Current calibration method, device, equipment and medium

Abstract

The invention relates to the technical field of current calibration, and discloses a current calibration method, device and equipment and a medium, and the method comprises the steps: enabling the high end side and the low end side of a source measurement unit to be connected with the positive electrode and the negative electrode of a measured assembly respectively, and obtaining the machine measurement current of the measured assembly and the meter measurement current of the source measurement unit; corresponding calibration parameters are obtained through the corresponding relation between the machine-measured current and the meter-measured current; the machine measurement current is calibrated based on the calibration parameters, so that the calibrated machine measurement current is consistent with the meter measurement current; after the machine measurement current is calibrated, under the condition that the output of the source measurement unit is no-load, different equidistant fixed voltages are output at the maximum voltage gear and then are measured, and a voltage measurement value and a current measurement value are obtained; common-mode compensation is performed on the current measurement error of the source measurement unit by using the voltage measurement value and the current measurement value. According to the invention, high-end acquisition of a digital current loop is focused, the influence of a high common mode can be effectively avoided, and the current precision is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of current calibration, and in particular to a current calibration method, device, equipment and medium. Background Art

[0002] A source meter, also known as a source measurement unit (SMU), is a test instrument that integrates the functions of a voltage source, a current source, an electronic load, a voltmeter, and an ammeter. It can provide precise DC (or pulse) voltage or current output or absorption, and can simultaneously measure the current, voltage and other parameters of the components under test (i.e., the device under test DUT, also called the load).

[0003] At present, in the digital current loop composed of source meters, the measurement of loop current includes low-end acquisition and high-end acquisition. Among them, low-end acquisition directly measures the current between the load and the ground, and high-end acquisition measures the current between the power supply and the load. Low-end acquisition is easy to introduce branch currents, thereby reducing the current accuracy of the loop. High-end acquisition can use low-voltage op amps to avoid the influence of high common mode, but it requires grounding, which is difficult to design. Therefore, a digital loop current calibration solution for high-end acquisition is urgently needed to ensure the current accuracy in the digital current loop. Summary of the invention

[0004] In view of this, the present invention provides a current calibration method, device, equipment and medium to solve the problems that the existing digital current loop cannot effectively avoid high common mode influence for high-end acquisition, has complex design and low loop current accuracy.

[0005] In a first aspect, the present invention provides a current calibration method, which is applied to a digital current loop for high-end collection, wherein the digital current loop includes a digital loop controller, a forward channel and a current feedback channel; wherein the forward channel is used to adjust the current accordingly according to the control of the digital loop controller, and includes a digital-to-analog converter, a conditioning circuit, a power amplifier and a sampling resistor; the current feedback channel is used to collect and feed back the corresponding loop current, and includes a current collection front-end buffer, an isolated power supply, a high common-mode amplifier, an instrumentation amplifier, a conditioning circuit and an analog-to-digital converter, wherein the current collection front-end buffer is powered by an isolated power supply alone and the reference ground of the isolated power supply is equipotential with the output end of the power amplifier, and the method includes: After the high-end side and the low-end side of the source measurement unit are connected to the positive and negative electrodes of the component under test respectively, the machine-measured current of the component under test and the meter-measured current of the source measurement unit are obtained; The corresponding calibration parameters are obtained through the correspondence between the machine-measured current and the meter-measured current; The machine-measured current is calibrated based on the calibration parameters so that the calibrated machine-measured current is consistent with the meter-measured current; and after the machine-measured current is calibrated, different equally spaced fixed voltages are output at the maximum voltage level and then measured under the condition that the source measurement unit output is no-loaded, and corresponding voltage measurement values ​​and current measurement values ​​are obtained; The voltage measurement value and the current measurement value are used to perform common mode compensation for the current measurement error of the source measurement unit.

[0006] The present invention focuses on the high-end acquisition of the digital current loop, obtains corresponding calibration parameters by measuring the machine-measured current of the component under test and the meter-measured current of the source measurement unit, calibrates the machine-measured current using the calibration parameters, and then measures different equally spaced fixed voltages at the maximum voltage level under the condition that the source measurement unit outputs no-load, obtains corresponding voltage measurement values ​​and current measurement values, and uses the measurement values ​​to perform common-mode compensation on the current measurement error of the source measurement unit, which can effectively avoid the gain error and common-mode influence of the high common-mode amplifier, thereby greatly improving the current accuracy of the digital current loop.

[0007] In an optional implementation, the current calibration method further includes: Verify that the output of the high common-mode amplifier is in the linear region; If it is in the linear region, the step of obtaining the machine-measured current of the component under test and the meter-measured current of the source measurement unit is performed; If it is in the nonlinear area, the preset nonlinear working area avoidance operation is executed, and then the step of verifying whether the output of the high common mode amplifier is in the linear area is returned again; wherein the preset nonlinear working area avoidance operation at least includes using a preset reference source to DC bias the output of the high common mode amplifier, and using an instrument amplifier cascaded at the output end of the high common mode amplifier to eliminate the influence of the bias voltage on the corresponding signal conditioning path.

[0008] The present invention takes into account the situation that there is a sudden linearity change in the output voltage zero-crossing gain error when the high common-mode amplifier is working, and accordingly designs a verification process for whether the current output of the high common-mode amplifier is in a linear region. When it is in a nonlinear region, corresponding avoidance operations are taken to stagger the nonlinear region when the high common-mode amplifier is working, which can effectively avoid the influence of high common mode and thus help to improve the loop current accuracy.

[0009] In an optional implementation, obtaining a machine-measured current of a component under test and a meter-measured current of a source measurement unit includes: Connect the positive and negative electrodes of the component under test to the corresponding ports on the high-end side and the low-end side of the four-wire measurement of the source measurement unit respectively; Configure the component under test to the current measurement mode, and measure to obtain the machine-measured current; Perform equally-spaced sampling at the preset current range of the source measurement unit to synchronously obtain the corresponding measured current shown on the meter.

[0010] After configuring the high-end acquisition mode of the digital current loop, the present invention respectively uses the component under test to obtain the corresponding measured current by the machine and the measured current shown on the meter of the source measurement unit, providing high-quality data for subsequent current calibration.

[0011] In an alternative embodiment, the corresponding calibration parameters are obtained through the corresponding relationship between the measured current by the machine and the measured current shown on the meter, including: Obtain the corresponding relationship between the current and the calibration parameters; Input the measured current by the machine and the measured current shown on the meter into the corresponding relationship and perform fitting to obtain the corresponding calibration parameters.

