JPS6315676B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble drive device used in a magnetic bubble memory. Magnetic bubble memory has attracted attention as a nonvolatile solid-state memory, and has reached the stage where it is put into practical use. Information is stored in bubble chips, and movement of the information is effected by a rotating magnetic field generated by a magnetic bubble driver. Bubble chips with magger-minor-loop configuration, which are currently mainstream, have various components such as the minor loop, mager line, generator, detector, and replicate/swap gate that connects the minor loop and mager line necessary for memory operation. Functional parts are formed. In order to obtain a bubble chip with a wide operating margin, it is necessary to improve each functional part so that it has a sufficiently wide operating margin. For this purpose, it is essential to measure the operating margin for each functional section. This operating margin is generally expressed as a rotating magnetic field versus bias magnetic field characteristic (HR-HB characteristic). Each functional part
The HR-HB characteristics can be measured by increasing or decreasing the amplitude of the rotating magnetic field while the test data exists in the functional part to be measured. In conventional magnetic bubble drive devices, the amplitude of the rotating magnetic field cannot be changed during operation, so when measuring the HR-HB characteristics of each functional section, the rotating magnetic field was stopped each time the amplitude was changed. Although the minor loop is designed to be unaffected by the stopping of the rotating magnetic field, other functional parts are not. For this reason, when using the conventional magnetic bubble drive device, it was not possible to accurately measure the HR-HB characteristics of each functional section.

Further, the required amplitude of the rotating magnetic field varies depending on the functional unit, and the replicate/swap gate that performs complicated operations tends to require the largest amplitude of the rotating magnetic field. Therefore, replicate/
By increasing the amplitude of the rotating magnetic field only a few cycles before and after operating the swap gate, it is possible to significantly improve the reliability of the magnetic bubble memory. However, since the amplitude cannot be changed in the conventional magnetic bubble drive device, it has not been possible to adopt such a drive that increases reliability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic bubble drive device that easily overcomes the drawbacks of the conventional magnetic bubble drive device and can rapidly increase and decrease the amplitude of a rotating magnetic field without stopping it.

That is, according to the present invention, a reference voltage terminal, a plurality of voltage terminals, a drive coil that supplies a rotating magnetic field to the magnetic bubble device, and a first drive coil connected between each of both ends of the drive coil and the reference voltage terminal. two sets of parallel circuits including a switch and a first clamp diode; a second switch connected between each end of the drive coil and each of the plurality of voltage terminals; and a second switch connected in parallel with the drive coil. a set of two second clamp diodes connected in series in opposite directions; and a third switch connected between a connection point between the two second clamp diodes and each of the plurality of voltage terminals. A magnetic bubble drive device is obtained.

The details of the present invention will be explained below using the drawings.

FIG. 1 shows a conventional magnetic bubble drive device. 2 so that the amplitude of the rotating magnetic field can be changed without stopping.
Voltage switches 111 and 112 are introduced which selectively utilize the different voltages V ₁ and V ₂ .

Circuit 1 that drives a rotating magnetic field to a magnetic bubble chip
10 is composed of four switches 101 to 104 and four diodes 105 to 108. When either of voltage switches 111 and 112 is on, when switches 101 and 104 are turned on, the drive coil 109 is turned on from left to right. A current flows through the coil.
When switches 101 and 104 are turned off, the positive coil current flows from diode 107 to 106 due to its inertia to flow in the same direction, and the coil current is attenuated (recovered to the power supply) after which
When switches 103 and 102 are turned on, a negative coil current flows. These switches 102 and 10
After cutting 3, diode 1 due to the same inertia
It flows through 08 and 105 and is attenuated. (Recovered to the power source.) As a result, a triangular wave coil current flows through the drive coil 109. A driving system for such a rotating magnetic field in which a rotating magnetic field is generated from the driving coil 109 at this time is described in ``Magnetic Bubble Drive Circuit System'' in Japanese Patent Application Laid-Open No. 50-147245. It is shown that the amplitude of the triangular wave coil current is proportional to the magnitude of the power supply voltages V ₁ and V ₂ .

Therefore, by switching the voltage switches 111 and 112, the voltage applied to the drive circuit 110 can be changed from V ₁ to V ₂ , and the coil current amplitude of any period can be changed proportional to V ₁ . From the value
It becomes possible to change the value to a value proportional to V ₂ .

However, a positive current that supplies a drive current to the drive coil 109 via the switch 101 or 103 flows through the voltage switches 111 and 112, and a negative current that is recovered to the power source via the diodes 105 and 106. In other words, the voltage switches 111 and 112 must be bidirectional switches.

