US3072892A

US3072892A - Magnetic core matrices

Info

Publication number: US3072892A
Application number: US837408A
Authority: US
Inventors: Wallace A Kluck
Original assignee: Texas Instruments Inc
Current assignee: Texas Instruments Inc
Priority date: 1959-09-01
Filing date: 1959-09-01
Publication date: 1963-01-08
Anticipated expiration: 1980-01-08

Description

Jan. 8, 1963 w. A. KLUCK MAGNETIC CORE MATRICES 2 Sheets-Sheet 1 Filed Sept. 1, 1959 4 2 2 Z W MO f v/ D. w W \U/ D \\W a 4 a 9 D b! Z7 4:

INVENTOR IlallaveA 1mm his, 1963 w. A. KLUCK MAGNETIC CORE MATRICES 2 Sheets-Sheet 2 Filed Sept. 2, 1959 INVENTOR WWII-[(11161 M iggg s Patented Jan. 8, 1963 Filed Sept. 1, 1959, Ser. No. 837,408 4 Claims. (Cl. 340-174) The present invention relates to magnetic switching core matrices of the type having cores with square hysteresis loops and to a method of operating such magnetic switching core matrices.

A magnetic switching core matrix, such as the one of this invention, comprises a plurality of magnetic cores having square hysteresis loops. These cores are arranged in columns and rows. A plurality of column and row driving coils are provided. Each column driving coil is inductively coupled to all of the cores of a different column, and each row driving coil is inductively coupled to all of the cores of a different row.

The function of the switching core matrix is to select one of its cores and switch the selected core to its opposite state. An output pulse will be induced in an output winding inductively coupled to the selected core. Thus, the switching core matrix comprises a means to produce an output signal from the selected one of a plurality of outputs.

The switching core matrices of the prior art use some form of coincidence of current so that only the selected core will be switched to its opposite state. Many other cores in systems of the prior art will receive in a direction to switch them, but the M.M.F. applied to these unselected cores will be insufficient to cause the unselected cores to switch. These insufiicient M.M.F.s are called half-currents. According to the method of this invention, these half-currents are substantially reduced, and when the method is applied to the matrix of the present invention, the half-currents are entirely eliminated. This elimination or reduction of the half-currents greatly improves the reliability and signal-to-noise ratio of the matrix and greatly decreases the time required for switching.

With the system of the prior art, drivers must be provided which are capable of delivering a relatively large amount of power to each column and row driving coil, because each driver must be capable of supplying half the power to switch one of the cores. This high power requirement tends to make use of transistorized drivers impractical. Applicants invention substantially reduces the power requirements of the column and row drivers and therefore makes the use of transistorized drivers more practical.

The method of the invention is practiced on a core matrix in which all of the column-driving coils are connected together and to a coil which threads all of the cores in the matrix. The polarity of the coil which threads all of the cores is opposite to that of the columndriving coils. Also, all of the row-driving coils may be connected together and to another coil which also threads all of the cores of the matrix. This second coil which threads all of the cores of the matrix will have a polarity opposite to that of the row-driving coils. These two coils, each of which threads all of the cores of the matrix, shall be referred to as common coils. A matrix having these common coils is disclosed in FIGURE 6 of the patent to Rajchman, No. 2,691,154, issued October 5, 1954.

According to the method of this invention, currents are applied to the driving coils of all the rows of the matrix other than the one which contains the selected core and to the driving coils of all the columns of the matrix other than the column which contains the selected core. These currents have a polarity to drive the cores toward the stable state which they are already in. The

currents which are applied to the column coils combine to form one large current which is applied to the common coil connected to the column-driving coils. Also, if there is a second common coil connected to the row coils, the currents applied to the row coils will be combined into one large current which will be applied to this second common coil. These large currents will apply M.M.E.s to all the cores in a direction opposite to that applied by the windings of the row and column-driving coils. As a result of this action, the selected core will receive the largest in a direction to cause switching. All other cores will receive the difference M.M.F.s resulting from the subtraction of the generated by the common coils from that generated by the driving coils.

