A wide-range current sensor based on gallium nitride and a current measurement method

Abstract

This invention provides a gallium nitride-based wide-range current sensor and current measurement method, relating to the field of current sensing technology. The sensor includes a chip body, a symmetrical differential sensing array, an on-chip temperature dead zone reference unit, a signal processing system, and a gate adaptive control loop. It employs an AlGaN / GaN heterostructure and a MIS insulated gate, achieving online adjustable sensitivity through dynamic gate voltage control of the two-dimensional electron gas concentration. Stray magnetic fields are suppressed by the differential array, and on-chip self-temperature compensation is achieved through the homogeneous reference unit. The measurement method includes initialization, synchronous acquisition, differential cancellation, temperature compensation, range determination, gate voltage adjustment, and signal output. This invention achieves high sensitivity and wide range compatibility on a single chip, possessing advantages such as low leakage current, low temperature drift, strong anti-interference, simple process, and high integration. It is suitable for high-precision current measurement scenarios such as new energy, power electronics, and industrial control.

Description

Technical Field

[0001] This invention relates to the field of current sensing technology, and in particular to a wide-range current sensor based on gallium nitride and a current measurement method. Background Technology

[0002] Current sensors are indispensable key sensing components in modern power electronic systems. Their function is to convert the current signal in the system into a voltage signal that can be acquired, processed, and controlled by the back-end circuitry, thereby realizing functions such as overcurrent protection, power metering, closed-loop control, and status monitoring of the system.

[0003] Traditional Si-based Hall sensors utilize the Hall effect of silicon-based materials to sense the magnetic field generated by the current. To improve sensitivity, they usually need to be combined with a large magnetic ring and the sensor is encapsulated in a specific location near the wire. Fixed-structure GaN Hall sensors: Some cutting-edge research has begun to utilize two-dimensional electron gas (2DEG) generated by AlGaN / GaN heterojunctions as a sensing channel; such schemes typically use fixed geometric dimensions (length / width ratio L / W) to determine the sensing sensitivity, and output Hall voltage signals through ohmic contact electrodes; In existing technologies, the sensitivity of sensors is fixed by their physical dimensions during the manufacturing stage. If designed for high sensitivity (micro-range), they will quickly enter magnetic saturation or signal overload under the strong magnetic field generated by a large current. If designed for low sensitivity (large range), the signal-to-noise ratio is extremely low when measuring minute currents, making it impossible to accurately capture signals. Conventional GaN devices, if using a metal Schottky gate directly, will generate a non-negligible gate leakage current when a control voltage is applied. This current will be mixed into the sensing channel, causing measurement reference drift and severely affecting measurement accuracy. Existing sensors are mostly single-point measurements, which are easily affected by stray magnetic fields in the external environment (such as interference from adjacent busbars). At the same time, the carrier concentration of GaN materials is extremely sensitive to temperature. Traditional solutions often require complex external temperature sensors for compensation, resulting in slow response speed and low integration. To achieve a wide measurement range, existing solutions often require multiple sensors of different specifications to be connected in parallel or complex mechanical structures to be added, thereby increasing the complexity of the sensors.

[0004] In summary, we propose a gallium nitride-based wide-range current sensor and current measurement method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a wide-range current sensor and current measurement method based on gallium nitride. By cooperating with the AlGaN / GaN heterojunction sensing unit with dynamic gate bias control and the symmetrical differential array plus on-chip temperature blind zone reference compensation structure, the invention achieves synergistic optimization in terms of structure, materials, working mechanism and measurement algorithm. This solves a series of technical problems existing in the prior art, such as the difficulty in balancing sensitivity and wide range, gate leakage current contamination of the signal, severe interference from external stray magnetic fields, complex temperature drift compensation lag, poor device consistency and complex process. The invention achieves single-chip, high sensitivity, wide range, high linearity, high anti-interference and wide temperature range stable current measurement.

[0006] To address the aforementioned technical problems, this invention provides a gallium nitride-based wide-range current sensor, comprising a sensor chip body integrated on the same substrate, symmetrically arranged left and right sensing arrays, a temperature blind zone reference unit located in the magnetic field blind zone of the chip, a complete signal conditioning circuit, an analog-to-digital conversion circuit, a microprocessor unit, a gate bias controller, and a range adaptive feedback loop.

