Magnetoresistive sensing device

Abstract

The present invention provides a magnetoresistive sensing device comprising the following: a substrate (2) having a reference surface (2a); wherein the reference surface (2a) comprises a first plurality of inclined surfaces (2a1) and a second plurality of inclined surfaces (2a2); a plurality of MR elements (3) having a resistance, wherein the plurality of MR elements include first, second, third and fourth types of MR elements; a first bridge circuit (4) having a first branch (4a) and a second branch (4b), wherein both the first branch (4a) and the second branch (4b) comprise a series circuit composed of a first resistor (4a1, 4b1), a second resistor (4a2, 4b2), a third resistor (4a3, 4b3) and a fourth resistor (4a4, 4b4) in this order, wherein each of the resistors (4a1-4a4, 4a1-4b4) comprises at least one of the plurality of MR elements (3) of the same type (3a1, 3a2, 3b1, 3b2), arranged on the same one of the first and second inclined surfaces (2a1-2a2), wherein MR elements (3) of at least two of the first, second, third and fourth resistor (4a1-4a4, 4a1-4b4) are arranged on opposite inclined surfaces (2a1-2a2).

Description

[0001] Description

[0002] title

[0003] The present invention provides a magnetoresistive detection device.

[0004] State of the art

[0005] This invention relates to the field of integrated magnetometers and, more particularly, to a device based on magnetoresistive (MR) technologies, such as MR tunneling technologies.

[0006] Magnetic sensing devices enable the measurement of a magnetic field from a variety of sources, such as a biomagnetic field, the Earth's magnetic field, an electric current, and magnetic fields from permanent magnets. Magnetometers capable of 3D geomagnetic field measurements can provide absolute heading and have therefore become key components for the application of today's outdoor / indoor navigation and AR / VR devices.

[0007] One of the design challenges for magnetic sensors for 3D magnetic field sensing lies in their ability to measure in-plane and out-of-plane magnetic fields simultaneously. Typical MR sensors, such as anisotropic MR sensors, giant MR sensors, and tunneling MR sensors, can detect either in-plane or out-of-plane components of a magnetic field applied to an MR sensing element.

[0008] Various technologies have been proposed to achieve 3-axis

[0009] Integrating sensing elements into a single package. A tilted substrate approach to implementing 3D magnetic field measurement has attracted particular attention. The structures, called mounds, are essentially "hill-like" structures integrated onto a planar substrate, on the sides of which the magnetically sensitive elements are constructed.

[0010] By constructing MR sensing elements on a planar and a tilted substrate, the in-plane magnetic field, i.e., along the X and Y axes, can be measured by sensing elements constructed on both the planar substrate and the tilted substrate, while the out-of-plane field, i.e., along the Z axis, can only be measured by the sensing elements constructed on the tilted substrate. Therefore, decoupling the crosstalk between the measured in-plane and out-of-plane components of a magnetic field determines the accuracy of a magnetic sensor.

[0011] To achieve 3-axis detection for a 3D magnetic field, MR magnetic sensors with at least three bridge circuits have been implemented. US 11,493,567 B2 describes a magnetic sensor device with a first and a second chip, wherein the first chip has a first magnetic sensor and the second chip has a second and a third magnetic sensor.

[0012] Brief description of the invention

[0013] The present invention provides a magnetoresistive detection device according to claim 1.

[0014] According to the invention, a magnetoresistive sensing device is provided. The magnetoresistive sensing device comprises a substrate having a reference surface; wherein the reference surface comprises a first plurality of inclined surfaces and a second plurality of inclined surfaces, each extending along a first direction orthogonal to a normal direction orthogonal to the reference surfaces, each surface in the first plurality of inclined surfaces opposing a surface in the second plurality of inclined surfaces, the first plurality of inclined surfaces and the second plurality of inclined surfaces having inclinations relative to the reference surface;a plurality of MR elements having a resistance, wherein the plurality of MR elements comprise first, second, third, and fourth types of MR elements, wherein for a magnetic field in a second direction orthogonal to the first direction and the normal direction, the resistance of the first and fourth types of MR elements increases and the resistance of the second and third types of MR elements decreases, wherein for a magnetic field in the normal direction, the resistance of the third and fourth types of MR elements increases and the resistance of the first and second types of MR elements decreases;a first bridge circuit having a first branch and a second branch, wherein each of the first branch and the second branch comprises a series connection of a first resistor, a second resistor, a third resistor, and a fourth resistor in that order, wherein for each of the two branches, a first voltage is provided between the first resistor and the second resistor, a second voltage is provided between the second resistor and the third resistor, and a third voltage is provided between the third resistor and the fourth resistor, wherein each of the resistors comprises at least one of the plurality of MR elements of the same type arranged on the same one of the first and second inclined surfaces, wherein MR elements of at least two of the first, second, third, and fourth resistors are arranged on opposite inclined surfaces;

[0015] Advantageous embodiments and improvements of the present invention can be found in the subordinate claims.

[0016] Advantages of the invention

[0017] One idea of ​​the present invention is to replace a third bridge with an intelligent connection and distribution of MR elements in the form of a bridge circuit. Therefore, a converter solution with two bridges with good SNR and three front-end circuits is described here.

[0018] It is understood that the inclination of the first to fourth inclined surfaces has a similar inclination to the reference surface, meaning that their inclination angle is equal within approximately 10 degrees. The first to fourth inclined surfaces differ from each other in their orientation, as described above. Furthermore, the inclined surfaces may form a hill or a valley with respect to the reference surface of the substrate.

[0019] According to a preferred embodiment of the invention, the substrate comprises a third plurality of inclined surfaces and a fourth plurality of inclined surfaces, each extending along a second direction orthogonal to the first direction and the normal direction, wherein the third plurality of inclined surfaces opposes the fourth plurality of inclined surfaces, wherein the third plurality of inclined surfaces and the fourth plurality of inclined surfaces have inclinations relative to the reference surface; further comprising: a second bridge having a first branch and the second branch, wherein both the first branch and the second branch comprise a series connection of a first resistor, a second resistor, a third resistor, and a fourth resistor in that order, wherein for each of the two branches, a first voltage is provided between the first resistor and the second resistor,a second voltage is provided between the second resistor and the third resistor, and a third voltage is provided between the third resistor and the fourth resistor, wherein each of the resistors comprises at least one of the plurality of MR elements of the same type arranged on the same of the first and second inclined surfaces, wherein MR elements of at least two of the first, second, third, and fourth resistors are arranged on opposite inclined surfaces. In this way, a measurement of the magnetic field in the first direction can be measured with high accuracy.

[0020] According to a preferred embodiment of the invention, the plurality of MR elements is configured as TMR elements, wherein each TMR element comprises a magnetized layer with a fixed reference magnetization direction and a free layer with a magnetization direction that can be changed by an external electric field, wherein TMR elements of the first type are magnetized with their respective reference magnetization parallel upstream of a gradient of the inclination of the respective first or third plurality of inclined surfaces, wherein TMR elements of the second type are magnetized with their respective reference magnetization parallel upstream of a gradient of the inclination of the respective second or fourth plurality of inclined surfaces, and wherein TMR elements of a third type are magnetized parallel downstream of the gradient of the inclination of the respective first or third plurality of inclined surfaces,wherein TMR elements of a fourth type are magnetized with their respective reference magnetization parallel down a gradient of the inclination of the respective second and fourth plurality of inclined surfaces.,

[0021] According to a preferred embodiment of the invention, MR elements of each of the first, second, third and fourth resistors are arranged on the same first, second, third or fourth plurality of inclined surfaces, and wherein MR elements of two of the first, second, third and fourth resistors are arranged on opposite inclined surfaces.

