B2 - Magnetic bubble memory drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble memory drive circuit in a magnetic bubble memory device.

In a magnetic bubble storage device, in order to transfer magnetic bubbles, it is necessary to apply a rotating magnetic field (hereinafter referred to as a rotating magnetic field) within the plane of the magnetic thin film where the magnetic bubbles exist.

In order to generate this rotating magnetic field, two coils wound around a magnetic bubble element and perpendicular to each other are generally used to generate a 90'
A method of passing sinusoidal currents out of phase is used.

In other words, the first
When the X current Ix as shown in the figure is caused to flow with a phase 90' ahead of the Y current y, a rotating magnetic field can be generated.

In order to generate this sine wave current, a method has been adopted in which a capacitor is connected in series with a rotating magnetic field generating coil and resonance between the coil and the capacitor is utilized.

An example of a conventional circuit of this kind is shown in FIG. 2 and explained as follows.
In the figure, 1 is a coil wound around a magnetic bubble, 2 is a capacitor connected in series with this coil 1, and these constitute a series resonant circuit.

The other end of the coil 1 is connected to the drive circuit side, and the other end of the capacitor 2 is connected.

In this case, the resonance frequency of the coil 1 and the capacitor 2 is set to be equal to the frequency of the rotating magnetic field that drives the magnetic bubble.

Reference numerals 3 and 4 denote transistors that constitute a drive circuit that drives a series resonant circuit from the coil 1 and the capacitor 2, and these transistors 3 and 4 are configured to be turned on and off alternately at a period of 1/2 of the rotating magnetic field. ing.

That is, when transistor 3 is turned on, a sine wave current flows in the positive direction (in the direction of the arrow shown by the solid line), while when transistor 4 is turned on, a sine wave current flows in the negative direction (in the direction of the arrow shown by the broken line). It is configured to allow current to flow through it.

In this way, by alternately turning on the driving transistors 3 and 4, a sinusoidal current can flow.

Here, the rotating magnetic field is stopped when the bubble is not used, and the rotating magnetic field repeats stopping and operation.

Therefore, the sine wave current also operates and stops.

5 is a power source for driving the transistors 3 and 4, that is, for flowing a sine wave current; 6 is a transistor connected in parallel to the coil 1; this transistor 6 is controlled by the output of the timing generation circuit 7; In order to discharge the current flowing in the positive direction, the collector and emitter are connected in such a direction that the direction of the transistor 6 allows the current to flow.

8 is a power supply for charging the voltage of capacitor 2 to a predetermined value in order to flow a current of the same magnitude as in a steady state when a sine wave current starts flowing, that is, at the start of operation; 9 is a power supply 8
10 is a resistor connected in parallel between the collector and emitter of the transistor 9, and this resistor 1
0 has a relatively high resistance value to prevent the voltage of the capacitor 2 from discharging.

In a sine wave current drive circuit with such a configuration, as described above, when the rotating magnetic field is stopped, when the sine wave current is stopped, the current does not ideally return from its peak value to zero, and as shown in Fig. 3. As shown, immediately after the current stops, a so-called undershoot i occurs, which is a current in the opposite direction to the direction in which it has been flowing.

In other words, when the sine wave current stops, the current flowing through the coil 1 is O and the voltage of the capacitor 2 reaches its maximum, so the moment the current stops, the voltage of the capacitor 2 reaches the output of the drive circuit. It takes up to

On the other hand, since there is stray capacitance in coil 1 or the circuit, when the voltage of capacitor 2 is applied to the whole, the current oscillates between the inductance of coil 1 and this stray capacitance, resulting in undershoot. be.

When the magnetic bubble is stopped, as shown in Figure 1, which is a waveform diagram showing the phase relationship and timing of the X current Ix and Y current Iy, first the current Iy of the Y coil is stopped, and then the current Iy of the X coil is stopped. By stopping the current Ix, the rotating magnetic field was stopped in the X direction, the magnetic field in the X direction was gradually weakened, and the magnetic bubble was stopped in the X direction.

In Fig. 1, when starting the rotating magnetic field, a
As shown in , first the
After the magnitude of the magnetic field in the X direction reaches a predetermined value, it becomes a rotating magnetic field that rotates counterclockwise.

On the other hand, when stopping the rotating magnetic field, as shown in b,
First, the Y current Iy is stopped, and then the X current Ix is stopped.

