Sensor circuit, sensor zero deviation correction method and mid-motor

Abstract

The invention provides a sensor circuit, a sensor zero point deviation correction method and a middle motor. The sensor circuit comprises a detection unit and a signal processing unit. The detection unit is used for accessing a first power supply; the detection unit has a power-on initial state and a detection state, and in the power-on initial state, the detection unit is used for outputting a zero compensation signal based on the first power supply; in the detection state, the detection unit is used for outputting a first detection signal based on the first power supply; the signal processing unit is used for acquiring the zero compensation signal and the detection signal, and correcting the first detection signal based on the zero compensation signal so as to output a second detection signal; according to the invention, the zero compensation signal in the power-on initial state is obtained, and the zero compensation signal is adopted to correct the first detection signal so as to output the second detection signal, thereby facilitating the reduction of the interference of the zero deviation voltage, and facilitating the improvement of the precision of the detection signal.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sensor detection, and particularly relates to a sensor circuit, a sensor zero-point deviation correction method and a middle motor. BACKGROUND

[0002] A sensor is a core device for realizing conversion of a non-electric physical quantity (such as pressure, displacement, temperature, etc.) into an electric signal in the fields of industrial detection and intelligent control.

[0003] In related technologies, the detection accuracy of a sensor is easily affected by the characteristics of components. Due to objective factors such as the limitation of internal manufacturing process of the sensor and the discreteness of device parameters, the core components (such as the bridge arm resistor of a Wheatstone bridge) of the detection unit are difficult to achieve consistency in an ideal state. As a result, the detection signal accuracy of the sensor is low. SUMMARY

[0004] The application aims to provide a sensor circuit, a sensor zero-point deviation correction method and a middle motor, and aims to solve the problem of low detection accuracy of a sensor circuit in the prior art.

[0005] A first aspect of the application provides a sensor circuit, which comprises: a detection unit configured to be connected to a first power supply; the detection unit has a power-on initial state and a detection state, in the power-on initial state, the detection unit is configured to output a zero-point compensation signal based on the first power supply; in the detection state, the detection unit is configured to output a first detection signal based on the first power supply; a signal processing unit configured to acquire the zero-point compensation signal and the detection signal, and correct the first detection signal based on the zero-point compensation signal to output a second detection signal.

[0006] In some embodiments of the application, the signal processing unit is configured to calculate a signal difference value of the zero-point compensation signal and the detection signal, and output the second detection signal based on the signal difference value.

[0007] In some embodiments of the application, the signal processing unit comprises a differential amplifier, the differential amplifier has a first input end, a second input end and a first output end, the first input end is configured to be connected to the zero-point compensation signal, the second input end is configured to be connected to the first detection signal, and the first output end is configured to output the second detection signal.

[0008] In some embodiments of the application, the first input end is a negative electrode connection end, and the second input end is a positive electrode connection end.

[0009] In some embodiments of the present application, the signal processing unit further comprises a first resistor and a second resistor, one end of the first resistor is connected with the first input end, and the other end of the first resistor is used for connecting the zero point compensation signal; one end of the second resistor is connected between the first resistor and the first input end, and the other end of the second resistor is connected with the first output end.

[0010] In some embodiments of the present application, the signal processing unit further comprises a third resistor and a fourth resistor, one end of the third resistor is connected with the second input end, and the other end of the third resistor is used for connecting the first detection signal; one end of the fourth resistor is connected between the third resistor and the second input end, and the other end of the fourth resistor is connected with the second output end.

[0011] In some embodiments of the present application, the resistance value of the first resistor is the same as the resistance value of the third resistor; And / or, the resistance value of the second resistor is the same as the resistance value of the fourth resistor.

[0012] In some embodiments of the present application, the signal processing unit is used for outputting the second detection signal based on the first detection signal, the zero point compensation signal, the resistance value of the first resistor and the resistance value of the second resistor.

[0013] In some embodiments of the present application, the calculation formula of the second detection signal is as follows: ; wherein, is the signal value of the second detection signal, is the signal value of the first detection signal, is the signal value of the zero point compensation signal, r5 is the resistance value of the first resistor, and r6 is the resistance value of the second resistor.

