Magnetoresistive sensor and associated manufacturing method

Abstract

The invention relates to a magnetoresistive sensor and an associated manufacturing method. A magnetoresistive sensor includes a bridge circuit having at least one magnetoresistive resistor, wherein the bridge circuit is designed to provide a first differential analog output voltage. The magnetoresistive sensor also includes an amplification circuit downstream of the bridge circuit, wherein the amplification circuit is designed to provide a second differential analog output voltage based on the first differential analog output voltage provided by the bridge circuit. Under the condition of non-zero preset magnetic field intensity, the second differential analog output voltage has a zero value. A common mode voltage assigned to the second differential analog output voltage corresponds to a preset percentage of a supply voltage of the bridge circuit.

Description

Technical Field

[0001] The present disclosure relates to a magnetoresistive sensor and a method for manufacturing a magnetoresistive sensor. Background Art

[0002] Magnetoresistive sensors can be used for various technical applications. For example, magnetoresistive sensors are used in miniaturized camera modules, which can be included in smartphones, for example. In this case, the target application can also be optical image stabilization, autofocus or optical zoom. Manufacturers and developers of magnetoresistive sensors are constantly striving to improve their products. In this context, it may also be of interest to provide sensors with stable and precisely defined operating parameters, such as the power consumption of the sensor. Summary of the invention

[0003] Different aspects relate to a magnetoresistive sensor. The magnetoresistive sensor comprises a bridge circuit having at least one magnetoresistive resistor, wherein the bridge circuit is designed to provide a first differential analog output voltage. The magnetoresistive sensor further comprises an amplifier circuit connected downstream of the bridge circuit, wherein the amplifier circuit is designed to provide a second differential analog output voltage based on the first differential analog output voltage provided by the bridge circuit. The second differential analog output voltage has a zero value at a non-zero preset magnetic field strength. A common mode voltage assigned to the second differential analog output voltage corresponds to a preset percentage of a supply voltage of the bridge circuit.

[0004] Different aspects relate to a method for producing a magnetoresistive sensor. The method includes generating a bridge circuit having at least one magnetoresistive resistor, wherein the bridge circuit is designed to provide a first differential analog output voltage. The method also includes generating an amplifier circuit connected downstream of the bridge circuit, wherein the amplifier circuit is designed to provide a second differential analog output voltage based on the first differential analog output voltage provided by the bridge circuit. The second differential analog output voltage has a zero value at a non-zero preset magnetic field strength. A common mode voltage assigned to the second differential analog output voltage corresponds to a preset percentage of a supply voltage of the bridge circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The device and method according to the present disclosure are explained in detail below with the aid of the accompanying drawings. Here, the same reference numerals may represent similar components. The features of the different examples shown may be combined with each other as long as they are not mutually exclusive, and / or if these features are not described as absolutely necessary, they may be selectively omitted.

[0006] Figure 1 1 shows a schematic diagram of a magnetoresistive sensor 100 according to the present disclosure,

[0007] Figure 2 2 shows a circuit diagram of a magnetoresistive sensor 200 according to the present disclosure,

[0008] Figure 3 shows a curve of the output voltage of the magnetoresistive sensor according to the present disclosure,

[0009] Figure 4 shows a curve of a differential analog output voltage of a magnetoresistive sensor according to the present disclosure,

[0010] Figure 5 Schematically illustrates a cross-sectional side view of a magnetoresistive sensor 500 according to the present disclosure,

[0011] Figure 6 shows a schematic diagram of a magnetoresistive sensor 600 according to the present disclosure,

[0012] Figure 7 A flow chart of a method for manufacturing a magnetoresistive sensor according to the present disclosure is shown. DETAILED DESCRIPTION

[0013] The magnetoresistive sensors described herein can be used for different technical applications. In a non-limiting example, magnetoresistive sensors can be used in miniaturized camera modules, which can be included in smartphones, for example. The latest technology in this field is based on actuator systems consisting of coils, magnets and sensors. Such systems can detect positions, distances and angles and use the measured data to appropriately move system components, such as optical lenses. In this case, the target application can also be optical image stabilization, autofocus or optical zoom.

[0014] Figure 1 The magnetoresistive sensor 100 is shown and described in simplified form in order to qualitatively illustrate various aspects of the present disclosure. The magnetoresistive sensor 100 can be expanded with one or more of the aspects described herein, such as in combination with Figure 2 Have a discussion.