At this time, the direction of the current just before the Y current ``y'' stops is opposite to that when it started, and the direction of the current just before the X current Ix stops is the same as when it started.

By doing this, the rotating magnetic field that was rotating is
The rotating magnetic field can be stopped when the object is facing in the X direction, and the magnetic field can be gradually weakened while the object is facing in the X direction.

Therefore, the stopping and starting of the magnetic bubble transfer is controlled by the stopping and starting operations of the rotating magnetic field as shown in FIGS. 1a and 1b.

However, if there is an undersh hi as shown in Fig. 3, for example, in the current Ix of the X coil corresponding to coil 1, the magnetic field will be generated in the direction opposite to the direction in which the rotating magnetic field is stopped (the negative direction of X). will occur.

As a result, the magnetic bubble that has stopped in the X direction moves in the negative direction of the X direction, causing malfunction because it moves from the stopped position.

Also, if waveform disturbances such as undershoot occur,
As a result, the bias magnetic field changes as shown by characteristics IIa and lb with respect to the characteristics Ia and Ib of the upper and lower limits of the operating margin that do not stop the rotating magnetic field, as shown in Fig. 4. This results in the disadvantage that the margin becomes narrow and the operating area becomes extremely small.

As described above, when the current stops, an undershoot occurs in the current, and as the current stops, the operating margin of the bubble decreases. In order to prevent this decrease, the coil 1 is short-circuited by the transistor 6.

However, when the capacity of the magnetic bubble storage device is large, the number of bubble memories becomes plural, and the circuit shown in FIG. 2 necessarily increases as the number of bubble memories increases.

For this reason, there is a drawback that the configuration of the device becomes complicated and is not economical.

In view of the above points, the present invention has been made to solve such problems, and is designed to simultaneously short-circuit a plurality of coils, each of which constitutes a series resonant circuit together with a plurality of capacitors, using a single transistor. be.

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 5 is a circuit diagram showing an embodiment of the magnetic bubble memory drive circuit according to the present invention, and only the parts necessary for explanation are shown.

In FIG. 5, the same numbers as in FIG. 2 indicate corresponding parts, 11a is the coil of the first bubble memory, and 11b is the coil of the second bubble memory, which are connected in series with the resonance capacitors 12a and 12b, respectively. connected to form first and second series resonant circuits.

13a. 13b, 14a, and 14b are driving transistors constituting a driving circuit, and the transistor 13
The collectors of a and 13b are connected to the positive side of a power supply 5 for flowing a sine wave current, and the collectors of transistors 14a and 14b
The emitters of transistors 13a, 14a and 13b, 14b are connected to coils 11a and 11b, respectively.

Also, 15a. 15b is a transistor whose collector is connected to the resonance capacitors 12a and 12b, and whose emitter is connected to the negative electrode side of the charging power source 8;
, 16b are transistors 15a, respectively.

This is a resistor connected in parallel between the collector and emitter of 15b.

Here, the resonance capacitor 12a and the driving transistors 13a and 14a are provided to cause a sinusoidal current to flow through the coil 11a, and the transistor 15a charges the resonance capacitor 12a with a negative voltage before starting operation. It was established for the purpose of

Furthermore, the resonance capacitor 12b and the driving transistors 13b and 14b are provided to cause a sinusoidal current to flow through the coil 11b, and the transistor 15b charges the resonance capacitor 12b with a negative voltage before starting operation. It was established for this purpose.

Moreover, the resistors 16a and 16b are the resonance capacitor 1.
It has a relatively high resistance value to prevent the charges accumulated in 2a and 12b from discharging.

Therefore, the resonant frequencies of the first and second series resonant circuits made up of the coils 11a and 11b and the resonant capacitors 12a and 12b are set to be equal to the frequency of the rotating magnetic field that drives the magnetic bubble, and transistor 13a.

14a and 13b, 14b is 1 of the period of the rotating magnetic field
When the driving transistors 13a and 13b are turned on, sinusoidal currents in the positive direction (in the direction of the solid arrow) flow through the coils 11a and 11b, respectively, while the driving transistors transistor 1
When 4a and 14b are turned on, sinusoidal currents in the negative direction (in the direction of the broken line arrow) flow through the coils 11a and 11b, respectively.

In this way, by alternately turning on the drive transistors 13a and 14a and 13b and 14b, the sine wave current Ix, as shown in a and b in FIG.
It is possible to flow Iy respectively.

