Method and system for magnetizing elements in a magnetic field sensor arrangement

Abstract

A magnetic field sensor arrangement has a plurality of sensor segments, each having a plurality of magnetic field sensors. A magnetization current conductor is routed in the region of the magnetic field sensors such that the elements of the magnetic field sensors can be magnetized. A plurality of parallel-connected half-bridges each having high switches p J and low switches n J have a center tap connection arranged between the switches p J and n J . The magnetization current conductor is connected to each center tap connection, whereby the magnetization current conductor is divided into individually controllable magnetization segments. In a method for magnetizing elements of a magnetic field sensor arrangement, the elements of a sensor segment S J are magnetized by simultaneously closing two switches n J and p J+1 or optionally p J and n J+1 of two directly adjacent half-bridges, which are at different potentials. Here, at least one further switch n X<J or p Y>J+1 or alternatively p X<J or n Y>J+1 is closed.

Description

Technical Field

[0001] The present invention relates to a method and a system for magnetizing elements in a magnetic field sensor arrangement by means of a magnetization device. Background Technology

[0002] Magnetoresistive magnetic field sensors are known from the prior art. Such sensors have two magnetized layers arranged vertically and separated by a separating layer. Here, the average magnetization direction of the fixed layer (gepinnten Schicht) is fixed and cannot be changed in an external magnetic field, while the average magnetization direction of the free layer depends on the external magnetic field. By applying a voltage to the two magnetized layers, a current can flow, the current depending on the angle enclosed by the magnetization directions of the layers.

[0003] If the external magnetic field exceeds the critical field strength, the magnetization of the free layer may be disturbed. This misorientation can lead to increased noise in the magnetic field sensor, especially with larger magnetic field strengths. Furthermore, undesirable variations in the nullfield error (offset) may occur. For example, the misorientation can be reversed by placing a magnetizing current conductor in the region of the layer to be magnetized. Such methods are known, for example, from US 9,291,687 B2, US 9,791,523 B2, and US 9,766,301 B2.

[0004] Typically, multiple magnetic field sensors undergo this process simultaneously. Here, a magnetization device with multiple switches is used to magnetize the layer array of magnetic field sensors. When switching the switches, an unwanted current flow may occur in the magnetizing current conductor, flowing in the opposite direction to the desired magnetizing current due to parasitic capacitance. This can cause at least partially misorientation of the layer to be magnetized. Summary of the Invention

[0005] One object of the present invention is to describe an improved method for arranging elements for magnetizing magnetic field sensors and to provide an improved system for arranging elements for magnetizing magnetic field sensors. This object is achieved by a method for magnetizing elements for arranging magnetic field sensors by means of a magnetizing device, and a system for arranging elements for magnetizing magnetic field sensors, having features according to the invention. Advantageous extensions are described in the preferred embodiments.

[0006] In a method for magnetizing elements of a magnetic field sensor arrangement, these elements are magnetized using a magnetizing device. Here, the magnetic field sensor arrangement has multiple sensor segments. Each sensor segment has multiple magnetic field sensors. The magnetizing current conductors of the magnetizing device are arranged such that the elements of the magnetic field sensors can be magnetized. An implementation of the magnetizing device has multiple parallel-connected half-bridges, each half-bridge having a high switching p... J and low switch n J And each has a switch p J With n J The center tap connection is between the magnetizing current conductors. A magnetizing current conductor is connected to each center tap connection, thereby dividing the magnetizing current conductor into individually operable magnetization segments. Each magnetization segment is equipped with an element of a magnetic field sensor for magnetizing a separate sensor segment. The method has the following steps: First, a voltage is applied to the magnetizing device. Then, the sensor segment S... J The components are magnetized in the following way: two switches n of two directly adjacent half-bridges located at different potentials. J and p J+1 Or alternatively p J and n J+1 Simultaneously closed, thus corresponding magnetization segment M J A current is being applied. Here, at least one additional switch n... X<J or p Y>J+1 Or alternatively p X<J or n Y>J+1 closure.

[0007] Advantageously, closing at least one additional switch has the following effect: at least in another magnetized segment M of the magnetized current conductor X≠J To prevent current flow in undesirable directions due to parasitic capacitance. Therefore, at least one sensor segment S X≠J Protected because of at least one sensor segment S X≠J The element to be magnetized in the magnetic field sensor is not exposed to a magnetic field extending in an undesirable direction. Therefore, the element to be magnetized in the magnetic field sensor is not misoriented. Advantageously, this reduces the noise of the magnetic field sensor. In particular, noise characteristics can be improved for large magnetic field strengths. Furthermore, this method ensures that the magnetic field sensor does not exhibit undesirable variations in zero-field error. This also prevents undesirable gain variations, where the gain is the quotient of the change in the output signal and the change in the external magnetic field being measured.