[0015] The magnetoresistive sensor 100 may include a bridge circuit 2 having at least one magnetoresistive resistor. Figure 1 In the simplified diagram of FIG. 1 , only the structure of the bridge circuit 2 is shown qualitatively. The bridge circuit 2 can be designed to provide a first differential analog output voltage 4. The magnetoresistive sensor 100 can also have an amplifier circuit 6 connected to the bridge circuit 2. The amplifier circuit 6 can be designed to provide a second differential analog output voltage 8 based on the first differential analog output voltage 4 provided by the bridge circuit 2. In the case of a non-zero preset magnetic field strength, the second differential analog output voltage 8 can have a zero value. In addition, the common mode voltage assigned to the second differential analog output voltage 8 can correspond to a preset percentage of the power supply voltage of the bridge circuit 2.

[0016] Figure 2 The magnetoresistive sensor 200 can be viewed as Figure 1A more detailed version of the magnetoresistive sensor 100. Therefore, Figure 1 The magnetoresistive sensor 100 can be Figure 2 Expands on one or more aspects described in . Figure 2 The magnetoresistive sensor 200 may include a bridge circuit 2, a first differential amplifier 10A, a first summing amplifier 12A, a second differential amplifier 10B, and a second summing amplifier 12B. The aforementioned components may be connected to each other, such as Figure 2 As shown. Return Figure 1 For example, Figure 2 The differential amplifiers 10A, 10B and the summing amplifiers 12A, 12B can form Figure 1 Amplifier circuit 6.

[0017] The bridge circuit 2 may have four resistors 14A to 14D and four nodes 16A to 16D. The bridge circuit 2 may be connected to the power supply voltage V via nodes 16A and 16C. DD In particular, the total supply voltage V DD The bridge circuit 2 may drop. The bridge circuit 2 may be designed to output a first voltage signal at the node 16B and a second voltage signal at the node 16D. Therefore, a differential analog output voltage may be intercepted or measured at the two nodes 16B and 16D. The differential output voltage may represent the magnetic field strength present at the location of the bridge circuit 2 (or the magnetic flux present there).

[0018] In the example shown, the bridge circuit 2 may correspond to a Wheatstone bridge circuit. However, it should be noted that Figure 2 The Wheatstone bridge circuit 2 is exemplary and may be replaced by another half-bridge circuit or bridge circuit as long as it is designed to provide a differential analog output voltage representative of the magnetic field strength present at the location of the bridge circuit 2 .

[0019] At least one of the resistors 14A to 14D may be a magnetoresistive resistor. In the example shown, the bridge circuit 2 may have four magnetoresistive resistors 14A to 14D. The magnetoresistive resistors 14A to 14D are not limited to a specific sensor technology. In the example shown, the magnetoresistive resistors 14A to 14D may be TMR (tunnel magnetoresistive) resistors. In other examples, the magnetoresistive resistors 14A to 14D may also be implemented differently, for example as AMR (anisotropic magnetoresistive) resistors or GMR (giant magnetoresistive) resistors. Subsequently, for simplicity, only TMR resistors are discussed. However, it should be noted that the following considerations may also be transferred to other xMR resistors.

[0020] Each TMR resistor 14A to 14D can have two ferromagnetic layers separated by a non-magnetic insulating tunnel barrier. One of the two ferromagnetic layers can correspond to a free layer, having a magnetization direction that can rotate freely in a magnetic field to be measured. The other ferromagnetic layer can correspond to a fixed layer (or pinned layer), having a fixed reference magnetization that does not rotate when it is in a magnetic field to be measured. If the magnetization directions of the two ferromagnetic layers are parallel to each other, the resistance of the tunnel barrier is very low. On the contrary, if the magnetization directions are antiparallel, the resistance is very high. Therefore, the magnetoresistive sensor 200 can convert the magnetic field to be measured into an electrical signal based on the TMR effect, in which the resistance changes as a response to the magnetic field due to the change in the angle of the free layer relative to the fixed layer.