[0007] The left sensing array, right sensing array and temperature blind zone reference unit adopt the same physical structure, geometric dimensions, material layer system and manufacturing process to form a highly homogeneous sensing unit group, so as to ensure that the output characteristics are highly matched under different temperatures, different stresses and different process deviations, thereby improving the differential cancellation accuracy and temperature compensation effect.

[0008] Preferably, the sensing unit includes a left sensing array and a right sensing array, adopting an AlGaN / GaN heterostructure, forming a high-mobility two-dimensional electron gas at the interface as a magnetic induction channel; the gate adopts a metal-insulator-semiconductor (MIS) structure, inserting a high-dielectric-constant insulating dielectric layer between the gate and the barrier layer to completely block the gate leakage current, avoid interference to the signal channel, and improve the output linearity and stability.

[0009] By applying a dynamically adjustable bias voltage to the gate, the concentration of the two-dimensional electron gas can be actively controlled, thereby enabling real-time, continuous, and online adjustment of the sensor sensitivity. This allows the sensor to maintain high sensitivity at low currents and automatically reduce sensitivity at high currents to avoid magnetic saturation, thus achieving ultra-wide measurement ranges from weak currents to large currents on a single chip.

[0010] Preferably, the signal processing system adopts a differential sampling structure, which performs a difference operation on the output signals of the left sensing array and the right sensing array. This cancels out the interference signals of the two sensing units caused by external common-mode magnetic fields, environmental interference, power supply noise, etc., from the physical structure level, thus significantly improving the anti-interference capability.

[0011] Preferably, the temperature dead zone reference unit is placed in a region of the chip unaffected by the magnetic field being measured. Its structure, materials, and dimensions are completely identical to the working sensing array. Therefore, its output signal only reflects common-mode errors such as temperature drift, process deviations, and stress changes, and does not include the signal of the magnetic field being measured. The system introduces this reference signal into the compensation loop in real time to dynamically calibrate the sensing output, achieving high-precision self-compensation over a wide temperature range. This eliminates the need for an external temperature sensor, significantly improving integration and response speed.

[0012] Preferably, the measurement method adopts an adaptive range switching strategy: the system defaults to high-sensitivity micro-range mode upon power-up; when the measured current exceeds the upper limit of the micro-range linear range, a negative bias voltage is automatically applied to the gate to deplete part of the two-dimensional electron gas, reduce the sensor sensitivity, and switch to a large range mode; after the current falls back to the micro-range range, the system automatically restores the high-sensitivity state, realizing smooth, uninterrupted, and continuous adaptive adjustment of the range.

[0013] Preferably, the sensor chip body is fabricated on a crystal-oriented silicon substrate and includes, from bottom to top, a substrate layer, a gallium nitride buffer layer, an undoped gallium nitride channel layer, an aluminum gallium nitride barrier layer, a high dielectric constant gate dielectric layer, source / drain ohmic contact electrodes, and a gate metal electrode.

[0014] Among them, the gallium nitride buffer layer is used to alleviate the lattice mismatch and thermal mismatch between the silicon substrate and the gallium nitride epitaxial layer, reduce the defect density, and improve the crystal quality; the undoped gallium nitride layer provides a stable channel substrate; and the high-concentration two-dimensional electron gas is formed between the aluminum gallium nitride barrier layer and the gallium nitride layer due to the polarization effect, which serves as the core conductive channel for magnetic field induction.

[0015] Preferably, the gate dielectric layer is made of Al2O3, HFO2, ZrO2, or SiN. X High dielectric constant insulating materials form a metal-insulator-semiconductor (MIS) structure, the functions of which include: (1) Block the direct contact between the gate metal and the semiconductor to completely eliminate Schottky leakage current; (2) Improve gate control capability and reduce the bias voltage amplitude required to achieve carrier control; (3) Improve the withstand voltage and stability of the device, and expand the operating voltage range; (4) Enhance the device’s tolerance to environmental factors such as electric field, temperature, and radiation.

[0016] Preferably, the source and drain are made of Ti / Al / Ti / Au multilayer metal structure and are alloyed at high temperature to form a low-resistance ohmic contact with the two-dimensional electron gas, thereby reducing contact resistance and improving device response speed and signal quality.

[0017] Preferably, the gate adopts a Ni / Au stacked structure, which has good thermal stability, conductivity and interface compatibility, and can maintain stable control characteristics during long-term operation.