[0008] In one implementation, in sensor segment S J During the magnetization of the component, all other switches n X<J and p Y>J+1 Or alternatively p X<J and nY>J+1 Simultaneously close. Advantageously, close all other switches n. X<J and p Y>J+1 Or alternatively p X<J and n Y>J+1 The following is achieved: in all additional magnetization segments M of the magnetized current conductor. X≠J In this way, it prevents current from flowing in the unwanted direction due to parasitic capacitance.

[0009] In one implementation, starting with the sensor segment located at the outermost end of the magnetizing current conductor, elements of successive sensor segments are magnetized sequentially along the magnetizing current conductor. Advantageously, this reduces the switching overhead in the method because it reduces the number of switching operations in each magnetization step.

[0010] In one implementation, in the magnetized sensor segment S J After the component and in the magnetized sensor segment S J+1 Before the component, disconnect switch p. J+1 Or alternatively n J+1 Advantageously, this introduces an intermediate step between the magnetization steps. This allows only one switch to be turned on or off in each step, thereby reducing circuit overhead in each step. Consequently, the occurrence of switching peaks that could cause undesirable current flow in each switching step is reduced.

[0011] In one embodiment, to magnetize the element of the first sensor segment S1 arranged at one end of the magnetizing current conductor, switch p2 or alternatively switch n2 is closed. In all remaining magnetization steps, switch p... J or n J It has already been closed in advance, i.e., in a previous switching step. In one embodiment, before magnetizing the elements of the first sensor segment S1, switch n1 is closed first, and then all switches p are closed. X>2 Alternatively, first close switch p1 and then close all switches n. X>2 In one implementation, the last sensor segment S is magnetized. N After the components are connected, first disconnect switch n. N And then switch p was disconnected. N+1 Alternatively, first disconnect switch p. N And then switch n was disconnected. N+1 Advantageously, these methods have the effect that the magnetizing device can be turned on or off in a particularly soft manner, i.e., the number of switching operations is reduced at the beginning or end of the method.

[0012] In one embodiment, the magnetic field sensor is configured as a free-layer ferromagnetic layer. In another embodiment, the magnetic field sensor is constructed as a TMR sensor or a GMR sensor.

[0013] A system for magnetizing elements of a magnetic field sensor arrangement includes a magnetic field sensor arrangement and a magnetization device. The magnetic field sensor arrangement has multiple sensor segments. Each sensor segment has multiple magnetic field sensors. The magnetization device has magnetizing current conductors. The magnetizing current conductors are arranged in such a manner within the region of the magnetic field sensors that the elements of the magnetic field sensors can be magnetized. The magnetization device has high-switching p values. J and low switch n J The multiple parallel-connected half-bridges each have a center tap connection arranged between the switches. A magnetizing current conductor is connected to each center tap connection, thereby dividing the magnetizing current conductor into individually operable magnetization segments. Each magnetization segment is equipped with an element for magnetizing a magnetic field sensor for a given sensor segment. The magnetization device has two additional switches p. AUX and n AUX Additional switch p AUX and n AUX Arranged at opposite ends of the magnetized current conductor and at the same potential as the switch p. J or n J Parallel connection. Additional switch p AUX and n AUX The switch is configured to remain closed when the element is arranged in the magnetized magnetic field sensor configuration. Advantageously, an additional switch is provided to ensure that the current flows in the desired direction along the magnetized current conductor. Attached Figure Description

[0014] The above features and advantages of the present invention become clearer and easier to understand in conjunction with the following description of the embodiments, which are illustrated in more detail with reference to the schematic diagrams. Hereinafter: Figure 1 The magnetic field sensor is shown in a three-dimensional view; Figure 2 The arrangement of the magnetic field sensor with magnetization device and the direction of the magnetizing current conductor of the magnetization device are shown. Figure 3 The arrangement of the magnetic field sensor and other components of the magnetization device are shown; Figure 4 A known method for arranging elements for a magnetizing magnetic field sensor is shown; Figure 5 Shown in magnetization according to Figure 4 The circuit diagram shows the magnetic field sensor components arranged in successive magnetization segments to control the current. Figure 6 A method is shown for arranging elements of a magnetic field sensor for magnetizing the magnetic field sensor arrangement; Figure 7 Shown in magnetization according to Figure 6 The circuit diagram shows the magnetic field sensor components arranged in successive magnetization sections for the current; and Figure 8 A system is shown for magnetizing a magnetic field sensor arrangement with an additional switch. Detailed Implementation

[0015] Figure 1 A magnetic field sensor 1 is schematically shown in a perspective view. The magnetic field sensor 1 is based, for example, on the principle of tunnel magnetoresistance (TMR). Therefore, the magnetic field sensor 1 can also be referred to as a TMR sensor 1.

[0016] The magnetic field sensor 1 has a substrate 2. For example, the substrate 2 may be made of silicon. However, the substrate 2 may also be made of other materials, such as other semiconductors and / or semiconductor oxides. The magnetic field sensor 1 also has an integrated circuit 3 disposed on the substrate 2. For example, the integrated circuit 3 may be configured to control the magnetic field sensor 1.