[0021] In the case shown, the bridge circuit 2 can correspond to a Wheatstone bridge circuit by way of example, which can have opposite or antiparallel sensitivity directions (or preferred directions) in each bridge branch. Here, the sensitivity direction can be described as the direction in which the magnetic field can be measured with the greatest possible sensitivity. The four resistors 14A to 14D can have the same nominal resistance absolute value and form two bridge branches, which have resistors 14A and 14D connected in series and resistors 14B and 14C connected in parallel therewith. Resistors 14A and 14C can have the same sensitivity direction, while resistors 14B and 14D can have a sensitivity direction that is offset 180° therefrom. An external magnetic field oriented in the sensitivity direction of resistors 14B and 14D can cause the resistance in resistors 14B, 14D to be minimized and the resistance in resistors 14A, 14C to be maximized, thereby generating a maximum or minimum output signal of the bridge circuit 2.

[0022] In a specific example, the resistors 14A to 14D of the bridge circuit 2 may be of the same structure. In other words, the resistors 14A to 14D may be based on the same or at least similar architecture. Therefore, the resistors 14A to 14D may have the same or at least similar temperature coefficients. Due to the similar temperature coefficients, measurement errors due to temperature fluctuations may be avoided.

[0023] The two differential amplifiers 10A and 10B can be powered by power supply voltages V DD The first differential amplifier 10A may include an operational amplifier 18, which may be connected to resistors 20A to 20D, such as Figure 2As shown. The first differential amplifier 10A can be designed to receive a voltage signal output at a node 16D of the bridge circuit 2 at the inverting input of the operational amplifier 18. The voltage V1 can be present at the non-inverting input of the operational amplifier 18. The second differential amplifier 10B can be constructed similarly to the first differential amplifier 10A and have the same or at least similar components. The second differential amplifier 10B can be designed to receive a second voltage signal output at a node 16B of the bridge circuit 2 at the inverting input of its operational amplifier 18. Each of the two differential amplifiers 10A and 10B can be designed to provide a processed output signal at its output.

[0024] The two summing amplifiers 12A and 12B can be respectively connected to the power supply voltage V DD The first summing amplifier 12A may be connected to the first differential amplifier 10A and may include an operational amplifier 18, which may be connected to resistors 20A to 20C, such as Figure 2 As shown. The first summing amplifier 12A can be designed to receive a voltage signal output by the first differential amplifier 10A at the inverting input of the operational amplifier 18. The non-inverting input of the operational amplifier 18 can be grounded. A voltage V2 can exist at the input resistor 20B. The second summing amplifier 12B can be constructed similarly to the first summing amplifier 12 and have the same or at least similar components. The second summing amplifier 12B can be designed to receive a voltage signal output by the second differential amplifier 10B at the inverting input of its operational amplifier 18. Each of the two summing amplifiers 12 can be designed to provide a voltage signal at its output.

[0025] During operation of the magnetoresistive sensor 200, a magnetic field present at the location of the bridge circuit 2 or at the location of the resistors 14A to 14D can be detected by the bridge circuit 2. A differential analog voltage representing the detected magnetic field can be provided at the two nodes 16B and 16D of the bridge circuit 2. Here, a first voltage signal can be provided at the node 16D and fed into the first differential amplifier 10A connected downstream. In a similar manner, the second voltage signal provided at the node 16B can be fed into the second differential amplifier 10B connected downstream.

[0026] The voltage signal fed into the differential amplifiers 10A and 10B can be processed by the differential amplifiers 10A and 10B, wherein each differential amplifier 10A and 10B can output a processed voltage signal at its output 22. Therefore, a differential analog voltage can be provided at the output 22 of the two differential amplifiers 10A and 10B. The resistances 20A to 20D and the voltage V1 of the two differential amplifiers 10A and 10B can be selected so that the differential analog voltage can have a zero value in the case of a preset or defined intensity of the magnetic field detected by the bridge circuit 2. In other words, by means of processing by the two differential amplifiers 10A and 10B, the differential analog voltage having a non-zero value provided at the nodes 16B and 16D of the bridge circuit 2 can be transformed to a zero value. In a non-limiting case, the differential analog voltage provided at the output 22 of the two differential amplifiers 10A and 10B can have a zero value, for example, in the case of a magnetic field intensity of about 47mT. However, it should be noted that in other examples, the preset value may be defined or selected arbitrarily differently as needed.

[0027] The voltage signals output at the output terminals 22 of the two differential amplifiers 10A and 10B can be fed into the subsequent summing amplifiers 12A and 12B and processed by them. The first voltage signal V processed by the first summing amplifier 12A p can be provided at its output 22 or at the output 24 of the magnetoresistive sensor 200. In a similar manner, the second voltage signal V processed by the second summing amplifier 12B is n It can be provided at its output terminal or the second output terminal 24 of the magnetoresistive sensor 200. Therefore, the differential analog output voltage V can be intercepted at the output terminal 24 of the magnetoresistive sensor 200. p -V n .