[0012] The present invention uses the corresponding relationship between the current and the calibration parameters to fit the relationship between the measured current by the machine and the measured current shown on the meter, obtaining the corresponding calibration parameters, which can ensure the rationality of the calibration parameters and thus improve the accuracy of subsequent current calibration to a certain extent.

[0013] In an alternative embodiment, the common-mode compensation for the current measurement error of the source measurement unit is performed using the voltage measurement value and the current measurement value, including: Disconnect the component under test from the source measurement unit and configure the source measurement unit in the feedback mode; Apply voltage points at equal intervals under the maximum voltage range and synchronously record the voltage measurement value and the current measurement value measured by the source measurement unit; Determine the common-mode compensation parameters based on the voltage measurement value and the current measurement value; Perform common-mode compensation for the current measurement error of the source measurement unit based on the common-mode compensation parameters.

[0014] After zero-point correction of the output of the high common-mode amplifier, the present invention also takes into account the common-mode rejection ability of the high common-mode amplifier, determines the corresponding common-mode compensation parameters in combination with the current accuracy description of the high-sampling common-ground system in the conventional architecture, and performs common-mode compensation for the current measurement error of the source measurement unit using the common-mode compensation parameters, which can comprehensively and effectively avoid the influence of high common mode, and thus greatly improve the current accuracy of the digital current loop.

[0015] In an alternative embodiment, determining the common-mode compensation parameters based on the voltage measurement value and the current measurement value includes: Perform linear fitting on the voltage measurement value and the current measurement value to obtain the common-mode voltage-current relationship; Determine the common-mode compensation parameters based on the common-mode voltage-current relationship.

[0016] The present invention determines the common-mode compensation parameters by using the common-mode voltage-current relationship obtained by linear fitting, which has the advantages of simple and accurate calculation and can improve the accuracy of digital loop current to a certain extent.

[0017] In an optional embodiment, before performing current calibration on the high-end collected digital current loop, the current calibration method also includes: executing preset temperature drift suppression measures, wherein the preset temperature drift suppression measures at least include physically isolating the heat-generating components in the digital current loop, using a water-cooling heat dissipation system and a high-efficiency air-cooling heat dissipation system to reduce the temperature rise of each component in the digital current loop, and performing thermal machine operations.

[0018] The present invention takes into account the overall temperature change of the meter current acquisition link. Before using the high-end acquisition digital current loop for current calibration, a series of temperature drift suppression measures are performed to avoid the influence of temperature on the calibration. This can greatly reduce the influence of temperature on the current calibration result, thereby greatly improving the current accuracy of the digital current loop.

[0019] In a second aspect, the present invention provides a current calibration device, which is applied to a digital current loop for high-end collection, wherein the digital current loop includes a digital loop controller, a forward channel and a current feedback channel; wherein the forward channel is used to adjust the current accordingly according to the control of the digital loop controller, and includes a digital-to-analog converter, a conditioning circuit, a power amplifier and a sampling resistor; the current feedback channel is used to collect and feed back the corresponding loop current, and includes a current collection front-end buffer, an isolated power supply, a high common-mode amplifier, an instrument amplifier, a conditioning circuit and an analog-to-digital converter, wherein the current collection front-end buffer is powered by an isolated power supply alone and the reference ground of the isolated power supply is at the same potential as the output end of the power amplifier, and the device includes: A data acquisition module is used to connect the high-end side and the low-end side of the source measurement unit to the positive and negative electrodes of the component under test respectively, and then obtain the machine-measured current of the component under test and the meter-measured current of the source measurement unit; A parameter determination module is used to obtain corresponding calibration parameters through the correspondence between the machine-measured current and the meter-measured current; The zero point calibration module is used to calibrate the machine-measured current based on the calibration parameters so that the calibrated machine-measured current is consistent with the meter-measured current; and after the machine-measured current is calibrated, under the condition that the source measurement unit outputs no-load, different equally spaced fixed voltages are output at the maximum voltage level and then measured, and corresponding voltage measurement values ​​and current measurement values ​​are obtained; The common mode compensation module is used to perform common mode compensation on the current measurement error of the source measurement unit by using the voltage measurement value and the current measurement value.

[0020] The current calibration device of the present invention aims to solve the problem of low current accuracy in high-end acquisition in a digital current loop. Specifically, the corresponding calibration parameters are obtained by measuring the machine-measured current of the component under test and the meter-measured current of the source measurement unit. After the machine-measured current is calibrated using the calibration parameters, different equally spaced fixed voltages are output at the maximum voltage level under the condition that the source measurement unit outputs no-load, and corresponding voltage measurement values ​​and current measurement values ​​are obtained. The measurement values ​​are used to perform common-mode compensation on the current measurement error of the source measurement unit, which can effectively avoid the gain error and common-mode influence of the high common-mode amplifier, and help to significantly improve the current accuracy of the digital current loop.

[0021] In a third aspect, the present invention provides an electronic device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to execute a current calibration method of the first aspect or any corresponding embodiment thereof.

[0022] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute a current calibration method according to the first aspect or any corresponding embodiment thereof; and the computer-readable storage medium is also used to store calibration parameters and common-mode compensation parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is the overall block diagram of the digital loop; Figure 2 This is the digital loop current loop architecture diagram; Figure 3 is a high common-mode amplifier gain error curve; Figure 4 This is a diagram illustrating the common-mode rejection capability of a high common-mode amplifier; Figure 5 is a flow chart of a current calibration method according to an embodiment of the present invention; Figure 6 It is the linearity curve before the measured inflection point avoidance; Figure 7 It is the linearity curve after the measured inflection point is avoided; Figure 8is a flow chart of another current calibration method according to an embodiment of the present invention; Fig. 9 is a flow chart of the calibration scheme; Fig.10 is a structural block diagram of a current calibration device according to an embodiment of the present invention; Fig.11 It is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0026] It should be noted that the current calibration method described in detail below in this embodiment is applied to the digital current loop of high-end acquisition. In practical applications, the digital loop is a technology used to adjust the system output in digital signal processing, and is widely used in communications, computers and other fields to realize signal processing, transmission and control. The digital loop is usually composed of a digital signal processing module and a feedback loop. The core idea is to adjust the output of the system by digitally processing the signal and using the feedback mechanism to achieve specific performance indicators, such as stable output and accurate frequency tracking. High-end acquisition refers to the direct measurement of current between the power supply (such as a battery or a power rail) and the load, rather than the traditional low-end (between the load and the ground) measurement. This type of acquisition method can detect the load short circuit to the ground, avoid ground loop interference, and is suitable for floating ground systems, but there is a high common mode voltage (which may be close to the power supply voltage) and the challenge of requiring a dedicated circuit to process high voltage difference signals. In addition, digital loop current calibration is a technology that adjusts the current measurement loop parameters (such as gain, offset, nonlinear compensation) in real time through digital signal processing or a microcontroller to improve accuracy and stability.