In the matrix of this invention, the ratio of the windings of the driving coils to that of the common coils is chosen such that only the selected core receives M.M.F. in a direction to cause switching. All other cores of the matrix receive either zero or in the direction to maintain the core in the state that it is already in. Thus, half-currents are eliminated. 1

Since the switching is caused by a combination of currents from several drivers, the power which must be supplied by each driver is substantially reduced.

It is therefore one object of the invention to provide a unique method for selectively switching the individual elements in a switching matrix.

Another object of the invention is to provide a switching matrix in which parallel operation of the drivers is utilized to accomplish the switching operation.

Still another object of the invention is to provide a switching matrix in which the driving coils are arranged so as to substantially reduce half-currents.

Further objects and advantages of the invention will be understood as the following detailed description of a preferred embodiment unfolds and when taken in conjunction with the drawings wherein:

FIGURE 1 shows a magnetic core matrix according to the invention with one common coil linking all of the cores.

FIGURE 2 shows a magnetic core matrix according to the invention with two common coils linking all of the cores of the matrix.

As shown in FIGURE 1, the matrix comprises 16 cores arranged in a rectangular array. These cores are of the type having a square hysteresis loop and thus have two stable states of magnetization. Each oi'the cores has three

windings

12, 13 and 14. The windings 12 on the cores in the same row are connected in series to form a row driving coil, thus providing the four row driving coils 21-24. These coils 21-24 are connected together and to a reference potential, which is ground, at one end. The winding 13 on each of the cores in the same column are connected together in series to form a column driving coil and thus four column driving coils 25-28 are provided. The column driving coils 25-28 are connected together at one end and this common connection is connected to a common coil 29 formed by the series connection of all the windings 14 of the matrix. The other end of the common coil 29 is connected to ground. The

windings

12 and 13 each have three turns and the windings 14 each are comprised of one turn and consist of a single wire threading the core as shown.

If current is applied to one of the coils 25 through 28 v to thereby apply M.M.F.s to the cores of one column,

this current will also pass through the coil 29 and thus through the windings 14 on each of the cores. The polarity of the windings 14 is selected such that the generated thereby will be in the opposite direction to that generated by the windings 13. The polarities of the

windings

12 and 13 are the same so that if positive currents are applied to any of the driving coils 21-28 it will tend to switch the cores linlced by such coils in the same direction. For purposes of description, these states to whichthe cores would tend to be switched shall be designated the ZERO states. The opposite states of the cores shall be designated the ONE states. Thus the Mix LE. generated by the windings 14 when a positive current is applied to one of the driving coils 25-28 will tend to switch the cores 11 to their ONE states.

The function of this matrix is to switch any selected one of the 16 cores from its ZERO state to its ONE state while leaving the remaining cores unswitched. To operate the matrix all of the cores start out in their ZERO states. Equal positive currents are applied to three of the driving coils 21 24 and three of the driving coils 2523. The core at the intersection of the two driving coils on which no currents are applied will then switch to its ONE state. For example, assume that the driving coils 21, 23 and 24 have positive currents applied thereto and no current is applied to the driving coil 22 and at the same

time driving coils

25, 26, and'28 each have positive currents applied thereto and no current is applied to the driving coil 27. Assuming that the currents applied to the driving coils 21-28 have a magnitude of I amperes, then each of the cores in the rows driven by driving

coils

21, 23 and 24 will receive an of 31 ampere turns. The minus symbol is used here to designate that the direction of the M.M.F. is to tend to switch the core to its ZERO state. Accordingly, the plus symbol shall designate that the direction of an M.M.F. is to switch a core to its ONE state. Table I illustrates the applied to each of the cores 11 of the matrix in accord- ,ance with its position as shown in FIGURE 1 due to the positive currents of I amperes applied to driving

coils

21,23 and 24.

