A multi-channel high-speed high-precision resistance testing device

Abstract

The utility model relates to the field of resistance test, concretely relates to a kind of multi-channel high-speed high-precision resistance test equipment. Through adopting ADC chip, different excitation strategy is implemented for different range, constant-current method is used for low resistance value element below 1kΩ, to eliminate the influence of contact resistance;For high resistance value element above 1kΩ, it is switched to constant-voltage method measurement, to effectively reduce the temperature rise error caused by test current;Through relay matrix, single-ADC channel multiplexing extension is realized, to support multiple test nodes, compared with traditional multi-device parallel scheme, the cost of core device is saved;Master MCU controls resistance test equipment through I2C bus non-real-time, and master MCU controls resistance test equipment through SPI bus real-time. Solve the problem that modern impedance test equipment exists higher price and maintenance cost of equipment itself under the demand of high efficiency, high precision, high stability.

Description

Technical Field

[0001] This utility model relates to the field of resistance testing technology, and in particular to a multi-channel, high-speed, and high-precision resistance testing device. Background Technology

[0002] In the field of precision testing in the electronics manufacturing industry, high-precision resistance testing instruments have long been monopolized by international instrument giants such as Keysight and Tektronix. Their high purchase and maintenance costs have become a significant bottleneck restricting the upgrading of domestic industries. Especially in fields requiring multi-dimensional parameter verification, such as consumer electronics and new energy batteries, testing systems often need to integrate dozens of single-function devices, resulting in a massive overall solution with a total cost exceeding one million yuan. Currently, representative resistance testing equipment from abroad is the Agilent 344 series multimeter. These manufacturers' multimeters feature high precision, fast response speed, and high stability, but they are also relatively expensive. Furthermore, their large size, low scalability, and functional redundancy also limit their automation development in China.

[0003] In the current economic climate, cost reduction and efficiency improvement have become a globally pursued business strategy. Therefore, improving production testing efficiency has become a key focus for the manufacturing industry. While traditional testing equipment offers high precision, it is bulky and only supports testing one channel at a time, resulting in long testing times. If increasing production efficiency necessitates purchasing more testing instruments to achieve simultaneous multi-channel measurements, this increases production testing costs and represents a waste of resources.

[0004] Therefore, there is an urgent need for a low-cost, small-size, universal bus-controlled, multi-channel, high-speed, and high-precision resistance testing device. Utility Model Content

[0005] To address the issue of high cost and maintenance expenses associated with modern impedance testing equipment, which demands high efficiency, high precision, and high stability.

[0006] This invention provides a multi-channel, high-speed, and high-precision resistance testing device, comprising a circuit board. The circuit board includes a main control MCU, a control bus, an ADC chip, a first PGA amplifier, a relay matrix, a constant voltage resistance testing module, a constant current resistance testing module, and a non-volatile memory. The control bus includes an I²C bus and an SPI serial bus. The main control MCU is electrically connected to the ADC chip, the constant voltage resistance testing module, and the constant current resistance testing module via the SPI serial bus, and is connected to the non-volatile memory via the I²C bus. The main control MCU coordinates and controls the operation of each component. The ADC chip acquires analog signals and converts them into digital signals. The input of the first PGA amplifier is connected to the output of the digital-to-analog converter, and the first PGA amplifier amplifies the digital signals. The relay matrix enables multi-channel switching. The constant voltage resistance testing module measures resistance using a constant voltage method. The constant current resistance testing module measures resistance using a constant current method. The non-volatile memory stores the device's identification code.

[0007] Preferably, a multi-channel high-speed and high-precision resistance testing device also includes a host computer, which is connected to the main control MCU via an SPI bus.

[0008] Preferably, the ADC chip is a 24-bit high-resolution ADC chip.

[0009] Preferably, the relay matrix includes a relay switch and a decoder. The output of the first PGA amplifier is connected to one end of the relay switch, and the other end of the relay switch is connected to the resistance test channel. The decoder is used to decode the input encoded signal and control the relay switch according to the decoding result to select the corresponding resistance test channel.

