Signal processing circuit for wheel speed sensor and wheel speed sensor

Abstract

The application provides a wheel speed sensor signal processing circuit and a wheel speed sensor, the signal processing circuit comprising a magnetic induction element, a first circuit and a signal processing chip, the first circuit comprising a first operational amplifier, a first arithmetic operation circuit, a first analog-to-digital converter and a first offset digital-to-analog converter. The wheel speed sensor signal processing circuit of the application can obtain a first offset voltage signal from the initial signal output by the first offset digital-to-analog converter through the signal processing chip in the case that the first wheel speed sensor signal output by the magnetic induction element is offset, and feed back the first offset voltage signal to the first offset digital-to-analog converter and transmit the first offset voltage signal to the first arithmetic operation circuit, so as to correct the first wheel speed sensor signal, thereby accurately measuring the positive and negative of the direction corresponding voltage signal when the speed corresponding voltage signal is zero, and further ensuring the accuracy of the direction signal processing and identification.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a signal processing circuit for a wheel speed sensor and a wheel speed sensor. Background Technology

[0002] Hall effect magnetic sensing technology is widely used in various industries. Based on the Hall effect principle, if magnetic lines of force pass through a powered Hall sensor, different potentials will be generated across the Hall sensor, creating a voltage difference. Amplifying and comparing this voltage difference allows for the sensing of magnetic fields, generating corresponding switching signals. In some applications, such as automotive gear systems, where real-time vehicle speed sampling is required, Hall sensors are used for speed sensing. For example, in speed sensing, the Hall sensor is fixed to the transmission gear, while a multi-pair S / N magnetic ring is embedded in the drive shaft and rotates with the gear. The sensor detects the movement of the magnetic ring, outputs a sensor signal, and then uses this signal to determine the gear speed and direction of rotation.

[0003] When a wheel speed sensor is operating, installation errors in the Hall element and magnet, as well as the shape of the wheel itself, can cause mean and difference drifts in the back magnetism, leading to errors in direction detection and making it difficult to effectively identify the sensor's direction signal, thus causing malfunctions in the detection process. Therefore, there is an urgent need for a device capable of accurately processing sensor signals to improve the accuracy of sensor signal processing and identification. Summary of the Invention

[0004] This invention provides a signal processing circuit for a wheel speed sensor to solve the defect of inaccurate direction signals output by wheel speed sensors in the prior art, and to achieve deviation correction processing of the output deviation signals of wheel speed sensors.

[0005] This invention provides a signal processing circuit for a wheel speed sensor, comprising:

[0006] A magnetic induction element is used to collect the signal from the first gear speed sensor.

[0007] A first circuit is connected to the output terminal of the magnetic sensing element; the first circuit includes a first operational amplifier, a first arithmetic operation circuit, and a first analog-to-digital converter connected in sequence; and a first offset digital-to-analog converter electrically connected between the output terminal of the first analog-to-digital converter and the first arithmetic operation circuit; wherein, the input terminal of the first operational amplifier is electrically connected to the output terminal of the magnetic sensing element, and is used to amplify the first wheel speed sensor signal, generate a first wheel speed amplified signal, and transmit it to the first arithmetic operation circuit;

[0008] The signal processing chip is electrically connected to the first analog-to-digital converter and the first offset digital-to-analog converter. The signal processing chip obtains the first offset voltage signal based on the initial signal output by the first offset digital-to-analog converter, feeds it back to the first offset digital-to-analog converter, and transmits it to the first arithmetic operation circuit. Then, the first arithmetic operation circuit processes the first wheel speed amplification signal and the first offset voltage signal to determine the rotation direction information of the gear.

[0009] According to a signal processing circuit for a wheel speed sensor provided by the present invention, the magnetic induction element includes a Hall element, and the first wheel speed sensor signal includes a first sub-signal and a second sub-signal.

[0010] The first circuit further includes a third arithmetic operation circuit and a fourth arithmetic operation circuit, the output terminals of the third arithmetic operation circuit and the fourth arithmetic operation circuit are both electrically connected to the input terminal of the first operational amplifier;

[0011] The Hall element used to determine the rotation direction information in the Hall wheel speed sensor includes a first Hall element and a second Hall element. The first Hall element includes a first Hall plate and a second Hall plate, and the second Hall element includes a third Hall plate and a fourth Hall plate. The potential of the first Hall plate is higher than that of the second Hall plate, and the potential of the third Hall plate is higher than that of the fourth Hall plate.

[0012] The output terminals of the first Hall plate and the third Hall plate are both electrically connected to the input terminal of the third arithmetic operation circuit, and the output terminals of the second Hall plate and the fourth Hall plate are both electrically connected to the input terminal of the fourth arithmetic operation circuit. The third arithmetic operation circuit is used to calculate the difference between the potential of the first Hall plate and the potential of the third Hall plate to obtain the first sub-signal, and the fourth arithmetic operation circuit is used to calculate the difference between the potential of the second Hall plate and the potential of the fourth Hall plate to obtain the second sub-signal.

[0013] According to the signal processing circuit of a wheel speed sensor provided by the present invention, the first operational amplifier is a differential operational amplifier, which is used to perform differential processing on the first sub-signal and the second sub-signal and then amplify the signal.