[0018] Preferably, the sensor chip is symmetrically arranged with the left and right sensing arrays based on the central axis of symmetry. The two arrays are geometrically symmetrical about the distance from the current-carrying conductor to be measured. Therefore, the magnetic field generated by the current to be measured produces induced signals of equal magnitude and opposite direction (or the same direction, which can be configured according to differential logic) on the two sensing arrays. Meanwhile, the external stray magnetic field generates common-mode signals of equal magnitude and the same direction on the two sensing arrays. Through differential operation, the signal to be measured can be retained and the common-mode interference can be greatly suppressed, thereby achieving high anti-interference measurement.

[0019] Preferably, the temperature blind zone reference unit is located on the chip in a region far from the wire to be tested and unaffected by the magnetic field to be tested. Its structure, size, material, epitaxial layer, electrode, and layout shape are completely consistent with the sensing array. Therefore, its output drift is caused only by non-magnetic field factors such as temperature, stress, and process deviation, and can be used as a high-precision real-time compensation reference.

[0020] Preferably, the chip has six functional pins on its periphery, including a power supply pin, a system ground pin, an I2C communication clock pin, an I2C data pin, an analog output positive terminal, and an analog output negative terminal. The digital interface is used to output a high-precision digital current value after calibration and compensation, and the analog interface is used to output the raw differential Hall voltage without digital processing. It has ultra-high bandwidth and ultra-low latency characteristics, which can meet high-end requirements such as high-frequency current monitoring and transient current capture.

[0021] Preferably, the signal processing system includes a differential preamplifier circuit, a temperature signal buffer circuit, a programmable gain amplifier, an analog-to-digital converter, a microprocessor, a gate bias controller, and a range adaptive feedback loop.

[0022] Preferably, the differential preamplifier circuit is used to amplify the weak Hall voltage output from the left and right sensing arrays with low noise; the temperature signal buffer circuit is used to buffer the output of the temperature dead zone reference unit with high impedance to avoid the load effect affecting the compensation accuracy; the programmable gain amplifier can automatically adjust the amplification factor according to different ranges to make the signal amplitude match the input range of the analog-to-digital converter; the analog-to-digital converter converts the analog signal into a digital signal for the microprocessor to operate on; the microprocessor executes core algorithms such as differential operation, temperature compensation, range judgment, gate voltage calculation, digital calibration, and communication output; the gate bias controller outputs a high-precision adjustable gate voltage according to the microprocessor instructions; and the range adaptive feedback loop stably delivers the gate voltage to the gate of each sensing unit to achieve sensitivity control.

[0023] This invention also provides a wide-range current measurement method based on gallium nitride, comprising the following steps: S1: The system is powered on and initialized. The microprocessor configures the internal registers, amplification factor, and communication parameters, and sets the gate bias voltage to 0V, so that the sensor enters the high-sensitivity micro-range measurement mode. At this time, the two-dimensional electron gas concentration is the highest and the magnetic field response sensitivity is the greatest. S2: Simultaneously acquire the differential output signals of the left and right sensing arrays, and at the same time acquire the output signal of the temperature blind zone reference unit. All signal acquisitions are strictly synchronized in timing to avoid compensation deviations caused by phase errors. S3: Perform spatial differential operation on the left and right sensing array signals to eliminate common-mode errors such as external common-mode magnetic field, environmental interference, and power supply noise; introduce the drift signal of the temperature blind zone reference cell into the compensation algorithm, perform real-time dynamic calibration on the differential results, eliminate errors caused by non-ideal factors such as temperature drift, process deviation, and packaging stress, and obtain a high-precision net magnetic field signal. S4: The microprocessor calculates the current current value based on the calibrated signal and determines whether it exceeds the preset micro-range linear threshold. If it does not exceed the threshold, the current gate voltage and sensitivity remain unchanged. If it exceeds the threshold, the automatic range switching process is initiated. S5: When the current exceeds the upper limit of the micro-range, the microprocessor applies a negative bias voltage to the gate through the gate bias controller, which depletes part of the two-dimensional electron gas through the field effect, reduces the channel carrier concentration, thereby reducing the magnetic field sensitivity, and enabling the sensor to enter the large-range working mode to avoid signal saturation. S6: In large range mode, the signal is reacquired, differential operation and temperature compensation are performed, and the current value is recalculated according to the sensitivity coefficient corresponding to the current gate voltage to ensure measurement accuracy and linearity across the entire range. S7: Output high-precision current value through I2C digital interface, and output original differential voltage signal through analog interface to complete a single measurement cycle. Return to step S1 to enter the next measurement cycle to realize continuous, real-time, adaptive wide-range current measurement.