[0027] In this embodiment, Figure 1This is the overall block diagram of the digital loop. It should be noted that in this embodiment, a digital loop is used to implement the relevant functions of the source measurement unit (i.e., SMU), that is, the digital loop can perform high-precision output (absorption) of voltage (or current) and high-precision synchronous acquisition of voltage (or current) between the HF (HI) and LF (LO) lines according to the instructions of the upstream interface (i.e., connected to the main device), wherein HS (sense HI) and LS (sense LO) serve as the sense lines for acquisition. It should be noted that the relevant functions of HF (HI) and LF (LO), as well as the sense lines including HS (sense HI) and LS (sense LO), can refer to the relevant wiring meanings of the source measurement unit, which will not be described in detail here. See. Figure 1 , the specific functions of each component in the digital loop include: 1. The uplink interface is used to communicate with the FPGA (Field Programmable Gate Array). It can use high-speed communication methods such as PIXE (Particle Induced X-ray Emission, a method of bombarding samples with particles generated by a particle accelerator to stimulate the samples to release characteristic X-rays), PCIE (Peripheral Component Interconnect Express, a high-speed serial point-to-point communication protocol used to connect high-performance peripherals inside the computer) and GTX (Gigabit Transceiver, a high-speed serial communication interface, mainly used for high-speed, real-time transmission of huge data in modern digital processing technology and computing technology) to provide configuration information and control commands for the digital loop, and receive the collected voltage and current data and loop status information.

[0028] 2. FPGA mainly integrates loop controller and clamp protection system, which exchanges data with the upstream interface, controls the output of digital-to-analog converter (DAC), and collects voltage and current output from analog-to-digital converter (ADC).

[0029] 3. DA (Digital to Analog), PA (Power Amplifier) ​​and sampling resistor together constitute the hardware forward channel of SMU.

[0030] 4. The current conditioning module and AD (Analog to Digital) form the current acquisition channel; the voltage conditioning module and AD form the voltage acquisition channel.

[0031] 5. BUFFER provides Guard signal (i.e. protection signal, for its specific meaning, please refer to the adaptability understanding of relevant content in this field) to prevent HF (HI) and HS (sense HI) leakage. The Guard signal has the same potential as HF (HI), providing equipotential shielding protection for HF (HI).

[0032] 6. DUT (Device Under Test) is the device under test or the equipment / unit under test.

[0033] It should be noted that since the digital loop includes a digital current loop and a digital voltage loop, the present application focuses on the digital current loop for high-end acquisition, which includes a digital loop controller, a forward channel and a current feedback channel; wherein the forward channel is used to adjust the current accordingly according to the control of the digital loop controller, and it includes a digital-to-analog converter, a conditioning circuit, a power amplifier and a sampling resistor; the current feedback channel is used to collect and feedback the corresponding loop current, and it includes a current acquisition front-end buffer, an isolated power supply, a high common-mode amplifier, an instrumentation amplifier, a conditioning circuit and an analog-to-digital converter, and the current acquisition front-end buffer is powered separately by an isolated power supply and the reference ground of the isolated power supply is at the same potential as the output end of the power amplifier.

[0034] In this embodiment, Figure 2 This is a diagram of the digital loop current loop architecture. It should be noted that the main functions of the digital current loop are to provide high-precision current output (or absorption) function, high-precision current acquisition function, and high-precision current clamping function. For details, see Figure 2 The digital current loop consists of three modules, namely the digital loop controller, the forward channel and the current feedback channel in the FPGA. The specific functions of each component are described as follows: 1. The digital loop controller is integrated in the FPGA and is mainly used for the control of the current loop to achieve fast, accurate and stable current output (or absorption) and current clamping. The digital PID (Proportional Integral Differential) controller is conventionally used.

[0035] 2. The forward channel is mainly built by analog hardware circuits, which are used to receive control signals and output (absorb) the size of current (or voltage); it mainly includes DA, conditioning circuit, PA and sampling resistor. Please note that the relevant contents of DA and PA can be found in the previous article, so they will not be repeated here.

[0036] 3. The current feedback channel (i.e., the current output (absorption) function) is also mainly built by analog hardware circuits, and is used for high-precision acquisition of output (absorption) current; it is mainly composed of the buffer BUFFER (BUFFER, BUF) at the front end of the acquisition, the isolated power supply that supplies power to the BUF separately, the high common-mode amplifier (High Common-Mode Amplifier, HCMA), the instrumentation amplifier (Instrumentation Amplifier, IA), the high-precision reference source (used to provide the reference voltage Vref), the conditioning circuit and AD. Please note that the AD-related content can be found in the previous text, and will not be repeated here.

[0037] It should be noted that HCMA is an electronic circuit that can effectively suppress common-mode signal interference and amplify differential-mode signals at the same time. Its core advantage lies in its high common-mode rejection ratio (CMRR), which is used in scenarios where weak signals are extracted in strong noise environments. CMRR (i.e., common-mode rejection ratio = the ratio of the absolute value of the voltage amplification factor of the differential-mode signal to the voltage amplification factor of the common-mode signal) is a parameter that measures the ability of a differential amplifier in an analog circuit to suppress input common-mode signals. It is an important parameter used in the hardware indicators of data acquisition products to evaluate the suppression of common-mode noise. Among them, common-mode signals refer to signals that exist at both input ends and have the same size and phase, such as power supply noise, ground interference, or other external interference. Common-mode rejection ratio determines the ability of a device to suppress interference signals by measuring the difference between the input common-mode signal and the output common-mode signal. It not only affects the accuracy of the op amp circuit, but also has an important impact on the electromagnetic interference performance of the circuit.

[0038] In this embodiment, the isolated power supply is mainly used to power the front-stage BUF of current collection and provide a reference for its PA output potential (that is, the ground of the power supply is connected to the output of the PA). The advantage is that the BUF can use an operational amplifier powered by a low voltage, so that the temperature drift, noise and leakage of the BUF can be controlled to be small enough to meet the use requirements, thereby ensuring the current collection accuracy requirement of 0.03%.