[0014] According to the present invention, a signal processing circuit for a wheel speed sensor further includes a second circuit. The input terminal of the second circuit is used to receive the second wheel speed sensor signal output by the Hall element. The second circuit includes a second operational amplifier and a second analog-to-digital converter connected in sequence. The input terminal of the second operational amplifier is electrically connected to the output terminal of the Hall element, and is used to amplify the second wheel speed sensor signal to generate a second wheel speed amplified signal and transmit it to the second analog-to-digital converter. The output terminal of the second analog-to-digital converter is electrically connected to the input terminal of the signal processing chip. The signal processing chip determines the gear rotation speed information after performing analog-to-digital conversion on the second wheel speed amplified signal through the second analog-to-digital converter.

[0015] According to a signal processing circuit for a wheel speed sensor provided by the present invention, the second circuit further includes a second arithmetic operation circuit electrically connected between the second operational amplifier and the second analog-to-digital converter, and a second offset digital-to-analog converter electrically connected between the output terminal of the second analog-to-digital converter and the second arithmetic operation circuit;

[0016] The signal processing chip obtains the second offset voltage signal based on the initial signal output by the second offset digital-to-analog converter, feeds it back to the second offset digital-to-analog converter, and transmits it to the second arithmetic operation circuit. Then, the second arithmetic operation circuit processes the second wheel speed amplification signal and the second offset voltage signal to determine the gear rotation speed information.

[0017] According to a signal processing circuit for a wheel speed sensor provided by the present invention, the Hall element used to determine rotation speed information in the magnetic sensing element includes a third Hall element and a fourth Hall element. At least one of the Hall elements used to determine rotation direction information in the magnetic sensing element is different from the third Hall element, or at least one of the Hall elements used to determine rotation direction information in the magnetic sensing element is different from the fourth Hall element.

[0018] According to a signal processing circuit for a wheel speed sensor provided by the present invention, the second wheel speed sensor signal includes a third sub-signal and a fourth sub-signal;

[0019] The second circuit further includes a fifth arithmetic operation circuit and a sixth arithmetic operation circuit, the output terminals of the fifth arithmetic operation circuit and the sixth arithmetic operation circuit are both electrically connected to the input terminal of the second operational amplifier;

[0020] The third Hall element includes a fifth Hall plate and a sixth Hall plate, and the fourth Hall element includes a seventh Hall plate and an eighth Hall plate; the potential of the fifth Hall plate is higher than the potential of the sixth Hall plate, and the potential of the seventh Hall plate is higher than the potential of the eighth Hall plate.

[0021] The output terminals of the fifth Hall plate and the seventh Hall plate are both electrically connected to the input terminal of the fifth arithmetic operation circuit, and the output terminals of the sixth Hall plate and the eighth Hall plate are both electrically connected to the input terminal of the sixth arithmetic operation circuit. The fifth arithmetic operation circuit is used to calculate the difference between the potential of the fifth Hall plate and the potential of the seventh Hall plate to obtain the third sub-signal, and the sixth arithmetic operation circuit is used to calculate the difference between the potential of the sixth Hall plate and the potential of the eighth Hall plate to obtain the fourth sub-signal.

[0022] According to the signal processing circuit of a wheel speed sensor provided by the present invention, the second operational amplifier is a differential operational amplifier, which is used to perform differential processing on the third sub-signal and the fourth sub-signal and then amplify the signal.

[0023] According to the present invention, a signal processing circuit for a wheel speed sensor is provided, wherein the first arithmetic operation circuit includes an adder or a subtractor, and the second arithmetic operation circuit includes an adder or a subtractor.

[0024] The present invention also provides a wheel speed sensor, including a signal processing circuit as described in any of the wheel speed sensors above.

[0025] The wheel speed sensor signal processing circuit and wheel speed sensor provided by the present invention, by setting a first offset digital-to-analog converter in the first circuit corresponding to the direction of measurement, can obtain a first offset voltage signal by the signal processing chip based on the initial signal output by the first offset digital-to-analog converter when the first wheel speed sensor signal output by the magnetic induction element is offset, and feed it back to the first offset digital-to-analog converter and transmit it to the first arithmetic operation circuit to perform offset correction processing on the first wheel speed sensor signal, thereby accurately measuring the positive and negative of the voltage signal corresponding to the direction when the voltage signal corresponding to the speed is zero, thus ensuring the accuracy of direction signal processing and recognition. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the signal processing circuit of the wheel speed sensor provided by the present invention;

[0028] Figure 2 This is a schematic diagram of the signal output mode of the first Hall element and the second Hall element in the signal processing circuit of the wheel speed sensor provided by the present invention;

[0029] Figure 3 This is a schematic diagram of the signal output mode of the third Hall element and the fourth Hall element in the signal processing circuit of the wheel speed sensor provided by the present invention;

[0030] Figure 4 This is a schematic diagram of the signal processing circuit of the wheel speed sensor provided by the present invention, which includes three Hall elements;

[0031] Figure 5 This is a schematic diagram of the signal processing circuit of the wheel speed sensor provided by the present invention, which includes four Hall elements.

[0032] Figure label:

[0033] 100: First circuit; 110: First operational amplifier; 120: First analog-to-digital converter; 130: First offset digital-to-analog converter; 140: First arithmetic operation circuit; 150: Third arithmetic operation circuit; 160: Fourth arithmetic operation circuit; 200: Second circuit; 210: Second operational amplifier; 220: Second analog-to-digital converter; 230: Second offset digital-to-analog converter; 240: Second arithmetic operation circuit; 250: Fifth arithmetic operation circuit; 260: Sixth arithmetic operation circuit 300: Magnetic induction element; 310: Third arithmetic operation circuit; 320: Fourth arithmetic operation circuit; 330: First Hall element; 331: First Hall plate; 332: Second Hall plate; 340: Second Hall element; 341: Third Hall plate; 342: Fourth Hall plate; 350: Third Hall element; 351: Fifth Hall plate; 352: Sixth Hall plate; 360: Fourth Hall element; 361: Seventh Hall plate; 362: Eighth Hall plate; 400: Signal processing chip. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] In the description of the embodiments of the present invention, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] The following is combined with Figure 1-5 The present invention describes the signal processing circuit of the wheel speed sensor and the Hall wheel speed sensor.