To achieve this, it is necessary to combine two unidirectional elements such as transistors to perform high-speed switching of a large current and maintain immediate ON operation, which is difficult to realize. Also, the drive coil 109 is connected through the switch 101 or 103.
During the period when current is supplied to the voltage switch 111 or 112, the current also flows to the voltage switch 111 or 112, and the duty ratio is not low, so the power consumption in this part is not reduced. This also causes deterioration of the drive waveform of the coil current.

In other words, the conventional magnetic bubble drive device shown in Fig. 1 requires a bidirectional voltage switch, which is difficult to implement, and has the drawbacks of increased power consumption and poor waveform. .

FIG. 2 is a block diagram of an embodiment of the magnetic bubble drive device according to the present invention. This device is entirely composed of unidirectional switches, and applies the voltage V ₁ supplied to the first voltage terminal 202 or the voltage V ₂ supplied to the second voltage terminal 203 to the drive coil 204 through one switch. Switches 209 and 210 are connected between the first voltage terminal 202 and both ends of the drive coil 204, and switches 211 and 2 are connected between the second voltage terminal 203 and both ends of the drive coil 204.
12 are connected. In order to recover the electromagnetic energy stored in the drive coil 204 into a power source, diodes 214 and 21 are installed at both ends of the drive coil 204.
5 is connected, and the connection point between the diodes 214 and 215 and the first voltage terminal 202 and the second voltage terminal 2
Switch 213 and Switch 2 during 03
16 are provided. Between each of both ends of the drive coil 204 and the ground terminal 201, a parallel connection circuit of a switch 205 and a diode 207 and a switch 20 are connected, as in the conventional magnetic bubble drive device.
A parallel connection circuit of 6 and a diode 208 is connected.

When driving a coil current with an amplitude proportional to the voltage _V1 , the sets of switches 209 and 206 and the set of switches 205 and 210 are turned on and off alternately, and the switch 213 is turned on. remaining switch 211,
212 and 216 are turned off. On the other hand, the voltage
When driving a coil current with an amplitude proportional to V ₂ , a pair of switches 211 and 206, 205 and 212
Switch 21 is turned on and off alternately.
Turn on 6. And in this case switch 2
Turn off 09, 210, and 213.

Such switches 209, 210, 205,
206 and 213 or switch 211, 21
The method of generating coil current by on/off control of coils 2, 205, 206, and 216 will become clearer with reference to FIG. 3, which shows the operating waveforms of FIG. In the figure, waveform 301 is waveform 30 of switch 209.
2 is the waveform 303 of switch 210 is switch 21
1, the waveform 304 of the switch 212, the waveform 305 of the switch 206, the waveform 306 of the switch 205, the waveform 307 of the switch 213, and the waveform 308 of the switch 213 indicate the operating states of the switch 216, with a high level being an on state and a low level being an off state. , waveform 3
09 indicates a coil current flowing through the drive coil 204. t ₁ to _{t 4} represent time, T ₁ to _{T 6} represent periods, and I ₁ and I ₂ represent peak amplitudes of coil currents corresponding to voltages V ₁ and V _2, respectively.

If the drive system of FIG. 2 follows the time chart of FIG. 3, at time t ₁ switch 209 and switch 206 are closed and voltage V ₁ is applied across drive coil 204. The time constant L/ determined by the drive coil inductance L and its internal resistance R
A coil current that increases exponentially based on R flows through the drive coil 204. Here, if the time constant L/R is made sufficiently larger than the period _T1 , the coil current can be considered to increase linearly. When the required peak amplitude _I1 is reached, switch 209 and switch 2
When 06 is opened, the electromagnetic energy stored in the drive coil 204 generates a back electromotive voltage across the drive coil ₂₀₄ in the opposite direction to the period t1. During this period _T1, the switch 213 is closed and the switch 216 is opened, so the back electromotive force is applied to the diodes 207 and 215.
is clamped to voltage V ₁ by . For this reason,
The coil current flows through the diodes 207, 215 during period t ₂
and via the switch 213, the peak amplitude I ₁ falls toward zero. When switch 210 and switch 205 are closed during period _t3 , _V1 in the opposite direction to period _t1 is applied to both ends of drive coil 204, and the coil current further falls from zero. After reaching the required negative amplitude, switch 210 and switch 205
When opened, a back electromotive force is generated across the drive coil 204. This back electromotive force is generated by the diodes 208 and 21.
4, _the drive coil ₂₀₄ has diodes 208, 21
A drive current that rises toward zero flows through the switch 213 and the switch 213. As described above, one period of triangular wave current flows through the drive coil 204. Period T ₂ ,
By operating T ₅ and T ₆ in the same manner as the period T ₁ , it becomes possible to flow a coil current having an amplitude I ₁ corresponding to the voltage V ₁ to the drive coil 204 .