[0039] In this embodiment, Figure 3 This is a high common-mode amplifier gain error curve. It should be noted that this figure shows the gain error curves for different power supply voltages (i.e., the V S) is the gain error measured under the conditions of load resistance R of 2kΩ and gain G of 1, which is used to describe the output error under different voltages; the horizontal axis represents the output voltage in volts V; the vertical axis represents the output error in 2mV / DIV (mV / DIV refers to the voltage value (mV) represented by each grid (DIV) on the oscilloscope; in an oscilloscope, mV / DIV represents the number of millivolts represented by each grid in the vertical direction; for example, assuming the oscilloscope is set to 100mV / DIV, each grid on the display represents 100 millivolts). As can be seen from the figure, each gain error curve shows the change in output error under different output voltages; the offset of the curve is to clearly show the characteristics of each curve; for V S = ±12V, there is a linearity mutation in the area circled when the voltage is zero, that is, at zero point, the high common mode amplifier operates in a nonlinear region. In practical applications, the overall comprehensive demand for high common mode amplifiers in conventional high sampling common ground systems is evaluated. The gain error curve of the best high common mode amplifier currently available on the market is as follows: Figure 3 As shown in the figure, it can be seen that the gain error at the zero-crossing point of the output voltage has an inflection point where the linearity suddenly changes. So when using this high common-mode amplifier, it is necessary to stagger this nonlinear area to ensure the accurate acquisition of the loop current.

[0040] In this embodiment, Figure 4 This is a diagram illustrating the common-mode rejection capability of a high common-mode amplifier. It should be noted that the figure shows the characteristic parameters and CMRR of an operational amplifier as they change with temperature (i.e., the change in common-mode rejection ratio at different temperatures); the horizontal axis represents temperature in degrees Celsius, and the vertical axis represents CMRR in microvolts per volt μV / V; there are multiple curves in the figure, each representing a different sample (10 samples). As the temperature rises, the CMRR value decreases, but generally remains within a relatively stable range. Referring to the rectangular area in the figure, it can be seen that since the CMRR is 91dB (28.18uV / V) and there is a maximum CMRR temperature drift of 5uV / V in the temperature range of 25°C to 75°C, the total is 33.18uV / V. Considering the current acquisition accuracy of 0.03% (i.e., the industry standard) and leaving a 10-fold margin, the common-mode effect needs to be controlled to 30uV / V. However, the current 33.18uV / V exceeds 30uV / V. Therefore, in this embodiment, the superposition effect of other accuracy influencing quantities on the current acquisition link needs to be considered, that is, the common mode needs to be compensated.

[0041] It should be explained that μV / V represents the voltage ratio, which refers to the ratio of the output voltage (in μV) to the input voltage (in V) in a circuit. This ratio is usually used to describe the gain or attenuation characteristics of the circuit. For example, in electronic circuits, gain or attenuation refers to the degree of voltage change during the transmission of the signal, that is, μV / V can be used to quantify the circuit's ability to amplify or attenuate weak signals. For example, if the gain of the circuit is 10,000, the output voltage will be 10,000 times the input voltage; if the attenuation is 0.001, the output voltage will be one thousandth of the input voltage. In addition, μV / V can also be used to describe the sensitivity of sensors or other electronic devices. If the sensitivity of a sensor is 10,000 μV / V, it means that when the input voltage changes by 1 volt, the output voltage will change by 10,000 microvolts. This type of representation can accurately quantify the device's response to tiny voltage changes during measurement.

[0042] Based on this, an embodiment of the present invention provides an embodiment of a current calibration method. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0043] In this embodiment, a current calibration method is provided, which is applied to a digital current loop collected at a high end. Figure 5 is a flow chart of a current calibration method according to an embodiment of the present invention. Figure 5 As shown, the process includes the following steps: Step S501 , after the high-end side and the low-end side of the source measurement unit are connected to the positive and negative electrodes of the component under test respectively, the machine-measured current of the component under test and the meter-measured current of the source measurement unit are obtained.

[0044] It should be noted that in this embodiment, the machine-measured current collected by the component under test is used as the reference data for corresponding processing of the meter-measured current of the source measurement unit. The specific type of the component under test is not limited here and is adaptively adjusted according to actual needs. For example, if the component under test is a digital multimeter (DMM), it is only used as an example.

[0045] Step S502, obtaining corresponding calibration parameters through the correspondence between the machine-measured current and the meter-measured current.

[0046] In this embodiment, the calibration parameters may be determined according to the corresponding relationship between the current and the calibration parameters, wherein the specific content of the corresponding relationship may be adaptively determined according to the relationship between the actual current and the calibration parameters.

[0047] Step S503, calibrate the machine-measured current based on the calibration parameters to make the calibrated machine-measured current consistent with the meter-measured current; and after calibrating the machine-measured current, under the condition that the source measurement unit outputs no-load, output different equally spaced fixed voltages at the maximum voltage level and then measure, and obtain corresponding voltage measurement values ​​and current measurement values.

[0048] It should be noted that the process of calibrating the machine-measured current in step S503 of this embodiment is essentially a current calibration at the voltage zero point (i.e., zero-point calibration), which aims to reduce the gain error of the high common-mode amplifier and ensure that when the high common-mode amplifier is in use, the gain error corresponding to the output voltage zero point is staggered and there is a linearity mutation inflection point. Figure 6 It is a linearity curve before the measured inflection point is avoided. It should be explained that the meter measurement on the horizontal axis of the figure is actually the measured voltage of the source measurement unit, and the machine measurement on the vertical axis is actually the measured voltage of the component under test (such as DMM). In this embodiment, a reference source is used to solve the sudden inflection point of linearity and raise the corresponding level bias. Specifically, the output range of ±1V is adjusted to the range of 1V-3V, and a 2.048V reference source is used to raise the DC level bias; it should be noted that the data needs to subtract the 2.048V bias-raised voltage before entering the signal conditioning circuit, so an instrument amplifier is used in this embodiment for corresponding processing. Figure 7 It is the linearity curve after the measured inflection point is avoided.

[0049] In this embodiment, the condition of the source measurement unit outputting no-load substantially represents the condition that the Force HI / LO port of the SMU is not connected to an external load. Specifically, when the SMU outputs no-load and at the maximum voltage level of the SMU, the voltage FV (Force Voltage, output voltage, refers to generating uniformly distributed measurement points with a fixed voltage step size to correspond to the collected output voltage during the voltage scanning process) is sampled at equal intervals, and the corresponding voltage measurement value and current measurement value are measured.