[0017] A lower contact element 4, electrically constructed, is disposed above the substrate 2. A lower ferromagnetic layer 5 is disposed on the lower contact element 4. The lower ferromagnetic layer 5 may, for example, be a ferromagnetic alloy, such as a CoFeB alloy or other ferromagnetic materials. An additional layer may also be disposed between the lower contact element 4 and the lower ferromagnetic layer 5. For example, an antiferromagnetic layer may also be provided. For example, the antiferromagnetic layer may be provided for pre-given magnetization within the lower ferromagnetic layer 5. For example, the antiferromagnetic layer may be a PtMn alloy or an IrMn alloy. Furthermore, an additional layer may be provided as a separation layer, which may be, for example, tantalum (Ta) and / or ruthenium (Ru).

[0018] An insulating layer 6 is disposed on the lower ferromagnetic layer 5. The insulating layer 6 may be made of, for example, manganese oxide (MgO) or aluminum oxide (Al2O3) or other electrically insulating materials. An upper ferromagnetic layer 7 is disposed on the insulating layer 6, which may also be made of, for example, a CoFeB alloy. An upper electrical contact element 8 is disposed on the upper ferromagnetic layer 7. An additional layer, such as a separation layer and / or other suitable layer, may also be disposed between the upper ferromagnetic layer 7 and the upper contact element 8.

[0019] If a voltage 9 is applied between the lower contact element 4 and the upper contact element 8, a tunneling current 10 can flow, which passes through the insulating layer 6. Here, the tunneling resistance depends on the magnetization of the lower ferromagnetic layer 5 and the upper ferromagnetic layer 7. More precisely, the tunneling resistance is proportional to the cosine of the angle between the average magnetization direction 11 of the lower ferromagnetic layer 5 and the average magnetization direction 12 of the upper ferromagnetic layer 7.

[0020] exist Figure 1 In the middle, the magnetization direction 11 of the lower ferromagnetic layer 5 is indicated by a solid arrow. Unless the critical magnetic field strength of the external magnetic field 13 is exceeded, the magnetization direction 11 of the lower ferromagnetic layer 5 is fixedly predetermined and cannot be changed within the external magnetic field 13. The external magnetic field 13... Figure 1 The middle section is symbolically shown in the form of a bar magnet. The magnetization direction 11 of the lower ferromagnetic layer 5 can be determined, for example, by means of an antiferromagnetic layer.

[0021] Another possibility for pre-defining and fixing the magnetization direction 11 of the lower ferromagnetic layer 5 is to heat the lower ferromagnetic layer 5 when an external magnetic field 13 is applied in the desired direction. The external magnetic field 13 is then turned off only after the lower ferromagnetic layer 5 has cooled. This process can also be called annealing. Since the magnetization direction 11 of the lower ferromagnetic layer 5 is unchangeable in the external magnetic field 13 as long as the critical magnetic field strength is not exceeded, the lower ferromagnetic layer 5 can also be called the fixed layer 5. If the critical magnetic field strength of the external magnetic field 13 is exceeded, the magnetization of the fixed layer 5 may be disturbed. In this case, re-annealing of the magnetization may not be possible because the integrated circuit 3 may be damaged during the annealing process. For the fixed layer 5, the critical magnetic field strength can be, for example, 40 mT.

[0022] The average magnetization direction 12 of the upper ferromagnetic layer 7 is in Figure 1 The upper ferromagnetic layer 7 is indicated by a dashed arrow. The magnetization direction 12 of the upper ferromagnetic layer 7 is not fixed compared to the lower ferromagnetic layer 5, and for this reason, it follows the external magnetic field 13 such that the magnetization direction 12 of the upper ferromagnetic layer 7 is oriented antiparallel to the component of the external magnetic field 13 projected onto the upper ferromagnetic layer 7. The upper ferromagnetic layer 7 can also be referred to as a free layer 7 because its magnetization direction 12 is not fixed. Within the scope of this specification, the upper ferromagnetic layer 7 is also referred to as a free layer 7, even though it does not yet have a preferred magnetization direction 12.

[0023] The tunneling resistance has a minimum value if the average magnetization direction of the lower ferromagnetic layer 5 is parallel to the average magnetization direction of the upper ferromagnetic layer 7. The tunneling resistance has a maximum value if the average magnetization direction of the lower ferromagnetic layer 5 is opposite to the average magnetization direction of the upper ferromagnetic layer 7. In this way, the magnetic field sensor 1 can detect the direction of the external magnetic field 13.

[0024] according to Figure 1 The magnetic field sensor 1 is configured, for example, as a TMR sensor. Alternatively, the magnetic field sensor 1 can also be configured as a GMR sensor (giant magnetoresistance). In this case, the ferromagnetic layers 5 and 7 are in lateral contact with the contact elements 4 and 8, allowing horizontal current flow relative to the substrate 2, whereas in the case of the TMR sensor, the tunneling current 10 flows vertically relative to the substrate 2. Furthermore, instead of an electrically insulating insulating layer 6, the GMR sensor has a non-magnetic insulating layer 6, which may, for example, be copper. However, the lower ferromagnetic layer 5, the insulating layer 6, and the upper ferromagnetic layer 7 are arranged vertically relative to each other relative to the substrate 2, as in the TMR sensor 1.