[0010] Preferably, the constant voltage resistance test module includes a first VDAC, a constant voltage feedback circuit, a first power amplifier module, a resistor under test R1, a constant voltage reference circuit, a first ADC, a second PGA amplifier, and a constant voltage output interface. The first VDAC is used to convert digital signals into analog voltage signals. The input terminal of the first VDAC is connected to the SPI serial bus, and the output terminal of the first VDAC is connected to the input terminal of the constant voltage feedback circuit. The constant voltage feedback circuit is connected to the constant voltage output interface and is used to acquire and compare the voltage value of the analog voltage signal output by the first VDAC with the voltage value of the analog voltage signal from the constant voltage output interface. The input terminal of the first power amplifier module is connected to the output terminal of the constant voltage feedback circuit, and the output terminal of the first power amplifier module is connected to one end of the resistor under test R1. The first power amplifier module amplifies the analog voltage signal output by the constant voltage feedback circuit to drive the resistor under test R1. The constant voltage reference circuit is connected to the first VDAC and the first ADC, respectively, and is used to provide a reference voltage. The positive and negative current detection terminals of the second PGA amplifier are connected to the two ends of the resistor under test R1, respectively. The output terminal of the second PGA amplifier is connected to the input terminal of the first ADC, and is used to amplify the analog voltage signal and analog current signal of the constant voltage output interface. The output terminal of the first ADC is connected to the SPI serial bus, and is used to convert the analog voltage signal into a digital signal. The constant voltage output interface is connected to the positive voltage detection terminal, the negative voltage detection terminal, the negative current detection terminal, and the second PGA amplifier.

[0011] Preferably, the constant current resistance test module includes a second VDAC, a constant current feedback circuit, a second power amplifier module, a resistor under test R2, a constant current reference circuit, a second ADC, a third PGA amplifier, an IDAC, a constant current circuit, and a constant current output interface. The second VDAC is used to convert digital signals into analog voltage signals. The input terminal of the second VDAC is connected to the SPI serial bus, and the output terminal of the second VDAC is connected to the input terminal of the constant current feedback circuit. The constant current feedback circuit is connected to the constant current output interface and is used to acquire and compare the voltage value of the analog voltage signal output by the second VDAC with the voltage value of the analog voltage signal from the constant current output interface. The input terminal of the second power amplifier module is connected to the output terminal of the constant current feedback circuit, and the output terminal of the second power amplifier module is connected to one end of the resistor under test R2. The second power amplifier module is used to amplify the analog voltage signal output by the constant current feedback circuit to drive the resistor under test R2. The constant current reference circuit is connected to the second VDAC, the third PGA amplifier, an IDAC, a constant current circuit, and a constant current output interface. The second VDAC and the second ADC are connected, and the constant current reference circuit is used to provide a reference voltage. The positive and negative current detection terminals of the third PGA amplifier are connected to the two ends of the resistor R2 under test, respectively. The output terminal of the third PGA amplifier is connected to the input terminal of the second ADC. The third PGA amplifier is used to amplify the analog voltage signal and analog current signal of the constant current output interface. The output terminal of the second ADC is connected to the SPI serial bus. The second ADC is used to convert the analog voltage signal into a digital signal. The input terminal of the IDAC is connected to the SPI serial bus. The IDAC is used to convert the digital signal into an analog current signal and provide a stable excitation current. The input terminal of the constant current circuit is connected to the output terminal of the IDAC. The constant current circuit is used to adjust the analog current signal output by the IDAC to ensure that the current passing through the test resistor R2 is constant. The constant current output interface is connected to the third PGA amplifier through the positive voltage detection terminal, the negative voltage detection terminal, and the negative current detection terminal.