[0050] Step S504: perform common-mode compensation on the current measurement error of the source measurement unit using the voltage measurement value and the current measurement value.

[0051] In this embodiment, performing common-mode compensation on the current measurement error of the source measurement unit substantially improves the common-mode rejection capability of the high common-mode amplifier, that is, compensating the common mode to reduce the common-mode influence.

[0052] The current calibration method of the embodiment of the present invention focuses on the problem of low current accuracy in high-end acquisition in the aforementioned digital current loop. The corresponding calibration parameters are obtained by measuring the machine-measured current of the component under test and the meter-measured current of the source measurement unit. After the machine-measured current is calibrated using the calibration parameters, different equally spaced fixed voltages are output at the maximum voltage level and then measured under the condition that the source measurement unit output is no-loaded, and corresponding voltage measurement values ​​and current measurement values ​​are obtained. The measurement values ​​are used to perform common-mode compensation for the current measurement error of the source measurement unit, which can effectively avoid the gain error and common-mode influence of the high common-mode amplifier, thereby greatly improving the current accuracy of the digital current loop.

[0053] In this embodiment, a current calibration method is provided, which is applied to a digital current loop collected at a high end. Figure 8 It is a flow chart of another current calibration method according to an embodiment of the present invention. In this embodiment, taking into account the overall temperature change of the meter current acquisition link, before using the digital current loop acquired by the high-end to perform current calibration, a series of temperature drift suppression measures are performed to avoid the influence of temperature on the calibration, which can reduce the influence of temperature on the current calibration result to a certain extent, thereby greatly improving the current accuracy. Therefore, before performing current calibration on the digital current loop acquired by the high-end, the current calibration method of this embodiment also includes: executing preset temperature drift suppression measures, wherein the preset temperature drift suppression measures at least include physical isolation of the heat generating devices in the digital current loop, using a water cooling heat dissipation system and a high-efficiency air cooling heat dissipation system to reduce the temperature rise of each device in the digital current loop, and performing a hot machine operation. It should be noted that the relevant contents of the water cooling heat dissipation system and the high-efficiency air cooling heat dissipation system in this embodiment can be known by referring to the common knowledge in the field, and will not be elaborated on here.

[0054] In this embodiment, if Figure 8 As shown, the process of the current calibration method includes the following steps: Step S801 , after the high-end side and the low-end side of the source measurement unit are connected to the positive and negative electrodes of the component under test respectively, the machine-measured current of the component under test and the meter-measured current of the source measurement unit are obtained.

[0055] It should be noted that before executing step S801, this embodiment takes into account the situation that the output voltage zero-crossing gain error of the high common-mode amplifier has a sudden linear change when it is working, and accordingly designs a verification process for whether the current output of the high common-mode amplifier is in the linear region to improve the loop current accuracy. Specifically, before obtaining the machine-measured current of the component under test and the meter-measured current of the source measurement unit, the current calibration method of this embodiment also includes: Step A1, verify whether the output of the high common-mode amplifier is in the linear region.

[0056] In this embodiment, the specific verification method of whether the output of the high common-mode amplifier is in the linear region is not limited here, and is adaptively determined according to actual needs; for example, detecting whether the output of the high common-mode amplifier is linearly proportional to the input, or observing whether the output waveform is saturated or distorted when the input signal amplitude increases to a certain level, that is, whether the output signal has clipping, distortion or phase shift, etc., is only used as an example.

[0057] Step A2: If it is in the linear region, the step of obtaining the machine-measured current of the component under test and the meter-measured current of the source measurement unit is performed.

[0058] Step A3, if it is in the nonlinear area, then execute the preset nonlinear working area avoidance operation, and then return to the step of verifying whether the output of the high common mode amplifier is in the linear area; wherein the preset nonlinear working area avoidance operation at least includes using a preset reference source to DC bias the output of the high common mode amplifier, and using an instrument amplifier cascaded at the output end of the high common mode amplifier to eliminate the influence of the bias voltage on the corresponding signal conditioning path.

[0059] It should be noted that DC bias refers to superimposing a fixed DC voltage or current on an AC signal, so that the overall level of the signal is offset. In this embodiment, the bias voltage is used to avoid the situation where the output voltage zero-crossing gain error has a sudden linearity change when the high common-mode amplifier is working. Specifically, by taking corresponding measures to stagger the nonlinear region when the high common-mode amplifier is working, the high common-mode influence can be effectively avoided, thereby greatly improving the loop current accuracy.

[0060] In this embodiment, the above step S801 includes: Step S8011, the positive and negative electrodes of the component under test are respectively connected to the corresponding ports on the high-end side and the low-end side of the four-wire measurement of the source measurement unit.

[0061] Step S8012, configuring the component under test to be in current measurement mode, and performing measurement to obtain machine-measured current.

[0062] Step S8013, performing equal-interval sampling at a preset current position of the source measurement unit to synchronously obtain the corresponding meter-measured current.

[0063] In this embodiment, through the data collection method of the source measurement unit in step S8013, the goal of synchronous measurement with the component under test can be achieved to eliminate the time deviation of data collection.

[0064] In the embodiment of the present invention, after configuring the high-end acquisition mode of the digital current loop, the corresponding machine-measured current and the meter-measured current of the source measurement unit are obtained by using the measured component, thereby providing high-quality data for subsequent current calibration.

[0065] Step S802, obtaining corresponding calibration parameters through the correspondence between the machine-measured current and the meter-measured current.

[0066] Specifically, the above step S802 includes: Step S8021, obtaining the corresponding relationship between the current and the calibration parameter.

[0067] In this embodiment, the correspondence between the current and the calibration parameter is determined according to actual machine requirements, for example, with reference to the current accuracy requirement of a high-sampling common ground system of a conventional architecture (i.e., a current acquisition accuracy requirement of 0.03 ten thousandths), which is not limited in detail here.

[0068] Step S8022: input the corresponding relationship between the machine-measured current and the meter-measured current, and perform fitting to obtain corresponding calibration parameters.

[0069] In this embodiment, the specific fitting method can be adaptively adjusted according to actual data.

[0070] In the embodiment of the present invention, the corresponding relationship between the current and the calibration parameter is used to fit the relationship between the machine-measured current and the meter-measured current to obtain the corresponding calibration parameters, which can ensure the rationality of the calibration parameters and thus improve the accuracy of subsequent current calibration to a certain extent.