[0028] Assigned to the differential output voltage V p -V n The common mode voltage V CM Can be based on The resistors 20A to 20C and the voltage V2 of the two summing amplifiers 12A and 12B can be selected so that the differential output voltage V p -V n The associated common-mode voltage V CM Corresponding to the power supply voltage V DD In a non-limiting case, the preset percentage may be an exemplary and non-limiting value of about 70%, i.e., it may be applicable that V CM ≈0.7 V DD However, it should be noted that in other examples, the preset value may be defined or selected arbitrarily differently as needed.

[0029] In summary, therefore, by means of signal processing through two differential amplifiers 10A, 10B and two summing amplifiers 12A, 12B, the differential analog output voltage output by the bridge circuit 2 can be converted into a common mode voltage V having a zero value under a non-zero preset magnetic field strength and a CM Corresponding to the power supply voltage V DD The differential analog output voltage is a preset percentage of the differential analog output voltage. Therefore, through the characteristics of the two differential amplifiers 10A, 10B and the two summing amplifiers 12A, 12B, the desired magnetic zero point and the desired common mode voltage can be set in a simple manner. In the example shown, the summing amplifiers 12A and 12B are connected after the differential amplifiers 10A and 10B. In other examples, the resistances of the amplifiers and the voltages V1, V2 can be adjusted in the following way, that is, the order of the differential amplifiers and the summing amplifiers can be exchanged.

[0030] The technical effects described later can be provided by the magnetoresistive sensor according to the present disclosure. Based on this, the magnetoresistive sensor according to the present disclosure can exceed the conventional magnetoresistive sensor in different aspects.

[0031] In order to be able to provide stable and precisely defined operating parameters of the magnetoresistive sensor, specific requirements on the sensor may have to be met. The operating parameter may be, for example, the power consumption of the sensor or the differential analog output voltage. According to a first exemplary requirement, the differential analog output voltage of the sensor should be zero at a preset magnetic field strength. According to a second exemplary requirement, the common mode voltage of the sensor should correspond to a preset percentage of the supply voltage. As described above, the magnetoresistive sensor according to the present disclosure can meet these requirements in a simple and effective manner, and thus contributes to providing stable and precisely defined operating parameters of the sensor.

[0032] According to the present disclosure, the mentioned requirements can be met in particular based on a bridge circuit with four identical resistors. In contrast, conventional sensors may require more than four resistors for this purpose. In the example, a fifth resistor connected in series with the bridge circuit can be used in conventional sensors for this purpose. However, in this case, the fifth resistor may consume part of the supply voltage in a disadvantageous manner. In contrast, in the sensor according to the present disclosure, the total supply voltage may drop at the bridge circuit. This means that the total supply voltage can be used for the measurement sensitivity of the sensor, thereby providing an improved measurement sensitivity compared to conventional sensors.

[0033] Other conventional sensors can only meet the above requirements by means of a bridge circuit with four different resistors. The different resistors may have different temperature coefficients, which may lead to measurement errors in the event of temperature fluctuations. In contrast, such measurement errors can be avoided in the magnetoresistive sensor according to the present disclosure, because all four resistors of the bridge circuit can have the same or at least similar structure.

[0034] Figure 3 shows the output voltage V of the magnetoresistive sensor according to the present disclosure p and V n Here, the output voltage in mV is applied relative to the magnetic flux or magnetic field strength (in mT) at the location of the bridge circuit of the magnetoresistive sensor. The magnetoresistive sensor can be, for example, Figure 2 The magnetoresistive sensor 200. Figure 3 It can be seen that the output voltage V p and V n It is possible to have a linear curve with a positive or negative slope.

[0035] Figure 4 FIG. 1 shows an exemplary curve of the differential analog output voltage of the magnetoresistive sensor according to the present disclosure. Here, the differential analog output voltage V in mV is DOUT =V p -V n The magnetic flux or magnetic field strength (in mT) relative to the location of the bridge circuit of the magnetoresistive sensor is applied. Figure 4 It can be seen that the differential analog output voltage V DOUT The magnetoresistive sensor may have a linear curve with a positive slope. The magnetoresistive sensor may be a linear sensor. In particular, the magnetoresistive sensor according to the present disclosure may be a linear in-plane sensor. Under a preset value of the magnetic field strength, the differential output voltage V DOUT Can have a value of zero. In the example shown, the preset magnetic field strength can have an exemplary and non-limiting value of about 47 mT. In other examples, the preset value can be defined or selected arbitrarily differently as needed.