[0014] In some embodiments of the present application, the detection unit comprises a first detection resistor and a fourth detection resistor connected in series with each other, and a second detection resistor and a third detection resistor connected in series with each other; the other end of the first detection resistor and the other end of the second detection resistor are both used for connecting the first power supply, and the other end of the fourth detection resistor and the other end of the third detection resistor are both used for grounding; A first signal end is arranged between the first detection resistor and the fourth detection resistor, a second signal end is arranged between the second detection resistor and the third detection resistor, and the zero point compensation signal and the detection signal are related to the signal value of the first signal end and the signal value of the second signal end.

[0015] In some embodiments of the present application, the detection unit further comprises an amplifier having a third input end, a fourth input end and a second output end, the third input end is connected with the first signal end, the fourth input end is connected with the second signal end, and the second output end is used for outputting the zero compensation signal and the first detection signal.

[0016] In some embodiments of the present application, the sensor circuit further comprises an analog-to-digital converter and a digital-to-analog converter, the analog-to-digital converter is connected with the second output end and is used for converting the zero compensation signal into a digital signal, and the digital-to-analog converter is arranged between the analog-to-digital converter and the signal processing unit and is used for converting the digital signal into an analog signal, the analog signal being the zero compensation signal.

[0017] In some embodiments of the present application, the first detection resistor, the second detection resistor, the third detection resistor and the fourth detection resistor have equal design resistance values.

[0018] The second aspect of the embodiments of the present application further provides a sensor zero deviation correction method, which is executed by using the above-mentioned sensor circuit; the sensor zero deviation correction method comprises: adjusting the detection unit to be in an initial power-on state to obtain a zero compensation signal; adjusting the detection unit to be in a detection state to obtain a first detection signal; correcting the first detection signal based on the zero compensation signal to output a second detection signal.

[0019] The third aspect of the embodiments of the present application further provides a interposing motor comprising the above-mentioned sensor circuit.

[0020] The present application has the beneficial effects that: in the sensor circuit, the sensor zero deviation correction method and the interposing motor, the sensor circuit comprises a detection unit and a signal processing unit; the detection unit is used for connecting a first power supply; the detection unit has an initial power-on state and a detection state, in the initial power-on state, the detection unit is used for outputting a zero compensation signal based on the first power supply; in the detection state, the detection unit is used for outputting a first detection signal based on the first power supply; the signal processing unit is used for obtaining the zero compensation signal and the first detection signal, and correcting the first detection signal based on the zero compensation signal to output a second detection signal; the present application obtains the zero compensation signal in the initial power-on state, and uses the zero compensation signal to correct the first detection signal to output the second detection signal, which is beneficial to reduce the interference of the zero deviation voltage, and further beneficial to improve the accuracy of the detection signal. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A schematic diagram of a framework structure of a sensor circuit provided by an embodiment of the present application is shown in FIG. 1. Figure 2 A schematic diagram of a framework structure of a sensor circuit provided by an embodiment of the present application is shown in FIG. 1. Figure 3 A schematic diagram of a circuit structure of a sensor circuit provided by an embodiment of the present application is shown in FIG. 2. Figure 4 A schematic diagram of steps of a sensor zero-point deviation correction method provided by an embodiment of the present application is shown in FIG. 3.

[0022] Specific element symbol explanations: 100 - first power supply, 200 - detection unit, 300 - signal processing unit, R1 - first detection unit, R2 - second detection resistor, R3 - third detection unit, R4 - fourth detection resistor, R5 - first resistor, R6 - second resistor, R7 - third resistor, R8 - fourth resistor, AMP - amplifier, OPA2 - differential amplifier, ADC1 - analog-to-digital converter, DAC1 - digital-to-analog converter, ADC2 - analog-to-digital conversion unit. DETAILED DESCRIPTION

[0023] In order to make the technical problems to be solved by the present application, the technical solutions and beneficial effects clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0024] It should be noted that when an element is referred to as being "provided on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0025] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implying the number of the indicated technical features. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0026] It should be noted that a sensor is a core device for converting a non-electric physical quantity (such as pressure, displacement, temperature, etc.) into an electric signal in the fields of industrial detection, intelligent control, etc.

