TWI633319B - Magnetic field sensing apparatus and detection method thereof - Google Patents

Abstract

Magnetic field sensing device and sensing method. The magnetic field sensing device includes an anisotropic magnetoresistance, a current generator, and an arithmetic unit. The anisotropic magnetoresistance acts through the magnetization direction to provide a first resistance value according to the measured magnetic field during the first magnetic field sensing phase and a second resistance value according to the measured magnetic field during the second magnetic field sensing phase. The current generator supplies current in accordance with the direction of the current to flow across the ends of the anisotropic magnetoresistance. The operator performs an arithmetic operation on the first magnetic field sensing phase and the second magnetic field sensing phase according to the first voltage difference and the second voltage difference respectively generated by the current and generates a magnetic field sensing voltage result.

Description

Magnetic field sensing device and sensing method

The present invention relates to a magnetic field sensing device and a sensing method, and more particularly to a magnetic field sensing device and a sensing method composed of an anisotropic magnetoresistance.

The magnetic field sensing device is the basic device that provides a compass and motion tracking system. For portable systems such as smartphones, tablets or smart watches, and commercial or industrial systems such as drones, the magnetic field sensing device must be very accurate, with a small package size and a very energy efficient data rate at high output. These requirements have made magnetoresistive sensors including anisotropic magneto-resistance (AMR), giant magneto-resistance (GMR), and tunneling magneto-resistance (TMR) sensors mainstream. Among them, the anisotropic magnetoresistive sensor is the earliest developed magnetoresistance technology. Although the sensitivity of the anisotropic magnetoresistive sensor is lower than that of the giant magnetoresistance and the tunnel magnetoresistive sensor, the production cost is low, the hysteresis is low, and the bidirectional magnetic setting operation mode is still competitive.

In the prior art, the anisotropic magnetoresistive sensor is dominated by a complete Wheatstone bridge structure. However, in an anisotropic magnetoresistive sensor of a Wheatstone bridge structure, four anisotropic magnetoresistances are required, which increases production costs and requires a large design layout area.

The invention provides a magnetic field sensing device and a sensing method, which can reduce production cost and reduce design layout area.

The magnetic field sensing device of the present invention includes an anisotropic magnetoresistance, a current generator, and an arithmetic unit. The anisotropic magnetoresistance acts through the magnetization direction to provide a first resistance value according to the measured magnetic field during the first magnetic field sensing phase, and provides a second resistance value according to the measured magnetic field during the second magnetic field sensing phase, first The resistance value is different from the second resistance value. The current generator is coupled to the anisotropic magnetoresistance to provide a current according to the direction of the current to flow through both ends of the anisotropic magnetoresistance. The operator has a first input end and a second input end respectively coupled to opposite ends of the anisotropic magnetoresistance. For the first magnetic field sensing phase and the second magnetic field sensing phase, the anisotropic magnetoresistance is respectively determined according to the current The generated first voltage difference and the second voltage difference are arithmetically operated and thereby generate a magnetic field sensing voltage result.

The magnetic field sensing method of the present invention comprises: providing a current according to a current direction to flow through both ends of the anisotropic magnetoresistance; and setting an action through the magnetization direction in the first magnetic field sensing phase, so that the anisotropic magnetoresistance is provided according to the measured magnetic field a first resistance value, and a first voltage difference is generated according to the current; and a magnetization direction is set in the second magnetic field sensing phase Acting to cause the anisotropic magnetoresistance to provide a second resistance value according to the measured magnetic field, and generating a second voltage difference according to the current; and performing an arithmetic operation according to the first voltage difference and the second voltage difference, thereby generating a magnetic field sensing voltage result .

Based on the above, the magnetic field sensing device of the present invention provides an action of the magnetizing direction through an anisotropic magnetoresistance to provide a first resistance value according to the measured magnetic field during the first magnetic field sensing phase, and the computing device adds The current is generated to generate a first voltage difference of the first magnetic field sensing phase. A second resistance value is provided in accordance with the measured magnetic field during the second magnetic field sensing phase, and the operator generates a second voltage difference in the second magnetic field sensing phase based on the applied current. And the operator generates a magnetic field sensing voltage result according to the first voltage difference and the second voltage difference. This solution can compensate for the voltage offset present in the magnetic field sensing device and reduce the effects of environmental interference. Moreover, the circuit area of the magnetic field sensing device of the embodiment of the present invention can be effectively reduced and the circuit cost can be reduced through the two-stage detection mode.