[0039] Before describing the signal processing circuit of the wheel speed sensor in the embodiments of the present invention, the wheel speed sensor will be described first.

[0040] The wheel speed sensor in this embodiment of the invention can be a Hall effect wheel speed sensor. The Hall effect wheel speed sensor consists of a sensing head and a gear ring. The sensing head comprises a permanent magnet, a Hall element, and electronic circuitry. The Hall effect wheel speed sensor can detect the rotational speed and direction of rotation of a rotating body.

[0041] Hall effect speed sensors utilize the Hall effect principle, which means that when a control current is passed through both ends of a Hall plate made of semiconductor wafers and a magnetic field of a certain strength is applied in the direction perpendicular to the wafer, a potential, namely the Hall potential, will be generated at the other ends of the wafer. The potential is proportional to the product of the control current and the magnetic induction intensity.

[0042] When Hall effect sensors are used as gear speed sensors in automobiles, magnetic flux density is often used as the input signal. The change in magnetic flux density with wheel speed generates Hall potential pulses. After processing within the signal processing circuit, a pulse sequence is output, the percentage of which varies with the angular velocity of the gear. In other words, the rotation of the gear alternately changes the magnetic reluctance, causing changes in magnetic flux density, which allows the measurement of the Hall potential pulses output by the sensor. Therefore, the gear speed and direction of rotation can be determined based on the pulse signal.

[0043] Taking a gear as an example, multiple Hall elements and a magnet are mounted on the gear. Usually, multiple Hall elements are evenly installed at a certain position on the gear to ensure that the peak voltage output by each Hall element is similar, thereby making the output speed detection value more accurate and ensuring that the detected rotation direction is accurate.

[0044] In some cases, due to improper installation of Hall elements or magnets, the back magnetism of Hall plates of different Hall elements may deviate significantly, or the average back magnetism may differ greatly under different application scenarios. This can cause errors in the sensor's directional signal. However, the system cannot effectively identify the sensor's directional signal as an erroneous signal, resulting in poor signal processing and recognition accuracy.

[0045] like Figure 1 As shown, the signal processing circuit of the wheel speed sensor in this embodiment of the invention mainly includes a magnetic induction element 300, a first circuit 100, and a signal processing chip 400.

[0046] The magnetic induction element 300 is used to collect the first wheel speed sensor signal of the gear. The magnetic induction element 300 may include Hall elements, etc., which are not limited here.

[0047] The first circuit 100 is used to process the signal corresponding to the rotation direction output by the Hall wheel speed sensor.

[0048] The input terminal of the first circuit 100 is used to receive the first wheel speed sensor signal output by the magnetic induction element 300. The first wheel speed sensor signal is used to determine the rotation direction information.

[0049] The first wheel speed sensor signal can be a voltage signal. By analyzing the positive and negative values ​​of the voltage signal under specific conditions, the rotation direction of the gear can be determined.

[0050] Understandably, the Hall wheel speed sensor also includes a Hall element for outputting a second wheel speed sensor signal, which is used to determine the rotation speed information.

[0051] In some embodiments, the first wheel speed sensor signal used to determine rotation direction information can be compared with the wheel speed sensor signal used to determine rotation speed information. When the wheel speed sensor signal crosses zero, the sign of the first wheel speed sensor signal is determined, thereby determining the rotation direction.

[0052] It should be noted that the wheel speed sensor signal used to determine the rotation speed information and the first wheel speed sensor signal used to determine the rotation direction information are both signals acquired by the same wheel speed sensor at the same detection time.

[0053] In some embodiments, the first circuit 100 mainly includes a first operational amplifier 110, a first arithmetic operation circuit 140, a first analog-to-digital converter 120, a signal processing chip 400, and a first offset digital-to-analog converter 130, which are connected in sequence and electrically between the output terminal of the first analog-to-digital converter 120 and the first arithmetic operation circuit 140.

[0054] The input terminal of the first operational amplifier 110 is electrically connected to the output terminal of the Hall element. The output terminal of the first operational amplifier 110 and the output terminal of the first offset digital-to-analog converter 130 are both electrically connected to the input terminal of the first arithmetic operation circuit 140. The output terminal of the first arithmetic operation circuit 140 is electrically connected to the input terminal of the first analog-to-digital converter 120. The output terminal of the first analog-to-digital converter 120 is electrically connected to the input terminal of the signal processing chip 400. The input terminal of the first offset digital-to-analog converter 130 is electrically connected to the output terminal of the signal processing chip 400.

[0055] The first operational amplifier 110 is used to amplify the first wheel speed sensor signal, generate a first wheel speed amplified signal, and transmit it to the first arithmetic operation circuit 140.

[0056] In some embodiments, the first operational amplifier 110 can process and amplify the voltage signal output by the Hall element. For example, when determining direction using the potential signals output by the two Hall plates of a Hall element, the first operational amplifier 110 can calculate and amplify the difference between the potentials of the two Hall plates to obtain a voltage signal, which can then be further processed.