[0027] However, the detection accuracy of the sensor in the related art is susceptible to the characteristics of components. Due to the limitations of the internal manufacturing process of the sensor, the discreteness of the device parameters, and other objective factors, the core components of the detection unit (such as the bridge arm resistors of the Wheatstone bridge, as shown in Figure 1 For example, in the ideal case of a Wheatstone bridge, the four bridge arm resistors are completely equal in resistance value, and the zero point output should be zero after connecting the first power supply. However, in reality, there are always differences in resistance values, causing the sensor to output a non-zero zero point deviation voltage in the baseline state without loading the measured physical quantity. This zero point deviation voltage will superimpose with the effective signal in the detection state to form a first detection signal, so that the original signal received by the signal processing unit contains inherent errors, ultimately leading to a deviation between the output detection result and the true physical quantity, and seriously affecting the detection accuracy of the sensor.

[0028] Based on this, the traditional sensor circuit, sensor zero point deviation correction method, and inverter motor are improved.

[0029] Please refer to Figure 2 , Figure 2 The frame structure schematic diagram of the sensor circuit provided for the embodiment; as Figure 2 The Vcc is the first power supply 100, and the sensor circuit of the embodiment of the present application includes a detection unit 200 and a signal processing unit 300. The detection unit 200 is used to connect the first power supply 100. The detection unit 200 has a power-on initial state and a detection state. In the power-on initial state, the detection unit 200 is used to output a zero point compensation signal based on the first power supply 100. In the detection state, the detection unit 200 is used to output a first detection signal based on the first power supply 100. The signal processing unit 300 is used to acquire the zero point compensation signal and the detection signal, and correct the first detection signal based on the zero point compensation signal to output a second detection signal.

[0030] It needs to be explained that the sensor circuit is an electronic circuit for sensing the measured physical quantity and converting it into an electrical signal, which is applied to the middle motor of the power-assisted bicycle. The detection unit 200 is a functional module in the sensor circuit that directly senses the physical quantity and outputs an electrical signal, and has the ability to receive power supply and respond to physical quantity changes. The signal processing unit 300 is a functional module that filters, corrects and optimizes the electrical signal output by the detection unit 200. The first power supply 100 is a power supply component that provides stable working power for the detection unit 200, outputs continuous and smooth voltage, and ensures that the detection unit 200 can normally output electrical signals in different working states. The initial state after power-on is the initial stage when the sensor circuit is connected to the power supply and has not yet started to sense the measured physical quantity. At this time, the detection unit 200 is not affected by external physical quantities, and the output signal only reflects the inherent characteristics of the circuit itself. The detection state is the normal working stage of the sensor circuit, and the detection unit 200 continuously senses the measured physical quantity and synchronously outputs the corresponding electrical signal.

[0031] The zero compensation signal is the electrical signal output by the detection unit 200 in the initial state after power-on, which is used to represent the zero offset of the circuit itself due to device process, parameter difference, etc. The first detection signal is the original electrical signal output by the detection unit 200 in the detection state, which contains the effective information of the measured physical quantity, and also superimposes the zero offset interference of the circuit itself. The second detection signal is the electrical signal output by the signal processing unit 300 after being corrected by the zero compensation signal, which has eliminated the zero offset interference and can truly reflect the actual situation of the measured physical quantity. The zero offset is the non-zero signal offset of the sensor circuit when it does not sense the measured physical quantity, caused by device characteristic difference, process error, etc.

[0032] It can be understood that the embodiments of the present application obtain the zero compensation signal in the initial state after power-on, directly correct the inherent zero offset in the first detection signal, avoid the superimposed interference of the zero offset on the effective signal, and make the second detection signal more consistent with the real situation of the measured physical quantity. Since the corrected second detection signal eliminates the fixed offset component, the recognition degree and reliability of the effective signal are greatly improved, which is suitable for industrial detection, precision measurement and other scenes with high detection accuracy requirements. And without additional compensation resistance and manual zero adjustment mechanism, automatic zero correction is realized through the cooperative work of the detection unit 200 and the signal processing unit 300, reducing the complexity and difficulty of circuit design.

[0033] In some embodiments of the present application, the signal processing unit 300 is configured to calculate the signal difference value of the zero compensation signal and the detection signal, and output the second detection signal based on the signal difference value.