Table II illustrates the M.M .F.s applied to cores 11 of the matrix in accordance with their position in FIG- URE 1, due to the positive currents of I amperes applied Table II indicates that the cores in the column of the driving coil 27 each receive an of +31 ampere turns and the remaining cores in the matrix receive 0 ampere turns. These M.M.F. s result from the combined elTect of the

windings

13 and 14. The windings 13 On each of the cores in the columns driven by

coils

25, 26 and 23 will apply an of 3I to each of these cores. The currents applied to the driving coils 25, 26 and 28 will combine and all will flow through the coil 29. Thus a current of 31 will flow through the windings 14 on all of the-cores of the matrix. Due to the polarity of the windings 14, this current of 31 will apply an M.M.F. of +31 ampere turns to each of the cores in the matrix. This +31 ampere turns will precisely cancel out the -31 ampere-turns applied to the cores by

coils

25, 26 and 28. Thus these cores will receive a total of 0 ampere turns of M.M.F. The cores in the column of the driving coil 27 will receive a total of +3I ampere turns since coil 27 did not have any current applied thereto.

From Table III it will be observed thatonly the core connected to both the driving coils 27 and 22 will receive a MivtF. in such a direction as to vswitch it to its ONE state. All of the other cores will either receive no total M.M.E. or M.M.F. in such a direction to drive these cores toward their ZERO states Thus only the core left undriven by both the driving coils 22 and 27 will be switched to its ONE state and all the rest of the cores will remain in their ZERO states. Table III indicates that none of the cores have half currentsand therefore much better switching action is obtained.

Since the +31 ampere turns causing the switching is provided from three different drivers, each driver need only supply /3 the amount of power required.

To switch the selected core back to the ZERO state, a bias winding, which isnot shown, is used threading all the cores and a current applied to this winding would switch the selected core back to its ZERO state.

It will now be apparent from the description 10f the operation that the ratio of the turns of the windingslZ and .13 to that of the windings 14 must be at least N-l to 1, N being the number of columns in the matrix, if only the selected core is to have M.M.F. applied thereto in a direction to cause switching. Also to get the greatest M.M.F. applied to the selected core and still have no unselected cores having M.M.F.s applied thereto in a direction to cause switching, the ratio should be precisely N-l to 1. The polarity of windings 12 or the windings 1.3 may be'reversed but the windings 14 must have a polarity opposite to that of windings 13. If the

windings

13 or 12 are reversed, then negative pulses must be applied to the driving coils comprising the reversed windings.

In the embodiment as shown in FIGURE 2, the matrix is similar to the matrix shown in FIGURE 1 except that each core 11 has an additional winding 15 thereon and these windings 15 comprising a single turn are connected together in series to form a coil 30. The driving coils 21, 22, 23, and 24, instead of being connected to ground at one end, are connected together and to one: end of the coil 3t). The other end of the coil 30 is connected to ground. Also, the windings 12 and 13-each consist of 6 turns instead of 3. The windings 14 still consistof only one turn.

The operation of this matrix is like the operation of the matrix of FIGURE 1. All of the cores 11 start out in their ZERO states and one of the cores 11 will be selected and switched to its ONE state with the remaining cores staying in their ZERO states. To switch the selected core to its ONE state, three of the driving coils 21-24 and three of the driving coils 2528 have equal currents applied simultaneously thereto. The core at the intersection of those two driving coils which do notreceivc currents will then be switched to its ONE state. For example, assume that currents of I amperes are applied to all of the driving coils except 22 and 27. The M.M.F.s applied to each of the cores of the matrix, due to the currents applied to the driving coils 21, 23 and.24 is accordance with the position ofv" shown in Table IV in such core in the matrix as shown in FIGURE .2,

Table I V All of the cores in the rows threaded by the driving coils 21, 23 and 2.4 will receive M.M.F.s of -61 ampere turns from the windings 12. These M.M.F.s will be opposed by the M.M.F.s from the windings 15, which will receive the sum of the currents through the driving coils 21, 23 and 24. The current through the windings 15 will therefore be 31 and the windings 15 will therefore each apply an of +31 ampere turns to each of the cores 11. Thus the total applied to the cores in the rows driven by the driving coils 21, 23 and 24, as a result of the currents applied to these driving coils, will be -31 ampere turns. The cores in the row linked by the driving coil 22 will not receive any M.M.F.s from the windings 12 on these cores. The cores in this row will therefore each receive an of +31 as a result of the currents applied to the driving coils 21, 23 and 24. 3

In the same manner, the currents of I amperes applied to the driving coils 25, 26 and 28 will cause the cores in the columns driven by the driving coils 25, 26 and 28 to receive M.M.F.s of 31 ampere turns and the cores in the columns driven by the driving coil 27 to receive M.M.F.s of +31 ampere turns. The resulting M.M.F.s applied to the cores 11 of the matrix of FIGURE 2 caused by the currents applied to the driving coils 25, 26 and 28 is shown in Table V in accordance with the position of the cores in FIGURE 2.