[0071] Step S803, calibrate the machine-measured current based on the calibration parameters to make the calibrated machine-measured current consistent with the meter-measured current; and after calibrating the machine-measured current, output different equidistant fixed voltages at the maximum voltage level under the condition that the source measurement unit outputs no load, and then measure, and obtain corresponding voltage measurement values ​​and current measurement values. For details, please refer to Figure 5 Step S503 of the illustrated embodiment will not be described in detail here.

[0072] Step S804: perform common-mode compensation on the current measurement error of the source measurement unit using the voltage measurement value and the current measurement value.

[0073] Specifically, the above step S804 includes: Step S8041, disconnect the component under test from the source measurement unit, and configure the source measurement unit to a feedback mode.

[0074] It should be noted that the feedback mode of the source measurement unit forms a closed-loop feedback loop to eliminate the influence of external loads, thereby achieving stability and calibration functions of high-precision output.

[0075] Step S8042: applying voltage points at equal intervals under the maximum voltage range, and synchronously recording the voltage measurement value and the current measurement value obtained by the source measurement unit.

[0076] Step S8043, determining common mode compensation parameters according to the voltage measurement value and the current measurement value.

[0077] Specifically, the above step S8043 includes: Step B1, performing linear fitting on the voltage measurement value and the current measurement value to obtain a common mode voltage-current relationship.

[0078] Step B2: determining common-mode compensation parameters based on a common-mode voltage-current relationship.

[0079] In this embodiment, the common mode compensation parameter mainly represents the influence of voltage on current.

[0080] In the embodiment of the present invention, the common-mode compensation parameters are determined by the common-mode voltage-current relationship obtained by linear fitting, which has the advantages of simple and accurate calculation and can improve the accuracy of the digital loop current to a certain extent.

[0081] Step S8044: performing common-mode compensation on the current measurement error of the source measurement unit based on the common-mode compensation parameter.

[0082] In the embodiment of the present invention, after zero-point correction is performed on the output of the high common-mode amplifier, the common-mode suppression capability of the high common-mode amplifier is also taken into consideration, and the corresponding common-mode compensation parameters are determined in combination with the current accuracy description of the high-sampling common-ground system in the conventional architecture. The common-mode compensation parameters are used to perform common-mode compensation on the current measurement error of the source measurement unit, which can comprehensively and effectively avoid the influence of the high common mode, thereby greatly improving the current accuracy of the digital current loop.

[0083] It should be noted that the current accuracy of the high-sampling common ground system of the conventional architecture is described as:

[0084] in, MI Measure the current value for the machine. offsetI is the allowable current deviation, MV is the measured voltage value, λ is the influence system of voltage on current, and its unified unit is A / V.

[0085] The conventional current calibration formula is:

[0086] in, x is the measured value (i.e. the reference value measured by DMM), y The measured value (i.e. the actual value measured by the SMU) also takes into account the need to compensate for the influence of the common mode, so the actual calibration formula used is:

[0087] in, v Indicates the current measured voltage value MV , dRepresents the common mode influence coefficient (i.e. the influence coefficient of voltage on current, also called compensation coefficient).

[0088] It can be seen from the above that the physical meaning of the current accuracy description corresponds to the calibration scheme one by one; therefore, the current calibration of this embodiment needs to consider the current calibration at the voltage zero point and the calibration of the common mode effect, that is, the common mode compensation. The specific calibration scheme can be found in Fig. 9 The process includes: 1. Current calibration at voltage zero point.

[0089] Step 1: Verify the linearity of the signal chain to ensure that the zero-crossing nonlinear inflection point of the high common-mode amplifier is avoided.

[0090] In this embodiment, this step is intended to ensure that the amplifier operates in a linear region, that is, to ensure that the linearity of the signal chain of current acquisition is good enough, thereby avoiding the zero-crossing nonlinear inflection point of the gain error of the high common mode amplifier.

[0091] Step 2: Connect the SMU and DMM devices, configure the measurement mode and synchronously acquire the meter measured value MI(x) and the machine measured value MI(y).

[0092] In this embodiment, when the linearity is good enough, the HF (HI) and LF (LO) of the SMU are directly connected to the red and black connectors of the 8.5-digit DMM device; the DMM turns on the current measurement mode, the SMU sets the current points FI at equal intervals on the current range, and starts the current measurement of the DMM and the current measurement of the SMU at the same time, and obtains the corresponding meter measurement value MI (x) and machine measurement value MI (y).

[0093] Step 3: Calculate the calibration parameters k and b, and establish a linear relationship between the meter-measured value x and the machine-measured value y (y=kx+b).

[0094] In this embodiment, the corresponding relationship between the meter measured value and the machine measured value, y=kx+b, can be used to obtain the calibration parameters k and b. Specifically, the least squares method is used to fit x and y to calculate the calibration parameters k and b; based on the calibration parameters k and b, the linear calibration equation y=kx+b is determined.

[0095] Step 4: Apply the calibration parameters, import k and b into the system, and achieve y=x correction.

[0096] In this embodiment, the obtained k and b are introduced into the digital current loop for calibration, and y and x are made equal to achieve zero-point error correction, so that kx+b can be corrected; at this time, only the parameter dv remains in the calibration relationship.

[0097] 2. Calibration of common mode effects (common mode compensation).

[0098] Step 5: Disconnect the external link, configure the SMU internal feedback mode, and leave the HS / LS detection terminal floating.

[0099] In this embodiment, this step is used to eliminate the influence of external load. Specifically, the SMU and DMM are disconnected, the SMU connector is left floating, and HS (sense HI) and LS (sense LO) are configured as internal feedback.

[0100] It should be noted that in SMU, when HS (Sense HI) and LS (Sense LO) are configured as internal feedback and the connector is left floating, the core of this mechanism is to achieve high-precision output stability and calibration through closed-loop control. Specifically, when the Force HI / LO (HF / LF) port of the SMU is left floating (no external load is connected), the HS / LS port is directly short-circuited with the Force output terminal through the internal circuit to form a closed-loop feedback loop, and then the internal feedback is used to eliminate the internal error and ensure the accuracy of the measurement results.

[0101] Step 6: At the maximum voltage level, sample the voltage FV at equal intervals and record the MV voltage and MI current.

[0102] In this embodiment, under the maximum voltage level, the voltage FV is sampled at equal intervals, the corresponding voltage value MV and current value MI are measured, and the corresponding compensation coefficient d (unit A / V) is calculated.