[0036] Figure 5 An exemplary structure of a magnetoresistive sensor according to the present disclosure is shown. Figure 5 The layer structure shown is qualitative and simplified. It should be noted that the magnetoresistive sensor 500 may have additional layers and components, which are not shown in the figure for simplicity. Figure 5 The magnetoresistive sensor 500 may have one or more characteristics of the magnetoresistive sensor described previously. In contrast, the magnetoresistive sensor described previously may be based on Figure 5 The structure shown is manufactured.

[0037] Magnetoresistive sensor 500 may have semiconductor material 26, analog circuitry 28, metal layer 30, and layer 32 with one or more magnetoresistive stacks 34. Figure 5 As shown by way of example, the above-mentioned components can be arranged one above the other. The semiconductor material 26 can be selected arbitrarily and in particular corresponds to silicon or comprises silicon. On the upper side of the semiconductor material 26, an analog circuit 28 can be integrated into the semiconductor material 26. In the example, the analog circuit 28 can be Figure 1 In another example, the analog circuit 28 may include Figure 2 Differential amplifiers 10A, 10B and summing amplifiers 12A, 12B.

[0038] Multiple magnetoresistive resistors may be formed in layer 32 or magnetoresistive stack 34, and the magnetoresistive resistors may form a bridge circuit. For example, the bridge circuit formed may correspond to Figure 2 The electrical connection between the magnetoresistive resistors and / or the electrical connection between the formed bridge circuit and the analog circuit 28 may be provided at least in part by the metal layer 30.

[0039] The magnetoresistive stack 34 may be at least partially arranged above the analog circuit 28. When viewed in the z-direction, the analog circuit 28 and the magnetoresistive stack 34 may at least partially (or completely) overlap. In particular, the entire analog circuit 28 may be arranged below the layer 32 having the magnetoresistive stack 34, i.e., when viewed in the z-direction, the base surface of the analog circuit 28 may be completely contained within the base surface of the layer 32 or the base surface of the magnetoresistive layout. Therefore, the analog circuit 28 may be implemented without additional area consumption of the semiconductor material 26.

[0040] Figure 6 The magnetoresistive sensor 600 may have one or more characteristics of the previously described magnetoresistive sensor. In addition to the above-mentioned components, the magnetoresistive sensor 600 may also have a compensation circuit, which may be designed to compensate for the influence of temperature or temperature changes and / or mechanical stress on the first differential analog output voltage 4 and / or the second differential analog output voltage 8. In the example shown, for simplicity, the compensation circuit is not explicitly shown. Instead, two arrows are shown, which should represent the influence of mechanical stress and temperature or temperature changes. The two arrows can also be regarded as measurement signals representing mechanical stress and temperature or temperature changes, based on which the compensation circuit can compensate for the influence of mechanical stress and temperature or temperature changes.

[0041] Figure 7 A flow chart of a method for manufacturing a magnetoresistive sensor according to the present disclosure is shown. For example, the method can be used to manufacture each magnetoresistive sensor described herein according to the present disclosure. Therefore, the method can be read in conjunction with each of the previous figures.

[0042] In block 36, a bridge circuit having at least one magnetoresistive resistor may be generated. The bridge circuit may be configured to provide a first differential analog output voltage. In block 38, an amplifier circuit may be generated that is connected to the bridge circuit. The amplifier circuit may be configured to provide a second differential analog output voltage based on the first differential analog output voltage provided by the bridge circuit. In the case of a non-zero preset magnetic field strength, the second differential analog output voltage may have a zero value. A common mode voltage assigned to the second differential analog output voltage may correspond to a preset percentage of a supply voltage of the bridge circuit.

[0043] Example

[0044] A magnetoresistive sensor and a related manufacturing method according to the present disclosure are subsequently described by means of examples.