[0025] An externally applied magnetic field 13 exceeding the critical magnetic field strength for the magnetization of the free layer 7 (which could be, for example, 3000 μT) causes disturbance to the average magnetization direction 12 of the free layer 7. This is referred to as persistent misorientation of the free layer 7. Misorientation can lead to an undesirable change in the magnetic field sensor 1 having zero field error, i.e., a change in the offset between the magnetization direction 11 of the fixed layer 5 and the magnetization direction 12 of the free layer 7. Furthermore, misorientation of the free layer 7 can lead to undesirable changes in gain (i.e., the quotient of the change in tunnel resistance to the change in the external magnetic field 13).

[0026] The misorientation of the magnetization direction 12 of the free layer 7 can be compensated by generating a sufficiently strong external magnetic field 13 at the location of the free layer 7, which re-establishes the desired average magnetization direction 12 of the free layer 7. This is achieved by a magnetizing current conductor arranged in the region of the magnetic field sensor 1 such that the free layer 7 of the magnetic field sensor 1 can be magnetized by means of the magnetizing current conductor. This corrects or resets the misorientation or misalignment. Here, a current of, for example, 30 mA can be applied to the magnetizing current conductor, thereby achieving a magnetic field strength of, for example, 15 mT at the location of the free layer 7. Applying the magnetizing current conductor for, for example, a period of tens of nanoseconds may be sufficient to re-establish the magnetization of the free layer 7. This generation or reset of the magnetization of the free layer 7 can also be referred to as a "bit reset".

[0027] In accordance with the destination, it is generally not just the upper ferromagnetic layer 7 of a single magnetic field sensor 1 that is magnetized in the "position reset" category, but rather the multiple free layers 7 of multiple magnetic field sensors 1 of the magnetic field sensor arrangement 14 that are magnetized in the "position reset" category. Figure 2 An exemplary circuit is schematically shown, having a magnetic field sensor arrangement 14 and a magnetization device 15 for magnetizing the magnetic field sensor 1. The magnetization device 15 may, for example, be a component of an integrated circuit 3.

[0028] The magnetic field sensor arrangement 14 has four resistive segments 48. Each resistive segment 48 has multiple magnetic field sensors 1. For example, a single resistive segment 48 may have hundreds of magnetic field sensors 1. This could involve TMR sensors 1 or GMR sensors 1. For clarity, the magnetic field sensors 1 of the resistive segment 48 are not shown in the diagram. Figure 2 As shown in the diagram, each of the magnetic field sensor 1, each with a resistive segment 48, forms a resistance due to its corresponding tunnel resistance. For the desired effect, the resistances of the resistive segments 48 can be of the same magnitude. However, this is not strictly necessary. The four resistive segments 48 are electrically connected to each other in such a way that they form a Wheatstone bridge circuit. Two signal feed lines 47—one of which is arranged between the two series-connected resistive segments 48—make it possible to obtain the total signal of the magnetic field sensor arrangement 14 by obtaining the differential signal from the signals present at the two signal feed lines 47.

[0029] The magnetization device 15 has a magnetizing current conductor 17. The magnetizing current conductor 17 is arranged in such a direction within the region of the magnetic field sensor 1 that the elements of the magnetic field sensor 1 can be magnetized. The magnetizing current conductor 17 could ideally be arranged along all the magnetic field sensors 1. Ideally, the magnetizing current would also flow simultaneously along all the magnetic field sensors 1. However, this is not possible due to the relatively high resistance of the magnetizing current conductor 17, the limited operating voltage, and the high magnetizing current, thus requiring the magnetic field sensor 1 to be segmented into a resistive segment 48 and a sensor segment 16. The segmentation into sensor segment 16 is... Figure 3 The description is within the scope of the specification. Segmenting into resistor segments 48 is optional and not mandatory.

[0030] For example, the magnetizing current conductor 17 can be provided for magnetizing the free layer 7 of the magnetic field sensor 1 in the magnetic field sensor arrangement 14. Alternatively, the magnetizing current conductor 17 can be used to magnetize the lower ferromagnetic layer 5 or the fixed layer 5 of the magnetic field sensor 1. For this purpose, the magnetizing current conductor 17 must be arranged in the region of the lower ferromagnetic layer 5 such that the lower ferromagnetic layer 5 can be magnetized. In the following description, the magnetization of the upper ferromagnetic layer 7, which is provided as a free layer 7, is illustrated by way of example only. However, the following description can be similarly applied to the magnetization of the lower ferromagnetic layer 5 or the fixed layer 5.