[0022] According to a preferred embodiment of the invention, for each of the first bridge circuits, the first voltage of the first branch forms a positive polarity of a first differential voltage signal, the first voltage of the second branch forms a negative polarity of the first differential voltage signal, the third voltage of the first branch forms a negative polarity of a second differential voltage signal, and the third voltage of the second branch forms a positive polarity of the second differential voltage signal, the second voltage of the first branch forms a positive polarity of a third differential voltage signal, and the second voltage of the second branch forms a negative polarity of the third differential voltage signal,wherein, for each of the second bridge circuits, the first voltage of the first branch forms a positive polarity of a fourth differential voltage signal, and the first voltage of the second branch forms a negative polarity of the fourth differential voltage signal, and the third voltage of the first branch forms a negative polarity of a fifth differential voltage signal, and the third voltage of the second branch forms a positive polarity of the fifth differential voltage signal, wherein the second voltage of the first branch forms a positive polarity of a sixth differential voltage signal, and the second voltage of the second branch forms a negative polarity of the sixth differential voltage signal. According to a preferred embodiment of the invention, for the first and second bridge circuits, MR elements of the second resistor of the first branch and the fourth resistor of the second branch are of the first type,MR elements of the first resistance of the first branch and the third resistance of the second branch are of the second type, MR elements of the fourth resistance of the first branch and the second resistance of the second branch are of the third type, and MR elements of the third resistance of the first branch and the first resistance of the second branch are of the fourth type.

[0023] According to a preferred embodiment of the invention, the second differential voltage signal is added to the first differential voltage signal to provide a differential voltage X output; the fifth differential voltage signal is added to the fourth differential voltage signal to provide a differential voltage Y output; the sixth differential voltage signal is added to the third differential voltage signal to form a first Z differential output. In this way, a value of the magnetic field in the first and second directions can be derived.

[0024] According to a preferred embodiment of the invention, the first and second differential voltage signals are amplified in parallel by a pair of transconductance amplifiers to provide respective first and second differential current signals, the first differential current signal being added to the second differential current signal to provide a differential current X output, and the differential current X output being amplified by a transresistance amplifier to provide the differential voltage X output. Adding the currents instead of the voltages is simpler, more reliable, and consistently provides more accurate added signals.

[0025] According to a preferred embodiment of the invention, the fourth and fifth differential voltage signals are amplified in parallel by a pair of transconductance amplifiers to provide respective fourth and fifth differential current signals, the fourth differential current signal being added to the fifth differential current signal to provide a differential current Y output, the differential current Y output being amplified by a transresistance amplifier to provide the differential voltage Y output.

[0026] According to a preferred embodiment of the invention, the third and sixth differential voltage signals are amplified by a pair of transconductance amplifiers to provide respective third and sixth differential current signals, the third differential current signal being added to the sixth differential current signal to provide a first differential current Z output, and the differential current Z output being amplified by a transresistance amplifier to provide the first differential voltage Z output. In this way, a value of the magnetic field in the normal direction can be derived.

[0027] According to a preferred embodiment of the invention, the magnetoresistive sensing device further comprises a first switch configured to switch between the first, third, and fourth differential voltage signals, a second switch configured to switch between the second, fifth, and sixth signals, and a controller configured to control the first and second switches to time-multiplex between the differential voltage X output, the differential voltage Y output, and the first differential voltage Z output via the same pair of transconductance amplifiers and transresistance amplifiers.

[0028] According to a preferred embodiment of the invention, the second differential voltage signal is subtracted from the first signal to provide a second differential voltage Z output, wherein the third differential voltage signal is subtracted from the fourth differential voltage signal to provide a third differential voltage Z output.

[0029] According to a preferred embodiment of the invention, the first and second differential voltage signals are amplified in parallel by a pair of transconductance amplifiers to provide respective first and second differential current signals, the second differential current signal being subtracted from the first differential current signal to provide a second differential current Z output, the second differential current Z output being amplified by a transresistance amplifier to provide the second differential voltage Z output.

[0030] According to a preferred embodiment of the invention, the fourth and fifth differential voltage signals are amplified in parallel by a pair of transconductance amplifiers to provide respective fourth and fifth differential current signals, wherein the fifth differential current signal is subtracted from the fourth differential current signal to provide a third differential current Z output, wherein the third differential current Z output is amplified by a transresistance amplifier to provide the third differential voltage Z output.

[0031] According to a preferred embodiment of the invention, for the first bridge circuit, MR elements of the fourth resistance of the first branch and MR elements of the second resistance of the second branch are of the first type, MR elements of the first resistance of the first branch and MR elements of the third resistance of the second branch are of the second type, MR elements of the fourth resistance of the first branch and MR elements of the fourth resistance of the second branch are of the third type, and MR elements of the third resistance of the first branch and MR elements of the first resistance of the second branch are of the fourth type, wherein for the second bridge circuit, MR elements of the third resistance of the first branch and MR elements of the first resistance of the second branch are of the first type, MR elements of the second resistance of the first branch and MR elements of the fourth resistance of the second branch are of the second type,MR elements of the first resistance of the first branch and MR elements of the third resistance of the second branch are of the third type, and MR elements of the fourth resistance of the first branch and MR elements of the second resistance of the second branch are of the fourth type.

[0032] According to a preferred embodiment of the invention, the third differential voltage signal is amplified by a transconductance amplifier to provide a third differential current signal, the third differential current signal being amplified by a transresistance amplifier to provide a differential voltage X output, the sixth differential voltage signal being amplified in parallel by a transconductance amplifier to provide a sixth differential current signal, the sixth differential current signal being amplified by a transresistance amplifier to provide a differential voltage Y output.

[0033] According to a preferred embodiment of the invention, the second differential voltage signal is added to the first differential voltage signal, and the fourth and fifth differential voltage signals are subtracted from the first voltage signals to provide a differential voltage Z output.

[0034] According to a preferred embodiment of the invention, the first, second, fourth and fifth differential voltage signals are amplified in parallel by respective transconductance amplifiers to provide respective first, second, fourth and fifth differential current signals, wherein the second differential current signal is added to the first differential current signal and the fourth and fifth differential voltage signals are subtracted from the first differential current signal to provide a differential current Z output, wherein the differential current Z output is amplified by a transresistance amplifier to provide the differential voltage Z output.

[0035] According to a preferred embodiment of the invention, at least one of the first, second, third, and fourth resistors of the first and second branches of the first and second bridge circuits comprises a plurality of MR elements, wherein the direction of magnetization of the free layer of one rounded half of the MR elements of the same resistor is opposite to the direction of magnetization of the free layer of the other rounded half of the MR elements of the same resistor. This increases the accuracy of the measurement because noise originating from the free layers is compensated.