[0034] It can be understood that the embodiments of the present application can directly calculate the difference between the two signals, specifically eliminate the inherent zero point offset superimposed in the first detection signal, make the second detection signal fit the true value of the measured physical quantity to the greatest extent, and significantly improve the accuracy of the detection signal. And without complex algorithm model or additional hardware calibration mechanism, only through the basic difference operation can complete the deviation offset, make the signal processing procedure more simple, reduce the system operation complexity and software development difficulty. Without reacquiring the zero point compensation signal and calculating the difference value every time the power is turned on, the zero point offset fluctuation caused by environmental temperature fluctuation, device aging and other factors can be responded in real time, and the stability and consistency of the detection results under different working conditions are ensured.

[0035] In some embodiments of the present application, please refer to Figure 3 , Figure 3 The circuit structure schematic diagram of the sensor circuit provided by the present embodiment is shown; the signal processing unit 300 of the present embodiment includes a differential amplifier OPA2, the differential amplifier OPA2 has a first input end, a second input end and a first output end, the first input end is used for accessing the zero point compensation signal, the second input end is used for accessing the first detection signal, and the first output end is used for outputting the second detection signal.

[0036] It needs to be explained that the differential amplifier OPA2 is an electronic element capable of amplifying the difference between two input signals, and has the characteristics of suppressing common mode interference and accurately amplifying differential mode signals.

[0037] It can be understood that the differential amplifier OPA2 of the present embodiment can directly perform difference operation and amplification on the zero point compensation signal and the first detection signal, so that the second detection signal is more consistent with the true value of the measured physical quantity, and the detection accuracy is significantly improved. And the differential amplifier OPA2 integrates the difference operation and signal amplification function, without additional operation module or calibration circuit, the zero point correction and signal amplification are completed at one step, and the system design complexity is reduced. At the same time, the differential amplifier OPA2 has strong common mode interference suppression ability, which can reduce the influence of environmental noise and power fluctuation on signal correction, and the stable amplification characteristics ensure the consistency of the detection results under different working conditions.

[0038] In some embodiments of the present application, please continue to refer to Figure 3 The first input end of the present embodiment is a negative access end, and the second input end is a positive access end. In this way, the zero point compensation signal of the negative access end and the first detection signal of the positive access end form a reverse difference operation.

[0039] In some embodiments of the present application, please continue to refer to Figure 3The signal processing unit 300 of the embodiment further comprises a first resistor R5 and a second resistor R6, one end of the first resistor R5 is connected with the first input end, and the other end of the first resistor R5 is used for connecting the zero point compensation signal; one end of the second resistor R6 is connected between the first resistor R5 and the first input end, and the other end of the second resistor R6 is connected with the first output end.

[0040] It can be understood that the first resistor R5 of the embodiment of the application plays a current limiting and voltage dividing role on the zero point compensation signal, avoiding the influence of abnormal signal amplitude on the difference operation of the differential amplifier OPA2; the feedback loop formed by the second resistor R6 can stabilize the operation characteristics of the amplifier AMP, so that the deviation of the zero point compensation signal and the first detection signal is more thoroughly offset, further improving the accuracy of the second detection signal. Moreover, the first resistor R5 can suppress the sudden interference of the zero point compensation signal, and the second resistor R6 stabilizes the output gain of the differential amplifier OPA2 through feedback adjustment, reduces the influence of environmental voltage fluctuation, device temperature drift and other factors on signal processing, and guarantees the consistency and reliability of the detection results under different working conditions.

[0041] In some embodiments of the application, please continue to refer to Figure 3 The signal processing unit 300 of the embodiment further comprises a third resistor R7 and a fourth resistor R8, one end of the third resistor R7 is connected with the second input end, and the other end of the third resistor R7 is used for connecting the first detection signal; one end of the fourth resistor R8 is connected between the third resistor R7 and the second input end, and the other end of the fourth resistor R8.

[0042] It can be understood that the third resistor R7 of the embodiment of the application has the input characteristics of stabilizing the first detection signal, avoiding the influence of signal distortion on the difference operation; the fourth resistor R8 and the second resistor R6 form a symmetrical feedback loop, so that the difference operation of the differential amplifier OPA2 on the zero point compensation signal and the first detection signal is more balanced, the deviation is more thoroughly offset, and the accuracy of the second detection signal is further improved. Moreover, the symmetrical matching of the third resistor R7 and the first resistor R5, and the fourth resistor R8 and the second resistor R6 makes the impedance characteristics of the positive and negative input ends of the differential amplifier OPA2 consistent, avoids the operation error caused by impedance imbalance, and guarantees the processing consistency when different amplitude signals are input. At the same time, the symmetrical resistor loop and the common mode interference suppression characteristics of the differential amplifier OPA2 work together, can effectively weaken the influence of environmental temperature fluctuation, power supply noise and other common mode interference on signal processing, and make the detection results still stable and reliable under complex working conditions.