17 is a coil 11a when stopping the sine wave current.

This transistor 1T is a transistor for short-circuiting both ends of 11b and gently stopping the sine wave current.
is the coil 11 that constitutes the first and second series resonant circuits.
It is connected to both ends of a and 11b via a diode connected in series with the same polarity as the transistor.

That is, the collector of transistor 17 is connected to diode 1.
8 and 19 in the forward direction, respectively, to one end (drive circuit side) of the coils 11a and 11b,
The emitters are connected to the other ends (capacitor side) of the coils 11a and 11b through diodes 20 and 21 in opposite directions, respectively, and these diodes 18 to 2
1 is configured to electrically separate coils 11a and 11b.

That is, the drive circuit side of the coil 11a and the drive circuit side of the coil 11b are connected to the collector side of the transistor 17 via diodes 18 and 19, respectively, but the drive circuit side of the coil 11a and the drive circuit side of the coil 11b are connected to each other via diodes 18 and 19, respectively. Since the diodes with opposite polarities are connected in series, the drive circuit sides of both coils 11a and 11b are non-conductive and electrically separated.

Further, the capacitor sides of the coils 11a and 11b are also connected to the emitter side of the transistor 1T via diodes 20 and 21, but there is no conduction between the two coils like the drive circuit side.

In this way, since the terminals of the coils 11a and 11b are electrically separated, they do not affect each other when current is passed through the coils.

Here, if there is no diode, the coils 11a and 1
1b are connected in parallel and influence each other.

Next, the operation of the embodiment shown in FIG. 5 will be explained.

First, when driving transistors 13a and 13b are turned on, positive sinusoidal currents flow through coils 11a and 11b, respectively, while when driving transistors 14a and 14b are turned on, coil 1
Negative sinusoidal currents flow through 1a and 11b, respectively.

In this way, the driving transistors 13a and 14
By alternately turning on a, 13b and 14b, sine wave currents in different directions are applied to the coil 11a.
, 11b, thereby generating a rotating magnetic field.

Next, when stopping the sine wave current, the transistor 1T, which is controlled by the output of the timing generation circuit T, is turned on to short-circuit the coil 11a or the coil 11b, and the current is gradually stopped.

That is, for the coil 11a, the diode 20-
By forming a closed loop with transistor 17 and diode 18 and turning on transistor 1T, the emitter
The connection between the collectors changes to a conductive state, shorting the coil 11,
The current waveform of the sinusoidal current flowing through the coil 11a when it is stopped can be made gentler.

Further, for the coil 11b, a closed loop is formed by the diode 21-transistor 1T-diode 19, and by turning on the transistor 1T, the emitter-collector becomes conductive, short-circuiting the coil 11b. It is possible to make the current waveform of the sinusoidal current flowing in the current waveform gentle when it stops.

In this way, the transistor 1T can be operated to soften the current waveform of the sinusoidal current for both the coil 11a and the coil 11b.
Multiple coils can be short-circuited at the same time with one transistor 1T, and even if the number of bubble memories increases, some functions of the conventional drive circuit can be performed in common, reducing the number of circuits. Therefore, the structure of the magnetic bubble storage device is simplified and economically effective.

Note that even if the coils 11a and 11b operate at the same time and stop at the same time, or even if the coils 11a and 11b do not operate at the same time and only one of them is selected and operates, the main The operation of the circuit is the same.

FIG. 6 is a circuit diagram showing another embodiment of the present invention.

In FIG. 6, the same parts as in FIG. 5 are given the same reference numerals, and their explanation will be omitted.

The difference from FIG. 5 is that the resonance capacitors 12a and 1
2b, transistors 15a and 15 for charging
b is omitted, and the drive circuit side of the transistor 1T, that is, the connection point between the anode common connection point of the diodes 18 and 19 and the collector of the transistor 1T, is connected to the negative electrode side of the power supply 8.

In the embodiment shown in FIG. 5, the coil 11a and the coil 11b on the drive circuit side are electrically separated by diodes 18 and 19.

However, it is thought that a capacitor is connected in parallel to the diode as a parasitic capacitor.

Here, although the value of this capacitance is small, since the switching time of the output voltage of the drive circuit is very short, this capacitance has a slight influence between the coils 11a and 11b, and the sine The current waveform of the wave current may change.