[0024] Preferably, the spatial difference operation in step S3 is performed using the following formula: V_diff = V_left - V_right Wherein, V_left is the sensed voltage output from the left sense array after being amplified by the differential preamplifier circuit, and V_right is the sensed voltage output from the right sense array after being amplified by the differential preamplifier circuit.

[0025] The technical effects and advantages of this invention are as follows: This invention achieves real-time, continuous, and online adjustable sensor sensitivity by dynamically controlling the two-dimensional electron gas concentration at the AlGaN / GaN heterojunction interface through gate bias voltage. It simultaneously balances high sensitivity for small currents and wide measurement range for large currents on a single chip, fundamentally solving the technical bottleneck of incompatibility between sensitivity and range in traditional devices. This significantly expands the measurement range and applicable scenarios. Furthermore, the use of a MIS insulated gate structure with a high dielectric constant dielectric layer completely blocks gate leakage current, eliminating signal contamination and reference drift. This significantly improves linearity, stability, and measurement accuracy under large range, high bias, and high temperature environments, and extends the device's lifespan.

[0026] This invention employs a symmetrical differential sensing array, which cancels out external stray magnetic fields, bus interference, and common-mode noise at the physical level through spatial differential sampling. It achieves high anti-interference measurement without additional shielding and complex filtering, improving measurement stability and reducing system complexity. The chip integrates a homogeneous temperature reference unit in the magnetic field blind zone, which can capture temperature drift signals in real time and achieve high-precision self-compensation over a wide temperature range. It eliminates the need for an external temperature sensor, effectively improving integration and reducing size, and solving the problems of slow response, low compensation accuracy, and poor consistency in traditional temperature compensation schemes.

[0027] All sensing and reference units in this invention adopt completely consistent structural dimensions and process design, which significantly improves device compatibility, reduces the impact of process deviations on measurement accuracy, increases chip yield and reduces manufacturing costs. Electrical control is used to achieve automatic range switching, eliminating the need for multiple sensors in parallel or mechanical structures. The overall design is compact and easy to integrate, meeting the requirements of miniaturization and high integration. The device supports both digital and high-bandwidth analog outputs, making it suitable for use in multiple scenarios. Combining the advantages of gallium nitride materials, it features fast response, wide temperature range, high voltage resistance, and radiation resistance, meeting the reliable application requirements of harsh industrial environments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall layout of the sensor chip of the present invention; Figure 2 This is a top view of the internal microstructure of the sensing unit of the present invention; Figure 3 This is a schematic diagram of the cross-sectional structure of the epitaxial layer of the sensing unit of the present invention; Figure 4 This is a functional block diagram of the signal processing system of the present invention; Figure 5 This is a schematic diagram of the wide-range adaptive current measurement method of the present invention.

[0029] The attached figures are labeled as follows: 100, sensor chip body; 110, left sensing array; 120, right sensing array; 130, temperature dead zone reference unit; 200, current-carrying conductor under test; 301, crystal-oriented silicon substrate; 302, gallium nitride buffer layer; 303, undoped gallium nitride channel layer; 304, aluminum gallium nitride barrier layer; 305, gate dielectric layer; 306, ohmic contact electrode; 307, metal gate; 401, edge-integrated power supply pin; 402, system ground pin; 403, serial clock line; 404, serial data line; 405, analog output positive terminal; 406, analog output negative terminal; 501, differential preamplifier circuit; 502, temperature signal buffer circuit; 503, programmable gain amplifier; 504, analog-to-digital converter; 505, microprocessor; 506, gate bias controller; 507, range adaptive feedback loop. Detailed Implementation

[0030] This invention provides a wide-range current sensor based on gallium nitride, such as... Figures 1-4 As shown, it includes a sensor chip body 100, which is disposed above the current-carrying wire 200 to be measured at a preset interval, for example, 0.5mm-5mm; The sensor chip body 100 is symmetrically arranged with the left sensing array 110 and the right sensing array 120 with the central axis of symmetry as the reference. A temperature blind zone reference unit 130 is set in the magnetic field blind zone inside the chip. The physical structure, geometric dimensions, material system, and fabrication process of the left sensing array 110, the right sensing array 120, and the temperature blind zone reference unit 130 are completely identical.