[0036] According to a preferred embodiment of the invention, the magnetoresistive sensing device further comprises a third bridge circuit and a fourth bridge circuit, wherein the third bridge circuit is identical to the first bridge circuit but has MR elements with opposite magnetization of the free layer of the respective TM R elements, and the fourth bridge circuit is identical to the second bridge circuit but has MR elements with opposite magnetization of the free layer of the respective MR elements. This increases the accuracy of the measurement because noise originating from the free layers is compensated.

[0037] According to a preferred embodiment of the invention, the substrate comprises a plurality of hills or valleys including a first surface and a second surface that are opposite to each other, or a third surface and a fourth surface that are opposite to each other, with MR elements of adjacent resistors arranged on the same hill or valley. This increases the flexibility of the device to be applied to various types of substrates.

[0038] Advantageous embodiments and further developments emerge from the description with reference to the figures.

[0039] Short description of the drawings

[0040] The following is a more specific explanation of the present invention based on the embodiments shown in the schematic figures, in which:

[0041] Fig. 1 AB show a schematic representation of MR elements of a magnetoresistive detection device according to an embodiment of the invention;

[0042] Figs. 2A-D show a schematic representation of MR elements of a magnetoresistive detection device according to an embodiment of the invention; Fig. 3 shows a schematic representation of a magnetoresistive detection device according to an embodiment of the invention;

[0043] 4A-B show a schematic representation of bridge circuits of a magnetoresistive detection device according to an embodiment of the invention;

[0044] Fig. 5 shows a schematic representation of a front end of a magnetoresistive sensing device according to an embodiment of the invention;

[0045] Fig. 6 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention;

[0046] Fig. 7 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention;

[0047] Fig. 8 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention;

[0048] Fig. 9 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention;

[0049] Figs. 10A-B show a schematic representation of bridge circuits of a magnetoresistive detection device according to another embodiment of the invention;

[0050] Fig. 11 shows a schematic diagram of a front end of a magnetoresistive detection device according to another embodiment of the invention; and Fig. 12 shows a schematic diagram of a front end of a magnetoresistive detection device according to another embodiment of the invention.

[0051] In the figures of the drawing, elements, features and components that are the same, have the same function and have the same effect are each provided with the same reference numeral - unless otherwise stated.

[0052] Fig. 1 AB shows a schematic representation of MR elements of a magnetoresistive sensing device according to an embodiment of the invention. In Fig. 1 A, a substrate 2 with a reference surface 2a is shown. The reference surface 2a comprises a first plurality of inclined surfaces 2a1 and a second plurality of inclined surfaces 2a2, each extending along a first direction Y orthogonal to a normal direction Z that is orthogonal to the reference surface 2a, as can be seen in Fig. 1 B. Each surface in the first plurality of inclined surfaces 2a1 is opposite a surface in the second plurality of inclined surfaces 2a2. The first plurality of inclined surfaces 2a1 and the second plurality of inclined surfaces 2a2 have inclinations I relative to the reference surface 2a.

[0053] It is understood that the first and second inclined surfaces 2a1, 2a2 have a similar inclination I to the reference surface 2a, which means that their inclination angle θ is the same within about 10 degrees. The inclination angle θ can have any value between about 10° and 80° and is preferably about 30°. The first and second inclined surfaces 2a1, 2a2 differ in their orientation, as they face each other, as described above. Although the first and second inclined surfaces 2a1, 2a2 are shown as hills with respect to the reference surface 2a, in further embodiments the first and second inclined surfaces 2a1, 2a2 can form a valley with respect to the reference surface 2a. These properties also apply to the third and fourth inclined surfaces 2a3, 2a4, which are presented in the following Fig. 2A. In Fig. 1B it is further shown that magnetoresistive andMR elements 3 are arranged on the first and second inclined surfaces 2a, 2b.

[0054] 2A-D show a schematic representation of MR elements of a magnetoresistive sensing device according to an embodiment of the invention. In Fig. 2A and Fig. 2B it is shown that the substrate 2 comprises a third plurality of inclined surfaces 3a3 and a fourth plurality of inclined surfaces 2a4, each extending along a second direction X orthogonal to the first direction Y and the normal direction Z. The third plurality of inclined surfaces 2a3 lies opposite the fourth plurality of inclined surfaces 2a4, wherein the third plurality of inclined surfaces 2a3 and the fourth plurality of inclined surfaces 2a4 have inclinations I relative to the reference surface 2a. In Fig. 2C and Fig. 2D it is shown that the substrate 2 comprises a first plurality of inclined surfaces 2a1 and a second plurality of inclined surfaces 2a2, each extending along a first direction Y orthogonal to the second direction X and the normal direction Z.The first plurality of inclined surfaces 2a1 opposes the second plurality of inclined surfaces 2a2. The first plurality of inclined surfaces 2a1 and the second plurality of inclined surfaces 2a2 have inclinations I relative to the reference surface 2a.

[0055] A plurality of MR elements 3 having a resistance includes first, second, third, and fourth types of MR elements. For a magnetic field in a second direction X orthogonal to the first direction Y and the normal direction Z, the resistance of the first to fourth types 3a1, 3b2 of MR elements 3 increases, and the resistance of the second and third types 3a1, 3b2 of MR elements 3 decreases. For a magnetic field in the normal direction Z, the resistance of the third and fourth types 3b1, 3b2 of MR elements 3 increases, and the resistance of the first and second types 3a1, 3b2 of MR elements 3 decreases. In the present embodiment, the plurality of MR elements 3 are configured as TMR elements. Each TMR element 3 comprises a magnetized layer with a fixed reference magnetization direction Mref and a free layer with a magnetization direction that can be changed by an external electric field.

[0056] TMR elements of the first type 3a1 are magnetized with their respective reference magnetization Mref parallel upstream of a gradient of the inclination I of the respective first or third plurality of inclined surfaces 2a1, 2a3, wherein TMR elements of the second type 3a2 are magnetized with their respective reference magnetization Mref parallel upstream of a gradient of the inclination I of the respective second or fourth plurality of inclined surfaces 2a2, 2a4, and wherein TMR elements of a third type 3b1 are magnetized parallel downstream of the gradient of the inclination I of the respective first or third plurality of inclined surfaces 2a1, 2a3, wherein TMR elements of a fourth type 3b2 are magnetized with their respective reference magnetization Mref parallel downstream of a gradient of the inclination I of the respective second and fourth plurality of inclined surfaces 2a2, 2a4.

[0057] Fig. 3 shows a schematic representation of a magnetoresistive detection device according to an embodiment of the invention.

[0058] Fig. 3 shows a first bridge circuit 4 having a first branch 4a and a second branch 4b. Both the first branch 4a and the second branch 4b comprise a series connection of a first resistor 4a1, 4b1, a second resistor 4a2, 4b2, a third resistor 4a3, 4b3, and a fourth resistor 4a4, 4b4, in that order.