[0043] In some embodiments of the application, the resistance value of the first resistor R5 is the same as the resistance value of the third resistor R7.

[0044] It can be understood that the first resistor R5 and the third resistor R7 have the same resistance value in the embodiment, so that the input impedance of the inverting input terminal and the non-inverting input terminal of the differential amplifier OPA2 is consistent, the signal voltage division deviation caused by impedance imbalance is avoided, the difference operation of the zero point compensation signal and the first detection signal is more accurate, and the accuracy of the second detection signal is further improved. In addition, the same input impedance makes the response characteristics of the differential amplifier OPA2 to common mode interference consistent, and the common mode rejection capability of the amplifier AMP itself can effectively weaken the influence of environmental noise, power supply fluctuation and other interference on signal processing, and ensure the stability of the detection result under complex working conditions.

[0045] In some embodiments, the resistance value of the second resistor R6 is the same as the resistance value of the fourth resistor R8.

[0046] In some embodiments of the present application, the signal processing unit 300 is configured to output a second detection signal based on the first detection signal, the zero point compensation signal, the resistance value of the first resistor R5 and the resistance value of the second resistor R6.

[0047] It can be understood that the signal processing unit 300 of the embodiment can integrate two types of signals and resistance value parameters for operation, which can not only specifically eliminate the inherent zero point offset in the first detection signal, but also stabilize the signal amplification gain through the resistance value relationship of the first resistor R5 and the second resistor R6, so that the second detection signal has no deviation interference and can maintain a suitable amplitude, which significantly improves the detection accuracy. In addition, the resistance value is a fixed parameter, and the cooperative operation of the signal can avoid signal distortion caused by gain fluctuation, reduce the influence of environmental temperature change and power supply fluctuation on the processing result, and ensure the stability and reliability of the detection result under different working conditions.

[0048] In some embodiments of the present application, the calculation formula of the second detection signal is as follows: ; wherein, is the signal value of the second detection signal, is the signal value of the first detection signal, is the signal value of the zero point compensation signal, r5 is the resistance value of the first resistor R5, and r6 is the resistance value of the second resistor R6.

[0049] It can be understood that the resistance value ratio of r6 and r5 can be adjusted in the embodiment, and the amplification multiple of the second detection signal can be freely set, which can amplify the weak effective signal to a suitable amplitude for subsequent processing, avoid signal overload distortion, adapt to different sensitivity sensors and different range detection scenes, and greatly improve the adaptability of the scheme.

[0050] Specifically, it can be seen from the above calculation formula that the output of the actual sensor has subtracted the zero-point error of the sensor. In addition, in order to prevent the output of the differential amplifier OP A2 from reaching the supply voltage V supply, the gain of the first-stage amplifier AMP is generally set not to be too large, and the gain is generally required to be set to satisfy V out1 < V supply / 2.

[0051] In some embodiments of the present application, please refer to Figure 3 The detection unit 200 of the embodiment includes a first detection resistor and a fourth detection resistor R4 connected in series with each other, and a second detection resistor R2 and a third detection resistor R3 connected in series with each other; the other end of the first detection resistor and the other end of the second detection resistor R2 are both used for connecting to the first power supply 100, and the other end of the fourth detection resistor R4 and the other end of the third detection resistor R3 are both used for grounding; a first signal end is arranged between the first detection resistor and the fourth detection resistor R4, and a second signal end is arranged between the second detection resistor R2 and the third detection resistor R3, and the zero-point compensation signal and the detection signal are related to the signal value of the first signal end and the signal value of the second signal end.

[0052] It can be understood that the four groups of detection resistors in the embodiment can constitute a Wheatstone bridge structure, can sensitively sense the change of the measured physical quantity, and convert it into a differential electrical signal of the first signal end and the second signal end, to provide an accurate original basis for the generation of the subsequent zero-point compensation signal and the detection signal, and to guarantee the accuracy of signal conversion. In the initial state of power-on, the signal difference of the first signal end and the second signal end directly reflects the inherent zero-point deviation of the detection unit 200 caused by device process and parameter difference, and the zero-point compensation signal generated based on the difference can accurately match the system zero-point offset characteristics, to provide a reliable reference for subsequent deviation cancellation. At the same time, the differential signal output by the first signal end and the second signal end has a natural inhibitory effect on common-mode interference (such as power supply fluctuation and environmental temperature change), reduces the influence of external interference on the zero-point compensation signal and the detection signal, and guarantees the stability and consistency of the detection results under different working conditions.