[0031] Furthermore, the sensor chip body 100 integrates power supply pin 401, system ground pin 402, serial clock line 403, serial data line 404, analog output positive terminal 405, and analog output negative terminal 406 at its edge.

[0032] Furthermore, the microstructure of the sensing unit, from bottom to top, consists of a crystal-oriented silicon substrate 301, a gallium nitride buffer layer 302, an undoped gallium nitride channel layer 303, an aluminum gallium nitride barrier layer 304, a gate dielectric layer 305, an ohmic contact electrode 306, and a metal gate 307. A two-dimensional electron gas magnetic induction channel is formed at the interface between the undoped gallium nitride channel layer 303 and the aluminum gallium nitride barrier layer 304.

[0033] Furthermore, the gate dielectric layer 305 is made of Al2O3, HFO2, ZrO2, or SiN. X The insulating material forms a metal-insulator-semiconductor gate structure; the ohmic contact electrode 306 is a Ti / Al / Ti / Au stacked structure, and the metal gate 307 is made of Ni / Au material.

[0034] Furthermore, it also includes a signal processing system: a differential preamplifier circuit 501 for extracting and initially amplifying the sensing array voltage signal; a temperature signal buffer circuit 502 for processing the temperature drift reference signal of the temperature dead zone reference unit 130; a programmable gain amplifier 503 for dynamically adjusting the signal gain to match the ADC range; an analog-to-digital converter 504 for converting analog signals to digital signals; a microprocessor 505 for the core computing and control unit, executing the wide-range judgment algorithm; and a gate bias controller 506 responsible for generating the gate feedback bias voltage Vg and a range adaptive feedback loop 507 for guiding the control voltage to the sensing array gate path. Figure 4 The dashed line in the middle.

[0035] This invention also provides a wide-range current measurement method based on gallium nitride, applied to the aforementioned current sensor, with the following specific steps: S1: System initialization, set the gate bias voltage Vg=0V, so that the sensor enters the high-sensitivity micro-range measurement mode; S2: Synchronously acquire the differential sensing signals output by the left sensing array 110 and the right sensing array 120, as well as the temperature drift reference signal output by the temperature blind zone reference unit 130; S3: Perform spatial difference operation on the sensing signals of the left sensing array 110 and the right sensing array 120 to eliminate common-mode interference; and perform real-time temperature drift compensation on the difference result according to the drift signal of the temperature blind zone reference unit 130 to obtain the calibrated current sensing signal. S4: Calculate the current value based on the calibrated current sensing signal and determine whether the current current exceeds the preset micro-range linear threshold; the micro-range linear threshold is the maximum current value at which the sensor maintains linear output in the high-sensitivity state of Vg=0V, which is determined by the device sensitivity and the signal range. S5: If the current exceeds the micro-range linear threshold, apply a negative gate bias voltage Vg<0V to deplete part of the two-dimensional electron gas concentration through the electric field effect, thereby reducing the sensor's measurement sensitivity. S6: Reacquire the differential sensing signals of the left sensing array 110 and the right sensing array 120 and the temperature drift reference signal of the temperature blind zone reference unit 130, perform spatial differential operation and real-time temperature drift compensation again, and calculate the high current measurement value based on the sensitivity coefficient corresponding to the current gate voltage. S7: Output current signal, return to step S1, and enter the next measurement cycle.

[0036] Furthermore, by adjusting the bias voltage of the metal gate 307, the sensing sensitivity is dynamically changed, enabling adaptive and smooth switching between micro and large ranges. The metal gate 307 is made of Ni / Au metal and is used for bias control of 2DEG concentration.

[0037] Furthermore, a symmetrical differential array is used to cancel out external stray magnetic fields and common-mode interference, and a temperature blind zone reference unit 130 is used to compensate for wide-temperature drift in real time. The temperature blind zone reference unit 130 is located in the magnetic field blind zone and is used for thermal drift compensation. Its structure is the same as that of the left sensing array 110 and the right sensing array 120.

[0038] Furthermore, a high-bandwidth original Hall voltage signal is output through analog output positive 405 and analog output negative 406, wherein analog output positive 405 is used as the positive terminal of the original analog differential signal output, and analog output negative 406 is used as the negative terminal of the original analog differential signal output.