[0057] The first analog-to-digital converter 120 is used to convert the output analog signal, i.e., the voltage signal, into a digital signal for the signal processing chip 400 to perform calculations and processing. The signal processing chip 400 outputs the rotation direction based on the received voltage signal.

[0058] It should be noted that the first offset digital-to-analog converter 130 can convert digital signals into analog signals, for example, it can output a first offset voltage signal. The first offset digital-to-analog converter 130 is an adjustable voltage source, which can be used to extend the voltage range input to the first analog-to-digital converter 120.

[0059] The first offset voltage signal output by the first offset digital-to-analog converter 130 can be used to correct positive or negative input voltage offsets. Given the presence of the first operational amplifier 110, to prevent excessive amplification of the first operational amplifier 110, its amplification amplitude must be reduced. However, by using the first offset digital-to-analog converter 130, which can apply a fixed-magnitude first offset voltage signal in the opposite direction, excessive amplification of the first operational amplifier 110 can be prevented, effectively reducing the probability of overload overflow of the first analog-to-digital converter 120.

[0060] When a Hall effect wheel speed sensor is operating normally, the rotation of the iron gear or magnetic ring induces different voltages on different Hall elements. When the gear rotates uniformly, sinusoidal voltages will be generated on different Hall elements, with a phase difference between them. The magnitude of the phase difference mainly depends on the spacing between the Hall elements and the relative size of the gears.

[0061] In some cases, due to installation errors of the Hall wheel speed sensor, excessive back magnetic bias, or excessive back magnetic difference on the Hall plates of different Hall elements, the signal of the first wheel speed sensor has a certain deviation, resulting in an excessively large voltage signal. This causes the first analog-to-digital converter 120 on the first circuit 100 to overflow, which in turn leads to the failure to determine the sign value of the direction branch signal when the speed signal is zero, and thus the failure to determine the rotation direction.

[0062] In this case, the first offset digital-to-analog converter 130 is used to output a first offset voltage signal, which can correct excessive voltage signals, making the signal output to the signal processing chip 400 more accurate.

[0063] The first offset voltage signal is determined by the signal processing chip 400 based on the initial signal output by the first analog-to-digital converter 120. The signal processing chip 400 can acquire the first offset voltage signal based on the initial signal output by the first offset digital-to-analog converter, feed it back to the first offset digital-to-analog converter 130, and transmit it to the first arithmetic operation circuit 140. Then, the first arithmetic operation circuit 140 processes the first wheel speed amplification signal and the first offset voltage signal to determine the rotation direction information of the gear.

[0064] Understandably, when the first circuit 100 first starts working, the output voltage of the first offset digital-to-analog converter 130 is zero. At this time, after receiving the signal from the first wheel speed sensor, the first circuit 100 outputs an initial signal to the signal processing chip 400 through the first analog-to-digital converter 120. The signal processing chip 400 can determine the offset of the voltage value in the initial signal based on the received initial signal, and then control the first offset digital-to-analog converter 130 to output a first offset voltage signal corresponding to the offset of the voltage value.

[0065] After the first offset voltage signal is determined, it remains unchanged during subsequent measurements. Upon receiving the first offset voltage signal, the signal processing chip 400 determines the rotation direction information based on the signal received from the first analog-to-digital converter.

[0066] It should be noted that the deviation of the first wheel speed sensor signal is related to the installation position of the Hall wheel speed sensor and the amount of back magnetism. After updating the installation position of the Hall wheel speed sensor and replacing and adjusting the back magnet, the first offset voltage signal needs to be recalibrated to ensure the accuracy of the output signal.

[0067] In this embodiment, by setting the first offset digital-to-analog converter 130, the voltage signal with offset on the first circuit 100 can be corrected, thereby ensuring that the sign value of the direction branch signal when the speed signal is zero is accurate, thus obtaining the correct rotation direction.

[0068] In some embodiments, the first arithmetic operation circuit 140 includes an adder or a subtractor.

[0069] It is understandable that the selection of adder or subtractor can be determined based on the sign of the first offset voltage signal output by the first offset digital-to-analog converter 130.

[0070] In this embodiment, the appropriate type of first arithmetic circuit 140 can be selected based on the actual cost of the components and the difficulty of debugging, thereby reducing hardware costs and debugging workload.

[0071] According to the signal processing circuit of the wheel speed sensor provided in the embodiment of the present invention, by setting a first offset digital-to-analog converter 130 in the first circuit 100 corresponding to the direction of measurement, when the first wheel speed sensor signal output by the magnetic induction element is offset, the signal processing chip 400 controls the first offset digital-to-analog converter 130 to perform offset correction processing on the first wheel speed sensor signal, thereby accurately measuring the positive and negative signs of the voltage signal corresponding to the direction when the voltage signal corresponding to the speed is zero, and thus ensuring the accuracy of direction signal processing and recognition.

[0072] In some embodiments, the first wheel speed sensor signal includes the potential signals of the two Hall plates of a Hall element used for determining direction. In this case, the first wheel speed sensor signal is acquired using only one Hall element.

[0073] In other embodiments, the first wheel speed sensor signal can be acquired using two Hall elements.

[0074] In this case, the first wheel speed sensor signal includes a first sub-signal and a second sub-signal.

[0075] Both the first and second sub-signals are voltage signals obtained by subtracting the potential of the Hall plate.

[0076] It is understood that the first circuit 100 also includes a third arithmetic operation circuit 310 and a fourth arithmetic operation circuit 320, and the output terminals of the third arithmetic operation circuit 310 and the fourth arithmetic operation circuit 320 are both electrically connected to the input terminal of the first operational amplifier 110.

