A reading circuit and control method for a tunneling magnetoresistive sensor

Abstract

This invention provides a reading circuit and control method for a tunneling magnetoresistive sensor, comprising: a bridge module acquiring a sensing signal, including a first resistor, a second resistor, a first capacitor, and a second capacitor; a first terminal of the first resistor being connected to a bias voltage, and its second terminal being connected to the first terminal of the first capacitor; the second terminal of the first capacitor being grounded; a first terminal of the second capacitor being connected to a bias voltage, and its second terminal being connected to the first terminal of the second resistor; the second terminal of the second resistor being grounded; and a monitoring module monitoring the sensing signal output by the bridge module in real time and switching the operating mode according to the sensing signal. By constructing a dynamic capacitive bridge using two resistors and two capacitors, the static current path in the tunneling magnetoresistive sensor is completely eliminated by utilizing the characteristic of capacitors to block DC and pass AC, thereby effectively reducing power consumption; and by enabling the monitoring module to switch the operating mode in a timely manner through real-time monitoring of the sensing signal, high-precision measurement is achieved, solving the problem of high power consumption in existing tunneling magnetoresistive sensors.

Description

Technical Field

[0001] This invention relates to the field of sensing technology, and in particular to a reading circuit and control method for a tunneling magnetoresistive sensor. Background Technology

[0002] Tunneling magnetoresistive (TMR) sensors can be used to detect weak magnetic fields and convert magnetic field signals into easily processed electrical signals. They exhibit excellent performance in terms of high sensitivity, temperature stability, anti-interference, miniaturization, integration, intelligence, and low power consumption.

[0003] Tunneling magnetoresistive sensors, with their higher sensitivity, better temperature characteristics, lower power consumption, and higher integration, can replace Hall current sensors and be used in fields such as frequency converters, servo drives, and electric vehicles. They are of great value in realizing coreless, closed-loop, high-current sensing applications.

[0004] Meanwhile, tunneling magnetoresistive sensing technology has demonstrated strong application potential in the field of smart grids. In terms of wide frequency domain measurement capabilities, the frequency response range (DC-10MHz) of the tunneling magnetoresistive sensor perfectly matches the monitoring requirements of smart grids for harmonics and transient processes. Furthermore, the differential structure design of the tunneling magnetoresistive sensor, through dual-sensor element common-mode suppression, can suppress external stray magnetic field interference by more than 80dB; even in strong magnetic field environments, the tunneling magnetoresistive sensor maintains 0.1-level accuracy, exhibiting excellent anti-interference capabilities.

[0005] Currently, the performance of TMR sensors is continuously improving through improvements in film materials, integration of magnetic flux concentrators, and optimization of structural and circuit design. However, existing TMR sensors have a DC current path, resulting in a constant quiescent current regardless of whether they are operating or not, causing current consumption. When applied to partially battery-powered or environmentally powered devices, this leads to significant power consumption. Summary of the Invention

[0006] The purpose of this invention is to provide a reading circuit and control method for a tunneling magnetoresistive sensor to solve the problem of high power consumption in existing tunneling magnetoresistive sensors.

[0007] To solve the above-mentioned technical problems, the present invention provides a reading circuit for a tunneling magnetoresistive sensor, comprising:

[0008] A bridge module for acquiring sensing signals includes a first resistor, a second resistor, a first capacitor, and a second capacitor. A first terminal of the first resistor is connected to a bias voltage, and its second terminal is connected to the first terminal of the first capacitor. The second terminal of the first capacitor is grounded. A first terminal of the second capacitor is connected to a bias voltage, and its second terminal is connected to the first terminal of the second resistor. The second terminal of the second resistor is grounded.

[0009] The monitoring module is used to monitor the sensor signals output by the bridge module in real time and switch the working mode according to the sensor signals.

[0010] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, the first capacitor and the second capacitor are MiM capacitors, MoM capacitors, ceramic capacitors, electrolytic capacitors, or silicon capacitors.

[0011] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, the resistance values ​​of the first resistor and the second resistor are the same, and the capacitance values ​​of the first capacitor and the second capacitor are the same.

[0012] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, the capacitance values ​​C of the first capacitor and the second capacitor are ≤ 1 / (2×π×R×f), where R represents the resistance value of the first resistor and f represents the transient switching frequency of the current to be detected.

[0013] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, the monitoring module is used to switch the working mode to the measurement mode when a transient change in the current of the sensing signal is detected; the monitoring module is also used to switch the working mode to the sleep mode when the rate of change of the sensing signal is detected to be within a preset range.