[0045] Example 1 is a magnetoresistive sensor, comprising: a bridge circuit having at least one magnetoresistive resistor, wherein the bridge circuit is designed to provide a first differential analog output voltage; and an amplifier circuit connected to the bridge circuit, wherein the amplifier circuit is designed to provide a second differential analog output voltage based on the first differential analog output voltage provided by the bridge circuit, wherein under a non-zero preset magnetic field strength, the second differential analog output voltage has a zero value, and wherein a common-mode voltage assigned to the second differential analog output voltage corresponds to a preset percentage of a power supply voltage of the bridge circuit.

[0046] Example 2 is a magnetoresistive sensor according to Example 1, wherein the bridge circuit includes four magnetoresistive resistors.

[0047] Example 3 is a magnetoresistive sensor according to example 1 or 2, wherein at least one magnetoresistive resistor of the bridge circuit is a TMR resistor.

[0048] Example 4 is a magnetoresistive sensor according to one of the foregoing examples, wherein the resistors of the bridge circuits are structurally identical.

[0049] Example 5 is a magnetoresistive sensor according to one of the aforementioned examples, wherein the amplification circuit includes: at least one differential amplifier, the at least one differential amplifier is designed to provide a differential analog output voltage based on a non-zero differential analog voltage provided to the at least one differential amplifier, and the differential analog output voltage has a zero value under a preset magnetic field strength; and at least one summing amplifier, the at least one summing amplifier is designed to provide a differential analog output voltage based on the differential analog voltage provided to the at least one summing amplifier, and the associated common-mode voltage of the differential analog output voltage corresponds to a preset percentage of the power supply voltage.

[0050] Example 6 is a magnetoresistive sensor according to Example 5, wherein at least one summing amplifier is connected after at least one differential amplifier.

[0051] Embodiment 7 is a magnetoresistive sensor according to one of embodiments 1 to 4, wherein the amplification circuit includes: a first differential amplifier and a first summing amplifier, the first differential amplifier and the first summing amplifier are connected in series and are designed to output a first processed voltage signal based on a first voltage signal output by a bridge circuit, and a second differential amplifier and a second summing amplifier, the second differential amplifier and the second summing amplifier are connected in series and are designed to output a second processed voltage signal based on a second voltage signal output by the bridge circuit.

[0052] Example 8 is a magnetoresistive sensor according to one of the foregoing examples, wherein the preset magnetic field strength is approximately 47 mT.

[0053] Example 9 is a magnetoresistive sensor according to one of the preceding examples, wherein the preset percentage is approximately 70%.

[0054] Example 10 is a magnetoresistive sensor according to one of the preceding examples, wherein the total supply voltage is dropped at the bridge circuit.

[0055] Example 11 is a magnetoresistive sensor according to one of the aforementioned examples, comprising: a semiconductor material, wherein an amplification circuit is integrated into the semiconductor material; and a magnetoresistive stack arranged above the amplification circuit, wherein, when viewed in a direction perpendicular to the magnetoresistive stack, the amplification circuit and the magnetoresistive stack at least partially overlap.

[0056] Example 12 is a magnetoresistive sensor according to one of the aforementioned examples, which further includes: a compensation circuit connected to the bridge circuit, the compensation circuit being designed to compensate for the influence of temperature and / or mechanical stress on the first differential analog output voltage or the second differential analog output voltage.

[0057] Example 13 is a magnetoresistive sensor according to one of the preceding examples, wherein the magnetoresistive sensor is a linear in-plane sensor.

[0058] Example 14 is a magnetoresistive sensor according to one of the preceding examples, wherein the magnetoresistive sensor is designed to be integrated into a camera module of a smartphone.

[0059] Example 15 is a method for manufacturing a magnetoresistive sensor, wherein the method includes: generating a bridge circuit having at least one magnetoresistive resistor, wherein the bridge circuit is designed to provide a first differential analog output voltage; and generating an amplifier circuit connected to the bridge circuit, wherein the amplifier circuit is designed to provide a second differential analog output voltage based on the first differential analog output voltage provided by the bridge circuit, wherein under a non-zero preset magnetic field strength, the second differential analog output voltage has a zero value, and wherein a common-mode voltage assigned to the second differential analog output voltage corresponds to a preset percentage of a power supply voltage of the bridge circuit.

[0060] Although specific embodiments are shown and described herein, it will be apparent to those skilled in the art that multiple alternative and / or equivalent implementations may replace the specific embodiments shown and described without departing from the scope of the present disclosure. This application should cover all adjustments or variations of the specific embodiments discussed herein. It is therefore intended that the present disclosure be limited only by the claims and their equivalents.