The above described features and advantages of the invention will be apparent from the following description.

100, 400, 500‧‧‧ magnetic field sensing device

110, 410, 510‧ ‧ anisotropic magnetoresistance

120, 420, 520‧‧‧ current generator

130, 430, 530‧‧‧ arithmetic

I‧‧‧current

D‧‧‧current direction

H‧‧‧Measured magnetic field

Ha‧‧‧ magnetic field value

V1, V2, △V‧‧‧ voltage difference

Vo‧‧‧ Magnetic field sensing voltage results

132, 432, 532‧‧‧ error amplifier

134‧‧‧ temporary storage device

136‧‧‧Arithmetic Operator

411, 412, 511, 512, 513, 514 ‧ ‧ sub-anterior magnetoresistance

GND‧‧‧ Ground Reference Potential

C1, C2‧‧‧ area

D1, D2, D3, D4‧‧‧ set direction

CV1, CV2‧‧‧ curve

S210, S220, S230, S240‧‧‧ steps

1 is a schematic view of a magnetic field sensing device according to a first embodiment of the present invention.

2 is a flow chart of a magnetic field sensing method according to an embodiment of the invention.

FIG. 3 is a schematic diagram of an arithmetic unit according to an embodiment of the present invention.

4 is a schematic view of a magnetic field sensing device according to a second embodiment of the present invention.

5A and 5B are schematic views of a magnetic field sensing device according to a third embodiment of the present invention.

6A is a waveform diagram of magnetic field detection of a magnetic field sensing device according to a third embodiment of the present invention.

FIG. 6B is a waveform diagram showing magnetic field detection results of the magnetic field sensing device according to the third embodiment of the present invention.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a magnetic field sensing device according to an embodiment of the present invention. The magnetic field sensing device 100 includes an anisotropic magnetoresistor 110, a current generator 120, and an arithmetic unit 130. The anisotropic magnetoresistance 110 transmits a magnetization direction setting operation to provide a first resistance value and a second resistance value in accordance with the measured magnetic field H. The current generator 120 is coupled to the anisotropic magnetoresistive resistor 110 to provide a current I according to the current direction D to flow through both ends of the anisotropic magnetoresistive resistor 110. The computing device 130 has an input end of the computing device coupled to the two ends of the anisotropic magnetoresistive resistor 110, and a first resistance value provided for the anisotropic magnetoresistance and a first voltage difference generated by the second resistance value according to the current respectively. And the second voltage difference performs an arithmetic operation, and thereby generates a magnetic field sensing voltage result Vo.

In the embodiment of FIG. 1, the anisotropic magnetoresistor 110 may be a body having a barber pole-like structure and having a ferromagnetic film material. That is, the surface of the anisotropic magnetoresistive resistor 110 is provided with a plurality of sets of shorting bars extending obliquely with respect to the direction in which the anisotropic magnetoresistance extends with respect to the anisotropic magnetoresistance, and the shorting bars are spaced apart from each other and parallel Set on the main body. The invention is not limited thereto.