[0014] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, the monitoring module includes a comparator and a processor; the comparator is used to compare the sensing signal with a reference signal to output a comparison signal; the processor is used to analyze and process the comparison signal to switch the working mode according to the analysis and processing results.

[0015] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, the processor includes a filtering algorithm unit, a compensation calibration unit, a range control unit, a data analysis unit, and a status control unit. The filtering algorithm unit is used to filter the comparison signal to obtain a filtered comparison signal. The compensation calibration unit is used to compensate and calibrate the filtered comparison signal to obtain a compensated and calibrated comparison signal. The range control unit is used to set the range. The data analysis unit is used to compare the compensated and calibrated comparison signal with the range to determine whether the comparison signal exceeds the range. The status control unit is used to switch the operating mode according to the result of the data analysis, wherein when the comparison signal exceeds the range, the operating mode is switched to the measurement mode; otherwise, the operating mode is switched to the sleep mode.

[0016] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, the monitoring module further includes an operational amplifier and an analog-to-digital converter; the operational amplifier is used to amplify the sensing signal and input it to the analog-to-digital converter; the analog-to-digital converter is used to convert the amplified sensing signal from an analog signal to a digital signal.

[0017] Optionally, in the reading circuit of the tunneling magnetoresistive sensor, when there are multiple bridge modules, the monitoring module further includes a multiplexer; the multiplexer is used to receive the sensing signal output by each bridge module and transmit the sensing signal to the comparator.

[0018] To address the aforementioned technical problems, the present invention also provides a control method for controlling the reading circuit of the tunneling magnetoresistive sensor as described in any of the preceding claims, the control method comprising:

[0019] Acquire sensor signals;

[0020] Real-time monitoring of sensor signals;

[0021] When a transient change in current of the sensor signal is detected, the operating mode is switched to measurement mode;

[0022] When the rate of change of the sensor signal is detected to be within the preset range, the working mode is switched to sleep mode.

[0023] The present invention provides a reading circuit and control method for a tunneling magnetoresistive sensor, comprising: a bridge module for acquiring sensing signals, including a first resistor, a second resistor, a first capacitor, and a second capacitor; a first terminal of the first resistor is connected to a bias voltage, and its second terminal is connected to the first terminal of the first capacitor; the second terminal of the first capacitor is grounded; a first terminal of the second capacitor is connected to a bias voltage, and its second terminal is connected to the first terminal of the second resistor; the second terminal of the second resistor is grounded; and a monitoring module for real-time monitoring of the sensing signals output by the bridge module and switching the operating mode according to the sensing signals. By constructing a dynamic capacitive bridge using two resistors and two capacitors, the static current path in the tunneling magnetoresistive sensor is completely eliminated by utilizing the characteristic of capacitors to block DC and pass AC, thereby effectively reducing power consumption; and by using the monitoring module to monitor the sensing signals in real time, the operating mode can be switched promptly, achieving high-precision measurement and solving the problem of high power consumption in existing tunneling magnetoresistive sensors. Attached Figure Description

[0024] Figure 1 This is a basic block diagram of the readout circuit of the tunneling magnetoresistive sensor provided in this embodiment;

[0025] Figure 2 This is a chip architecture diagram of the readout circuit of the tunneling magnetoresistive sensor provided in this embodiment;

[0026] Figure 3 This is a complete chip architecture diagram of the readout circuit of the tunneling magnetoresistive sensor provided in this embodiment;

[0027] Figure 4 A flowchart illustrating the control method for the reading circuit of the tunneling magnetoresistive sensor provided in this embodiment. Detailed Implementation

[0028] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the reading circuit and control method of the tunneling magnetoresistive sensor proposed in this invention. It should be noted that the drawings are all in a very simplified form and use non-precise scales, intended only to facilitate and clarify the illustration of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different figures may emphasize different aspects and sometimes use different scales.

[0029] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects in order to describe embodiments of the invention, and are not used to describe a specific order or sequence. It should be understood that such uses of terminology are interchangeable where appropriate. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] This embodiment provides a readout circuit for a tunneling magnetoresistive sensor, such as... Figure 1 As shown, including:

[0031] The bridge module, used to acquire sensing signals, includes a first resistor R1, a second resistor R2, a first capacitor C1, and a second capacitor C2; the first terminal of the first resistor R1 is connected to a bias voltage, and the second terminal is connected to the first terminal of the first capacitor C1; the second terminal of the first capacitor C1 is grounded; the first terminal of the second capacitor C2 is connected to a bias voltage, and the second terminal is connected to the first terminal of the second resistor R2; the second terminal of the second resistor R2 is grounded.

[0032] The monitoring module is used to monitor the sensor signals output by the bridge module in real time and switch the working mode according to the sensor signals.