[0103] Step 7: Calculate the compensation coefficient d (i.e., compensation parameter), import d(A / V) into the system, and complete common-mode compensation.

[0104] In this embodiment, the voltage value MV and the current value MI are linearly fitted to obtain the common-mode voltage-current relationship; the compensation coefficient d is determined based on the common-mode voltage-current relationship, where the unit of the compensation coefficient d is A / V. Then, the corresponding value of the compensation coefficient d is compensated into the calibration system, and the calibration compensation corresponding to y=kx+b+dv is completed.

[0105] It should be noted that the current acquisition link needs to consider temperature changes as a whole, and relevant measures need to be designed to keep temperature changes within the scope of what can be done (i.e., minimize the temperature impact). Specifically, it includes considering the impact of temperature drift on the key parameters of all devices on the link and making targeted adjustments; keeping power or heat generation modules as far away from the acquisition link as possible; using water cooling as much as possible for heat dissipation; it is best to calibrate in a test environment; after a cold start, the device needs to be warmed up for a certain period of time (such as 20 minutes) before testing and use.

[0106] In summary, the above current calibration scheme can greatly improve the current accuracy and can reach the accuracy requirement of 0.03% or even higher.

[0107] In this embodiment, a current calibration device is further provided. This device is used to implement the above embodiments and preferred implementation manners, and those that have been described will not be repeated here. As used hereinafter, the term "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0108] The present invention provides a current calibration device, which is applied to a digital current loop for high-end acquisition, such as Fig.10 shown. The device includes: A data acquisition module 1001, configured to connect the high-end side and the low-end side of the source measurement unit to the positive and negative electrodes of the component under test respectively, and then acquire the measured current of the component under test and the measured current of the source measurement unit.

[0109] A parameter determination module 1002, configured to obtain corresponding calibration parameters through the correspondence between the measured current and the measured current.

[0110] A zero-point calibration module 1003, configured to calibrate the measured current based on the calibration parameters to make the calibrated measured current consistent with the measured current; and after calibrating the measured current, under the condition that the source measurement unit outputs no load, output different equally spaced fixed voltages at the maximum voltage level and then measure, and correspondingly obtain voltage measurement values and current measurement values.

[0111] A common-mode compensation module 1004, configured to perform common-mode compensation on the current measurement error of the source measurement unit by using the voltage measurement values and the current measurement values.

[0112] In some alternative implementation manners, the device further includes: a temperature drift suppression module, configured to perform a preset temperature drift suppression measure before performing current calibration on the digital current loop for high-end acquisition, where the preset temperature drift suppression measure at least includes physically isolating the heating components in the digital current loop, using a water-cooled heat dissipation system and an efficient air-cooled heat dissipation system to reduce the temperature rise of each component in the digital current loop, and performing a warm-up operation.

[0113] In some alternative implementation manners, the device further includes: a region verification module, configured to verify whether the output of the high common-mode amplifier is in the linear region; if it is in the linear region, perform the step of acquiring the measured current of the component under test and the measured current of the source measurement unit; if it is in the non-linear region, perform a preset non-linear working area avoidance operation and then return to perform the step of verifying whether the output of the high common-mode amplifier is in the linear region again; where the preset non-linear working area avoidance operation at least includes performing a DC bias on the output of the high common-mode amplifier by using a preset reference source, and eliminating the influence of the bias voltage on the corresponding signal conditioning path through an instrumentation amplifier cascaded at the output end of the high common-mode amplifier.

[0114] In some optional embodiments, the data acquisition module 1001 includes: a first acquisition submodule, a second acquisition submodule and a third acquisition submodule; wherein the first acquisition submodule is used to connect the positive and negative poles of the component under test to the corresponding ports on the high-end side and the low-end side in the four-wire measurement of the source measurement unit respectively; the second acquisition submodule is used to configure the component under test to a current measurement mode, and measure to obtain the machine-measured current; the third acquisition submodule is used to perform equally spaced sampling under a preset current position of the source measurement unit, and synchronously obtain the corresponding meter-measured current.

[0115] In some optional embodiments, the parameter determination module 1002 includes: a first determination submodule and a second determination submodule; wherein the first determination submodule is used to obtain the corresponding relationship between the current and the calibration parameter; the second determination submodule is used to input the corresponding relationship between the machine-measured current and the meter-measured current, and perform fitting to obtain the corresponding calibration parameters.

[0116] In some optional embodiments, the common-mode compensation module 1004 includes: a first compensation submodule, a second compensation submodule, a third compensation submodule and a fourth compensation submodule; wherein the first compensation submodule is used to disconnect the component under test from the source measurement unit and configure the source measurement unit to a feedback mode; the second compensation submodule is used to apply voltage points at equal intervals under the maximum voltage range and synchronously record the voltage measurement values ​​and current measurement values ​​measured by the source measurement unit; the third compensation submodule is used to determine common-mode compensation parameters based on the voltage measurement values ​​and the current measurement values; and the fourth compensation submodule is used to perform common-mode compensation on the current measurement error of the source measurement unit based on the common-mode compensation parameters.

[0117] In some optional embodiments, the third compensation submodule includes: a first compensation unit and a second compensation unit; wherein the first compensation unit is used to perform linear fitting on the voltage measurement value and the current measurement value to obtain a common-mode voltage-current relationship; and the second compensation unit is used to determine the common-mode compensation parameters based on the common-mode voltage-current relationship.

[0118] The further functional description of each of the above modules is the same as that of the above corresponding embodiments and will not be repeated here.

[0119] The current calibration device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0120] The current calibration device of the embodiment of the present invention can solve the problem of low current accuracy in high-end acquisition in the digital current loop. The corresponding designed zero-point calibration and common-mode compensation method effectively avoids the gain error and common-mode influence of the high common-mode amplifier, thereby greatly improving the current accuracy of the digital current loop.

[0121] An electronic device is also provided in an embodiment of the present invention. Fig.11 , Fig.11 is a schematic diagram of the structure of the electronic device provided in an optional embodiment of the present invention, such as Fig.11 As shown, the electronic device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process instructions executed in the electronic device, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display electronic device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple electronic devices can be connected, and each electronic device provides some necessary operations (for example, determined as a server array, a group of blade servers, or a multi-processor system). Fig.11 A processor 10 is taken as an example.

[0122] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0123] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0124] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the electronic device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the electronic device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0125] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0126] The electronic device also includes a communication interface 30, which is used for the main control chip to communicate with other electronic devices or a communication network.