[0077] like Figure 2 As shown, the Hall element used to determine the rotation direction information in the Hall wheel speed sensor includes a first Hall element 330 and a second Hall element 340. The first Hall element 330 includes a first Hall plate 331 and a second Hall plate 332, and the second Hall element 340 includes a third Hall plate 341 and a fourth Hall plate 342. The potential of the first Hall plate 331 is higher than the potential of the second Hall plate 332, and the potential of the third Hall plate 341 is higher than the potential of the fourth Hall plate 342.

[0078] The output terminals of the first Hall plate 331 and the third Hall plate 341 are both electrically connected to the input terminal of the third arithmetic operation circuit 310, and the output terminals of the second Hall plate 332 and the fourth Hall plate 342 are both electrically connected to the input terminal of the fourth arithmetic operation circuit 320. The third arithmetic operation circuit 310 is used to calculate the difference between the potential of the first Hall plate 331 and the potential of the third Hall plate 341 to obtain the first sub-signal, and the fourth arithmetic operation circuit 320 is used to calculate the difference between the potential of the second Hall plate 332 and the potential of the fourth Hall plate 342 to obtain the second sub-signal.

[0079] It should be noted that the two Hall plates of a Hall element have different potentials, one with a larger potential and the other with a smaller potential. The magnitude of the Hall plate potential is related to the strength of the excitation signal and the distance between the two Hall plates. There is a phenomenon of one large and one small potential between the two Hall plates of a Hall element. The two Hall plates with the same relative potential in two Hall elements can be the two Hall plates corresponding to the larger potential of the two Hall elements, or the two Hall plates corresponding to the smaller potential of the two Hall elements; that is, one Hall plate can be selected from each of the two Hall elements.

[0080] Understandably, when the back magnetism is too high, the induced voltage value on each Hall element is high, which will make the final output first wheel speed sensor signal too large, resulting in an excessive voltage signal. This will cause the first analog-to-digital converter 120 on the first circuit 100 to overload and overflow, which will lead to the failure of the sign value of the direction branch signal when the speed signal is zero, and thus the failure of the rotation direction determination.

[0081] In this embodiment, the four Hall plates of the two Hall elements are subtracted according to the relative magnitude of the Hall plate potential in each Hall element. This can reduce the offset of the first wheel speed sensor signal caused by excessive output voltage of a single Hall element when the back magnetism is too large, thereby making the direction determination more accurate.

[0082] Furthermore, when detecting wide-tooth gears, if the first wheel speed sensor signal is obtained by a single Hall element, and the second wheel speed sensor signal used to determine the speed comes from two Hall elements, and the two Hall elements are arranged on both sides of the Hall element determining the direction, then the phase of the first wheel speed sensor signal and the second wheel speed sensor signal will be extremely close, leading to inaccurate direction determination.

[0083] In this embodiment, the first wheel speed sensor signal is obtained by subtracting the output signals of the two Hall elements, which can reduce the probability of judgment error caused by small phase difference in wide tooth detection, thereby making the direction determination more accurate.

[0084] In some embodiments, the first operational amplifier 110 is a differential operational amplifier, which is used to perform differential processing on the first sub-signal and the second sub-signal and then amplify the signal.

[0085] It is understandable that the first sub-signal and the second sub-signal are input to the first operational amplifier 110 and differentially amplified to obtain a voltage signal, so that the voltage signal can meet the processing range of the first analog-to-digital converter 120.

[0086] In some embodiments, the signal processing circuit of the wheel speed sensor of the present invention further includes a second circuit 200, the input terminal of the second circuit 200 being used to receive a second wheel speed sensor signal output by a Hall element, the second wheel speed sensor signal being used to determine rotation speed information.

[0087] It should be noted that, as Figure 3 As shown, the second circuit 200 mainly includes a second operational amplifier 210 and a second analog-to-digital converter 220 connected in sequence. The input terminal of the second operational amplifier 210 is electrically connected to the output terminal of the Hall element, the output terminal of the second operational amplifier 210 is electrically connected to the input terminal of the second analog-to-digital converter 220, and the output terminal of the second analog-to-digital converter 220 is electrically connected to the input terminal of the signal processing chip 400.

[0088] It should be noted that the second operational amplifier 210 can process and amplify the voltage signal output by the Hall element, so that the voltage signal can be within the processing range of the second analog-to-digital converter 220.

[0089] The second analog-to-digital converter 220 is used to convert the output analog signal, i.e., the voltage signal, into a digital signal for the signal processing chip 400 to perform calculations and processing. The signal processing chip 400 outputs the rotation speed based on the received voltage signal.

[0090] Understandably, the second operational amplifier 210 amplifies the signal from the second wheel speed sensor, generates a second wheel speed amplified signal, and transmits it to the second analog-to-digital converter 220. The signal processing chip 400 determines the gear rotation speed information after performing analog-to-digital conversion on the second wheel speed amplified signal through the second analog-to-digital converter 220.

[0091] In this embodiment, by providing a second operational amplifier 210 and a second analog-to-digital converter 220, the second wheel speed sensor signal output by the Hall element can be processed, enabling the signal processing chip 400 to determine the rotation speed based on the processed signal.