[0012] Preferably, a multi-channel high-speed and high-precision resistance testing device also includes a temperature sensor and a PWM fan. Both the temperature sensor and the PWM fan are connected to the main control MCU via an I²C bus. The temperature sensor is used to monitor temperature changes. The non-volatile memory is also used to store calibration coefficients, which include gain coefficients and zero-point offset.

[0013] Preferably, a multi-channel high-speed and high-precision resistance testing device also includes a heat sink connected to a circuit board.

[0014] The beneficial effects of this utility model are reflected in:

[0015] 1) In terms of improving measurement accuracy, an ADC chip is used to build the signal acquisition core, and different excitation strategies are implemented for different ranges. For low resistance components below 1kΩ, a constant current method is used, preferably a four-wire constant current source measurement method to eliminate the influence of contact resistance. For high resistance components above 1kΩ, the constant voltage method is switched to measurement, preferably a constant voltage source excitation mode to effectively reduce the temperature rise error caused by the test current.

[0016] 2) The multiplexing and expansion of a single ADC channel is achieved through a relay matrix to support multiple test nodes, saving core component costs compared to the traditional multi-device parallel solution.

[0017] 3) In terms of the design of the control bus, the main control MCU controls the resistance testing equipment in non-real-time through the I²C bus, and controls the resistance testing equipment in real time through the SPI bus; the standardized I²C bus and SPI serial bus ensure compatibility and interchangeability between different components, facilitate maintenance and replacement, and further reduce maintenance costs.

[0018] This solves the problem of high equipment price and maintenance costs in modern impedance testing equipment, which requires high efficiency, high precision, and high stability. Attached Figure Description

[0019] Figure 1 This is one of the perspective views of a multi-channel high-speed and high-precision resistance testing device provided by this utility model.

[0020] Figure 2 The second perspective view of a multi-channel high-speed and high-precision resistance testing device provided by this utility model.

[0021] Figure 3 This is a block diagram of the constant voltage resistance test module provided by this utility model.

[0022] Figure 4 This is a block diagram of the constant current resistance testing module provided by this utility model.

[0023] Figure 5 This is a block diagram of a multi-channel test provided by this utility model.

[0024] Figure 6 This is a schematic block diagram illustrating the connection relationship of the control bus provided by this utility model.

[0025] Figure 7 The constant voltage feedback circuit provided by this utility model.

[0026] Figure 8 The constant current feedback circuit provided by this utility model.

[0027] Figure 9The first power amplifier module provided by this utility model.

[0028] Figure 10 The second power amplifier module provided by this utility model.

[0029] Figure 11 The constant voltage reference circuit provided by this utility model.

[0030] Figure 12 The constant current reference circuit provided by this utility model.

[0031] Figure 13 The constant current circuit provided by this utility model.

[0032] In the diagram: 1-Host computer; 2-Main control MCU; 3-Control bus; 4-ADC chip; 5-First PGA amplifier; 6-Relay matrix; 7-Constant voltage resistor test module; 8-Constant current resistor test module; 9-Non-volatile memory; 10-Temperature sensor; 11-PWM fan; 12-Heat sink. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] Reference Figures 1-6 A multi-channel, high-speed, high-precision resistance testing device includes a circuit board. The circuit board comprises a main control MCU2, a control bus 3, an ADC chip 4, a first PGA amplifier 5, a relay matrix 6, a constant voltage resistance testing module 7, a constant current resistance testing module 8, and a non-volatile memory 9. The control bus 3 includes an I²C bus and an SPI serial bus. The main control MCU2 is electrically connected to the ADC chip 4, the constant voltage resistance testing module 7, and the constant current resistance testing module 8 via the SPI serial bus. The main control MCU2 is connected to the non-volatile memory 9 via the I²C bus. The main control MCU2 coordinates and controls the operation of each component. The ADC chip 4 acquires analog signals and converts them into digital signals. The input terminal of the first PGA amplifier 5 is connected to the output terminal of the digital-to-analog converter, and the first PGA amplifier 5 amplifies the digital signals. The relay matrix 6 is used to achieve multi-channel switching. The constant voltage resistance testing module 7 is used to measure resistance values ​​using the constant voltage method. The constant current resistance testing module 8 is used to measure resistance values ​​using the constant current method. The non-volatile memory 9 stores the device's identification code.