In periods T ₃ and T ₄ , the switch 213 opens and the switch 216 closes, as shown by waveforms 307 and 308. In these cycles T ₃ and T ₄ , the switch 211 and the switch 206 produce waveforms 303 and 305, respectively.
The switch 212 and the switch 205 are controlled as shown in waveform 304 and waveform 306, respectively. Therefore, drive coil 2
A voltage V ₂ is applied to both ends of the voltage V 2 , and a triangular wave current having a peak of an amplitude I ₂ corresponding to the voltage V ₂ flows through the drive coil 204 .

In this way, as shown in waveform 309, the period
At T ₁ , T ₂ , T ₅ , and T ₆ , a triangular wave current with a peak amplitude I ₁ corresponding to the voltage V ₁ is applied to the drive coil, and at periods T ₃ and T ₄ , a triangular wave current with a peak amplitude I ₂ corresponding to the voltage V ₂ is applied to the drive coil. 204. Voltage V ₁ and Voltage V ₂
can be preset to an arbitrary voltage value externally by using a D/A converter, an operational amplifier, etc.

Comparing the drive device in FIG. 2 with that in FIG. 1, there is no difference in the number of parts, but the voltage switch 1 in FIG.
The large power consumption at 11 and 112 and the deterioration of the coil current waveform due to the resistance there are easily eliminated in FIG. That is, the switch 111 in FIG.
Turning on , 101 and 104 corresponds to turning on switches 209 and 206 in FIG. 2, and the number of switches in the positive coil current path is smaller in the invention of FIG. The smaller the number of switches, the smaller the power loss in the switch resistance, and the larger the time constant L/R, resulting in a sharper current waveform. Furthermore, the voltage switches 111 and 112 in FIG. 1 have a high duty ratio when the current is turned on, so it is difficult to design them to be compact, but the switch 20 in FIG.
9 and 210 have low duty ratios, so they can be made compact.

As described above, the present invention is much more practical than the conventional one shown in FIG.

In addition, in the above explanation, the switches 205 and 20
The closing period of 6,209,210,211,212 was set to 1/4 cycle, but switch 20
5,206 closing periods or switches 20
By extending any of the closing periods 9, 210, 211, and 212 to one-fourth period or more, a pseudo trapezoidal wave coil current can be caused to flow through the drive coil 204. Furthermore, other reference voltages may be applied to the ground terminal 201.

Furthermore, in the above explanation, two types of power supplies were used to apply voltage V ₁ and voltage V ₂ to the magnetic bubble drive device, but even more types of voltages can be applied to generate coil currents with peak amplitudes of two or more types. It is possible to switch either one of them on a periodic basis and send it to the drive coil. This is made possible by providing a switch between the additional voltage terminal and both ends of the drive coil and between the additional voltage terminal and the junction of diodes 214 and 215, respectively.

As described above, the present invention easily overcomes the need for a high speed, bidirectional voltage switch and the drawbacks of high power consumption in conventional magnetic bubble drive devices. Therefore, by using the magnetic bubble drive device according to the present invention, it is possible to accurately measure the operating margin of each functional section of the bubble chip, and it is also possible to drive the bubble chip to increase the amplitude of the rotating magnetic field during the period in which the replicate/swap gate is operated. , it becomes easy to increase the reliability of bubble memory.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a conventional magnetic bubble drive device, FIG. 2 is a circuit diagram showing an embodiment of the present invention, and FIG. 3 is an operation waveform diagram of each part thereof. 101, 102, 103, 104, 205, 2
06,209,210,211,212,21
3,216...Switch, 111,112...Voltage switch, 105,106,107,108,20
7,208,214,215...Diode, 11
0... Conventional triangular wave drive circuit, 201... Earth terminal, 202... Power 1 voltage terminal, 203... Second voltage terminal.

Claims (1)

[Claims] 1 a reference voltage terminal and a plurality of different voltage terminals,
a drive coil for supplying a rotating magnetic field to the magnetic bubble device; a parallel circuit of a first switch and a first clamp diode connected between respective reference voltage terminals at both ends of the drive coil; a second switch connected between each of the plurality of voltage terminals; a set of two second clamp diodes connected in parallel with the drive coil and connected in series in opposite directions;
A magnetic bubble driving device comprising: a third switch connected between a connection point of the plurality of second clamp diodes and each of the plurality of voltage terminals.