[0053] In some embodiments of the present application, please refer to Figure 3 The detection unit 200 of the embodiment further includes an amplifier AMP, the amplifier AMP has a third input end, a fourth input end, and a second output end, the third input end is connected with the first signal end, the fourth input end is connected with the second signal end, and the second output end is used for outputting the zero-point compensation signal and the first detection signal.

[0054] Understandably, the original differential signal output by the Wheatstone bridge is typically weak and susceptible to transmission interference or conversion distortion. In this embodiment, the amplifier AMP amplifies this signal differentially to a suitable amplitude, ensuring accurate acquisition of the zero-point deviation signal in the initial power-on state (as a zero-point compensation signal) and providing sufficient amplitude for the effective signal in the detection state (the first detection signal) to facilitate subsequent ADC conversion and signal correction. Furthermore, in the initial power-on state, the amplifier AMP amplifies the inherent zero-point deviation signal of the Wheatstone bridge, making the zero-point offset characteristics more significant and avoiding acquisition errors caused by the weak original deviation signal. This provides a more accurate reference for the deviation cancellation of the subsequent signal processing unit 300. Simultaneously, the amplifier AMP has the characteristic of suppressing common-mode interference. While amplifying the differential signal, it can reduce the impact of environmental noise and power fluctuations on the original signal, making the output zero-point compensation signal and the first detection signal purer, reducing the impact of interference on subsequent correction calculations, and improving the reliability of the detection results.

[0055] Please refer to the embodiments described in this application. Figure 3 The sensor circuit in this embodiment also includes an analog-to-digital converter (ADC1) and a digital-to-analog converter (DAC1). The ADC1 is connected to the second output terminal and is used to convert the zero-point compensation signal into a digital signal. The DAC1 is disposed between the ADC1 and the signal processing unit 300 and is used to convert the digital signal into an analog signal, wherein the analog signal is the zero-point compensation signal.

[0056] It needs to be explained that the analog-to-digital converter (ADC1) is an electronic component that converts continuously changing analog electrical signals into discrete digital signals. It has signal acquisition and quantization functions, and its core function is to convert analog signals into a digital form that is easy to store and process, ensuring the stability of signal transmission and storage. The digital-to-analog converter (DAC1) is an electronic component that can restore discrete digital signals to continuous analog electrical signals. It has signal decoding and analog output capabilities, and can convert digitally stored reference signals into analog signals that can be directly used in circuit operations.

[0057] Understandably, in this embodiment, the analog-to-digital converter (ADC1) quantizes the analog zero-point compensation signal into a digital signal. During digital storage, it is less susceptible to environmental noise and signal attenuation, ensuring the original accuracy of the zero-point reference. The digital-to-analog converter (DAC1) then accurately restores the digital signal to an analog signal, ensuring that the zero-point compensation signal used in the correction calculation is completely consistent with the original acquired zero-point deviation characteristics, thus improving correction accuracy. Furthermore, the DAC1 can continuously and stably output the analog zero-point compensation signal, avoiding amplitude drift and interference superposition problems that occur during direct analog signal transmission. This ensures that the signal processing unit 300 obtains a precise and consistent reference signal throughout the entire power-on operating cycle, guaranteeing the consistency of detection and correction at different times.

[0058] Please refer to the embodiments described in this application. Figure 3 In this embodiment, the design resistance values ​​of the first detection resistor, the second detection resistor R2, the third detection resistor R3, and the fourth detection resistor R4 are equal.

[0059] Understandably, designing four sets of bridge arms with equal resistance values ​​meets the structural requirements of an ideal Wheatstone bridge. Furthermore, the symmetrical bridge arm structure provides a natural common-mode interference suppression basis for the differential signals output from the first and second signal terminals. Combined with the differential amplification characteristics of the amplifier AMP, it can more effectively reduce the impact of common-mode interference such as power supply fluctuations and ambient temperature changes on the original signal, making the zero-point compensation signal and the first detection signal purer and ensuring the accuracy of the correction calculation.