[0039] Example 1: A wide-range current sensor structure based on gallium nitride; like Figures 1-4 As shown, a wide-range current sensor based on gallium nitride includes a sensor chip body 100, which is placed above the current-carrying wire 200 to be measured, and is used to sense the magnetic field signal generated when the wire is energized.

[0040] The sensor chip body 100 is based on the central axis of symmetry L1, with a left sensing array 110 arranged on the left and a right sensing array 120 arranged on the right, and the left and right arrays are completely symmetrical. A temperature blind zone reference unit 130 is set in the magnetic field blind zone position inside the chip. This unit is completely consistent with the left sensing array 110 and the right sensing array 120 in terms of structure, size, material and process, to ensure a high degree of matching of temperature drift characteristics.

[0041] The chip edge has six pins: edge integrated power pin 401, system ground pin 402, serial clock line 403, serial data line 404, analog output positive 405, and analog output negative 406.

[0042] The cross-sectional structure of the sensing unit is as follows Figure 3 As shown, from bottom to top, the structure consists of: a silicon substrate 301, a gallium nitride buffer layer 302, an undoped gallium nitride channel layer 303, an aluminum gallium nitride barrier layer 304, a gate dielectric layer 305, an ohmic contact electrode 306, and a metal gate 307. A high-concentration two-dimensional electron gas is formed at the interface between the channel layer 303 and the barrier layer 304, serving as a magnetic field sensing channel. The gate dielectric layer 305 is made of Al₂O₃, forming a MIS insulated gate structure to block leakage current.

[0043] Signal processing systems such as Figure 4As shown, it includes a differential preamplifier circuit 501, a temperature signal buffer circuit 502, a programmable gain amplifier 503, an analog-to-digital converter 504, a microprocessor 505, a gate bias controller 506, and a range adaptive feedback loop 507, which realize signal acquisition, amplification, compensation, calculation, range control and output.

[0044] The range adaptive feedback loop 507 includes a multiplex analog switch, an RC low-pass filter network, and a gate drive buffer.

[0045] The input terminal of the multiplexer is connected to the output terminal of the gate bias controller 506, and the channel selection control terminal is connected to the general-purpose input / output port of the microprocessor 505. The multiplexer has at least two output channels, which are respectively connected to the metal gate 307 of each sensing unit in the left sensing array 110 and the metal gate 307 of each sensing unit in the right sensing array 120.

[0046] An RC low-pass filter network is set between each output channel of the multi-channel analog switch and the corresponding metal gate 307. It consists of a series resistor and a parallel capacitor. The series resistor ranges from 100Ω to 1kΩ, and the parallel capacitor ranges from 10pF to 100pF. It is used to filter out high-frequency noise in the gate bias voltage and suppress transient oscillations during gate voltage switching.

[0047] The gate drive buffer is a voltage follower structure implemented using a low-noise operational amplifier. It is located between the RC low-pass filter network and the metal gate 307 to provide gate drive capability with low output impedance, ensuring the synchronization and consistency of the gate voltages of the sensing units of the left sensing array 110 and the right sensing array 120.

[0048] During range switching, the microprocessor 505 sends a target gate voltage command to the gate bias controller 506 and simultaneously controls the multiplex analog switch to select the gate channels of the left sensing array 110 and the right sensing array 120. The adjustable gate voltage output by the gate bias controller 506 is smoothed by an RC low-pass filter network and then driven by the gate drive buffer to be synchronously applied to all the metal gates 307 of the left sensing array 110 and the right sensing array 120. The two-dimensional electron gas concentration in the channel of each sensing unit is uniformly adjusted through the electric field effect, thereby achieving adaptive and consistent adjustment of the entire chip range.

[0049] Example 2: Wide-range current measurement method; like Figure 5 As shown, a wide-range current measurement method based on gallium nitride includes the following steps: S1: System initialization, gate bias voltage Vg=0V, sensor enters high sensitivity micro-range mode; S2: Synchronously acquire the output signals of the left sensing array 110, the right sensing array 120 and the temperature blind zone reference unit 130; S3: Perform differential operation to eliminate common-mode magnetic field interference and use temperature reference signal for real-time drift compensation; Spatial difference operations are performed by the microprocessor 505, and the formula is as follows: V_diff = V_left - V_right Wherein, V_left is the sensing voltage output from the left sensing array 110 after being amplified by the differential preamplifier circuit 501, and V_right is the sensing voltage output from the right sensing array 120 after being amplified by the differential preamplifier circuit 501.

