JPS6215949B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a portion of a magnetic bubble memory device that generates a rotating magnetic field.

The rotating magnetic field is essential for bubble propagation, transfer, expansion, etc. within the magnetic bubble chip. In order to generate this rotating magnetic field, a rotating magnetic field drive device that can drive periodic coil currents with a phase difference of 90 degrees between two orthogonal drive coils wound around a bubble chip is required. Sine waves and triangular waves are well known as coil currents, but if you try to miniaturize the drive coil and use selective drive to integrate the drive device with an IC, you will need a large resonant capacitor. The sine wave driving method is not very suitable.
The triangular wave drive method is suitable for IC implementation, but it is difficult to match the rise time and fall time, and if left as is, the amplitude will become highly uneven. In order to solve this problem, we proposed in patent application No. 53-112781 that a trapezoidal coil current drive system is appropriate. However, it does not present an economical implementation method for a selective drive circuit for trapezoidal coil currents.

The trapezoidal coil current can be driven by simply changing the control in the triangular wave coil current drive circuit.

This also applies to the selection drive circuit.
Therefore, a triangular wave coil current drive circuit can be used to drive the trapezoidal coil current. However, conventional selective rotating magnetic field drive circuits have the disadvantage that the number of components per coil cannot be reduced very much, and that many components are connected to the path through which the coil current flows, resulting in large losses.

It is an object of the present invention to overcome these drawbacks, and more specifically to provide a rotating magnetic field drive device in which the number of components per drive coil is significantly reduced by employing a selective drive circuit configuration. It is in.

Therefore, the present invention is characterized by including the following components. That is, a plurality of drive coils arranged in a matrix, a row direction voltage common line connected to the first terminal of each drive coil, and a first
A first and second switch connected to a power source and a ground power source respectively, diodes connected in parallel to these, and two switches connected from the second terminal of each drive coil via a pair of selection diodes are combined into one. A pair of column direction current common lines, a third switch and a diode respectively connected between one of the pair of column direction current common lines and the first power supply and a ground power source, and a pair of column direction current common lines. It includes a diode and a fourth switch connected between the other common line and the first power source and the ground power source, respectively.

In order to drive the trapezoidal coil current, the coil can be turned on by turning on the fourth switch when the first switch is turned on, or by turning on the third switch when turning on the second switch. The rising period of the current and either one of the first and fourth switches or one of the second and third switches
A period in which only one switch remains on and the coil current falls slowly, and a period in which all four switches remain off and the coil current falls sharply are repeated in sequence.

A more detailed explanation will be given below with reference to the drawings.

FIG. 1 is an explanatory diagram of a conventional selective rotating magnetic field drive device to which the invention described in Japanese Patent Application Laid-Open No. 52-99726 is applied. In the invention described in JP-A No. 52-99726, a plurality of coils are driven at the same time, a pair of positive and negative power supplies are used, and a triangular wave coil current is driven. However, it has been rewritten so that only a single coil is driven by a trapezoidal wave and is driven by a unipolar power supply. Further, in this example, the drive coils are arranged in a 2×2 matrix. Therefore, in this figure, the row direction common line B ₁₁ is connected to the lower end of the drive coil (for example, L ₁₁ ) via the selection diode D ₁₁₁ , and the row direction common line B ₂₁ is connected via the diode D ₂₁₁ .
A column direction common line _B31 is connected to the upper end via a selection diode _D311 , and a column direction common line _D41 is connected via _D411 . The common line B ₁₁ in the row direction has a first switch S ₁₁ and a diode D ₁₁ for the high voltage first power supply (in this case +V) and the ground power supply, respectively, and the common line B ₂₁ has a first +V power supply. A diode D ₂₁ and a second switch S ₂₁ are connected to the ground of the second power supply. In contrast, the common line in the column direction
A third switch S ₃₁ and a diode D ₃₁ are connected to B ₃₁ for the +V first power supply and the ground power supply, respectively, and a diode D ₄₁ and a column direction switch S ₄₁ are connected to the common line B ₄₁ , respectively. There is. Therefore, among the row direction switches S ₁₁ , S ₂₁ , S ₁₂ , S ₂₂
S ₁₁ , S ₂₁ are selected, and on the other hand, if S ₃₁ , S 41 among the column direction switches S ₃₁ , S ₄₁ , S ₃₂ , _{S 42 are} selected, the selection diodes (D ₁₁₁ , D ₂₁₁ ,
A triangular wave or trapezoidal coil current is driven only to the drive coil L ₁₁ connected to these via the coils D ₃₁₁ , D ₄₁₁ ), and the remaining drive coils L ₁₂ , L ₂₁ , and L ₂₂ remain connected even when voltage changes are applied to the coils. No current flows. Wandering is also prevented by the selection diode.