The operation mode of the magnetic field sensing device will be described. FIG. 2 is a flow chart showing the magnetic field sensing method according to an embodiment of the present invention. Referring to FIG. 1 and FIG. 2, in step S210, the current generator 120 supplies a current I and flows through both ends of the anisotropic magnetoresistor 110 according to the current direction D. Next, the sensing of the measured magnetic field H is started. In the embodiment of FIGS. 1 and 2, the sensing action of the measured magnetic field H can be temporally distinguished into a first magnetic field sensing phase and a second magnetic field sensing phase. . In step S220, the magnetic field sensing device 100 performs a first magnetic field sensing phase, and in the first magnetic field sensing phase, the magnetization direction setting action is performed for the anisotropic magnetoresistive resistor 110, and the anisotropic magnetoresistive resistor 110 is set. The magnetization direction is the first set direction. Thus, the anisotropic magnetoresistor 110 can provide a first resistance value according to the measured magnetic field H, and can generate a first voltage difference according to the current I provided by the current generator 120. In step S220, the magnetic field sensing device 100 performs a second magnetic field sensing phase. In the second magnetic field sensing phase, the magnetization direction setting action may be first performed on the anisotropic magnetoresistive resistor 110, and the magnetization direction of the anisotropic magnetoresistive resistor 110 is set to a second set direction. Thus, the anisotropic magnetoresistor 110 is subjected to The magnetic field H can provide a second resistance value and can generate a second voltage difference depending on the current I provided by the current generator 120. Wherein, the first setting direction is opposite to the second setting direction.

Next, in step S240, the arithmetic unit 130 performs an arithmetic operation according to the first voltage difference provided by the anisotropic magnetoresistive resistor 110 in the first magnetic field sensing phase and the second voltage difference provided in the second magnetic field sensing phase, and Thereby generating a magnetic field sensing voltage result Vo.

With respect to the magnetization direction setting operation of the present embodiment, the anisotropic magnetoresistance 110 can perform the magnetization direction setting operation through the magnetization direction setting elements in the first magnetic field sensing phase and the second magnetic field sensing phase. The magnetization direction setting element can be disposed adjacent to the anisotropic magnetoresistance without particular limitation. Referring to FIGS. 1 and 2, the magnetization direction of the anisotropic magnetoresistive resistor 110 is set by a magnetization direction setting member (not shown) such that the magnetization direction of the anisotropic magnetoresistive resistor 110 is set to be the first in step S220. A direction is set, and the magnetization direction of the anisotropic magnetoresistive resistor 110 is set to the second set direction in step S230. Wherein, the first setting direction and the second setting direction may be opposite directions.

Referring to FIG. 1 and FIG. 2, the magnetization direction of the anisotropic magnetoresistive resistor 110 in the first magnetic field sensing phase and the current direction D of the current I provided by the current generator 120 may be the same in step S220, in step S230. The magnetization direction of the intermediate anisotropic magnetoresistive resistor 110 in the second magnetic field sensing phase may be opposite to the current direction D of the current I supplied by the current generator 120. The above described method is only an example. In other embodiments of the present invention, the first set direction in the first magnetic field sensing phase may be opposite to the current direction D, and the second set direction in the second magnetic field sensing phase. It can be the same as the current direction D.

When the anisotropic magnetoresistive resistor 110 does not receive the measured magnetic field H, the anisotropic magnetoresistive resistor 110 maintains a fixed original resistance value. When the anisotropic magnetoresistive resistor 110 receives the measured magnetic field H, the resistance value of the anisotropic magnetoresistor 110 varies with the magnitude of the measured magnetic field H. For example, when the first resistance value R1 provided by the anisotropic magnetoresistive resistor 110 in the first magnetic field sensing phase is caused by the measured magnetic field H, the first resistance value is used. R1 is increased to R1=R0+ΔR. Where R0 is the original resistance value and ΔR is the change value. Since the magnetization direction of the anisotropic magnetoresistive resistor 110 is opposite to the second magnetic field sensing phase during the first magnetic field sensing phase, the second resistance value R2 provided by the anisotropic magnetoresistive resistor 110 during the second magnetic field sensing phase is The same measured magnetic field H has a corresponding decrease, that is, the second resistance value R2 is reduced to R2=R0-ΔR. Conversely, when the first resistance value provided by the anisotropic magnetoresistive resistor 110 during the first magnetic field sensing phase is reduced by the influence of the measured magnetic field H, the second resistance value provided during the second magnetic field sensing phase It will increase accordingly.