[0050] The magnetic field generated by the current in the current-carrying conductor 200 is antisymmetrically distributed on both sides of the central axis of symmetry L1. Therefore, the Hall voltages induced by the left sensing array 110 and the right sensing array 120 have opposite polarities. After the above differential operation, the components of the signal under test are superimposed and enhanced. The induced voltages generated by the external stray magnetic field and environmental common-mode interference at the left sensing array 110 and the right sensing array 120 have the same polarity and approximately equal amplitude, denoted as V_common. After differential operation: V_common_cancel = V_common - V_common = 0 As a result, the common-mode interference component is eliminated, leaving only the differential voltage V_diff, which is proportional to the current under test.

[0051] Real-time temperature drift compensation is performed by the microprocessor 505, and the compensation algorithm formula is as follows: V_comp = V_diff - k_T × (V_temp - V_temp_ref) - V_offset Wherein, V_comp is the calibration current sensing signal after temperature drift compensation, V_diff is the differential voltage after spatial differential operation, V_temp is the real-time temperature drift reference voltage output by the temperature blind zone reference unit 130 after being buffered by the temperature signal buffer circuit 502, V_temp_ref is the output voltage of the temperature blind zone reference unit 130 at the reference temperature of 25℃, k_T is the temperature compensation coefficient, and V_offset is the zero-point drift correction amount.

[0052] The temperature compensation coefficient k_T and the zero-point drift correction V_offset are determined during the factory calibration stage: the sensor chip body 100 is placed in a temperature-controlled environment, and V_temp_ref and the corresponding V_diff zero-point value are recorded at a reference temperature of 25℃; the ambient temperature is changed, and the relationship between V_temp and V_diff at different temperatures is recorded. The temperature compensation coefficient k_T and the zero-point drift correction V_offset are obtained by least squares fitting. During online measurement, the microprocessor 505 acquires the V_temp output by the temperature blind zone reference unit 130 in real time, substitutes it into the above formula to calculate V_comp, and eliminates errors introduced by temperature drift, process deviation, and packaging stress.

[0053] S4: Determine whether the current current exceeds the micro-range threshold; S5: If the threshold is exceeded, a negative gate voltage is applied to deplete the two-dimensional electron gas and reduce the sensitivity; S6: Reacquire the signal and complete the compensation and calculation to obtain the large-range current value; The sensitivity coefficient S(Vg) is defined as: the differential Hall voltage output value generated by the sensor per unit current under a specific gate bias voltage Vg, i.e., S(Vg) = V_diff / I, where V_diff is the differential Hall voltage amplified by the differential preamplifier circuit 501, and I is the standard current in the current-carrying wire 200 under test.

[0054] S7: Output current signal through digital and analog interfaces, return to step S1, and enter the next measurement cycle.

[0055] In this embodiment, by dynamically adjusting the gate voltage, a range adjustment range of at least 100 times can be achieved while maintaining high linearity and high accuracy.

[0056] Example 3: Operating mode under high temperature environment; Within a wide temperature range of -40℃ to 150℃, the temperature blind zone reference unit 130 outputs a temperature drift signal synchronized with the sensing array in real time. The microprocessor corrects the sensitivity coefficient and zero-point offset in real time based on this signal, enabling the sensor to maintain high-precision and stable output across the entire temperature range without the need for an external temperature compensation circuit.

[0057] Example 4: Anti-interference capability under strong interference environment; In environments with stray magnetic field interference from external motors, buses, transformers, etc., the symmetrical differential array suppresses common-mode interference by more than 60dB, ensuring that the measurement results are not affected by external magnetic fields and improving system stability and reliability.

[0058] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A wide-range current sensor based on gallium nitride, characterized in that, Includes a sensor chip body (100), which is disposed above the current-carrying wire (200) to be measured; The sensor chip body (100) is symmetrically arranged with the left sensing array (110) and the right sensing array (120) with the central axis of symmetry as the reference. A temperature blind zone reference unit (130) is set in the magnetic field blind zone inside the chip. The physical structure, geometry, material system and fabrication process of the left sensing array (110), the right sensing array (120) and the temperature blind zone reference unit (130) are completely identical.