[0035] In terms of improving measurement accuracy, an ADC chip 4 is used to construct the signal acquisition core, and different excitation strategies are implemented for different ranges. For low-resistance components below 1kΩ, a constant current method is used, preferably a four-wire constant current source measurement method to eliminate the influence of contact resistance. For high-resistance components above 1kΩ, the constant voltage method is switched to measurement, preferably a constant voltage source excitation mode to effectively reduce the temperature rise error caused by the test current.

[0036] The single ADC channel is multiplexed and expanded by relay matrix 6 to support multiple test nodes, saving core component costs compared to traditional multi-device parallel solutions.

[0037] In the design of control bus 3, the main control MCU2 controls the resistance testing equipment in non-real-time via the I²C bus, and controls the resistance testing equipment in real-time via the SPI bus; the standardized I²C bus and SPI serial bus ensure compatibility and interchangeability between different components, facilitate maintenance and replacement, and further reduce maintenance costs.

[0038] This solves the problem of high equipment price and maintenance costs in modern impedance testing equipment, which requires high efficiency, high precision, and high stability.

[0039] In some implementations, a multi-channel high-speed and high-precision resistance testing device also includes a host computer 1, which is connected to the main control MCU 2 via an SPI bus.

[0040] The host computer 1 can program or adjust the parameters of the main control MCU2 via the SPI bus, facilitating firmware upgrades and configuration modifications. This makes the resistance testing equipment more flexible, easier to maintain and upgrade. The host computer 1 can provide a graphical user interface, making operation more intuitive and convenient. Users can monitor the testing process and view results in real time through this interface.

[0041] In some implementations, ADC chip 4 is a 24-bit high-resolution ADC chip 4.

[0042] A 24-bit ADC can provide very high resolution, enabling more accurate measurement of resistance values; in addition, a 24-bit ADC can reduce errors and noise in the quantization process, thereby improving the overall measurement quality.

[0043] In some implementations, the relay matrix 6 includes a relay switch and a decoder. The output of the first PGA amplifier 5 is connected to one end of the relay switch, and the other end of the relay switch is connected to the resistance test channel. The decoder is used to decode the input encoded signal and control the relay switch according to the decoding result to select the corresponding resistance test channel.

[0044] The main control MCU2 sends specific coded signals to the decoder to control which relay switch should be closed, thereby selecting the corresponding resistance test channel. Whether using the constant voltage or constant current method for resistance measurement, different resistance test channels can be switched by controlling the relay matrix 6, increasing the system's versatility and adaptability. Rapid encoder switching achieves the effect of almost "simultaneously" measuring multiple resistance test channels.

[0045] In some embodiments, the constant voltage resistance test module 7 includes a first VDAC, a constant voltage feedback circuit, a first power amplifier module, a resistor under test R1, a constant voltage reference circuit, a first ADC, a second PGA amplifier, and a constant voltage output interface. The first VDAC converts digital signals into analog voltage signals. The input of the first VDAC is connected to an SPI serial bus, and the output of the first VDAC is connected to the input of the constant voltage feedback circuit. The constant voltage feedback circuit is connected to the constant voltage output interface and is used to acquire and compare the voltage value of the analog voltage signal output by the first VDAC with the voltage value of the analog voltage signal from the constant voltage output interface. The input of the first power amplifier module is connected to the output of the constant voltage feedback circuit, and the output of the first power amplifier module is connected to the input of the resistor under test R1. One end is connected to the first power amplifier module, which amplifies the analog voltage signal output by the constant voltage feedback circuit to drive the resistor under test R1; the constant voltage reference circuit is connected to the first VDAC and the first ADC respectively, and the constant voltage reference circuit is used to provide a reference voltage; the positive and negative current detection terminals of the second PGA amplifier are connected to the two ends of the resistor under test R1 respectively, and the output terminal of the second PGA amplifier is connected to the input terminal of the first ADC. The second PGA amplifier is used to amplify the analog voltage signal and analog current signal of the constant voltage output interface; the output terminal of the first ADC is connected to the SPI serial bus, and the first ADC is used to convert the analog voltage signal into a digital signal; the constant voltage output interface is connected to the second PGA amplifier through the positive voltage detection terminal, the negative voltage detection terminal, the negative current detection terminal, and the voltage detection terminal.