Table V Table V1 is obtained by adding for each core the total M.M.F.s applied thereto as caused by the simultaneous application of currents of I amperes applied to the

row driving coils

21, 23 and 24 as shown in Table IV and the column driving coils 25, 26 and 28 as shown in Table V. From Table VI it will be seen that the only core that receives a plus is the core which is commonly driven by the driving coils 27 and 22, which do not have currents .applied thereto. This selected. core will receive a plus M.M.F. of 61. All the remaining cores in the matrix will receive zero total or a total of a minus 6I. Thus the selected core driven by the two driving coils which do not have currents applied thereto will be switched to its ONE state and the remaining cores will not be switched.

Since the +61 ampere turns causing the switching is provided from six different drivers, each driver need only supply the amount of power required.

From this description of the operation, it will be apparent that the ratio of the turns of the

windings

12 and 13 to the ratio of the

windings

14 and 15 must be M+N2 to l, N being the number of columns in the matrix and M being the number of rows in the matrix.

The polarity of the windings 12 may be reversed in which case the polarity of the windings 15 must be reversed and negative currents applied to the selected three of the driving coils 2124. Similarly, the polarity of the windings 13 may be reversed, in which case the polarity of the windings 14 must be reversed and negative currents must be applied to the selected three of the driving coils 25-28. The windings 15 must have a polarity to generate M.M.F.s in the opposite direction to the M.M.F.s generated by the windings 12 and the windings 14- must have a polarity to generate M.M.F.s in the opposite direction to the .M.M.F.s generated by the windings 13.

In both of the above embodiments of the invention the turns of the common coil or coils are such that when positive equal currents are applied to all but one of the row driving coils and to all but one of the comn driving coils, only one of the cores of the matrix will have plus M.M.F. generated therein.

The matrix has been disclosed as being positioned in columns and rows and this is the most convenient arrangement for winding the matrix. Actually, however, it is not necessary that the cores be positioned in this manner but it is only necessary that they have the same circuit as in the physical arrangement. Accordingly, in the claims the term electrically arranged shall not define the physical arrangement of the cores, but only the electrical grouping of the cores.

Many other modifications may be made to the above description of the invention without departing from the spirit and scope of the invention, which is limited only as defined in the appended claims.

What is claimed is:

1. A switching core matrix comprising a plurality of magnetic cores having two stable states of magnetization electrically arranged in columns and rows, a plurality of row driving coils each inductively coupled to all the cores of a different row, a plurality of column driving coils each inductively coupled to allthe cores of a different column, a common coil inductively coupled to all of the cores of said column driving coils and said row driving coils, means to add the currents simultaneously applied to said row coils into a single large current and to apply the single large current to said common coil, said column driving coils having a polarity to generate in said cores in one direction when positive currents are applied thereto, said common coil having a polarity to generate in said cores in the opposite direction when positive currents are applied to said column driving coils, said common coil comprising at least one winding on each of said cores having a number of turns such that when currents are applied to all but one of said column driving coils and all but one of said row driving coils, only one of said cores, said one of said cores being common to said row and said column of driving coils to which current is not applied, will have M.M.F. generated therein in said opposite direction.