[0033] The reading circuit of the tunneling magnetoresistive sensor provided in this embodiment constructs a dynamic capacitive bridge through a first resistor R1, a second resistor R2, a first capacitor C1, and a second capacitor C2. By utilizing the characteristic of capacitors to block DC and pass AC, the static current path in the tunneling magnetoresistive sensor is completely eliminated, thereby effectively reducing power consumption. The monitoring module monitors the sensing signal in real time and can switch the working mode in a timely manner to achieve high-precision measurement, thus solving the problem of high power consumption in existing tunneling magnetoresistive sensors.

[0034] Specifically, in this embodiment, the first resistor R1 and the second resistor R2 have the same resistance value, and the first capacitor C1 and the second capacitor C2 have the same capacitance value.

[0035] In practical applications, the resistance values ​​of the first resistor R1 and the second resistor R2 need to be determined based on the sensitivity, measurement range, and other requirements of the tunneling magnetoresistive sensor. For example, for a conventional tunneling magnetoresistive sensor, the resistance values ​​of the first resistor R1 and the second resistor R2 can be around 10KΩ; for a sensitive tunneling magnetoresistive sensor, the resistance values ​​of the first resistor R1 and the second resistor R2 can be around 50KΩ. Of course, the first resistor R1 and the second resistor R2 can also be set to other values, and this application does not impose any restrictions on this.

[0036] Furthermore, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 need to be determined and adjusted based on the resistance values ​​of the first resistor R1 and the second resistor R2. Specifically, the capacitance value C of the first capacitor C1 and the second capacitor C2 should be ≤ 1 / (2×π×R×f), where R represents the resistance value of the first resistor R1, and f represents the transient frequency of the current to be detected. For example, if a tunneling magnetoresistive sensor needs to detect a 1MHz current transient, and the resistance values ​​of the first resistor R1 and the second resistor R2 are 10KΩ, then the capacitance value C of the first capacitor C1 and the second capacitor C2 should not exceed 15.9pF.

[0037] In practical applications, the first capacitor C1 and the second capacitor C2 can be MiM capacitors, MoM capacitors, ceramic capacitors, electrolytic capacitors, or silicon capacitors, etc.

[0038] Preferably, in order to enable the tunneling magnetoresistive sensor to be applied in high-precision scenarios, such as smart grid monitoring equipment and high-density deployment scenarios, in this embodiment, the first capacitor and the second capacitor are MiM (metal-insulator-metal) capacitors. Thus, by utilizing the high stability, high linearity, and low parasitic effects of MiM capacitors, they can achieve high reliability in high-precision applications.

[0039] Furthermore, in this embodiment, the monitoring module is used to switch the working mode to the measurement mode when a transient change in the current of the sensing signal is detected (such as a short circuit fault or a lightning strike event); the monitoring module is also used to determine that the tunneling magnetoresistive sensor is in a steady state when the rate of change of the sensing signal is detected to be within a preset range, and to switch the working mode to the sleep mode.

[0040] Specifically, in measurement mode, the first capacitor C1 and the second capacitor C2 of the bridge module are equivalent to two resistors, making the bridge module effectively composed of four resistors, thus achieving high-precision measurement. In sleep mode, the bridge module consists of two resistors and two capacitors, retaining only the capacitor charge to maintain the basic potential. This utilizes the capacitor's characteristic of blocking DC and passing AC to completely eliminate the static current path in the tunneling magnetoresistive sensor, effectively reducing power consumption. Simultaneously, the capacitor's noise filtering effect reduces input noise. Thus, not only is the power consumption of the tunneling magnetoresistive sensor significantly reduced, but it also provides an innovative event-driven solution for new energy equipment status monitoring and edge computing nodes.

[0041] Furthermore, in this embodiment, as Figure 2 As shown, the monitoring module includes a comparator Comp and a processor; the comparator Comp is used to compare the sensing signal with the reference signal Vref to output a comparison signal; the processor is used to analyze and process the comparison signal to switch the working mode according to the analysis and processing results.

[0042] Specifically, in this embodiment, the processor includes a filtering algorithm unit, a compensation calibration unit, a range control unit, a data analysis unit, and a state control unit. The filtering algorithm unit has a preset filtering algorithm for filtering the comparison signal to obtain a filtered comparison signal. The compensation calibration unit has a preset compensation calibration algorithm for compensating and calibrating the filtered comparison signal to obtain a compensated and calibrated comparison signal. The range control unit is used to set the range, which can be manually input. The data analysis unit compares the compensated and calibrated comparison signal with the range to determine whether the comparison signal exceeds the range. The state control unit switches the operating mode according to the data analysis result; when the comparison signal exceeds the range, the operating mode is switched to measurement mode; otherwise, the operating mode is switched to sleep mode.