Moreover, when the anisotropic magnetoresistive resistor 110 receives the measured magnetic field H, the current generator 120 provides a current I flowing through the two ends of the anisotropic magnetoresistive resistor 110 having the first resistance value according to the current direction D, so that the anisotropic magnetoresistance The first voltage difference corresponding to the first resistance value is generated during the first magnetic field sensing phase. And, in the second magnetic field sensing phase, the anisotropic magnetoresistive resistor 110 having the second resistance value generates a second voltage difference corresponding to the second resistance value. The operator 130 can respectively receive the first and second voltage differences in the first and second magnetic field sensing stages by coupling the two ends of the anisotropic magnetoresistive 110, and the first and second voltage differences are performed. An arithmetic operation (eg, a subtraction operation) to generate a magnetic field sensing voltage result Vo.

As such, the magnetic field sensing device 100 of the embodiment of the present invention receives the first and second voltage differences by the arithmetic unit 130 and performs an arithmetic operation to generate the magnetic field sensing voltage result Vo, which may be used in the circuit of the computing unit 130. The voltage offset creates a compensating effect and reduces the effects of environmental interference. Moreover, the circuit area of the magnetic field sensing device 100 of the embodiment of the present invention can be effectively reduced by means of time-sharing detection. Reduce circuit costs.

Please refer to FIG. 3. FIG. 3 is a schematic diagram showing an embodiment of an arithmetic unit according to an embodiment of the present invention. In the embodiment of FIG. 3, the arithmetic unit 130 includes an error amplifier 132, a temporary storage device 134, and an arithmetic operator 136. The input ends of the error amplifiers 132 are respectively coupled to the two ends of the anisotropic magnetoresistors for calculating the voltage difference V1 according to the voltage difference between the two ends of the anisotropic magnetoresistance in the first magnetic field sensing phase. Further, the error amplifier 132 calculates the voltage difference V2 in accordance with the voltage difference across the anisotropic magnetoresistance in the second magnetic field sensing phase. The temporary storage device 134 can be any type of volatile or non-volatile memory, or any other data storage device known to those of ordinary skill in the art. The temporary storage device 134 is coupled to the output of the error amplifier 132 and can be used to store the voltage difference V1. The arithmetic operator 136 is coupled to the error amplifier 132 and the temporary storage device 134 for receiving the voltage difference V1 by the temporary storage device 134 and directly receiving the voltage difference V2 by the error amplifier 132, and performing arithmetic operations for the voltage difference V1 and the voltage difference V2. To generate a magnetic field sensing voltage result Vo. In other embodiments, the temporary storage device 134 can be used to store the voltage difference V1 and the voltage difference V2, and the arithmetic operator 136 can read the voltage difference V1 and the voltage difference V2 from the temporary storage device 134 to perform an arithmetic operation to generate a magnetic field sense. Measure the voltage result Vo.

4 is a schematic diagram of a magnetic field sensing device performing a first magnetic field sensing phase according to another embodiment of the present invention. Different from FIG. 1, the anisotropic magnetoresistive resistor 410 of the embodiment of FIG. 4 has the first and second anisotropic magnetoresistances 411, 412, and the sub- anisotropy magnetoresistors 411, 412 are connected in series with the operator 430. Between the input and the second input. That is, the anisotropic magnetoresistive resistor 410 is composed of sub- anisotropy magnetoresistors 411, 412, A single magnetoresistive structure is formed, and both ends of the anisotropic magnetoresistive 410 are coupled to both ends of the arithmetic unit 430, respectively. The second input end of the operator 430 can be coupled to the ground reference potential GND.

In the embodiment of FIG. 4, the anisotropic magnetoresistive resistor 410 can be oscillated by the magnetization direction during the first magnetic field sensing phase such that the anisotropic magnetoresistors 411, 412 in the anisotropic magnetoresistive resistor 410 have the same or The opposite magnetization direction and the first resistance value are generated according to the measured magnetic field, and the error amplifier 432 in the operator 430 can generate the voltage difference V1 according to the current I supplied by the current generator 420. The magnetization direction of the sub anisotropy 411 is the same as or opposite to the current direction. Then, the anisotropic magnetoresistive resistor 410 can pass the magnetization direction setting action during the second magnetic field sensing phase, so that the anisotropic magnetoresistors 411, 412 have the same or opposite magnetization directions and generate a second according to the same measured magnetic field. The resistance value, and the error amplifier 432 in the operator 430 can generate a voltage difference V2 according to the current I supplied by the current generator 420. The magnetization direction of each of the anisotropic magnetoresistors 411, 412 in the first magnetic field sensing phase is opposite to the magnetization direction of the second magnetic field sensing phase. The arithmetic unit 430 performs an arithmetic operation on the voltage differences V1, V2 to generate a magnetic field sensing voltage result.