[0059] MR elements 3 of each of the first, second, third, and fourth resistors 4a1-4a4, 4b1-4b4, 5a1-5a4, 5b1-5b4 are arranged on the same one of the first, second, third, and fourth plurality of inclined surfaces 2a1-2a4. MR elements of two of the first, second, third, and fourth resistors 4a1-4, 4b1-4, 5a1-4, 5b1-5 are arranged on an opposite inclined surface 2a1-2a4. The first resistor 4a1, 4b1 of each branch 4a, 4b is connected to the power supply VTMR. The fourth resistor 4a4, 4b4 of each branch is connected to ground GND.

[0060] Fig. 4A-B show a schematic representation of bridge circuits of a magnetoresistive detection device according to an embodiment of the invention.

[0061] In Fig. 4A, MR elements 3 of at least two of the first, second, third and fourth resistors 4a1 -4a4, 4b1 -4b4 are arranged on opposite inclined surfaces 2a3, 2a4.

[0062] Each of the resistors 4a1 -4a4, 4b1 -4b4 comprises at least one of the plurality of MR elements 3 of the same type 3a1, 3a2, 3b1, 3b2 arranged on the same one of the first and second inclined surfaces 2a1 -2a2.

[0063] For each of the two branches 4a, 4b, a first voltage 4aV1, 4bV1 is provided between the first resistor 4a1, 4b1 and the second resistor 4a2, 4b2, a second voltage 4aV2, 4bV2 is provided between the second resistor 4a2, 4b2 and the third resistor 4a3, 4b3, and a third voltage 4aV3, 4bV3 is provided between the third resistor 4a3, 4b3 and the fourth resistor 4a4, 4b4.

[0064] For each first bridge circuit 4, the first resistor 4a1, 4b1 of each branch 4a, 4b is connected to the power supply VTMR, with the fourth resistor 4a4, 4b4 of each branch being connected to ground GND.

[0065] In Fig. 4B, a second bridge circuit 5 having a first branch 5a and a second branch 5b, wherein each of the first branch 5a and the second branch 5b comprises a series connection of a first resistor 5a1, 5b1, a second resistor 5a2, 5b2, a third resistor 5a3, 5b3, and a fourth resistor 5a4, 5b4 in this order. For the second bridge circuit 5 shown in Fig. 4B, MR elements 3 of at least two of the first, second, third, and fourth resistors 5a1-5a4, 5b1-5b4 are arranged on opposite inclined surfaces 2a1, 2a2.

[0066] For each of the two branches 5a, 5b, a first voltage 5aV1, 5bV1 is provided between the first resistor 5a1, 5b1 and the second resistor 5a2, 5b2, a second voltage 5aV2, 5bV2 is provided between the second resistor 5a2, 5b2 and the third resistor 5a3, 5b3, and a third voltage 5aV3, 5bV3 is provided between the third resistor 5a3, 5b3 and the fourth resistor 5a4, 5b4.

[0067] Each of the resistors 5a1-5a4, 5b1-5b4 comprises at least one of the plurality of MR elements 3 of the same type 3a1, 3a2, 3b1, 3b2 arranged on the same one of the third and fourth plurality of inclined surfaces 2a3-2a4.

[0068] For every second bridge circuit 5, the first resistor 5a1, 5b1 of each branch 4a, 4b is connected to the power supply VTMR, with the fourth resistor 4a4, 4b4 of each branch being connected to ground GND.

[0069] For both the first and the second bridge circuit 4, 5, MR elements of the second resistor 4a2, 5a2 of the first branch 4a, 5a and the fourth resistor 4b4, 5b4 of the second branch 4b, 5b are of the first type 3a, MR elements of the first resistor 4a1, 5a1 of the first branch 4a, 5a and the third resistor 4b3, 5b3 of the second branch 4b, 5b are of the second type 3a2, MR elements of the fourth resistor 4a4, 5a4 of the first branch 4a, 5a and the second resistor 4b2, 5b2 of the second branch 4b, 5b are of the third type 3b1, and MR elements of the third resistor 4a1, 5a1 of the first branch 4a, 5a and the first resistor 4b3, 5b3 of the second branch 4b, 5b are of the fourth type 3b2.

[0070] In particular, for the first and second bridge circuits 4, 5, MR elements of the second resistor 4a2, 5a2 of the first branch 4a, 5a and the fourth resistor 4b4, 5b4 of the second branch 4b, 5b are of the first type 3a1, MR elements of the first resistor 4a1, 5a1 of the first branch 4a, 5a and the third resistor 4b3, 5b3 of the second branch 4b, 5b are of the second type 3a2, MR elements of the fourth resistor 4a4, 5a4 of the first branch 4a, 5a and the second resistor 4b2, 5b2 of the second branch 4b, 5b are of the third type 3b1, and MR elements of the third resistor 4a1, 5a1 of the first branch 4a, 5a and the first resistor 4b3, 5b3 of the second branch 4b, 5b are of the fourth type 3b2.

[0071] Fig. 5 shows a schematic representation of a front end of a magnetoresistive sensing device according to an embodiment of the invention.

[0072] For each of the first bridge circuits 4, the first voltage 4aV1 of the first branch 4a forms a positive polarity of a first differential voltage signal SV1. The first voltage 4bV1 of the second branch 4a forms a negative polarity of the first differential voltage signal SV1. The third voltage 4aV3 of the first branch 4a forms a negative polarity of a second differential voltage signal SV2, and the third voltage 4bV3 of the second branch 4b forms a positive polarity of the second differential voltage signal SV2.

[0073] In this embodiment, the second differential voltage signal SV2 is added to the first differential voltage signal SV1 to provide a differential voltage X output DVX.

[0074] Specifically, the first and second differential voltage signals SV1, SV2 are amplified in parallel by a pair of transconductance amplifiers A1, A2 to provide respective first and second differential current signals SI1, SI2. The first differential current signal SI1 is added to the second differential current signal SI2 to provide a differential current X output DIX, wherein the differential current X output DIX is amplified by a transresistance amplifier B to provide the differential voltage X output DVX.

[0075] For the first amplification step, the voltages are thus converted into currents for addition. For this purpose, the first voltage 4aV1 of the first branch 4a of the first bridge circuit 4 is amplified as the positive polarity of the first differential voltage signal SV1 by a positive polarity of a first transconductance amplifier A1 of the pair of transconductance amplifiers A1, A2 to provide an amplified first current 4al1. The first voltage 4baV1 of the second branch 4b of the first bridge circuit 4 is amplified as the negative polarity of the first differential voltage signal SV1 by a negative polarity of the first transconductance amplifier A1 to provide an amplified first current 4bl1. The first amplified currents 4al1, 4bl1 thus form the first differential current signal SI1.

[0076] Likewise, the third voltage 4aV3 of the second branch 4b of the first bridge circuit 4 is amplified as the positive polarity of the second differential voltage signal SV2 by a positive polarity of a second transconductance amplifier A2 of the pair of transconductance amplifiers A1, A2 to provide an amplified third current 4bl3. The third voltage 4baV3 of the first branch 4a of the first bridge circuit 4 is amplified as the negative polarity of the second differential voltage signal SV2 by a negative polarity of the second transconductance amplifier A2 to provide an amplified third current 4bl3. The third amplified currents 4al3, 4bl3 thus form the second differential current signal SI2.