Such a selective drive device uses 8 switches and 24 diodes for every 4 drive coils.

The forward voltage drop is small for a diode,
A diode with high reverse breakdown voltage and a current capacity of close to 1A is required, so diodes cannot be ignored in terms of both cost and size. Therefore, the defect of too many diodes is noticeable.

FIG. 2 shows operating waveforms for the selected drive coils in FIG. Waveform 21 in the figure,
22, 23, 24 are switches S ₁₁ , S ₂₁ , S ₄₁ , S ₃₁
This is the control pulse given to the switch, and a high level indicates on operation. Other switches S ₁₂ , S ₂₂ , S ₃₂ , S ₄₂
As shown in waveform 25, no control pulse is applied to. Therefore, the trapezoidal coil current i _C11 flows only in the selected drive coil L ₁₁ as shown in the waveform 26. The waveform of the coil current i _C11 in half-cycle units is divided into an average rising period A, a gradual falling period B, and a steep falling period C.

Table 27 shows the order in which components pass along the coil current path in each period in the vertical direction. The horizontal direction shows the passage of time. To explain the half period of the positive polarity coil current, during the rising period A, the coil current i _C1
1 is the switch S ₁₁ from the power supply +V, the diode D ₁₁₁ ,
The current flows through the drive coil L ₁₁ , diode D ₄₁₁ , and switch S ₄₁ to the ground power source.

During the slow falling period B of the next column, the power supply +V flows through the switch S ₁₁ , the diode D ₁₁₁ , the coil L ₁₁ , the diode D ₄₁₁ , and D ₄₁ to +V, and during the steep falling period C, the ground power supply From diode D ₁₁ and
Coil current i _C11 is recovered to +V through D ₁₁₁ , coil L ₁₁ , diodes D ₄₁₁ and D ₄₁ . Therefore,
In both periods, the coil current i _C11 passes through five components, resulting in large circuit losses. The above description is not disclosed in JP-A-52-99726.

FIG. 3 is an explanatory diagram of one embodiment of the present invention. The drive coils are arranged in a 2×2 matrix. The difference from FIG. 1 is that the pair of row-direction common lines are combined into one, and the selection diode connected to one of the common lines is omitted. In this case as well, the switches S 11 and S ₂₁ among the direction row switches S ₁₁ , S ₂₁ , S ₁₂ , and _{S 22 are} selected, and the column direction switches S ₃₁ ,
When switches S _{31 and} S ₄₁ among S ₄₁ , S 32 and S ₄₂ are selected, a switch is selected among drive coils L ₁₁ and L ₁₂ connected to switches S ₁₁ and S ₂₁ via a common line B ₁ in the row direction.
Drive coil connected to S ₃₁ and S ₄₁ via column direction common lines B ₃₁ and B ₄₁ and selection diodes D ₃₁₁ and D ₄₁₁
A triangular wave or trapezoidal coil current flows only in L ₁₁ , and no coil current flows in the other drive coils L ₁₂ , L ₂₂ , and L ₂₁ even if a voltage change is applied. Wandering is also prevented by the selection diode.

Such a selective drive device uses 8 switches and 16 diodes for every 4 drive coils, which is 8 fewer diodes than in the first case. As the number of drive coils increases, the difference in the number of diodes further increases, so the improvement from FIG. 1 to FIG. 3 has a great effect.