[0127] A computer-readable storage medium is also provided in the embodiment of the present invention. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium and downloaded through a network, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk, or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor main control chip, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented; and the computer-readable storage medium of this embodiment is also used to store calibration parameters and common-mode compensation parameters, that is, after executing the current calibration method shown in the above embodiment, the present application can obtain the corresponding calibration parameters and common-mode compensation parameters, which are stored for subsequent direct use.

[0128] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A current calibration method, characterized in that: A digital current loop for high-end acquisition, the digital current loop comprising a digital loop controller, a forward channel and a current feedback channel; wherein the forward channel is used to adjust the current accordingly according to the control of the digital loop controller, and comprises a digital-to-analog converter, a conditioning circuit, a power amplifier and a sampling resistor; the current feedback channel is used to acquire and feed back the corresponding loop current, and comprises a current acquisition front-end buffer, an isolated power supply, a high common-mode amplifier, an instrumentation amplifier, a conditioning circuit and an analog-to-digital converter, the current acquisition front-end buffer is powered by an isolated power supply alone and the reference ground of the isolated power supply is equipotential with the output terminal of the power amplifier, and the method comprises: After the high-end side and the low-end side of the source measurement unit are connected to the positive and negative electrodes of the component under test respectively, the machine-measured current of the component under test and the meter-measured current of the source measurement unit are obtained; Obtaining corresponding calibration parameters through the correspondence between the machine-measured current and the meter-measured current; The machine-measured current is calibrated based on the calibration parameters so that the calibrated machine-measured current is consistent with the meter-measured current; and after the machine-measured current is calibrated, different equally spaced fixed voltages are output at the maximum voltage level and then measured under the condition that the source measurement unit outputs no load, and corresponding voltage measurement values ​​and current measurement values ​​are obtained; The voltage measurement value and the current measurement value are used to perform common mode compensation on a current measurement error of the source measurement unit.

2. The current calibration method according to claim 1, characterized in that: The method further comprises: Verify that the output of the high common-mode amplifier is in the linear region; If it is in the linear region, the step of obtaining the machine-measured current of the component under test and the meter-measured current of the source measurement unit is performed; If it is in the nonlinear area, after executing the preset nonlinear working area avoidance operation, return to the step of verifying whether the output of the high common mode amplifier is in the linear area; wherein the preset nonlinear working area avoidance operation at least includes using a preset reference source to DC bias the output of the high common mode amplifier, and using an instrument amplifier cascaded at the output end of the high common mode amplifier to eliminate the influence of the bias voltage on the corresponding signal conditioning path.

3. The current calibration method according to claim 1, characterized in that: The obtaining of the machine-measured current of the component under test and the meter-measured current of the source measurement unit includes: Connect the positive and negative electrodes of the component under test to the corresponding ports on the high-end side and the low-end side of the four-wire measurement of the source measurement unit respectively; Configuring the component under test to be in current measurement mode and measuring to obtain machine-measured current; The source measurement unit performs sampling at equal intervals under the preset current position, and obtains the corresponding meter-measured current synchronously.

4. The current calibration method according to claim 1, characterized in that: The corresponding calibration parameters are obtained by the correspondence between the machine-measured current and the meter-measured current, including: Obtaining the corresponding relationship between the current and the calibration parameters; The machine-measured current and the meter-measured current are input into a corresponding relationship, and fitting is performed to obtain corresponding calibration parameters.

5. The current calibration method according to claim 1, characterized in that: The method of performing common-mode compensation on a current measurement error of the source measurement unit by using the voltage measurement value and the current measurement value comprises: Disconnecting the component under test from the source measurement unit, and configuring the source measurement unit to a feedback mode; Apply voltage points at equal intervals under the maximum voltage range, and simultaneously record the voltage and current measurement values ​​obtained by the source measurement unit; Determining a common mode compensation parameter according to the voltage measurement value and the current measurement value; Common-mode compensation is performed on a current measurement error of the source measurement unit based on the common-mode compensation parameter.

6. The current calibration method according to claim 5, characterized in that: The determining of the common mode compensation parameter according to the voltage measurement value and the current measurement value comprises: Performing linear fitting on the voltage measurement value and the current measurement value to obtain a common mode voltage-current relationship; A common mode compensation parameter is determined based on the common mode voltage-current relationship.

7. The current calibration method according to any one of claims 1 to 6, characterized in that: Before performing current calibration on the high-end collected digital current loop, the method further includes: executing preset temperature drift suppression measures, wherein the preset temperature drift suppression measures at least include physically isolating the heat-generating components in the digital current loop, using a water-cooling heat dissipation system and a high-efficiency air-cooling heat dissipation system to reduce the temperature rise of each component in the digital current loop, and performing thermal operation.

8. A current calibration device, characterized in that: A digital current loop for high-end acquisition, the digital current loop comprising a digital loop controller, a forward channel and a current feedback channel; wherein the forward channel is used to adjust the current accordingly according to the control of the digital loop controller, and comprises a digital-to-analog converter, a conditioning circuit, a power amplifier and a sampling resistor; the current feedback channel is used to acquire and feed back the corresponding loop current, and comprises a current acquisition front-end buffer, an isolated power supply, a high common-mode amplifier, an instrumentation amplifier, a conditioning circuit and an analog-to-digital converter, the current acquisition front-end buffer is powered by an isolated power supply alone and the reference ground of the isolated power supply is equipotential with the output terminal of the power amplifier, and the device comprises: A data acquisition module, used to connect the high-end side and the low-end side of the source measurement unit to the positive and negative electrodes of the component under test respectively, and then obtain the machine-measured current of the component under test and the meter-measured current of the source measurement unit; A parameter determination module, used for obtaining corresponding calibration parameters through the correspondence between the machine-measured current and the meter-measured current; A zero point calibration module is used to calibrate the machine-measured current based on the calibration parameters so that the calibrated machine-measured current is consistent with the meter-measured current; and after calibrating the machine-measured current, under the condition that the source measurement unit outputs no-load, outputs different equally spaced fixed voltages at the maximum voltage level and then measures them, and correspondingly obtains voltage measurement values ​​and current measurement values; The common mode compensation module is used to perform common mode compensation on the current measurement error of the source measurement unit by using the voltage measurement value and the current measurement value.

9. An electronic device, characterized in that: The electronic device comprises: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the current calibration method according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the current calibration method described in any one of claims 1 to 7; and the computer-readable storage medium is also used to store calibration parameters and common-mode compensation parameters.

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