5A and 5B are schematic views of a magnetic field sensing device according to another embodiment of the present invention. Different from the embodiment of FIG. 1 and FIG. 4, in the embodiment of FIGS. 5A and 5B, the anisotropic magnetoresistance 510 in the magnetic field sensing device 500 includes sub- anisotropy magnetoresistors 511, 512, and 513. 514. And the sub- anisotropy magnetoresistors 511, 512, 513, 514 are connected in series between the first input end and the second input end of the arithmetic unit. That is, the anisotropic magnetoresistance 510 is formed by the sub anisotropy magnetoresistors 511, 512, 513, and 514. A single magnetoresistive structure, and two ends of the anisotropic magnetoresistance 510 are respectively coupled to both ends of the arithmetic unit 530.

In the present embodiment, the anisotropic magnetoresistance 510 may be configured to cause the anisotropic magnetoresistances 511, 512 to be disposed in the region C1, and the anisotropic magnetoresistances 513, 514 are disposed in the region C2. The number, series connection order, and number of regions of the sub-anthogonal magnetoresistance of the present invention are not limited thereto.

Referring to FIG. 5A, FIG. 5A is a schematic diagram of the magnetic field sensing device 500 of the embodiment performing a first magnetic field sensing phase. In FIG. 5A, the magnetic field sensing device 500 performs a first magnetic field sensing phase, and the magnetization direction of the sub-anisotropy magnetoresistors 511, 512 in the magnetization direction setting action setting region C1 is the first setting direction D1, and the setting region C2 The magnetization directions of the intermediate anisotropic magnetoresistances 513 and 514 are the second set direction D2. The anisotropic magnetoresistance 510 is caused to provide a first resistance value in accordance with the measured magnetic field, and a voltage difference V1 is generated in accordance with the current I supplied from the current generator 520.

In the present embodiment, the first set direction D1 is opposite to the second set direction D2, and the first set direction D1 and the current direction D may be the same or opposite. In other embodiments, the first setting direction D1 and the second setting direction D2 may be the same.

Referring to FIG. 5B, FIG. 5B is a schematic diagram showing a second magnetic field sensing phase performed by the magnetic field sensing device of the same embodiment as FIG. 5A. The magnetic field sensing device 500 can change the magnetization direction of the sub-anisotropy magnetoresistors 511 and 512 in the magnetization direction setting action setting region C1 to the third setting direction D3 in the second magnetic field sensing phase, and set the sub-differentiation in the region C2. The magnetization direction of the directional magnetic resistances 513, 514 is the fourth set direction D4, so that the anisotropic magnetoresistance 510 provides the second resistance value according to the measured magnetic field, and is based on the electric The current I provided by the stream generator 520 produces a voltage difference V2. In this embodiment, the third set direction D3 is opposite to the fourth set direction D4. In other embodiments, the third setting direction D3 and the fourth setting direction D4 may be the same.

It should be noted here that the third setting direction D3 is opposite to the first setting direction D1, and the fourth setting direction D4 is opposite to the second setting direction D2.

5A, 5B, in the embodiment of the first magnetic field sensing phase of FIG. 5A, the first set direction D1 and the second set direction D2 are head-to-head opposite directions. Then, in the embodiment of the second magnetic field sensing phase of FIG. 5B, the third set direction D3 and the fourth set direction D4 are opposite directions of tail to tail.

Regarding the hardware architecture portion of the error amplifier 532, a differential amplifier architecture well known to those skilled in the art can be implemented as the error amplifier 532 of the present invention without particular limitation. Regarding the portion of the current generator 520, a current generator circuit well known to those skilled in the art can be used to implement the current generator 520 of the present invention, and there is no particular limitation.