.2. A switching core matrix comprising a plurality of magnetic cores having two stable states of magnetization electrically arranged in rows and columns, a plurality of row driving coils each inductively coupled to all of the cores of a different row, a plurality of column driving coils each inductively coupled to all of the cores of a diflerent column, a common coil inductively coupled to all of the cores of said matrix, said column driving coils having a polarity to generate M.M.F. in said cores in one direction when positive currents are applied thereto, means to add the current simultaneously applied to said column driving coils into a single large current and to apply said single large current to said common coil in a polarity to generate in said cores in the opposite direction from said one direction, means connecting said row driving coils together and to a reference potential at one end, said column driving coils each comprising windings on said cores, said common coil comprising a :winding on each of said cores, the-turns ratio of the windings comprising said column coils to the windings comprising said common coil being not greater than N-1, N being the number of columns in said matrix.

3. A switching core matrix comprising a plurality of magnetic cores having two stable states of magnetization electrically arranged in columns and rows, a plurality of row driving coils each inductively coupled to all of the cores of a different row of said matrix, a plurality of column driving coils each inductively coupled to all the cores of a different column of said matrix, a first comvmon coil inductively coupled to all of the cores of said matrix, means to add the currents applied simultaneously to said column driving coils into a single large current and apply said single large current to said first common coil in a polarity to generate in said cores in a direction opposite to that generated by said column driving coils, a second common coil inductively coupled to all the cores of said matrix, and means to add the currents simultaneously applied to said row driving coils into arsingle large current and to apply said last mentioned single large current to said second common coil in a polarity to generate M.M.F. in said cores in a direction opposite to that generated by said row driving coils, said first and second common coils each comprising at least one winding on each of said cores and said column driving coils and said row driving coils each comprising magnetization electrically arranged incolumns and rows, (2) a plurality of column driving coils each inductively coupled to all the cores of a different column, and (3) a plurality of row driving coils each inductively coupled to all of the cores ofatdiiferent row, the means for select- :ing one of said cores of the matrix and magnetizing the selected core in a predetermined direction, comprising means for simultaneously applying to all of said row driving coils except the one inductively coupled to said selected core and to all ofsaid column driving coils except the one inductively coupled to said selected core currents having a polarity to magnetize the cores coupled therewith in a direction opposite to said predetermined direction, and means for applying each of the currents applied :to said column driving coils to at least one winding on each of said cores in a polarity to generate M.M.F. in said predetermined direction simultaneously with the application, of the currents to, said driving coils.

No references cited.

Claims

2. A SWITCHING CORE MATRIX COMPRISING A PLURALITY OF MAGNETIC CORES HAVING TWO STABLE STATES OF MAGNETIZATION ELECTRICALLY ARRANGED IN ROWS AND COLUMNS, A PLURALITY OF ROW DRIVING COILS EACH INDUCTIVELY COUPLED TO ALL OF THE CORES OF A DIFFERENT ROW, A PLURALITY OF COLUMN DRIVING COILS EACH INDUCTIVELY COUPLED TO ALL OF THE CORES OF A DIFFERENT COLUMN, A COMMON COIL INDUCTIVELY COUPLED TO ALL OF THE CORES OF SAID MATRIX, SAID COLUMN DRIVING COILS HAVING A POLARITY TO GENERATE M.M.F. IN SAID CORES IN ONE DIRECTION WHEN POSITIVE CURRENTS ARE APPLIED THERETO, MEANS TO ADD THE CURRENT SIMULTANEOUSLY APPLIED TO SAID COLUMN DRIVING COILS INTO A SINGLE LARGE CURRENT AND TO APPLY SAID SINGLE LARGE CURRENT TO SAID COMMON COIL IN A POLARITY TO GENERATE M.M.F. IN SAID CORES IN THE OPPOSITE DIRECTION FROM SAID ONE DIRECTION, MEANS CONNECTING SAID ROW DRIVING COILS TOGETHER AND TO A REFERENCE POTENTIAL AT ONE END, SAID COLUMN DRIVING COILS EACH COMPRISING WINDINGS ON SAID CORES, SAID COMMON COIL COMPRISING A WINDING ON EACH OF SAID CORES, THE TURNS RATIO OF THE WINDINGS COMPRISING SAID COLUMN COILS TO THE WINDINGS COMPRISING SAID COMMON COIL BEING NOT GREATER THAN N-1, N BEING THE NUMBER OF COLUMNS IN SAID MATRIX.