[0077] The addition of the first and second differential current signals SI1, SI2 is achieved by adding their positive polarities, i.e., the first amplified current 4al1 and the third amplified current 4bl3, at node NXa to provide a first added current DIXa, and the first amplified current 4bl1 and the third amplified current 4al3 at node NXb to provide a second added current DIXb. The first and second currents DIXa, DIXb thus form the differential current X output DIX.

[0078] In the second amplification step, the added currents DIXa, DIXb of the differential current X output DIX are converted back into a differential voltage. For this purpose, the first added current DIXa is amplified by the positive polarity of the transresistance amplifier B, which includes a first resistor Ra, to provide a first amplified X voltage DVXa. The second added current DIXb is amplified by the negative polarity of the transresistance amplifier B, which includes a second resistor Rb, to provide a second amplified X voltage DVXb. The first and second amplified X voltages DVXa and DVXb form the differential voltage X output DVX.

[0079] It is understood that the difference in the respective gain of the first and second transconductance amplifiers A1, A2 is very small, preferably less than 1%. Furthermore, the gain of the transresistance amplifier B in both polarities is determined by the first and second resistors Ra and Rb and is very small, preferably less than 1% in each case.

[0080] Fig. 6 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention.

[0081] For the second bridge circuit 5, the first voltage 5aV1 of the first branch 5a forms a positive polarity of a fourth differential voltage signal SV4, and the first voltage 5bV1 of the second branch 5b forms a negative polarity of the fourth differential voltage signal SV4. Furthermore, the third voltage 5aV3 of the first branch 5a forms a negative polarity of a fifth differential voltage signal SV5, and the third voltage 5bV3 of the second branch 5b forms a positive polarity of the fifth differential voltage signal SV5.

[0082] The fifth differential voltage signal SV5 is added to the fourth differential voltage signal SV4 to provide a differential voltage Y output DVY.

[0083] In particular, the fourth and fifth differential voltage signals SV4, SV5 are amplified in parallel by a pair of transconductance amplifiers A1, A2 to provide respective fourth and fifth differential current signals SI4, SI5, wherein the fourth differential current signal SI4 is added to the fifth differential current signal SI5 to provide a differential current Y output DIY, wherein the differential current Y output DIY is amplified by a transresistance amplifier B to provide the differential voltage Y output DVY. The amplification and addition of the fourth and fifth differential voltage signals SV4, SV5 to achieve the differential voltage Y output DVY is analogous to the amplification and addition of the first and second differential voltage signals SV1, SV2 to achieve the differential voltage X output DVX, as described above with reference to Fig. 5. The voltages and currents involved can be directly deducted from Fig. 6.

[0084] Fig. 7 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention.

[0085] The second voltage 4aV2 of the first branch 4a forms a positive polarity of a third differential voltage signal SV3 and the second voltage 4bV2 of the second branch 5b forms a negative polarity of the third differential voltage signal SV3.

[0086] For each of the second bridge circuits 5, the second voltage 5aV2 of the first branch 5b forms a positive polarity of a sixth differential voltage signal SV6, and the second voltage 5bV2 of the second branch 5b forms a negative polarity of the fourth differential voltage signal SV6.

[0087] The sixth differential voltage signal SV6 is added to the third differential voltage signal SV6 to provide a first differential voltage Z output DZ1.

[0088] The third and sixth differential voltage signals SV3, SV6 are amplified by a pair of transconductance amplifiers A1, A2 to provide respective third and sixth differential current signals SI3, SI6, wherein the third differential current signal SI3 is added to the sixth differential current signal SI6 to provide a first differential current Z output DIZ1, wherein the first differential current Z output DIZ1 is amplified by a transresistance amplifier B to provide the first differential voltage Z output DZ1. The amplification and addition of the third and sixth differential voltage signals SV3, SV6 to achieve the differential voltage Z output DVZ1 is analogous to the amplification and addition of the first and second differential voltage signals SV1, SV2 to achieve the differential voltage X output DVX, as described above with reference to Fig. 5. The voltages and currents involved can be directly deducted from Fig. 7.

[0089] Although the embodiments of Figs. 5 to 7 have been described using separate circuits and devices, the front ends for providing the differential voltage X, Y, and Z outputs can be achieved with only one amplification circuit. In these embodiments, the front end of the magnetoresistive sensing device further comprises a first switch (not shown) configured to switch between the first, fourth, and third differential voltage signals SV1, SV4, SV3, a second switch (not shown) configured to switch between the second, fifth, and sixth signals SV2, SV5, SV6, and a controller configured to control the first and second switches to time-multiplex between the differential voltage X output DVX, the differential voltage Y output DVY, and the first differential voltage Z output DVZ1 via the same pair of transconductance amplifiers A1, A2 and transresistance amplifiers B.

[0090] Fig. 8 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention.

[0091] In this embodiment, the second differential voltage signal SV2 is subtracted from the first signal SV1 to provide a second differential voltage Z output DZ2.

[0092] For this purpose, the first and second differential voltage signals SV1, SV2 are amplified in parallel by a pair of transconductance amplifiers A1, A2 to provide respective first and second differential current signals SI1, SI2, wherein the second differential current signal SI2 is subtracted from the first differential current signal SI1 to provide a second differential current Z output DIZ2, wherein the second differential current Z output DIZ2 is amplified by a transresistance amplifier B to provide the second differential voltage Z output DZ2.

[0093] The amplification and addition of the first and second differential voltage signals SV1, SV2 to achieve the second differential voltage Z output DVZ2 is performed analogously to the amplification and addition of the first and second differential voltage signals SV1, SV2 to achieve the differential voltage X output DVX, as described above with reference to Fig. 5, except that for the subtraction, the first amplified current 4al1 and the third amplified current 4al3 are added in node NZ2a to provide a first added current DIZ2a, and the first amplified current 4bl1 and the third amplified current 4bl3 are added in node NZ2b to provide a second added current DIZ2b. The remaining voltages and currents involved can be subtracted directly from Fig. 8.

[0094] Fig. 9 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention.

[0095] In this embodiment, the third differential voltage signal SV3 is subtracted from the fourth differential voltage signal SV4 to provide a third differential voltage Z output DZ3.

[0096] The fourth and fifth differential voltage signals SV4, SV5 are amplified in parallel by a pair of transconductance amplifiers A1, A2 to provide respective fourth and fifth differential current signals SI4, SI5, wherein the fifth differential current signal SI5 is subtracted from the fourth differential current signal SI4 to provide a third differential current Z output DIZ3, wherein the third differential current Z output DIZ3 is amplified by a transresistance amplifier B to provide the third differential voltage Z output DZ3.

[0097] The amplification and subtraction of the fourth and fifth

[0098] Differential voltage signal SV4, SV5 to reach the third

[0099] Differential voltage Z output DZ3 is analogous to the amplification and subtraction of the first and second differential voltage signals SV1, SV2 to achieve the second differential voltage Z output DZ2 as described above with reference to Fig. 8. The included voltages and currents can be directly subtracted from Fig. 9.

[0100] Fig. 10A-B show a schematic representation of bridge circuits of a magnetoresistive detection device according to another embodiment of the invention.