Please refer to FIG. 6A. FIG. 6A is a waveform diagram of magnetic field detection of the magnetic field sensing device of the embodiment of FIGS. 5A and 5B of the present invention. In FIG. 6A, the vertical axis represents the voltage value of the first magnetic field detection result V _O , and the horizontal axis represents the magnitude of the measured magnetic field H. Referring to FIG. 5A and FIG. 6A simultaneously, when the magnetic field sensing device 400 receives the measured magnetic field H during the first magnetic field sensing phase, and when the first magnetic field is in the first set direction and the second set direction In the opposite direction relationship of the head-to-head, the fixed range of the measured magnetic field H has a linear positive correlation with the first resistance value provided by the anisotropic magnetoresistor 510, such as the curve CV1. When the measured magnetic field H is equal to Ha during the first magnetic field sensing phase, the error amplifier 532 in the operator 530 calculates the corresponding magnetic field by receiving the voltage difference across the anisotropic magnetoresistance 510. The first voltage difference V1 = ΔV when H is equal to Ha, and the result of the first voltage difference V1 is stored in the temporary storage device.

It is worth mentioning here that the first voltage difference V1 of the error amplifier for the voltage difference across the anisotropic magnetoresistive 410 can reduce the system electrical offset and environmental interference during the first magnetic field sensing phase. The impact, so the sensing accuracy can be improved.

Referring to FIG. 5B and FIG. 6A simultaneously, the measured magnetic field H is received during the first magnetic field sensing phase, and when the first set direction of the second magnetic field sensing phase is opposite to the second set direction In the directional relationship, the magnitude of the measured magnetic field H exhibits a linear negative correlation with the second resistance value provided by the anisotropic magnetoresistor 510, such as curve CV2. When the measured magnetic field H is equal to Ha during the second magnetic field sensing phase, the error amplifier 532 in the arithmetic unit 530 calculates the corresponding magnetic field by receiving the voltage difference across the anisotropic magnetoresistance 510. The second voltage difference V2 when H is equal to Ha = -ΔV.

It is worth mentioning here that the error amplifier 532 operates on the second voltage difference V2 of the voltage difference across the anisotropic magnetoresistance 510 to reduce the system electrical offset and environment during the first magnetic field sensing phase. The influence of interference, so the sensing accuracy can be improved.

Please refer to FIG. 6B. FIG. 6B is a waveform diagram showing magnetic field detection results of the magnetic field sensing device of the embodiment of FIGS. 5A and 5B of the present invention. In FIG. 6B, the vertical axis represents the voltage value of the first magnetic field detection result V _O , and the horizontal axis represents the magnitude of the measured magnetic field H. After the second magnetic field sensing phase is completed and the second voltage difference V2 is calculated, the arithmetic operator inside the arithmetic unit receives the first voltage difference V1 stored from the temporary storage device and the second voltage difference V2 from the error amplifier. And performing an arithmetic operation on the first voltage difference V1 and the second voltage difference V2, thereby generating a magnetic field sensing voltage result Vo. In other embodiments, the result of the second voltage difference may be stored in the temporary storage device, and the arithmetic operator inside the computing device receives the first voltage difference and the second voltage difference stored from the temporary storage device, and A voltage difference and a second voltage difference are arithmetically operated to generate a magnetic field sensing voltage result.

Next, an arithmetic operation will be described in detail to generate a magnetic field sensing voltage result. In the embodiment of FIGS. 5A, 5B, the magnitude of the measured magnetic field H exhibits a nearly linear positive correlation with the first resistance value provided by the anisotropic magnetoresistor 510 during the first magnetic field sensing phase, and the measured magnetic field H The magnitude exhibits a nearly linear negative correlation with the second resistance value provided by the anisotropic magnetoresistor 510 during the second magnetic field sensing phase. Therefore, under the same current and current direction supply, the voltage difference V1 generated by the anisotropic magnetoresistance 510 in the first magnetic field sensing phase and the voltage difference V2 generated in the second magnetic field sensing phase correspond to the magnitude of the measured magnetic field H. It has an opposite waveform, that is, if the voltage difference V1 is a positive value, and the voltage difference V2 is a negative value. When the magnetic field Ha is sensed during the first magnetic field sensing phase and the second magnetic field sensing phase, the arithmetic operator inside the operator may target the first voltage difference V1=ΔV and the second voltage corresponding to Ha The difference V2 = - ΔV. Therefore, the arithmetic operator inside the operator can be directed to the first voltage. The difference V1 and the second voltage difference V2 are subjected to an arithmetic operation including a subtraction operation, and a magnetic field sensing voltage result Vo=V1-V2=ΔV-(−ΔV)=2×ΔV is obtained, thereby obtaining a magnetic field sensing voltage. The result doubles the output.