[0060] In some embodiments, the sensor circuit further includes an analog-to-digital converter (ADC2), which is connected to the first output terminal and is used to perform analog-to-digital conversion on the second detection signal.

[0061] The advantage of this application is that it eliminates the need for zeroing the Wheatstone bridge. A zero-point compensation signal Voffset is set using the amplifier AMP, analog-to-digital converter ADC1, and digital-to-analog converter DAC1, and this Voffset can be subtracted through the differential amplifier OPA2. Since common control chips on the market typically integrate the amplifier AMP, ADC1, and DAC1, zero-point elimination is automatically achieved by writing the corresponding application program on a single control chip.

[0062] Furthermore, in order to better implement the sensor circuit in any of the above embodiments, based on the above sensor circuit, please refer to [reference needed]. Figure 4 , Figure 4 The diagram illustrates the steps of the sensor zero-point deviation correction method provided in this embodiment; this application embodiment also provides a sensor zero-point deviation correction method, which employs the sensor circuit described above to perform the sensor zero-point deviation correction method; the sensor zero-point deviation correction method includes: S100: Adjust the detection unit 200 to the initial power-on state to obtain the zero-point compensation signal; specifically, in the initial power-on state, the detection unit 200 is not affected by the measured physical quantity, and the output zero-point compensation signal can truly reflect the inherent offset caused by differences in device process and parameters, avoiding external factors from interfering with the accuracy of the reference signal.

[0063] Furthermore, unlike traditional solutions that require manual adjustment of compensation resistors and repeated testing, zero-point compensation signals can be obtained by automatically switching to the initial power-on state, reducing manual intervention steps and improving calibration efficiency during production and use.

[0064] S200: Adjust the detection unit 200 to the detection state to acquire the first detection signal; specifically, in the detection state, the detection unit 200 can sensitively respond to changes in the measured physical quantity and convert it into an electrical signal, ensuring that the first detection signal completely contains the effective information of the measured physical quantity. Furthermore, the detection unit 200 does not require interruption of circuit power supply during state switching, and the transition from the initial power-on state to the detection state is smooth, ensuring that the deviation characteristics of the zero-point compensation signal and the first detection signal are consistent.

[0065] S300: Corrects the first detection signal based on the zero-point compensation signal to output the second detection signal. Specifically, through the operation of the zero-point compensation signal and the first detection signal, the fixed deviations caused by differences in device technology and parameters superimposed on the first detection signal can be eliminated, allowing the second detection signal to truly reflect the measured physical quantity, significantly improving detection accuracy and solving the problem of difficulty in accurately zeroing with traditional manual zeroing. Furthermore, the correction logic does not depend on a specific type of Wheatstone bridge sensor. By adjusting the operation parameters of the signal processing unit 300, it can be adapted to sensors with different sensitivities and different types of physical quantities, broadening the applicability of the solution.

[0066] In some embodiments, step S100 includes: digitally storing the zero-point compensation signal (e.g., via ADC conversion). This avoids human error that may occur during manual zeroing, while digital storage reduces distortion during signal transmission and storage, ensuring long-term stability of the reference signal.

[0067] In some embodiments, step S200 includes: the detection unit 200 continuously outputting a first detection signal in the detection state. This can be combined with subsequent real-time correction processes to meet the need for continuous monitoring of changes in physical quantities and improve the practical adaptability of the sensor.

[0068] Furthermore, in order to better implement the sensor circuit in any of the above embodiments, based on the above sensor circuit, this application embodiment also provides a mid-mounted motor for an electric bicycle. The mid-mounted motor includes the sensor circuit as described above. The electric bicycle provided in this embodiment includes a frame and a mid-mounted motor. The mid-mounted motor is mounted on the frame and is used to provide electric assistance to the rider according to the rider's riding intention and riding status, so as to reduce the rider's fatigue and improve the rider's riding experience.

[0069] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0070] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0071] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0072] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0073] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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. Such 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 this application, and should all be included within the protection scope of this application.