[0031] Figure 3 Show Figure 2 The magnetic field sensor arrangement 14 and other components of the magnetization device 15. The magnetic field sensor arrangement 14 has multiple sensor segments 16. For example, Figure 2 The magnetic field sensor arrangement has a total of six sensor segments 16. However, the number of sensor segments 16 can be arbitrary. Each sensor segment 16 has multiple magnetic field sensors 1. For example, a sensor segment 16 can have hundreds of magnetic field sensors 1. Here, this could involve TMR sensors 1 or GMR sensors 1. For clarity, the magnetic field sensors 1 of the sensor segment 16 are not shown in the diagram. Figure 3 As shown in the diagram. Therefore, the number of sensor segments 16 does not necessarily correspond to the number of resistor segments 48. Any number of sensor segments 16 can be grouped into four resistor segments 48. For the desired purpose, the number of sensor segments 16 can be divisible by four so that four resistor segments 48 of the same size can be implemented as a Wheatstone bridge circuit. The magnetic field sensors 1 of the sensor segments 16 can, for example, be arranged separately on individual substrates 2 or on a common substrate 2. Individual substrates 2 can also be provided for any subset of the sensor segments 16. Accordingly, the magnetizing device 15 can be implemented on multiple substrates 2 and as part of multiple integrated circuits 3.

[0032] The magnetizing device 15 has a plurality of half-bridges 18 connected in parallel, each half-bridge having a high switching p J and low switch n J And each has a switch p J With n J The center tap connection 19 is between the points. The switch can be configured, for example, as a MOSFET (metal-oxide-semiconductor field-effect transistor). A magnetizing current conductor 17 is connected to each center tap connection 19, thereby dividing the magnetizing current conductor 17 into individually operable magnetization segments 20. Each magnetization segment 20 is provided with an element for magnetizing a magnetic field sensor 1 of one sensor segment 16. Since there are six sensor segments 16 in the exemplary embodiment, it is appropriate for the magnetizing device 15 to have a total of six magnetization segments 20. For this reason, in the illustrated exemplary embodiment, the magnetizing device 15 has a total of seven half-bridges 18, i.e., seven high-voltage switches p. J and seven low switches n J Switch p J n J It can be used as a means Figure 3The control device, not shown, can be constructed in a freely controllable manner. The characteristic of free control is that the sequence of switching processes can be arbitrarily selected. Each sensor segment 16 can be magnetized in this way by applying a voltage to the half-bridge 18 and applying a circuit diagram suitable for the purpose. The applied voltage can, for example, be in the range of 2V to 3V, but is not limited thereto. In principle, within the scope of this specification, the descriptions of values ​​or value ranges should not be construed as restrictive, but rather as descriptions on a suitable order of magnitude that allow those skilled in the art to practice the invention.

[0033] Figure 4 A switching scheme 21 is shown for the method of magnetizing the elements of the magnetic field sensor arrangement 14 by means of magnetization device 15. Switching scheme 21 is shown by way of example only for the magnetization of the elements of four sensor segments 16. However, the elements of each sensor segment 16 can be magnetized in the same type and manner. For this reason, only steps 22, 23, and 24 are described, within the scope of which a single but arbitrary sensor segment S J The components are magnetized. If the switch is open, i.e., in a non-conductive state, this... Figure 4 The symbol "0" indicates this. Conversely, if the switch is closed, i.e., in the conducting state, then this is indicated by... Figure 4 The number "1" is used to indicate this.

[0034] After applying voltage to the magnetization device 15, sensor segment S J The components are magnetized according to the following scheme. First, in the first step 22, switch n is closed. J Since all the other switches are open, no current is flowing yet. In step 23, switch p is additionally closed. J+1 Therefore, current flows through the magnetized segment M of the magnetized current conductor 17. J Thus, the magnetic field sensor is arranged in sensor segment S of 14. J The magnetic field sensor 1 is magnetized. In the third step 24, switch p is disconnected again. J+1 Thus, no current can flow again. Now, regarding the subsequent sensor segment S... J+1 Repeat steps 22, 23, and 24. Thus, the elements of sensor segment 16 are magnetized in sequence.

[0035] When magnetizing the elements of sensor segment 16, the current must always be applied in the desired direction. If this is not the case, the layers 5 and 7 to be magnetized may be at least partially and repeatedly magnetized along the preferred direction. Here, magnetization interference may be affected by random effects, which become apparent as unwanted additional noise at the output of magnetic field sensor 1.

[0036] Figure 5 The current diagram 25 is shown, in which time is plotted on the horizontal axis 26 and current is plotted on the vertical axis 27. The diagram shows the currents 28, 29, 30, and 31 of the four successive magnetized segments 20 of the magnetized current conductor 17 when the elements of the magnetized magnetic field sensor arrangement 14 are arranged.

[0037] A total of four consecutive current pulses 32 can be observed. Current pulses 32 occur when the four consecutive sensor segments 16 are magnetized. Current pulses 32 can occur within a time period of, for example, 10 ns and have an amplitude of, for example, 30 mA. Current pulses 32 occur such that the current flow is always in the desired direction 33. Figure 3 As shown in the figure. However, the polarity of the magnetizing device 15 can also be reversed, so that the current pulse 32 will occur in the opposite direction.