It is worth mentioning that in the embodiment, the above-mentioned arithmetic operation manner can also reduce the influence of system electrical offset and environmental interference in the first magnetic field sensing phase and the second magnetic field sensing phase. . And when the measured magnetic field H is 0, the magnetic field sensing device is substantially zero output.

In summary, the magnetic field sensing device of the present invention includes an anisotropic magnetoresistance, a current generator, and an arithmetic unit. The magnetic field sensing device is configured to move through the magnetization direction by an anisotropic magnetoresistance to provide a first resistance value according to the measured magnetic field during the first magnetic field sensing phase, and the operator generates the current according to the applied current provided by the current generator. The first voltage difference of the first magnetic field sensing phase. A second resistance value is provided in accordance with the measured magnetic field during the second magnetic field sensing phase, and the operator generates a second voltage difference in the second magnetic field sensing phase according to the applied current provided by the current generator. And the operator generates a magnetic field sensing voltage result according to the first voltage difference and the second voltage difference. The magnetic field sensing device of the present invention requires only one to complete the magnetic field sensing operation, reducing the design layout area. Moreover, the magnetic field sensing device of the present invention has the effects of reducing system electrical offset and environmental interference, and improves the signal-to-noise ratio of the sensing device.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

Claims (14)

A magnetic field sensing device includes: an anisotropic magnetoresistance that is set in a magnetization direction to provide a first resistance value according to a measured magnetic field during a first magnetic field sensing phase, and a second magnetic field The sensing phase provides a second resistance value according to the measured magnetic field, the first resistance value is different from the second resistance value, wherein the magnetization direction setting action sets the anisotropic magnetoresistance in the first magnetic field sensing phase The magnetization direction is a first set direction, and the magnetization direction of the anisotropic magnetoresistance is set to a second set direction in the second magnetic field sensing phase, the first set direction is opposite to the second set direction; a current generator coupled to the anisotropic magnetoresistor to provide a current according to a current direction to flow through both ends of the anisotropic magnetoresistance; and an operator having a first input end coupled to the second input end Connected to both ends of the anisotropic magnetoresistance, in the first magnetic field sensing phase and the second magnetic field sensing phase, a first voltage difference generated by the anisotropic magnetoresistance according to the current and a First Subtraction voltage difference, and so as to generate a magnetic field sensing voltage results. The magnetic field sensing device of claim 1, wherein the first set direction is the same as or opposite to the current direction. The magnetic field sensing device of claim 1, wherein the operator comprises: an error amplifier, the first input end and the second input end of the error amplifier Not coupled to both ends of the anisotropic magnetoresistor for providing the first voltage difference according to the voltage across the anisotropic magnetoresistive resistor during the first magnetic field sensing phase and according to the second magnetic field sensing phase The voltage across the anisotropic magnetoresistance provides the second voltage difference; a temporary storage device coupled to the output of the error amplifier for storing the first voltage difference; and an arithmetic operator coupled to The temporary storage device and the error amplifier are configured to receive the first voltage difference and the second voltage difference, and perform an arithmetic operation on the first voltage difference and the second voltage difference to generate the magnetic field sensing voltage result. The magnetic field sensing device of claim 3, wherein the temporary storage device is configured to store the first voltage difference and the second voltage difference. The magnetic field sensing device of claim 1, wherein the anisotropic magnetoresistance comprises at least a first anisotropic magnetoresistance and at least a second anisotropic magnetoresistance, the at least one first The sub anisotropy magnetoresist and the at least one second sub anisotropy magnetoresistor are connected in series between the first input end and the second input end of the arithmetic unit. The magnetic field sensing device of claim 5, wherein the magnetization direction setting operation sets a magnetization direction of the at least one first anisotropic magnetoresistor to the first