[0092] In some embodiments, the second circuit 200 further includes a second offset digital-to-analog converter 230 and a second arithmetic operation circuit 240, wherein the second arithmetic operation circuit 240 is electrically connected between the second operational amplifier 210 and the second analog-to-digital converter 220, and the second offset digital-to-analog converter 230 is electrically connected between the output terminal of the second analog-to-digital converter 220 and the second arithmetic operation circuit 240.

[0093] In this embodiment, the input terminal of the second offset digital-to-analog converter 230 is electrically connected to the output terminal of the signal processing chip 400, the output terminal of the second offset digital-to-analog converter 230 and the output terminal of the second operational amplifier 210 are both electrically connected to the input terminal of the second arithmetic operation circuit 240, and the output terminal of the second arithmetic operation circuit 240 is electrically connected to the input terminal of the second analog-to-digital converter 220.

[0094] In some embodiments, the second arithmetic circuit 240 includes an adder or a subtractor.

[0095] Understandably, the selection of adder or subtractor can be determined based on the sign of the second offset voltage signal output by the second offset digital-to-analog converter 230.

[0096] In this embodiment, the appropriate type of second arithmetic circuit 240 can be selected based on the actual cost of the components and the difficulty of debugging, thereby reducing hardware costs and debugging workload.

[0097] Understandably, the second offset digital-to-analog converter 230 can convert digital signals into analog signals, for example, it can output a second offset voltage signal. The second offset digital-to-analog converter 230 is an adjustable voltage source that can be used to extend the voltage range input to the second analog-to-digital converter 220.

[0098] The second offset voltage signal output by the second offset digital-to-analog converter 230 can be used to correct positive or negative input voltage offsets. Given the second operational amplifier 210, to prevent excessive amplification of the second operational amplifier 210, its amplification amplitude must be reduced. However, by using the second offset digital-to-analog converter 230, which can apply a fixed-magnitude second offset voltage signal in the opposite direction, excessive amplification of the second operational amplifier 210 can be prevented, effectively reducing the probability of overload overflow of the second analog-to-digital converter 220.

[0099] It is understandable that due to the installation error of the Hall wheel speed sensor, the back magnetic bias or the excessive difference in back magnetic field on the Hall plate of different Hall elements, there is a certain deviation in the signal of the second wheel speed sensor, resulting in an excessively large voltage signal. This causes the second analog-to-digital converter 220 on the second circuit 200 to overflow, which in turn leads to inaccurate branch signal for speed determination, and consequently, inaccurate rotation speed recognition.

[0100] In this case, the second offset digital-to-analog converter 230 outputs a second offset voltage signal, and the signal processing chip 400 determines the rotation speed information based on the signal received from the second analog-to-digital converter 220. The second offset voltage signal can correct excessive voltage signals, making the signal output to the signal processing chip 400 more accurate.

[0101] It should be noted that the second offset voltage signal is determined by the signal processing chip 400 based on the initial signal output by the second analog-to-digital converter 220. The signal processing chip 400 acquires the second offset voltage signal based on the initial signal output by the second offset digital-to-analog converter 220, feeds it back to the second offset digital-to-analog converter 220, and transmits it to the second arithmetic operation circuit 240. The second arithmetic operation circuit 240 then processes the second wheel speed amplification signal and the second offset voltage signal to determine the gear's rotational speed information.

[0102] Understandably, when the second circuit 200 first starts operating, the output voltage of the second offset digital-to-analog converter 230 is zero. At this time, after receiving the signal from the second wheel speed sensor, the second circuit 200 outputs an initial signal to the signal processing chip 400 via the second analog-to-digital converter 220. The signal processing chip 400 can determine the offset of the voltage value in the initial signal based on the received initial signal, and then control the second offset digital-to-analog converter 230 to output a second offset voltage signal corresponding to the offset of the voltage value.

[0103] After the second offset voltage signal is determined, it remains unchanged during subsequent measurements. Upon receiving the second offset voltage signal, the signal processing chip 400 determines the rotational speed information based on the signal received from the second analog-to-digital converter.

[0104] It should be noted that the deviation of the second wheel speed sensor signal is related to the installation position of the Hall wheel speed sensor and the amount of back magnetism. After changing the installation position of the Hall wheel speed sensor and replacing or adjusting the back magnet, the second offset voltage signal needs to be recalibrated to ensure the accuracy of the output signal.

[0105] In this embodiment, by setting a second offset digital-to-analog converter 230, the voltage signal with offset on the second circuit 200 can be corrected, thereby ensuring the accuracy of the speed signal and obtaining a more precise rotation speed.

[0106] In some embodiments, such as Figure 3 , Figure 4 and Figure 5 As shown, the Hall elements in the magnetic induction element 300 used to determine rotation speed information include a third Hall element 350 and a fourth Hall element 360. At least one of the Hall elements in the magnetic induction element 300 used to determine rotation direction information is different from the third Hall element 350, or at least one of the Hall elements in the magnetic induction element 300 used to determine rotation direction information is different from the fourth Hall element 360.

[0107] refer to Figure 4 If the Hall wheel speed sensor only has three Hall elements, such as Figure 4 Hall elements B1, B2, and B3 are used in the circuit. Hall elements B1 and B2 are used to output the first wheel speed sensor signal on the direction branch, while Hall elements B2 and B3 are used to output the second wheel speed sensor signal on the speed branch. Notably, Hall element B1 on the direction branch is different from both Hall elements B2 and B3 on the speed branch.

[0108] In some embodiments, when there is only one Hall element for determining rotation direction information, both the third Hall element 350 and the fourth Hall element 360 are different from the Hall element used to determine rotation direction information.