Claims

1. A sensor circuit, characterized in that, The sensor circuit includes: A detection unit is used to connect to a first power supply; the detection unit has a power-on initial state and a detection state. In the power-on initial state, the detection unit is used to output a zero-point compensation signal based on the first power supply; in the detection state, the detection unit is used to output a first detection signal based on the first power supply. A signal processing unit is configured to acquire the zero-point compensation signal and the detection signal, and correct the first detection signal based on the zero-point compensation signal to output a second detection signal.

2. The sensor circuit according to claim 1, characterized in that, The signal processing unit is used to calculate the signal difference between the zero-point compensation signal and the detection signal, and output the second detection signal based on the signal difference.

3. The sensor circuit according to claim 2, characterized in that, The signal processing unit includes a differential amplifier, which has a first input terminal, a second input terminal, and a first output terminal. The first input terminal is used to receive the zero-point compensation signal, the second input terminal is used to receive the first detection signal, and the first output terminal is used to output the second detection signal.

4. The sensor circuit according to claim 3, characterized in that, The first input terminal is the negative terminal, and the second input terminal is the positive terminal.

5. The sensor circuit according to claim 3, characterized in that, The signal processing unit further includes a first resistor and a second resistor. One end of the first resistor is connected to the first input terminal, and the other end of the first resistor is used to receive the zero-point compensation signal. One end of the second resistor is connected between the first resistor and the first input terminal, and the other end of the second resistor is connected to the first output terminal.

6. The sensor circuit according to claim 5, characterized in that, The signal processing unit further includes a third resistor and a fourth resistor. One end of the third resistor is connected to the second input terminal, and the other end of the third resistor is used to receive the first detection signal. One end of the fourth resistor is connected between the third resistor and the second input terminal, and the other end of the fourth resistor is connected between the third resistor and the second input terminal.

7. The sensor circuit according to claim 6, characterized in that, The resistance value of the first resistor is the same as the resistance value of the third resistor; And / or, the resistance value of the second resistor is the same as the resistance value of the fourth resistor.

8. The sensor circuit according to claim 6, characterized in that, The signal processing unit is used to output the second detection signal based on the first detection signal, the zero-point compensation signal, the resistance value of the first resistor, and the resistance value of the second resistor.

9. The sensor circuit according to claim 8, characterized in that, The formula for calculating the second detection signal is as follows: ;in, The signal value of the second detection signal. The signal value of the first detection signal. r5 is the signal value of the zero-point compensation signal, r6 is the resistance value of the first resistor, and r7 is the resistance value of the second resistor.

10. The sensor circuit according to claim 1, characterized in that, The detection unit includes a first detection resistor and a fourth detection resistor connected in series, and a second detection resistor and a third detection resistor connected in series; the other end of the first detection resistor and the other end of the second detection resistor are both used to connect to the first power supply, and the other end of the fourth detection resistor and the other end of the third detection resistor are both used to ground. A first signal terminal is provided between the first detection resistor and the fourth detection resistor, and a second signal terminal is provided between the second detection resistor and the third detection resistor. The zero-point compensation signal and the detection signal are related to the signal values ​​of the first signal terminal and the second signal terminal.

11. The sensor circuit according to claim 10, characterized in that, The detection unit further includes an amplifier, which has a third input terminal, a fourth input terminal, and a second output terminal. The third input terminal is connected to the first signal terminal, the fourth input terminal is connected to the second signal terminal, and the second output terminal is used to output the zero-point compensation signal and the first detection signal.

12. The sensor circuit according to claim 11, characterized in that, The sensor circuit further includes an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The ADC is connected to the second output terminal and is used to convert the zero-point compensation signal into a digital signal. The DAC is disposed between the ADC and the signal processing unit and is used to convert the digital signal into an analog signal, wherein the analog signal is the zero-point compensation signal.

13. The sensor circuit according to claim 10, characterized in that, The design resistance values ​​of the first detection resistor, the second detection resistor, the third detection resistor, and the fourth detection resistor are equal.

14. A method for correcting zero-point deviation of a sensor, characterized in that, The sensor zero-point deviation correction method is performed using the sensor circuit described in any one of claims 1 to 13; The sensor zero-point deviation correction method includes: Adjust the detection unit to the initial power-on state to obtain a zero-point compensation signal; Adjust the detection unit to a detection state to obtain a first detection signal; The first detection signal is corrected based on the zero-point compensation signal to output the second detection signal.

15. A mid-drive motor, characterized in that, Includes the sensor circuit as described in any one of claims 1 to 13.

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