[0101] This embodiment of a magnetoresistive detection device is based on the embodiments shown and described with reference to Figs. 4 and 5. However, in this alternative embodiment, the arrangement of the MR elements differs from the embodiment described with reference to Figs. 4 and 5. Fig. 10A shows the first bridge circuit 5 of this alternative embodiment.For the first bridge circuit 4, MR elements of the fourth resistor 4a4 of the first branch 4a and MR elements of the second resistor 4b2 of the second branch 4b are of the first type 3a1, MR elements of the first resistor 4a1 of the first branch 4a and MR elements of the third resistor 4b3 of the second branch 4b are of the second type 3a2, MR elements of the second resistor 4a2 of the first branch 4a and MR elements of the fourth resistor 4b4 of the second branch 4b are of the third type 3b1, and MR elements of the third resistor 4a3 of the first branch 4a and MR elements of the first resistor 4b1 of the second branch 4b are of the fourth type 3b2.

[0102] In Fig. 10B, the second bridge circuit 5 is shown. For the second bridge circuit 5, MR elements of the third resistor 5a3 of the first branch 5a and MR elements of the first resistor 5b1 of the second branch 5b are of the first type 3a1, MR elements of the second resistor 5a2 of the first branch 5a and MR elements of the fourth resistor 5b4 of the second branch 5b are of the second type 3a2, MR elements of the first resistor 5a1 of the first branch 5a and MR elements of the third resistor 5b3 of the second branch 5b are of the third type 3b1, and MR elements of the fourth resistor 5a4 of the first branch 5a and MR elements of the second resistor 5b3 of the second branch 5b are of the fourth type 3b2.

[0103] Fig. 11 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention.

[0104] The third differential voltage signal SV3 is amplified by a transconductance amplifier A to provide a third differential current signal SI3, the third differential current signal SI3 being amplified by a transresistance amplifier B to provide a differential voltage X output DVX, the sixth differential voltage signal SV6 being amplified in parallel by a transconductance amplifier A to provide a sixth differential current signal SI6, the sixth differential current signal SI6 being amplified by a transresistance amplifier B to provide a differential voltage Y output DVY.

[0105] The amplification of the third and sixth differential voltage signals SV3, SV6 to achieve the differential voltage X and Y outputs DVX, DVY in this alternative embodiment is analogous to the amplification of the respective first to sixth signals SV1 to SV6, as previously described in Figs. 5 to 9. The voltages and currents involved can be directly deducted from Fig. 11.

[0106] Fig. 12 shows a schematic representation of a front end of a magnetoresistive detection device according to another embodiment of the invention.

[0107] The second differential voltage signal SV2 is added to the first differential voltage signal SV1 and the fourth and fifth differential voltage signals SV4, SV5 are subtracted from the first voltage signals SV1 to provide a differential voltage Z output DVZ.

[0108] The first, second, fourth and fifth differential voltage signals SV1, SV2, SV4, SV5 are amplified in parallel by respective transconductance amplifiers A1-A4 to provide respective first, second, fourth and fifth differential current signals SI1, SI2, SI4, SI5, wherein the second differential current signal SI2 is added to the first differential current signal SI1 and the fourth and fifth differential voltage signals SI4, SI5 are subtracted from the first differential current signal SI1 to provide a differential current Z output DIZ, wherein the differential current Z output DIZ is amplified by a transresistance amplifier B to provide the differential voltage Z output DVZ1.

[0109] The amplification, addition and subtraction of the first, second, fourth and fifth differential voltage signals SV1, SV2, SV4, SV5 to achieve the differential voltage Z output DVZ in this alternative embodiment is analogous to the amplification and addition of, for example, the first and second differential voltage signals SV1, SV2 to achieve the differential voltage X output DVX, as described above with reference to Fig. 5, and the amplification and subtraction of the first and second differential voltage signals SV1, SV2 to achieve the first differential voltage Z output DVZ1, as described above with reference to Fig. 7. The voltages and currents involved can be directly deducted from Fig. 12.

[0110] The embodiments were chosen and described in order to best illustrate the principles underlying the invention and its possible practical applications. As a result, those skilled in the art can optimally modify and utilize the invention and its various embodiments for the intended purpose.

[0111] For example:

[0112] According to further embodiments of the magnetoresistive sensing device, at least one of the first, second, third and fourth resistors 4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4 of the first and second branches 4a, 4b, 5a, 5b of the first and second bridge circuits 4, 5 comprises a plurality of MR elements 3. In these embodiments, the magnetization direction of the free layer M of a rounded half of the MR element 3 of the same resistor 4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4 is opposite to the magnetization direction M of the free layer of the other rounded half of the MR element 3 of the same resistor 4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4.

[0113] According to further embodiments, the magnetoresistive sensing device further comprises a third bridge circuit and a fourth bridge circuit. The third bridge circuit is generally identical to the first bridge circuit 4, except that it comprises MR elements 3 with opposite magnetization M of the free layer of the respective TMR elements 3. The fourth bridge circuit 4 is identical to the second bridge circuit 5, except that it comprises MR elements 3 with opposite magnetization M of the free layer of the respective MR elements 3.

[0114] According to further embodiments of the magnetoresistive sensing device, the substrate 2 comprises a plurality of hills and valleys, including a first surface 2a1 and a second surface 2a2 that oppose each other, or a third surface 2a3 and a fourth surface 2a4 that oppose each other. In such embodiments, the MR elements 3 of adjacent resistors 4a1-4a4, 4b1-4b4, 5a1-5a4, 5b1-5b4 are arranged on the same hill or valley.

[0115] Although the front end is based on transconductance amplifiers and transresistance amplifiers, in further embodiments the transconductance amplifiers and transresistance amplifiers are replaced by switched capacitor circuits that implement a similar function in a similar way without changing the meaning of the proposed principle and ideas.

Claims

Claims 1. A magnetoresistive sensing device comprising: a substrate (2) having a reference surface (2a); wherein the reference surface (2a) comprises a first plurality of inclined surfaces (2a1) and a second plurality of inclined surfaces (2a2), each extending along a first direction (Y) orthogonal to a normal direction (Z) orthogonal to the reference surface (2a), wherein each surface in the first plurality of inclined surfaces (2a1) is opposite to a surface in the second plurality of inclined surfaces (2a2), wherein the first plurality of inclined surfaces (2a1) and the second plurality of inclined surfaces (2a2) have inclinations (I) relative to the reference surface (2a);a plurality of MR elements (3) having a resistance, wherein the plurality of MR elements comprise first, second, third and fourth types of MR elements, wherein for a magnetic field in a second direction (X) orthogonal to the first direction (Y) and the normal direction (Z), the resistance of the first and fourth types (3a1, 3b2) of MR elements (3) increases and the resistance of the second and third types (3a2, 3b1) of MR elements (3) decreases, wherein for a magnetic field in the normal direction (Z), the resistance of the third and fourth types (3b1, 3b2) of MR elements (3) increases and the resistance of the first and second types (3a1, 3a2) of MR elements (3) decreases;a first bridge circuit (4) having a first branch (4a) and a second branch (4b), wherein both the first branch (4a) and the second branch (4b) have a series connection of a first resistor (4a1, 4b1), a second resistor (4a2, 4b2), a third resistor (4a3, 4b3) and a fourth resistor (4a4, 4b4) in this order; wherein for each of the two branches (4a, 4b), a first voltage (4aV1, 4bV1) is provided between the first resistor (4a1, 4b1) and the second resistor (4a2, 4b2), a second voltage (4aV2, 4bV2) is provided between the second resistor (4a2, 4b2) and the third resistor (4a3, 4b3), and a third voltage (4aV3, 4bV3) is provided between the third resistor (4a3, 4b3) and the fourth resistor (4a4, 4b4), wherein each of the resistors (4a1-4a4, 4b1-4b4) comprises at least one of the plurality of MR elements (3) of the same type (3a1, 3a2, 3b1, 3b2), arranged on the same of the first and second inclined surfaces (2a1-2a2), wherein MR elements (3) of at least two of the first, second, third and fourth resistors (4a1 -4a4, 4b1 -4b4) are arranged on opposite inclined surfaces (2a1 -2a2).