[0038] In addition to the expected current pulse 32, an additional pulse 34 appears. When transitioning to another magnetization segment 20, the additional pulse 34 appears in the magnetization segment M of the magnetized current conductor 17. J In the middle. Here, especially when the adjacent and subsequent magnetization segment M J+1 A current is applied to magnetize sensor segment S. J+1 When the element is magnetized, the magnetization segment M J The additional pulse 34 has a high amplitude. In the region of the rising edge 35 of the current pulse 32, the additional pulse 34 is negative, that is, it proceeds in the opposite direction 36, which also occurs in... Figure 3 This can lead to repeated magnetization of the element to be magnetized in the magnetic field sensor 1. Due to the electrical coupling of the magnetized segment 20 of the magnetizing current conductor 17, an additional current flows in the opposite direction 36. The electrical coupling of the magnetized segment 20 is inevitable due to space constraints. To overcome the electrical coupling, each magnetized segment 20 must have its own half-bridge 18. Two adjacent magnetized segments 20 will therefore not have a common half-bridge 18. However, this would require a significantly higher number of switches. For this reason, the magnetized segments 20 are constructed with electrical coupling. However, this causes parasitic capacitance 37 to act in the region of each magnetized segment 20. These cause reverse current flow. Therefore, in Figure 4 A disadvantage of the method or switching scheme 21 shown is that, within the scope of the second step 23 of the element of the magnetized sensor segment 16, reverse current flow may occur in the adjacent magnetized segment 20.

[0039] This invention is based on a concept that overcomes this drawback. Figure 6 Demonstrates magnetization using magnetization device 15 Figure 3A method 38 for arranging the elements of the magnetic field sensor 1 in the magnetic field sensor arrangement 14. Method 38 is performed in accordance with a switching scheme 39, which includes instructions for switching steps 101 to 115, within which the switch p of the magnetizing device 15 is switched after applying voltage to the magnetizing device 15 to magnetize the elements of each sensor segment 16. J and n J .

[0040] Sensor segment S J The components are magnetized by two switches n at different potentials in two directly adjacent half-bridges 18. J and p J+1 Or alternatively p J and n J+1 Simultaneously closed. Therefore, the corresponding magnetization segment M... J A current is applied, thus the sensor segment S J The magnetic field sensor 1 is magnetized. This is Figure 6 The situation following the third switching step 103, the fifth switching step 105, the seventh switching step 107, the ninth switching step 109, the eleventh switching step 111, and the thirteenth switching step 113. Furthermore, at least one additional switch n. X<J or p Y>J+1 Or alternatively p X<J or n Y>J+1 Closed. In Figure 6 In the exemplary embodiment, in the third switching step 103, the fifth switching step 105, the seventh switching step 107, the ninth switching step 109, the eleventh switching step 111, and the thirteenth switching step 113, all the other switches n X<J or p Y>J+1 Close. However, this is not necessary. Another switch n X<J or p Y>J+1 Closing one of the switches is sufficient. Closing at least one additional switch n is also necessary. X<J or p Y>J+1 This results in the magnetization segment M J (This magnetization section is for magnetizing sensor section S) J (The component is loaded with current) and another switch n X<J or p Y>J+1 There is no current flowing in the opposite direction 36 between them that can flow along the magnetized current conductor 17. If—as in the exemplary embodiment—all the other switches n X<J or p Y>J+1 If the circuit is closed, the reverse current cannot flow through the magnetized segment M. X≠J Flowing in any one of them. Thus, protecting all remaining sensor segments S. X≠JIt is protected from reverse current and therefore from misorienting magnetic fields. This is especially true because reverse current occurs particularly in the directly adjacent, pre-loaded magnetized segment M. J-1 (See also) Figure 5 What might be suitable for the objective is: only switch n. J-1 It is closed as an additional switch in order to effectively protect all magnetic field sensors 1 of the magnetic field sensor arrangement 14.

[0041] For example only, Figure 6 The diagram illustrates an element in which sensor segments 16, arranged at the outermost end of the magnetized current conductor 17, are sequentially magnetized along the conductor 17. However, this is not strictly necessary. The order in which the magnetized segments 20 are loaded with current can also be arbitrary. However, sequential magnetization offers the advantage of reducing the number of switching operations. This is especially true when the sensor segments 16 are sequentially magnetized along the current conductor 17 and all other switches are also magnetized. X<J or p Y>J+1 Or alternatively p X<J or n Y>J+1 Closing the switch in the corresponding switching steps 103, 105, 107, 109, 111, and 113 can reduce the number of switching operations.

[0042] In the magnetized sensor segment S J After the component and in the magnetized sensor segment S J+1 Before the component, switch p can be disconnected within the optional additional switching steps 104, 106, 108, 110, and 112. J+1 Or alternatively n J+1 Similarly, close at least one other switch n. X<J or p Y>J+1 Or alternatively p X<J or n Y>J+1 This is to prevent reverse current flow in at least one magnetization segment 20. The additional switching steps 104, 106, 108, 110, and 112 can also be omitted, but this provides the following advantages: only one switching operation needs to be performed between each switching step 103 and 113, that is, only one switch needs to be opened or closed, thereby reducing switching peaks.