[0046] The first VDAC communicates with the main control MCU2 via the SPI serial bus, converting the digital signal from the main control MCU2 into a high-precision analog voltage signal, allowing the main control MCU2 to precisely control the output voltage to adapt to different testing requirements.

[0047] The constant voltage feedback circuit achieves closed-loop control by acquiring and comparing the voltage value of the analog voltage signal output by the first VDAC and the voltage value of the analog voltage signal from the constant voltage output interface. When the voltage value of the analog voltage signal output by the first VDAC is greater than the voltage value of the analog voltage signal from the constant voltage output interface, the constant voltage feedback circuit outputs a positive voltage, which causes the first power amplifier module to increase its output voltage. When the voltage value of the analog voltage signal output by the first VDAC is less than the voltage value of the analog voltage signal from the constant voltage output interface, the constant voltage feedback circuit outputs a negative voltage, which causes the first power amplifier module to decrease its output voltage.

[0048] The first ADC converts the analog signal amplified by the second PGA amplifier into a digital signal, and transmits it back to the main control MCU2 via the SPI serial bus for further data processing and analysis.

[0049] In some embodiments, the constant current resistance test module 8 includes a second VDAC, a constant current feedback circuit, a second power amplifier module, a resistor under test R2, a constant current reference circuit, a second ADC, a third PGA amplifier, an IDAC, a constant current circuit, and a constant current output interface. The second VDAC converts digital signals into analog voltage signals. The input of the second VDAC is connected to an SPI serial bus, and the output of the second VDAC is connected to the input of the constant current feedback circuit. The constant current feedback circuit is connected to the constant current output interface and is used to acquire and compare the voltage value of the analog voltage signal output by the second VDAC with the voltage value of the analog voltage signal from the constant current output interface. The input of the second power amplifier module is connected to the output of the constant current feedback circuit, and the output of the second power amplifier module is connected to one end of the resistor under test R2. The second power amplifier module amplifies the analog voltage signal output by the constant current feedback circuit to drive the resistor under test R2. The constant current reference circuit... The constant current reference circuit is connected to the second VDAC and the second ADC. The positive and negative current detection terminals of the third PGA amplifier are connected to the two ends of the resistor R2 under test, respectively. The output of the third PGA amplifier is connected to the input of the second ADC. The third PGA amplifier is used to amplify the analog voltage and analog current signals of the constant current output interface. The output of the second ADC is connected to the SPI serial bus. The second ADC is used to convert the analog voltage signal into a digital signal. The input of the IDAC is connected to the SPI serial bus. The IDAC is used to convert the digital signal into an analog current signal and provide a stable excitation current. The input of the constant current circuit is connected to the output of the IDAC. The constant current circuit is used to adjust the analog current signal output by the IDAC to ensure that the current through the test resistor R2 is constant. The constant current output interface is connected to the third PGA amplifier through the positive voltage detection terminal, the negative voltage detection terminal, and the negative current detection terminal.

[0050] The IDAC converts the digital signal into an analog current signal, communicating with the main control MCU2 via the SPI serial bus. This allows the main control MCU2 to set the output current value to adapt to different testing requirements. A constant current circuit regulates the current generated by the IDAC, ensuring a constant current flowing through the resistor under test (R2) even under varying load conditions. The second ADC converts the analog signal amplified by the third PGA amplifier into a digital signal and transmits it back to the main control MCU2 via the SPI serial bus for further data processing and analysis. The constant current resistance test module 8, by integrating the IDAC, constant current feedback circuit, power amplifier module, PGA amplifier, ADC, and reference circuit, constructs an efficient, accurate, and stable constant current resistance test environment. It not only provides precise and controllable current output but also monitors and adjusts the output current in real time to maintain its stability. Furthermore, it achieves accurate measurement of weak signals through the high-resolution ADC chip 4.