Claims

1. A magnetoresistive sensor, comprising: A bridge circuit (2) having at least one magnetoresistive resistor (14), wherein the bridge circuit (2) is designed to provide a first differential analog output voltage (4); and an amplifier circuit (6) connected downstream of the bridge circuit (2), wherein the amplifier circuit (6) is configured to provide a second differential analog output voltage (8) based on the first differential analog output voltage (4) provided by the bridge circuit (2), wherein in the case of a non-zero preset magnetic field strength, the second differential analog output voltage (8) has a zero value, and The common mode voltage associated with the second differential analog output voltage (8) corresponds to a predetermined percentage of the power supply voltage of the bridge circuit (2).

2. The magnetoresistive sensor according to claim 1, wherein: The bridge circuit (2) includes four magnetoresistive resistors (14A-14D).

3. The magnetoresistive sensor according to claim 1 or 2, wherein: At least one magnetoresistive resistor (14) of the bridge circuit (2) is a TMR resistor.

4. A magnetoresistive sensor according to any one of the preceding claims, wherein: The resistors (14A-14D) of the bridge circuit (2) have the same structure.

5. A magnetoresistive sensor according to any one of the preceding claims, wherein: The amplifier circuit (6) comprises: at least one differential amplifier (10), the at least one differential amplifier being configured to provide a differential analog output voltage based on a non-zero differential analog voltage supplied to the at least one differential amplifier (10), the differential analog output voltage having a zero value under the condition of the preset magnetic field strength; and At least one summing amplifier (12) is configured to provide a differential analog output voltage based on a differential analog voltage provided to the at least one summing amplifier (12), the differential analog output voltage having an associated common mode voltage corresponding to a preset percentage of the supply voltage.

6. The magnetoresistive sensor according to claim 5, wherein the at least one summing amplifier (12) is connected downstream of the at least one differential amplifier (10).

7. The magnetoresistive sensor according to any one of claims 1 to 4, wherein the amplification circuit (6) comprises: a first differential amplifier (10A) and a first summing amplifier (12A), the first differential amplifier and the first summing amplifier being connected in series and being designed to output a first processed voltage signal based on a first voltage signal output by the bridge circuit (2), and A second differential amplifier (10B) and a second summing amplifier (12B) are connected in series and are designed to output a second processed voltage signal based on a second voltage signal output by the bridge circuit (2).

8. A magnetoresistive sensor according to any one of the preceding claims, wherein: The preset magnetic field strength is about 47 mT.

9. A magnetoresistive sensor according to any one of the preceding claims, wherein: The preset percentage is approximately 70%.

10. A magnetoresistive sensor according to any one of the preceding claims, wherein: The total power supply voltage drops at the bridge circuit (2).

11. A magnetoresistive sensor according to any one of the preceding claims, comprising: Semiconductor material (26), wherein the amplification circuit (6, 28) is integrated into the semiconductor material (26); and a magnetoresistive stack (34) arranged above the amplifying circuit (6, 28), Wherein, when viewed in a direction perpendicular to the magnetoresistive stack (34), the amplifying circuit (6, 28) and the magnetoresistive stack (34) at least partially overlap.

12. The magnetoresistive sensor according to any one of the preceding claims, further comprising: A compensation circuit is connected to the bridge circuit (2), and the compensation circuit is designed to compensate for the influence of temperature and / or mechanical stress on the first differential analog output voltage (4) or the second differential analog output voltage (8).

13. The magnetoresistive sensor according to any one of the preceding claims, wherein the magnetoresistive sensor is a linear in-plane sensor. 14 . The magnetoresistive sensor according to claim 1 , wherein the magnetoresistive sensor is designed to be integrated into a camera module of a smartphone.

15. A method for manufacturing a magnetoresistive sensor, wherein the method comprises: Producing a bridge circuit (2) having at least one magnetoresistive resistor (14), wherein the bridge circuit (2) is designed to provide a first differential analog output voltage (4); and generating an amplifier circuit (6) connected to the bridge circuit (2), wherein the amplifier circuit (6) is designed to provide a second differential analog output voltage (8) based on the first differential analog output voltage (4) provided by the bridge circuit (2), wherein in the case of a non-zero preset magnetic field strength, the second differential analog output voltage (8) has a zero value, and The common mode voltage associated with the second differential analog output voltage (8) corresponds to a predetermined percentage of the power supply voltage of the bridge circuit (2).

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