[0043] In practical applications, the comparator Comp can be a high-speed comparator, thus adapting to high-frequency sensing signals and achieving high-precision comparison. Furthermore, the various units of the processor can be integrated into the CPU; the specific implementation methods are well known to those skilled in the art, and will not be elaborated upon here.

[0044] Furthermore, in this embodiment, as Figure 2 As shown, the monitoring module also includes an operational amplifier (OP) and an analog-to-digital converter (ADC); the OP amplifies the sensing signal and inputs it to the ADC; the ADC converts the amplified sensing signal from an analog signal to a digital signal.

[0045] In practical applications, the operational amplifier (OP) can specifically be a programmable gain amplifier (PGA), which allows for programmable adjustment of the amplification factor, thereby homogenizing the full-scale signal of the analog-to-digital converter (ADC) and significantly improving measurement accuracy. Furthermore, the ADC can be a successive approximation ADC (SD ADC), thus reducing system power consumption and area.

[0046] When there are multiple bridge modules, such as Figure 3 As shown, the monitoring module also includes a multiplexer MUX; the multiplexer MUX is used to receive the sensing signals output by each of the bridge modules and transmit the sensing signals to the comparator Comp and the operational amplifier OP.

[0047] In practical applications, the monitoring module can be a system-on-a-chip (SoC), thereby integrating various functional units and components, improving the system's integration level, and reducing system power consumption and area.

[0048] Specifically, such as Figure 3 As shown, the monitoring module can also be equipped with a power supply, a bandgap reference circuit, a power-on control circuit, an on-chip clock circuit, and an on-chip temperature sensor.

[0049] The system includes: a power supply circuit for powering various devices on the monitoring module; a bandgap reference circuit for providing reference voltages to various devices on the monitoring module, such as the reference voltage of the comparator Comp; a power-on control circuit for controlling the power supply or power-off of various devices on the monitoring module, thereby controlling their operating status; an on-chip clock circuit for providing clock signals to various devices on the monitoring module, such as the clocks required by the operational amplifier OP, comparator Comp, analog-to-digital converter ADC, and processor; and an on-chip temperature sensor for monitoring the temperature of the on-chip system to prevent high-temperature damage.

[0050] Data and signals generated by the monitoring module, such as sensor signals in digital signal format output by the analog-to-digital converter and log data output by the processor, can be further sent to the digital signal processing module (DSP) for subsequent processing.

[0051] Of course, in practical applications, other functional units can be added to the monitoring module according to actual needs, and this application does not impose any restrictions on this.

[0052] This embodiment also provides a control method for controlling the reading circuit of the tunneling magnetoresistive sensor as described above, such as... Figure 4 As shown, the control method includes:

[0053] S1, acquire sensor signals.

[0054] Specifically, in this embodiment, the sensing signal is acquired by the bridge module.

[0055] S2 monitors sensor signals in real time.

[0056] Specifically, in this embodiment, the monitoring module monitors the sensor signal in real time.

[0057] S3-1, when a transient change in current of the sensing signal is detected, the working mode is switched to measurement mode;

[0058] S3-2, when the rate of change of the sensor signal is detected to be within the preset range, the working mode is switched to sleep mode.

[0059] Specifically, the comparator and processor in the monitoring module are used to monitor the sensor signal in real time, and the working mode is switched according to the detection results.

[0060] In measurement mode, the two capacitors in the control bridge module are equivalent to two resistors, making the bridge module effectively composed of four resistors, thus achieving high-precision measurement. In sleep mode, the control bridge module consists of two resistors and two capacitors, retaining only the capacitor charge to maintain the basic potential. This utilizes the capacitor's characteristic of blocking DC and passing AC to completely eliminate the static current path in the tunneling magnetoresistive sensor, effectively reducing power consumption. Simultaneously, the capacitor's noise-filtering effect reduces input noise.

[0061] The tunneling magnetoresistive sensor reading circuit and its control method provided in this embodiment are applicable to various scenarios, especially high-precision measurement scenarios. By monitoring the sensing signal in real time and switching different working modes according to different states of the sensing signal, event-driven measurement can be achieved while reducing system power consumption. Simultaneously, the capacitors in the bridge module not only reduce static power consumption but also filter out noise, improving measurement accuracy.

[0062] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, the different parts between embodiments can also be combined with each other, and this invention does not limit this.