[0043] To magnetize the element of the first sensor segment S1 located at one end of the magnetizing current conductor 17, switch p2 or alternatively switch n2 can be closed within the scope of the third switching step 103, i.e., the switch can be opened after the second switching step 102. Alternatively, before magnetizing the element of the first sensor segment S1, switch n1 can be closed first within the scope of the first switching step 101, and then all switches p2 can be closed within the scope of the second switching step 102. X>2 Alternatively, first close switch p1 and then close all switches n. X>2 Therefore, the state after the second switching step 102 is the same as the state after the fourth switching step 104. However, after the second switching step 102, switch p is closed. X>2 At least one of them or alternatively switch n X>2 At least one of them may be sufficient. The first switching step 101 and the second switching step 102 can also be interchanged. In summary, the first switching step 101 and the second switching step 102 provide the advantage that the magnetizing device 15 is particularly softly switched on with respect to the reverse current. However, the first switching step 101 and the second switching step 102 can also be omitted.

[0044] In the magnetization of the last sensor segment S N After the element, wherein in the exemplary embodiment N=6, switch n can be disconnected within the scope of the fourteenth switching step 114. N And then, in the scope of the fifteenth switching step 115, switch p is disconnected. N+1 Alternatively, first disconnect switch p. N And then switch n was disconnected. N+1 Therefore, the state after the fourteenth switching step 114 is the same as the state after the twelfth switching step 112. The fourteenth switching step 114 and the fifteenth switching step 115 have the advantage that the magnetizing device 15 is particularly softly shut off with respect to reverse current. The fourteenth switching step 114 and the fifteenth switching step 115 can also be interchanged. However, the fourteenth switching step 114 and the fifteenth switching step 115 can also be omitted.

[0045] Figure 7 A current graph 40 is shown, in which time is plotted on the horizontal axis 26 and current is plotted on the vertical axis 27. An example is shown where, according to... Figure 6 When using method 38 to magnetize the magnetic field sensor arrangement 14, Figure 3 The currents 41, 42, and 43 in the last three magnetization segments 20 of the magnetization current conductor 17 of the magnetization device 15.

[0046] The magnetic field sensor 1 elements in sensor segments S4, S5, and S6 are magnetized sequentially. According to... Figure 6After the thirteenth switching step 113, sensor segment S6 is magnetized. The corresponding current 41 of the magnetized segment M6 reaches its maximum after the thirteenth switching step 113. Similarly, the current 42 of the magnetized segment M5 reaches its maximum after the eleventh switching step 111, and the current 43 of the magnetized segment M4 reaches its maximum after the ninth switching step 109. The precise changes in currents 41, 42, and 43 can be traced based on Kirchhoff's laws. This will not be elaborated further here. In particular, Figure 7 As shown, Figure 6 The switching scheme 39 results in no negative magnetizing current flowing at any point in time. This provides the following advantage: the ferromagnetic layers 5 and 7 to be magnetized in the magnetic field sensor 1 are always magnetized in the desired direction.

[0047] Figure 6 An alternative to method 38 for magnetizing elements of magnetic field sensor arrangement 14 using magnetization device 14 is provided as a system 44 for magnetizing elements of magnetic field sensor arrangement 14, the system being... Figure 8 As shown in the diagram. System 44 has the same... Figure 3 The magnetic field sensor arrangement 14 has the same structure as the magnetic field sensor arrangement 14 and another magnetizing device 45. The other magnetizing arrangement 45 has the same structure as the magnetic field sensor arrangement 14. Figure 3 The magnetization arrangement 15 is extremely similar. In the following description, only the differences between magnetization devices 15 and 45 will be explained.

[0048] Another magnetizing device 45 has two additional switches p AUX and n AUX Additional switch p AUX and n AUX Arranged at opposite ends of the magnetizing current conductor 17 and at the same potential as the switch p J or n J Parallel connection. Additional switch p AUX and n AUX The device is configured to remain closed when the magnetized magnetic field sensor arrangement 14 is in place. Conversely, the additional switch p... AUX and n AUX exist Figure 8 Therefore, it is only shown as open so that it can be identified. The additional closed switch p AUX and n AUX This ensures that the current flow always occurs in the desired direction 33 and never in the opposite direction 36, thereby ensuring that the layers 5 and 7 to be magnetized in the magnetic field sensor 1 can always be magnetized in the desired direction. For example, system 44 enables... Figure 4 Switching scheme 21 or other switching schemes can be used for magnetization, while the reverse current that would interfere with the magnetization of ferromagnetic layers 5 and 7 cannot flow. Therefore, switch p is introduced. AUX and nAUX Additional overhead through Figure 4 A simpler switching scheme can be used for compensation.