[0109] In the case where there are two Hall elements used to determine the direction of rotation, one or both of the Hall elements used to determine the direction of rotation information are different from the third Hall element 350, or one or both of the Hall elements used to determine the direction of rotation information in the Hall wheel speed sensor are different from the fourth Hall element 360.

[0110] Reference Figure 5 If the Hall wheel speed sensor only has four Hall elements, such as Figure 5 Hall elements B1, B2, B3, and B4 are used in the system. Hall elements B1 and B2 are used to output the first wheel speed sensor signal on the direction branch, while Hall elements B3 and B4 are used to output the second wheel speed sensor signal on the speed branch. The two Hall elements B1 and B2 on the direction branch are different from those B3 and B4 on the speed branch.

[0111] In this embodiment, by distinguishing the Hall elements that determine the rotation direction information and rotation speed to a certain extent, it is possible to ensure that there is a certain phase difference between the first wheel speed sensor signal and the second wheel speed sensor signal, thereby ensuring the accuracy of speed direction determination.

[0112] In some embodiments, the second wheel speed sensor signal can be acquired using two Hall elements. The second wheel speed sensor signal includes a third sub-signal and a fourth sub-signal. Both the third and fourth sub-signals are voltage signals obtained by subtracting the potential from the Hall plate.

[0113] like Figure 3 As shown, the second circuit 200 also includes a fifth arithmetic operation circuit 250 and a sixth arithmetic operation circuit 260. The output terminals of the fifth arithmetic operation circuit 250 and the sixth arithmetic operation circuit 260 are both electrically connected to the input terminal of the second operational amplifier 210.

[0114] The third Hall element 350 includes a fifth Hall plate 351 and a sixth Hall plate 352, and the fourth Hall element 360 includes a seventh Hall plate 361 and an eighth Hall plate 362; the potential of the fifth Hall plate 351 is higher than the potential of the sixth Hall plate 352, and the potential of the seventh Hall plate 361 is higher than the potential of the eighth Hall plate 362.

[0115] The output terminals of the fifth Hall plate 351 and the seventh Hall plate 361 are both connected to the input terminal of the fifth arithmetic operation circuit 250, and the output terminals of the sixth Hall plate 352 and the eighth Hall plate 362 are both connected to the input terminal of the sixth arithmetic operation circuit 260. The fifth arithmetic operation circuit 250 is used to calculate the difference between the potential of the fifth Hall plate 351 and the potential of the seventh Hall plate 361 to obtain the third sub-signal, and the sixth arithmetic operation circuit 260 is used to calculate the difference between the potential of the sixth Hall plate 352 and the potential of the eighth Hall plate 362 to obtain the fourth sub-signal.

[0116] Understandably, when the back magnetism is too high, the induced voltage value on each Hall element is high, which will make the final output second wheel speed sensor signal too large, resulting in an excessively large voltage signal. This will cause the second analog-to-digital converter 220 on the second circuit 200 to overload and overflow, thus leading to inaccurate speed value determination.

[0117] In this embodiment, the four Hall plates of the two Hall elements are subtracted according to the relative magnitude of the Hall plate potential in each Hall element. This can reduce the offset of the second wheel speed sensor signal caused by excessive output voltage of a single Hall element when the back magnetism is too large, thereby making the direction determination more accurate.

[0118] In some embodiments, the second operational amplifier 210 is a differential operational amplifier, which is used to perform differential processing on the third sub-signal and the fourth sub-signal and then amplify the signal.

[0119] It is understandable that the third and fourth sub-signals are input to the second operational amplifier 210 and differentially amplified to obtain a voltage signal, so that the voltage signal can meet the processing range of the second analog-to-digital converter 220.

[0120] This invention also provides a Hall wheel speed sensor, which includes the signal processing circuit of the wheel speed sensor described above.

[0121] The wheel speed sensor of this invention can be used in rotating components such as gears for detecting wheel speed and rotation direction. No specific application scenario is limited here.

[0122] According to the Hall wheel speed sensor provided in the embodiment of the present invention, by setting a first offset digital-to-analog converter in the first circuit corresponding to the direction of measurement, when the first wheel speed sensor signal output by the magnetic induction element is offset, the first offset digital-to-analog converter is controlled by the signal processing chip to perform offset correction processing on the first wheel speed sensor signal, thereby accurately measuring the positive and negative signs of the voltage signal corresponding to the direction when the voltage signal corresponding to the speed is zero, thereby ensuring the accuracy of direction signal processing and recognition.