2. A wide-range current sensor based on gallium nitride according to claim 1, characterized in that, The sensor chip body (100) has an edge-integrated power supply pin (401), system ground pin (402), serial clock line (403), serial data line (404), analog output positive terminal (405), and analog output negative terminal (406).

3. A wide-range current sensor based on gallium nitride according to claim 1, characterized in that, The microstructures of the left sensing array (110) and the right sensing array (120) from bottom to top are: a crystal-oriented silicon substrate (301), a gallium nitride buffer layer (302), an undoped gallium nitride channel layer (303), an aluminum gallium nitride barrier layer (304), a gate dielectric layer (305), an ohmic contact electrode (306), and a metal gate (307). A two-dimensional electron gas magnetic induction channel is formed at the interface between the undoped gallium nitride channel layer (303) and the aluminum gallium nitride barrier layer (304).

4. A wide-range current sensor based on gallium nitride according to claim 3, characterized in that, The gate dielectric layer (305) is made of Al2O3, HFO2, ZrO2 or SiN. X The insulating material forms a metal-insulator-semiconductor gate structure; the ohmic contact electrode (306) is a Ti / Al / Ti / Au stacked structure, and the metal gate (307) is made of Ni / Au material.

5. A wide-range current sensor based on gallium nitride according to claim 1, characterized in that, It also includes a signal processing system: a differential preamplifier circuit (501), a temperature signal buffer circuit (502), a programmable gain amplifier (503), an analog-to-digital converter (504), a microprocessor (505), a gate bias controller (506), and a range adaptive feedback loop (507).

6. A gallium nitride-based wide-range current measurement method, applied to a gallium nitride-based wide-range current sensor according to any one of claims 1-5, characterized in that, The specific steps are as follows: S1: System initialization, set the gate bias voltage Vg=0V, so that the sensor enters the high-sensitivity micro-range measurement mode; S2: Synchronously acquire the differential sensing signals output by the left sensing array (110) and the right sensing array (120), as well as the temperature drift reference signal output by the temperature blind zone reference unit (130); S3: Perform spatial difference operation on the sensing signals of the left sensing array (110) and the right sensing array (120) to eliminate common-mode interference; and perform real-time temperature drift compensation on the difference result according to the drift signal of the temperature blind zone reference unit (130) to obtain the calibrated current sensing signal. S4: Calculate the current value based on the calibrated current sensing signal and determine whether the current current exceeds the preset micro-range linear threshold; the micro-range linear threshold is the maximum current value at which the sensor maintains linear output in the high-sensitivity state of Vg=0V, which is determined by the device sensitivity and the signal range. S5: If the current exceeds the micro-range linear threshold, apply a negative gate bias voltage Vg<0V to deplete part of the two-dimensional electron gas concentration through the electric field effect, thereby reducing the sensor's measurement sensitivity. S6: Reacquire the differential sensing signals of the left sensing array (110) and the right sensing array (120) and the temperature drift reference signal of the temperature blind zone reference unit (130), perform spatial differential operation and real-time temperature drift compensation again, and calculate the high current measurement value according to the sensitivity coefficient corresponding to the current gate voltage. S7: Output current signal, return to step S1, and enter the next measurement cycle.

7. A wide-range current measurement method based on gallium nitride according to claim 6, characterized in that, The sensing sensitivity is dynamically changed by adjusting the bias voltage of the metal gate (307) to enable adaptive and smooth switching between micro and large ranges.

8. A wide-range current measurement method based on gallium nitride according to claim 6, characterized in that, A symmetrical differential array is used to cancel external stray magnetic fields and common-mode interference, and a temperature blind zone reference unit (130) is used to compensate for wide-temperature drift in real time.

9. A wide-range current measurement method based on gallium nitride according to claim 6, characterized in that, A high-bandwidth original Hall voltage signal is output through the analog output positive terminal (405) and the analog output negative terminal (406).

10. A wide-range current measurement method based on gallium nitride according to claim 6, characterized in that, The spatial difference operation in step S3 is calculated using the following formula: V_diff = V_left - V_right Wherein, V_left is the sensing voltage output from the left sensing array (110) after being amplified by the differential preamplifier circuit (501), and V_right is the sensing voltage output from the right sensing array (120) after being amplified by the differential preamplifier circuit (501).

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