set direction in the first magnetic field sensing phase And setting a magnetization direction of the at least one second sub-antotropic magnetoresistance to the second set direction, and setting a magnetization direction of the at least one first anisotropic magnetoresistance to the second magnetic field sensing stage Setting a direction of three, setting a magnetization direction of the at least one second sub-anisotropy magnetoresor to the fourth set direction, The first setting direction is the same as or opposite to the second setting direction, wherein the first setting direction is opposite to the third setting direction and the second setting direction is opposite to the fourth setting direction. The magnetic field sensing device of claim 6, wherein the first set direction is the same as or opposite to the current direction. A magnetic field sensing method includes: providing a current according to a current direction to flow through both ends of an anisotropic magnetoresistance; and setting an action through a magnetization direction in a first magnetic field sensing phase to cause the anisotropic magnetoresistance Providing a first resistance value according to a measured magnetic field, and generating a first voltage difference according to the current, wherein a magnetization direction of the anisotropic magnetoresistor is set by the magnetization direction setting action during the first magnetic field sensing phase a first setting direction; a magnetizing direction setting action in a second magnetic field sensing phase, the anisotropic magnetoresistance providing a second resistance value according to the measured magnetic field, and generating a second voltage difference according to the current The magnetizing direction of the anisotropic magnetoresistor is set to a second set direction by the magnetization direction setting operation, wherein the first set direction is opposite to the second set direction; and The first voltage difference and the second voltage difference are subtracted and thereby generate a magnetic field sensing voltage result. The magnetic field sensing method of claim 8, wherein the first set direction is the same as or opposite to the current direction. The magnetic field sensing method of claim 8, wherein the magnetizing direction is set in the first magnetic field sensing phase to cause the anisotropic magnetoelectric The step of providing the first resistance value according to the measured magnetic field, and generating the first voltage difference according to the current further comprises: comparing the voltages of the two ends of the anisotropic magnetoresistance during the first magnetic field sensing phase a difference is provided to provide the first voltage difference; and the first voltage difference is temporarily stored; and the magnetizing direction setting action is performed in the second magnetic field sensing phase, so that the anisotropic magnetoresistance provides the second according to the measured magnetic field And the step of generating the second voltage difference according to the current further comprises: comparing the difference between the voltages across the anisotropic magnetoresistance in the second magnetic field sensing phase to provide the second voltage difference. The magnetic field sensing method of claim 10, further comprising: temporarily storing the second voltage difference. The magnetic field sensing method of claim 8, further comprising: providing at least one first sub-anisotropy magnetoresistance and at least one second sub-anisotropy magnetoresistance connected in series to form the anisotropy Magnetoresistance. The magnetic field sensing method of claim 12, wherein the magnetizing direction setting action is performed during the first magnetic field sensing phase, so that the anisotropic magnetoresistance provides the first resistance value according to the measured magnetic field. The step of: setting, in the first magnetic field sensing phase, the magnetization direction of the at least one first anisotropic magnetoresistor to the first set direction, and setting the at least one second sub-inotropic direction The magnetization direction of the magnetoresistance is the second set direction, wherein the first set direction is the same as or opposite to the second set direction; The step of setting the magnetization direction through the magnetization direction during the second magnetic field sensing phase, the step of providing the anisotropic magnetoresistance according to the measured magnetic field includes: setting the magnetization direction through the second magnetic field sensing phase The action sets the magnetization direction of the at least one first anisotropic magnetoresistance to the third set direction, and sets the magnetization direction of the at least one second sub-anisotropy magnetoresistor to the fourth set direction, wherein the first The set direction is opposite to the third set direction and the second set direction is opposite to the fourth set direction. The magnetic field sensing method of claim 13, wherein the first set direction is the same as or opposite to the current direction.