[0063] The reading circuit and control method of the tunneling magnetoresistive sensor provided in this embodiment include: a bridge module for acquiring sensing signals, comprising a first resistor, a second resistor, a first capacitor, and a second capacitor; a first terminal of the first resistor is connected to a bias voltage, and its second terminal is connected to the first terminal of the first capacitor; the second terminal of the first capacitor is grounded; a first terminal of the second capacitor is connected to a bias voltage, and its second terminal is connected to the first terminal of the second resistor; the second terminal of the second resistor is grounded; and a monitoring module for real-time monitoring of the sensing signals output by the bridge module and switching the operating mode according to the sensing signals. By constructing a dynamic capacitive bridge using two resistors and two capacitors, the static current path in the tunneling magnetoresistive sensor is completely eliminated by utilizing the characteristic of capacitors to block DC and pass AC, thereby effectively reducing power consumption; and the real-time monitoring of the sensing signals by the monitoring module enables timely switching of the operating mode, achieving high-precision measurement and solving the problem of high power consumption in existing tunneling magnetoresistive sensors.

[0064] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A reading circuit for a tunneling magnetoresistive sensor, characterized in that, include: A bridge module for acquiring sensing signals includes a first resistor, a second resistor, a first capacitor, and a second capacitor. A first terminal of the first resistor is connected to a bias voltage, and its second terminal is connected to the first terminal of the first capacitor. The second terminal of the first capacitor is grounded. A first terminal of the second capacitor is connected to a bias voltage, and its second terminal is connected to the first terminal of the second resistor. The second terminal of the second resistor is grounded. The monitoring module is used to monitor the sensing signal output by the bridge module in real time and switch the working mode according to the sensing signal. The monitoring module is used to switch the working mode to the measurement mode when a transient change in the current of the sensing signal is detected. The monitoring module is also used to switch the working mode to sleep mode when the rate of change of the sensor signal is detected to be within a preset range.

2. The reading circuit of the tunneling magnetoresistive sensor according to claim 1, characterized in that, The first capacitor and the second capacitor are MiM capacitors, MoM capacitors, ceramic capacitors, electrolytic capacitors, or silicon capacitors.

3. The reading circuit of the tunneling magnetoresistive sensor according to claim 1, characterized in that, The first resistor and the second resistor have the same resistance value, and the first capacitor and the second capacitor have the same capacitance value.

4. The reading circuit of the tunneling magnetoresistive sensor according to claim 3, characterized in that, The capacitance values ​​C of the first capacitor and the second capacitor are ≤ 1 / (2×π×R×f), where R represents the resistance value of the first resistor and f represents the transient switching frequency of the current to be detected.

5. The reading circuit of the tunneling magnetoresistive sensor according to claim 1, characterized in that, The monitoring module includes a comparator and a processor; the comparator is used to compare the sensing signal with a reference signal to output a comparison signal; the processor is used to analyze and process the comparison signal to switch the working mode according to the analysis and processing results.

6. The reading circuit of the tunneling magnetoresistive sensor according to claim 5, characterized in that, The processor includes a filtering algorithm unit, a compensation calibration unit, a range control unit, a data analysis unit, and a status control unit; the filtering algorithm unit is used to filter the comparison signal to obtain a filtered comparison signal; the compensation calibration unit is used to compensate and calibrate the filtered comparison signal to obtain a compensated and calibrated comparison signal. The range control unit is used to set the range; the data analysis is used to compare the compensated and calibrated comparison signal with the range to obtain the result of whether the comparison signal exceeds the range. The status control unit is used to switch the working mode according to the results of the data analysis. When the comparison signal exceeds the range, the working mode is switched to the measurement mode; otherwise, the working mode is switched to the sleep mode.

7. The reading circuit of the tunneling magnetoresistive sensor according to claim 5, characterized in that, The monitoring module also includes an operational amplifier and an analog-to-digital converter; the operational amplifier amplifies the sensing signal and inputs it to the analog-to-digital converter; the analog-to-digital converter converts the amplified sensing signal from an analog signal to a digital signal.

8. The reading circuit of the tunneling magnetoresistive sensor according to claim 5, characterized in that, When there are multiple bridge modules, the monitoring module further includes a multiplexer; the multiplexer is used to receive the sensing signal output by each bridge module and transmit the sensing signal to the comparator.

9. A control method for controlling the reading circuit of a tunneling magnetoresistive sensor as described in any one of claims 1 to 8, characterized in that, The control method includes: Acquire sensor signals; Real-time monitoring of sensor signals; When a transient change in current of the sensor signal is detected, the operating mode is switched to measurement mode; When the rate of change of the sensor signal is detected to be within the preset range, the working mode is switched to sleep mode.

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