[0049] In order to perform a "bit reset" in both directions 33 and 36, system 44 may have an additional switch P. AUX and N AUX These in Figure 7 The additional switch P is shown in dashed lines. AUX With additional switch n AUX Together, they form an additional half-bridge. An additional switch N... AUX With additional switch p AUX Together, they form another additional half-bridge. Therefore, it can be executed as follows. Figure 4 Method 21 or Figure 6 Method 38 allows the magnetizing current to flow in the opposite directions 33 and 36.

Claims

1. A method for magnetizing elements (5, 7) in a magnetic field sensor arrangement (14) using a magnetizing device (15), in, The magnetic field sensor arrangement (14) has multiple sensor segments (16). Each sensor segment (16) has multiple magnetic field sensors (1). In this arrangement, the magnetizing current conductor (17) of the magnetizing device (15) is arranged in the region of the magnetic field sensor (1) in such a manner that the elements (5, 7) of the magnetic field sensor (1) can be magnetized. The magnetizing device (15) has multiple parallel-connected half-bridges (18), each half-bridge having a high switching p. J and low switch n J And each has a switch p J With n J The central tap connection part (19) between them. The magnetized current conductor (17) is connected to each center tap connection (19), thereby dividing the magnetized current conductor (17) into individually operable magnetized segments (20). Each magnetization segment (20) is configured as the element (5, 7) of the magnetic field sensor (1) for magnetizing each of the sensor segments (16). The method comprises the following steps: - Apply voltage to the magnetizing device (15), - Magnetize the elements (5, 7) of each sensor segment (16). Among them, sensor segment S J The elements (5, 7) of (16) are magnetized by two switches n of two directly adjacent half-bridges (18) located at different potentials. J and p J+1 Or alternatively p J and n J+1 Simultaneously closed, thus corresponding magnetization segment M J (20) Current is applied, wherein at least one additional switch n X<J or p Y>J+1 Or alternatively p X<J or n Y>J+1 closure.

2. The method according to claim 1, wherein, In the sensor segment S J During the magnetization of the elements (5, 7) of (16), all the other switches n X<J and p Y>J+1 Or alternatively p X<J and n Y>J+1 Simultaneously closed.

3. The method according to any one of the preceding claims, wherein, Starting from the sensor segment (16) located at the outermost end of the magnetized current conductor (17), the elements (5, 7) of the successive sensor segments (16) are magnetized sequentially along the magnetized current conductor (17).

4. The method according to claim 3, wherein, In magnetizing the sensor segment S J (16) after the elements (5, 7) and in the magnetization sensor segment S J+1 Before the elements (5, 7) of (16) are connected, switch p is disconnected. J+1 Or alternatively disconnect switch n J+1 .

5. The method according to claim 3, wherein, In order to magnetize the element (5, 7) of the first sensor segment S1 (16) arranged at one end of the magnetizing current conductor (17), switch p2 is closed or alternatively switch n2 is closed.

6. The method according to claim 5, wherein, Before magnetizing the elements (5, 7) of the first sensor segment S1 (16), first close switch n1 and then close all switches p. X>2 Alternatively, first close switch p1 and then close all switches n. X>2 .

7. The method according to claim 3, wherein, In the magnetization of the last sensor segment S N After the elements (5, 7) of (16) are connected, the switch n is first disconnected. N And then switch p was disconnected. N+1 Alternatively, first disconnect switch p. N And then switch n was disconnected. N+1 .

8. The method according to claim 1 or 2, wherein, The ferromagnetic layer (7) of the magnetic field sensor (1) arranged in the magnetic field sensor arrangement (14) is magnetized, wherein the ferromagnetic layer (7) is set as a free layer (7).

9. The method according to claim 1 or 2, wherein, The magnetic field sensor (1) is constructed as a TMR sensor or a GMR sensor.

10. A system (44) for magnetizing elements (5, 7) in a magnetic field sensor arrangement (14). The system has a magnetic field sensor arrangement (14) and a magnetization device (15). in, The magnetic field sensor arrangement (14) has multiple sensor segments (16). Each sensor segment (16) has multiple magnetic field sensors (1). The magnetizing device (15) has a magnetizing current conductor (17). The magnetizing current conductor (17) is arranged in the region of the magnetic field sensor (1) in such a manner that the elements (5, 7) of the magnetic field sensor (1) can be magnetized. The magnetizing device (15) has a high switching p. J and low switch n J The multiple parallel-connected half-bridges (18) each have a center tap connection (19) arranged between the switches. The magnetized current conductor (17) is connected to each center tap connection (19), thereby dividing the magnetized current conductor (17) into individually operable magnetized segments (20). Each magnetization segment (20) is provided with the element (5, 7) of the magnetic field sensor (1) for magnetizing each sensor segment (16). The magnetizing device (15) has two additional switches p. AUX and n AUX , Wherein, the additional switch p AUX and n AUX Arranged at opposite ends of the magnetizing current conductor (17) and at the same potential as the switch p J or n J Parallel connection, Wherein, the additional switch p AUX and n AUX The magnetic field sensor arrangement (14) is configured to remain closed in the presence of elements (5, 7) that are magnetized.

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