FIG. 4 shows operating waveforms for selected drive coils of FIG. Waveforms 41 and 4 in the diagram
2, 43, and 44 are control signals for switches S ₁₁ , S ₂₁ , S ₄₁ , and S ₃₁ , and waveform 45 is for the remaining switches.
These are control signals for S ₁₂ , S ₂₂ , S ₃₂ , and S ₄₂ . Waveform 46
shows a trapezoidal wave coil current i _C11 driven by the drive coil L ₁₁ as a result of such control. Table 47 shows the order in which components pass along the current path in each period of coil current i _C11 shown in waveform 46 in the vertical direction.

Regarding the current flow during the half-cycle period of the positive polarity coil current, first, during the rising period A, the coil current i _C11 flows from the first power supply +V through the switch S ₁₁ , the drive coil L ₁₁ , the diode D ₄₁₁ , and the switch S ₄₁ . and flows to the ground power supply. Going to other paths is prevented by selection diodes. During the slow falling period B, the current i _C11 flows from +V to +V through the switch S ₁₁ , the coil L ₁₁ , the diode D ₄₁₁ and the diode D ₄₁ . For the steep falling period C, the brand uses diode D ₂₁ , coil L ₁₁ , diode D ₄₁₁ ,
Current recovery occurs through diode D ₄₁ to +V.
Therefore, in any period, the coil current i _C11 passes through only four components, and the circuit loss is reduced compared to the case of FIG. 1.

As described above, according to the present invention, it is possible to easily solve the defects in the conventional device in which the number of parts per drive coil is not small and the defects in which the circuit loss in each coil current path is large.

In addition, in the above embodiment of the present invention, 2×2
The case of a selection-driven matrix of 1×
4 or 4.times.4 selection drive matrices can be easily handled, and the above description is not intended to limit the scope of the present invention in any way.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional selective rotating magnetic field drive device, Fig. 2 is a waveform diagram explaining its operation, Fig. 3 is a circuit diagram showing an embodiment of the present invention, and Fig. 4 is its operation. FIG. S ₁₁ , S ₂₁ , S ₁₂ , S ₂₂ ... row direction switch, S ₃₁ ,
S ₄₁ , S ₃₂ , S ₄₂ ... Column direction switch, B ₁₁ , B ₂₁ ,
B ₁₂ , B ₂₂ , B ₁ , B ₂ ... Row direction common line, B ₃₁ , B ₄₁ ,
B ₃₂ , B ₄₂ ... Column direction common line, D ₁₁ , D ₂₁ , D ₁₂ , D ₂₂ ,
D ₃₁ , D ₄₁ , D ₃₂ , D ₄₂ ... Diode (for back electromotive voltage clamp), D ₁₁₁ , D ₂₁₁ , D ₁₁₂ , D ₂₁₂ , D ₁₂₁ ,
D ₂₂₁ , D ₁₂₂ , D ₂₂₂ , D ₃₁₁ , D ₄₁₁ , D ₃₁₂ , D ₄₁₂ ,
D ₃₂₁ , D ₄₂₁ , D ₃₂₂ , D ₄₂₂ ... selection diode,
L ₁₁ , L ₁₂ , L ₂₁ , L ₂₂ ... Drive coil, 21, 2
2, 23, 24, 25, 41, 42, 43, 4
4, 45...Switch control signal, 26, 46...
...Coil current waveform, 27, 47... Corresponding to the coil current waveform, a table of parts passage order of current in the coil current path at each time.

Claims (1)

[Claims] 1 A plurality of drive coils arranged in a matrix, a common row voltage line connected to the first terminal of each drive coil, and a first and a second switch and a diode connected in parallel to these switches;
Connect two wires connected through a pair of selection diodes to one
a pair of column direction current common lines; a third switch and diode connected between one of the pair of column direction current common lines and a first power source and a ground power source; and the column direction current common line. a diode and a fourth switch connected between the other of the power supplies and the first power supply and the ground power supply, respectively, and when the first switch is turned on, the fourth switch is turned on or the second switch is turned on. By turning on the third switch when turning on the coil current, the rising period of the coil current and either the first switch or the fourth switch or the second switch and the third switch can be changed.
A period in which only one of the four switches continues to be on and the coil current falls slowly, and a period in which all four switches are turned off and the coil current falls sharply are repeated in sequence. Selective rotating magnetic field drive device.