2. Magnetoresistive detection device according to claim 1, wherein the substrate (2) comprises a third plurality of inclined surfaces (3a1) and a fourth plurality of inclined surfaces (3a2), each extending along a second direction (X) orthogonal to the first direction (Y) and the normal direction (Z), the third plurality of inclined surfaces (2a3) being opposite to the fourth plurality of inclined surfaces (2a4), the third plurality of inclined surfaces (2a3) and the fourth plurality of inclined surfaces (2a4) having inclinations (I) relative to the reference surface (2a); further comprising: a second bridge circuit (5) having a first branch (5a) and a second branch (5b), wherein both the first branch (5a) and the second branch (5b) have a series connection of a first resistor (5a1, 5b1), a second resistor (5a2, 5b2), a third resistor (5a3, 5b3) and a fourth resistor (5a4, 5b4) in this order, wherein for each of the two branches a first voltage (5aV1, 5bV1) is provided between the first resistor (5a1, 5b1) and the second resistor (5a2, 5b2), a second voltage (5aV2, 5bV2) is provided between the second resistor (5a2, 5b2) and the third resistor (5a3, 5b3), and a third voltage (5aV3, 5bV3) is provided between the third resistor (5a3, 5b3) and the fourth resistor (5a4, 5b4), wherein each of the resistors (5a1-5a4, 5b1-5b4) comprises at least one of the plurality of MR elements (3) of the same type (3a1, 3a2, 3b1, 3b2), arranged on the same of the third and fourth plurality of inclined surfaces (2a3-2a4), wherein MR elements (3) of at least two of the first, second, third and fourth resistors (5a1 -5a4, 4b1 -4b4) are arranged on opposite inclined surfaces (2a1 -2a4).

3. Magnetoresistive sensing device according to claim 1 or 2, wherein the plurality of MR elements (3) are configured as TMR elements, each TMR element (3) comprising a magnetized layer with a fixed reference magnetization direction (Mref) and a free layer with a magnetization direction that can be changed by an external electric field, wherein TMR elements of the first type (3a1) are magnetized with their respective reference magnetization (Mref) in parallel up a gradient of the inclination (I) of the respective first or third plurality of inclined surfaces (2a1, 2a3), wherein TMR elements of the second type (3a2) are magnetized with their respective reference magnetization (Mref) in parallel up a gradient of the inclination (I) of the respective second or fourth plurality of inclined surfaces (2a2, 2a4),and wherein TMR elements of a third type (3b1) are magnetized parallel downstream of the gradient of the inclination (I) of the respective first or third plurality of inclined surfaces (2a1, 2a3), wherein TMR elements of a fourth type (3b2) are magnetized with their respective reference magnetization (Mref) parallel downstream of a gradient, the inclination (I) of the respective second and fourth plurality of inclined surfaces (2a2, 2a4) are magnetized.

4. A magnetoresistive detection device according to any one of the preceding claims, wherein MR elements (3) of each of the first, second, third and fourth resistors (4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4) are arranged on the same one of the first, second, third and fourth plurality of inclined surfaces (2a1 - 2a4), and wherein MR elements of two of the first, second, third and fourth resistors (4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4) are arranged on an opposite inclined surface (2a1 - 2a4).

5. Magnetoresistive detection device according to claim 2, wherein for each of the first bridge circuits (4), the second voltage (4aV1) of the first branch (4a) forms a positive polarity of a first differential voltage signal (SV1), the first voltage (4bV1) of the second branch (4a) forms a negative polarity of the first differential voltage signal (SV1), the third voltage (4aV3) of the first branch (4a) forms a negative polarity of a second differential voltage signal (SV2), and the third voltage (4bV3) of the second branch (4b) forms a positive polarity of the second differential voltage signal (SV2), the second voltage (4aV2) of the first branch (4a) forms a positive polarity of a third differential voltage signal (SV3), and the second voltage (4bV2) of the second branch (5b) forms a negative polarity of the third differential voltage signal (SV3), wherein for each of the second bridge circuits (5),the first voltage (5aV1) of the first branch (5a) forms a positive polarity of a fourth differential voltage signal (SV4) and the first voltage (5bV1) of the second branch (5b) forms a negative polarity of the fourth differential voltage signal (SV4), and the third voltage (5aV3) of the first branch (5a) forms a negative polarity of a fifth differential voltage signal (SV5) and the third voltage (5bV3) of the second branch (5b) forms a positive polarity of the fifth differential voltage signal (SV5), wherein the second voltage (5aV2) of the first branch (5b) forms a positive polarity of a sixth differential voltage signal (SV6) and the second voltage (5bV2) of the second branch (5b) forms a negative polarity of the sixth differential voltage signal (SV6).

6. Magnetoresistive detection device according to claim 5, wherein for the first and second bridge circuits (4, 5), MR elements of the second resistor (4a2, 5a2) of the first branch (4a, 5a) and the fourth resistor (4b4, 5b4) of the second branch (4b, 5b) are of the first type (3a1), MR elements of the first resistor (4a1, 5a1) of the first branch (4a, 5a) and the third resistor (4b3, 5b3) of the second branch (4b, 5b) are of the second type (3a2), MR elements of the fourth resistor (4a4, 5a4) of the first branch (4a, 5a) and the second resistor (4b2, 5b2) of the second branch (4b, 5b) are of the third type (3b1), and MR elements of the third resistor (4a1, 5a1) of the first branch (4a, 5a) and the first resistor (4b3, 5b3) of the second branch (4b, 5b) are of the fourth type (3b2).

7. The magnetoresistive sensing device of claim 6, wherein the second differential voltage signal (SV2) is added to the first differential voltage signal (SV1) to provide a differential voltage X output (DVX); wherein the fifth differential voltage signal (SV5) is added to the fourth differential voltage signal (SV4) to provide a differential voltage Y output (DVY); wherein the sixth differential voltage signal (SV6) is added to the third differential voltage signal (SV6) to provide a first differential voltage Z output (DZ1).

8. Magnetoresistive sensing device according to claim 7, wherein the first and second differential voltage signals (SV1, SV2) are amplified in parallel by a pair of transconductance amplifiers (A1, A2) to provide respective first and second differential current signals (SI1, SI2), wherein the first differential current signal (SI1) is added to the second differential current signal (SI2) to provide a differential current X output (DIX), wherein the differential current X output (DIX) is amplified by a transresistance amplifier (B) to provide the differential voltage X output (DVX).