[0123] Of course, in other embodiments, the signal processing circuit of the wheel speed sensor can exist as a separate circuit independent of the wheel speed sensor. That is, the signal processing circuit of the wheel speed sensor is not integrated into the wheel speed sensor itself, but is used as a separate component in conjunction with the wheel speed sensor.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A signal processing circuit for a wheel speed sensor, characterized in that, include: A magnetic induction element is used to collect the signal from the first gear speed sensor. A first circuit is connected to the output terminal of the magnetic sensing element. The first circuit includes a first operational amplifier, a first arithmetic operation circuit, a first analog-to-digital converter, and a first offset digital-to-analog converter electrically connected in sequence between the output terminal of the first analog-to-digital converter and the first arithmetic operation circuit. The input terminal of the first operational amplifier is electrically connected to the output terminal of the magnetic sensing element, and is used to amplify the first wheel speed sensor signal, generate a first wheel speed amplified signal, and transmit it to the first arithmetic operation circuit. A signal processing chip is electrically connected to the first analog-to-digital converter and the first offset digital-to-analog converter. Based on the initial signal output by the first offset digital-to-analog converter, the signal processing chip acquires a first offset voltage signal, feeds it back to the first offset digital-to-analog converter, and transmits it to the first arithmetic operation circuit. The first arithmetic operation circuit then processes the first wheel speed amplification signal and the first offset voltage signal to determine the gear's rotation direction information. The initial signal is determined based on the first wheel speed sensor signal when the output voltage of the first offset digital-to-analog converter is zero. The magnetic sensing element includes a Hall element, and the first wheel speed sensor signal includes a first sub-signal and a second sub-signal; The first circuit further includes a third arithmetic operation circuit and a fourth arithmetic operation circuit, the output terminals of the third arithmetic operation circuit and the fourth arithmetic operation circuit are both electrically connected to the input terminal of the first operational amplifier; The Hall element includes a first Hall element and a second Hall element. The first Hall element includes a first Hall plate and a second Hall plate. The second Hall element includes a third Hall plate and a fourth Hall plate. The potential of the first Hall plate is higher than the potential of the second Hall plate, and the potential of the third Hall plate is higher than the potential of the fourth Hall plate. The output terminals of the first Hall plate and the third Hall plate are both electrically connected to the input terminal of the third arithmetic operation circuit, and the output terminals of the second Hall plate and the fourth Hall plate are both electrically connected to the input terminal of the fourth arithmetic operation circuit; the third arithmetic operation circuit is used to calculate the difference between the potential of the first Hall plate and the potential of the third Hall plate to obtain the first sub-signal, and the fourth arithmetic operation circuit is used to calculate the difference between the potential of the second Hall plate and the potential of the fourth Hall plate to obtain the second sub-signal; The first operational amplifier is a differential operational amplifier, which is used to perform subtraction processing on the first sub-signal and the second sub-signal and then amplify the signal.

2. The signal processing circuit for the wheel speed sensor according to claim 1, characterized in that, It also includes a second circuit, the input of which is used to receive the second wheel speed sensor signal output by the Hall element. The second circuit includes a second operational amplifier and a second analog-to-digital converter that are connected in sequence. The input terminal of the second operational amplifier is electrically connected to the output terminal of the Hall element, and is used to amplify the second wheel speed sensor signal to generate a second wheel speed amplified signal and transmit it to the second analog-to-digital converter; the output terminal of the second analog-to-digital converter is electrically connected to the input terminal of the signal processing chip, and the signal processing chip determines the gear rotation speed information after performing analog-to-digital conversion on the second wheel speed amplified signal through the second analog-to-digital converter.

3. The signal processing circuit for the wheel speed sensor according to claim 2, characterized in that, The second circuit further includes a second arithmetic operation circuit electrically connected between the second operational amplifier and the second analog-to-digital converter, and a second offset digital-to-analog converter electrically connected between the output terminal of the second analog-to-digital converter and the second arithmetic operation circuit; The signal processing chip obtains the second offset voltage signal based on the initial signal output by the second offset digital-to-analog converter, feeds it back to the second offset digital-to-analog converter, and transmits it to the second arithmetic operation circuit. Then, the second arithmetic operation circuit processes the second wheel speed amplification signal and the second offset voltage signal to determine the gear rotation speed information.

4. The signal processing circuit for the wheel speed sensor according to claim 2, characterized in that, The Hall element used to determine rotation speed information in the magnetic induction element includes a third Hall element and a fourth Hall element. At least one of the Hall elements used to determine rotation direction information in the magnetic induction element is different from the third Hall element, or at least one of the Hall elements used to determine rotation direction information in the magnetic induction element is different from the fourth Hall element.

5. The signal processing circuit for the wheel speed sensor according to claim 4, characterized in that, The second wheel speed sensor signal includes a third sub-signal and a fourth sub-signal; The second circuit further includes a fifth arithmetic operation circuit and a sixth arithmetic operation circuit, the output terminals of the fifth arithmetic operation circuit and the sixth arithmetic operation circuit are both electrically connected to the input terminal of the second operational amplifier; The third Hall element includes a fifth Hall plate and a sixth Hall plate, and the fourth Hall element includes a seventh Hall plate and an eighth Hall plate; the potential of the fifth Hall plate is higher than the potential of the sixth Hall plate, and the potential of the seventh Hall plate is higher than the potential of the eighth Hall plate. The output terminals of the fifth Hall plate and the seventh Hall plate are both electrically connected to the input terminal of the fifth arithmetic operation circuit, and the output terminals of the sixth Hall plate and the eighth Hall plate are both electrically connected to the input terminal of the sixth arithmetic operation circuit. The fifth arithmetic operation circuit is used to calculate the difference between the potential of the fifth Hall plate and the potential of the seventh Hall plate to obtain the third sub-signal, and the sixth arithmetic operation circuit is used to calculate the difference between the potential of the sixth Hall plate and the potential of the eighth Hall plate to obtain the fourth sub-signal.

6. The signal processing circuit for the wheel speed sensor according to claim 5, characterized in that, The second operational amplifier is a differential operational amplifier, which is used to perform differential processing on the third sub-signal and the fourth sub-signal and then amplify the signal.

7. The signal processing circuit for the wheel speed sensor according to claim 3, characterized in that, The first arithmetic operation circuit includes an adder or a subtractor; The second arithmetic operation circuit includes an adder or a subtractor.

8. A wheel speed sensor, characterized in that, Includes the signal processing circuit of the wheel speed sensor as described in any one of claims 1-7.

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