[0051] In some embodiments, a multi-channel high-speed and high-precision resistance testing device also includes a temperature sensor 10 and a PWM fan 11. Both the temperature sensor 10 and the PWM fan 11 are connected to the main control MCU2 via an I²C bus. The temperature sensor 10 is used to monitor temperature changes. The non-volatile memory 9 is also used to store calibration coefficients, which include gain coefficients and zero-point offset.

[0052] The PWM fan 11, connected via the I²C bus, can dynamically adjust its speed based on data provided by the temperature sensor 10 to maintain the optimal operating temperature inside the device. This helps improve device stability and extend its service life.

[0053] The gain coefficient and zero-point offset stored in the non-volatile memory 9 are obtained during device calibration. During calibration, the calibration coefficients are written to the non-volatile memory 9 via software and loaded at each startup, enabling the resistance testing equipment to automatically apply calibration parameters, reducing the need for manual intervention and improving operational convenience. Based on data from the temperature sensor 10, a temperature compensation algorithm can be implemented to correct resistance drift caused by temperature changes.

[0054] In some embodiments, a multi-channel high-speed and high-precision resistance testing device also includes a heat sink 12 connected to a circuit board.

[0055] Electronic components generate heat during operation. The heat sink 12 effectively conducts heat away by increasing the surface area in contact with the air, thereby reducing the operating temperature.

[0056] In the description of embodiments of this utility model, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0057] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-channel, high-speed, high-precision resistance testing device, comprising a circuit board, characterized in that: The circuit board includes a main control MCU, a control bus, an ADC chip, a first PGA amplifier, a relay matrix, a constant voltage resistor test module, a constant current resistor test module, and a non-volatile memory; The control bus includes an I²C bus and an SPI serial bus. The main control MCU is electrically connected to the ADC chip, the constant voltage resistor test module and the constant current resistor test module through the SPI serial bus. The main control MCU is connected to the non-volatile memory through the I²C bus. The main control MCU is used to coordinate and control the operation of various components; ADC chips are used to acquire analog signals and convert them into digital signals; The input terminal of the first PGA amplifier is connected to the output terminal of the digital-to-analog converter. The first PGA amplifier is used to amplify digital signals. A relay matrix is ​​used to implement multi-channel switching; The constant voltage resistance test module is used to measure resistance values ​​using the constant voltage method; The constant current resistance test module is used to measure resistance values ​​using the constant current method; Non-volatile memory is used for the identification encoding of storage devices.

2. The multi-channel high-speed and high-precision resistance testing device according to claim 1, characterized in that: It also includes a host computer, which is connected to the main control MCU via the SPI bus.

3. A multi-channel high-speed and high-precision resistance testing device according to claim 1 or 2, characterized in that: The ADC chip is a 24-bit high-resolution ADC chip.

4. A multi-channel high-speed and high-precision resistance testing device according to claim 1 or 2, characterized in that: The relay matrix includes a relay switch and a decoder. The output of the first PGA amplifier is connected to one end of the relay switch, and the other end of the relay switch is connected to the resistance test channel. The decoder is used to decode the input encoded signal and control the relay switch according to the decoding result to select the corresponding resistance test channel.