9. A magnetoresistive sensing device according to claim 7 or 8, wherein the fourth and fifth differential voltage signals (SV4, SV5) are amplified in parallel by a pair of transconductance amplifiers (A1, A2) to provide respective fourth and fifth differential current signals (SI4, SI5), the fourth differential current signal (SI4) being added to the fifth differential current signal (SI5) to provide a differential current Y output (DIY), the differential current Y output (DIY) being amplified by a transresistance amplifier (B) to provide the differential voltage Y output (DVY).

10. Magnetoresistive sensing device according to one of claims 7 to 9, wherein the third and sixth differential voltage signals (SV3, SV6) are amplified by a pair of transconductance amplifiers (A1, A2) to provide respective third and sixth differential current signals (SI3, SI6), wherein the third differential current signal (SI3) is added to the sixth differential current signal (SI6) to provide a first differential current Z output (DIZ1), wherein the first differential current Z output (DIZ1) is amplified by a transresistance amplifier (B) to provide the first differential voltage Z output (DZ1).

11. Magnetoresistive sensing device according to one of claims 8 to 10, further comprising a first switch configured to switch between the first, third and fourth differential voltage signals (SV1, SV3, SV4), a second switch configured to switch between the second, fifth and sixth signals (SV2, SV5, SV6), and a controller configured to control the first and second switches to time-multiplex between the differential voltage X output (DVX), the differential voltage Y output (DVY) and the first differential voltage Z output (DVZ1) via the same pair of transconductance amplifiers (A1, A2) and transresistance amplifiers (B).

12. The magnetoresistive sensing device of claim 6, wherein the second differential voltage signal (SV2) is subtracted from the first signal (SV1) to provide a second differential voltage Z output (DZ2), wherein the third differential voltage signal (SV3) is subtracted from the fourth differential voltage signal (SV4) to provide a third differential voltage Z output (DZ3).

13. The magnetoresistive sensing device of claim 12, wherein the first and second differential voltage signals (SV1, SV2) are amplified in parallel by a pair of transconductance amplifiers (A1, A2) to provide respective first and second differential current signals (SI1, SI2), the second differential current signal (SI2) being subtracted from the first differential current signal (SI1) to provide a second differential current Z output (DIZ2), the second differential current Z output (DIZ2) being amplified by a transresistance amplifier (B) to provide the second differential voltage Z output (DZ2).

14. A magnetoresistive sensing device according to claim 12 or 13, wherein the fourth and fifth differential voltage signals (SV4, SV5) are amplified in parallel by a pair of transconductance amplifiers (A1, A2) to provide respective fourth and fifth differential current signals (SI4, SI5), wherein the fifth differential current signal (SI5) is subtracted from the fourth differential current signal (SI4) to provide a third differential current Z output (DIZ3), wherein the third differential current Z output (DIZ3) is amplified by a transresistance amplifier (B) to provide the third differential voltage Z output (DZ3).

15. Magnetoresistive detection device according to claim 2, wherein for the first bridge circuit (4), MR elements of the fourth resistor (4a4) of the first branch (4a) and MR elements of the second resistor (4b2) of the second branch (4b) are of the first type (3a1), MR elements of the first resistor (4a1) of the first branch (4a) and MR elements of the third resistor (4b3) of the second branch (4b) are of the second type (3a2), MR elements of the second resistor (4a2) of the first branch (4a) and MR elements of the fourth resistor (4b4) of the second branch (4b) are of the third type (3b1) and MR elements of the third resistor (4a3) of the first branch (4a) and MR elements of the first resistor (4b1) of the second branch (4b) are of the fourth type (3b2), wherein for the second bridge circuit (5) MR elements of the third resistor (5a3) of the first branch (5a) and MR elements of the first resistor (5b1) of the second branch (5b) are of the first type (3a1), MR elements of the second resistor (5a2) of the first branch (5a) and MR elements of the fourth resistor (5b4) of the second branch (5b) are of the second type (3a2), MR elements of the first resistor (5a1) of the first branch (5a) and MR elements of the third resistor (5b3) of the second branch (5b) are of the third type (3b1) and MR elements of the fourth resistor (5a4) of the first branch (5a) and MR elements of the second resistor (5b3) of the second branch (5b) are of the fourth type (3b2).

16. The magnetoresistive sensing device of claim 5 and 15, wherein the third differential voltage signal (SV3) is amplified by a transconductance amplifier (A) to provide a third differential current signal (SI3), wherein the third differential current signal (SI3) is amplified by a transresistance amplifier (B) to provide a differential voltage X output (DVX), wherein the sixth differential voltage signal (SV6) is amplified in parallel by a transconductance amplifier (A) to provide a sixth differential current signal (SI6), wherein the sixth differential current signal (SI6) is amplified by a transresistance amplifier (B) to provide a differential voltage Y output (DVY).

17. Magnetoresistive detection device according to claim 5 and 15, wherein the second differential voltage signal (SV2) is added to the first differential voltage signal (SV1) and the fourth and fifth differential voltage signals (SV4, SV5) are derived from the first voltage signals (SV1) to provide a differential voltage Z output (DVZ).

18. The magnetoresistive sensing device of claim 17, wherein the first, second, fourth, and fifth differential voltage signals (SV1, SV2, SV4, SV5) are amplified in parallel by respective transconductance amplifiers (A1-A4) to provide respective first, second, fourth, and fifth differential current signals (SI1, SI2, SI4, SI5), the second differential current signal (SI2) being added to the first differential current signal (SI1) and the fourth and fifth differential voltage signals (SI4, SI5) being subtracted from the first differential current signal (SI1) to provide a differential current Z output (DIZ), the differential current Z output (DIZ) being amplified by a transresistance amplifier (B) to provide the differential voltage Z output (DVZ).

19. Magnetoresistive detection device according to claim 3, wherein at least one of the first, second, third and fourth resistors (4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4) of the first and second branches (4a, 4b, 5a, 5b) of the first and second bridge circuits (4, 5) comprises a plurality of MR elements (3), wherein the magnetization direction of the free layer (M) of a rounded half of the MR element (3) of the same resistor (4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4) is opposite to the magnetization direction (M) of the free layer of the other rounded half of the MR element (3) of the same resistor (4a1 - 4a4, 4b1 - 4b4, 5a1 - 5a4, 5b1 - 5b4). is.

20. The magnetoresistive sensing device according to claim 2, further comprising a third bridge circuit and a fourth bridge circuit, wherein the third bridge circuit is identical to the first bridge circuit (4) but has MR elements (3) with opposite magnetization (M) of the free layer of the respective TM R elements (3), wherein the fourth bridge circuit (4) is identical to the second bridge circuit (5) but has MR elements (3) with opposite magnetization (M) of the free layer of the respective MR elements (3).

21. A magnetoresistive detection device according to any one of the preceding claims, wherein the substrate (2) comprises a plurality of hills or valleys including a first surface (2a1) and a second surface (2a2) facing each other, or a third surface (2a3) and a fourth surface (2a4) facing each other, wherein MR elements (3) of adjacent resistors (4a1 -4a4, 4b1 -4b4, 5a1 -5a4, 5b1 -5b4) are arranged on the same hill or valley.

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