In order to avoid this problem, FIG.
The drive circuit side of the power source 8 is connected to the negative electrode side of the power source 8.

As a result, the anode sides of diodes 18 and 19 are fixed at a negative potential, and this potential is applied to the coil 11.
There is no change even if a or 11b operates, so
It is possible to prevent mutual influence based on stray capacitance.

Therefore, when the sine wave current is stopped, the resonance capacitor 12a or 12b is at a positive voltage, but when the operation starts, it is necessary to keep it at a negative voltage. In this case, charging to a negative voltage was performed by transistors 15a and 15b.

However, in the embodiment shown in FIG. 6, when the transistor 17 is made conductive in order to soften the current waveform of the sine wave current when the current is stopped, the collector side is connected to the negative power supply, so the resonance An operation is also performed in which capacitors 12a and 12b are charged to a negative voltage.

In this way, the transistor 1T can have both the function of moderating the current during a power outage and the function of charging the resonance capacitor with a negative voltage.

Furthermore, the embodiment shown in FIG. 6 is characterized in that the current waveform when the sine wave current is stopped is larger than that in the steady state, and then the current waveform is gradually stopped.

Here, increasing the current waveform at the time of stop in this manner has the effect of preventing a decrease in the operating margin due to the stop of the bubble, as is well known.

Therefore, in order to drive the magnetic bubble memory, there are two sets of coils in the X and Y directions corresponding to the coils 11a and 11b of the embodiment shown in FIGS. 5 and 6. Current is flowing.

In the above embodiment, the case where the vehicle stops in the X direction is explained.

In this case, the last current that ends is X current Ix, and Y
As shown in FIG. 7, the current Iy will stop when the X current Ix has reached its maximum value.

Therefore, the circuit of the present invention only needs to adopt a circuit for the X current, and by increasing the time constant of discharge, the time that the magnetic field is oriented in the X direction can be extended and stopped.
Stable stopping operation can be performed.

In the above explanation process, we have not mentioned the specific configuration and operation of the timing generation circuit 10 that controls the transistor 1T, but since these belong to normal digital technology (pulse technology), we will not discuss them as necessary. Depending on the situation, this can be realized by known means.

As explained above, according to the present invention, even if the number of bubble memories increases, some functions of the conventional drive circuit can be performed in common throughout the circuit, with a simple configuration without using complicated means. Since the number can be reduced, the structure of the magnetic bubble storage device is simplified and economically effective.

In addition, current undershoot when the rotating magnetic field stops is eliminated, greatly improving the operating margin area, and malfunctions caused by stopping the magnetic bubble are eliminated, ensuring reliable and stable operation. It is also extremely effective.

[Brief explanation of the drawing]

Figure 1 is a waveform diagram showing the phase relationship and timing of X current Ix and Y current ■y, Figure 2 is a circuit diagram showing an example of a conventional sine wave current drive circuit, and Figure 3 is the operation of Figure 2. 4 is a bias magnetic field characteristic diagram for explaining the operation of FIG. 2, FIG. 5 is a circuit diagram showing an embodiment of the magnetic bubble memory drive circuit according to the present invention, and FIG. 6 is a diagram showing the characteristics of the magnetic bubble memory according to the present invention. FIG. 7 is a waveform diagram for explaining the operation of FIG. 6. 5.8...Power supply, 11a, 11b...
Coil, 12a, 12b-:ydenser, 13
a, 13b. 14a, 14b, 17...transistor, 18
~21...Diode.

Claims (1)

[Scope of Claims] 1. A magnetic bubble memory device comprising a plurality of sine wave current circuits formed by connecting the coil side of a series resonant circuit consisting of a coil and a capacitor to a drive circuit side and grounding the capacitor side, The drive circuit side of each coil of the sine wave current circuit is connected to the cathode side of the first diode group, and the anode side of the first diode group is connected in common, and the capacitor side of each coil is connected to the second diode group. are respectively connected to the anode sides of the diode group, and the cathodes of the second diode group are connected in common, and a common connection point on the anode side of the first diode group and a common connection point on the cathode side of the second diode group. A magnetic bubble memory drive circuit characterized in that a transistor is connected in a forward direction between and. 2. The magnetic bubble memory drive circuit according to claim 1, wherein a common connection point on the anode side of the first diode group and a connection point of the transistor are connected to a power source.