5. A multi-channel high-speed and high-precision resistance testing device according to claim 1 or 2, characterized in that: The constant voltage resistance test module includes a first VDAC, a constant voltage feedback circuit, a first power amplifier module, a resistor under test R1, a constant voltage reference circuit, a first ADC, a second PGA amplifier, and a constant voltage output interface. The first VDAC is used to convert digital signals into analog voltage signals. The input of the first VDAC is connected to the SPI serial bus, and the output of the first VDAC is connected to the input of the constant voltage feedback circuit. The constant voltage feedback circuit is connected to the constant voltage output interface. The constant voltage feedback circuit is used to acquire and compare the voltage value of the analog voltage signal output by the first VDAC with the voltage value of the analog voltage signal from the constant voltage output interface. The input terminal of the first power amplifier module is connected to the output terminal of the constant voltage feedback circuit, and the output terminal of the first power amplifier module is connected to one end of the resistor R1 under test. The first power amplifier module is used to amplify the analog voltage signal output by the constant voltage feedback circuit to drive the resistor R1 under test. The constant voltage reference circuit is connected to the first VDAC and the first ADC respectively, and the constant voltage reference circuit is used to provide a reference voltage. The positive and negative terminals of the current detection of the second PGA amplifier are connected to the two ends of the resistor R1 under test, respectively. The output terminal of the second PGA amplifier is connected to the input terminal of the first ADC. The second PGA amplifier is used to amplify the analog voltage signal and analog current signal of the constant voltage output interface. The output of the first ADC is connected to the SPI serial bus. The first ADC is used to convert analog voltage signals into digital signals. The constant voltage output interface is connected to the positive voltage detection terminal, the negative voltage detection terminal, the negative current detection terminal, and the second PGA amplifier.

6. A multi-channel high-speed and high-precision resistance testing device according to claim 1 or 2, characterized in that: The constant current resistance test module includes a second VDAC, a constant current feedback circuit, a second power amplifier module, a resistor under test R2, a constant current reference circuit, a second ADC, a third PGA amplifier, an IDAC, a constant current circuit, and a constant current output interface. The second VDAC is used to convert digital signals into analog voltage signals. The input of the second VDAC is connected to the SPI serial bus, and the output of the second VDAC is connected to the input of the constant current feedback circuit. The constant current feedback circuit is connected to the constant current output interface. The constant current feedback circuit is used to acquire and compare the voltage value of the analog voltage signal output by the second VDAC with the voltage value of the analog voltage signal from the constant current output interface. The input terminal of the second power amplifier module is connected to the output terminal of the constant current feedback circuit, and the output terminal of the second power amplifier module is connected to one end of the resistor R2 under test. The second power amplifier module is used to amplify the analog voltage signal output by the constant current feedback circuit to drive the resistor R2 under test. The constant current reference circuit is connected to the second VDAC and the second ADC respectively, and the constant current reference circuit is used to provide a reference voltage. The positive and negative terminals of the current detection of the third PGA amplifier are connected to the two ends of the resistor R2 under test, respectively. The output terminal of the third PGA amplifier is connected to the input terminal of the second ADC. The third PGA amplifier is used to amplify the analog voltage signal and analog current signal of the constant current output interface. The output of the second ADC is connected to the SPI serial bus. The second ADC is used to convert analog voltage signals into digital signals. The input of the IDAC is connected to the SPI serial bus. The IDAC is used to convert digital signals into analog current signals to provide a stable excitation current. The input terminal of the constant current circuit is connected to the output terminal of the IDAC. The constant current circuit is used to regulate the analog current signal output by the IDAC to ensure that the current passing through the test resistor R2 is constant. The constant current output interface is connected to the third PGA amplifier through the positive voltage detection terminal, the negative voltage detection terminal, and the negative current detection terminal.

7. The multi-channel high-speed and high-precision resistance testing device according to claim 1, characterized in that: It also includes a temperature sensor and a PWM fan. Both the temperature sensor and the PWM fan are connected to the main control MCU via the I²C bus. The temperature sensor is used to monitor temperature changes, and the non-volatile memory is also used to store calibration coefficients, which include gain coefficients and zero-point offset.

8. A multi-channel high-speed and high-precision resistance testing device according to claim 1 or 7, characterized in that: It also includes a heat sink, which is connected to the circuit board.

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