ESD resistance measuring circuit

Abstract

The invention relates to the technical field of resistance measurement, and discloses an ESD resistance measuring circuit which comprises a measuring circuit, a multiplexing circuit and a measuring point, the measuring circuit and the multiplexing circuit are both connected with the measuring point, and the measuring point is connected with an ESD resistor of a measured object. According to the invention, the design of the anti-parallel triodes in the measuring circuit eliminates the voltage bias caused by the reverse bias current, and solves the nonlinear error problem of a conventional circuit. The multiplexing circuit switches a calibration resistor and a to-be-measured resistor through an analog multiplexer, and realizes self-calibration in combination with ADC sampling and operation of a microcontroller so as to improve measurement consistency and accuracy. The impedance conversion, filtering and amplification functions in the circuit ensure that the signal is stable, and the acquisition requirement of a microcontroller is met; the circuit is simple in structure and low in cost, meets the requirement for rapid measurement of large-span resistance values of human body ESD resistance and the like in electronic equipment production, further improves the precision, and is suitable for efficient detection of electrostatic sensitive places.

Description

Technical Field

[0001] The present application relates to the field of resistance measurement technology, and in particular to an ESD resistance measurement circuit. Background Art

[0002] Electrostatic discharge (ESD), a key risk in the manufacturing and use of electronic devices, poses a serious threat to the reliability of circuit components. In the production environment of precision electronic devices (such as integrated circuits and sensors), static electricity accumulated on the human body or on the surface of the device can instantly release thousands of volts, causing chip breakdown, functional failure, and even safety accidents. Therefore, accurately measuring ESD protection resistance (such as the human body grounding resistance and the resistance of anti-static equipment) has become a core component of ESD protection systems.

[0003] Traditional ESD resistance measurement techniques rely primarily on bridge circuits or diode rectifier circuits, but they have significant limitations:

[0004] The measurement range is narrow and cannot cover the full range of human body protection resistance;

[0005] Nonlinear error: the reverse bias current of the diode will cause the measured voltage and resistance value to show a nonlinear relationship;

[0006] The response speed is slow. Traditional circuits require multiple sampling and calibration, which makes it difficult to meet the rapid detection requirements of industrial assembly lines.

[0007] Calibration is complex, different measurement objects (such as wrist straps and anti-static shoes) need to be calibrated separately, and the equipment integration is low.

[0008] Existing improvements focus on expanding the measurement range and improving accuracy, but have yet to effectively resolve the conflict between nonlinear error and dynamic response. For example, some solutions use operational amplifiers to compensate for bias current, but this introduces additional noise; others expand the measurement range through segmented calibration, but this increases system complexity.

[0009] In summary, a new technical solution for ESD resistance measurement is urgently needed that can achieve high-precision real-time measurement within a large dynamic range while taking into account calibration convenience and cost control. Summary of the Invention

[0010] The purpose of this application is to provide an ESD resistance measurement circuit to solve the technical problems raised in the above background technology.

[0011] To achieve the above objectives, the present application discloses the following technical solutions: an ESD resistance measurement circuit, comprising a measurement circuit, a multiplexing circuit, and a measurement point, wherein the measurement circuit and the multiplexing circuit are both connected to the measurement point, and the measurement point is connected to the ESD resistance of a measurement object;

[0012] The measurement circuit includes: a bias elimination module for eliminating reverse bias, and an operational amplifier module for impedance transformation, filtering, and signal amplification; the input end of the bias elimination module is connected to a power supply, and the output end of the bias elimination module is connected to the input end of the operational amplifier module;

[0013] The multiplexing circuit includes a multiplexing module for analog multiplexing and a calibration module for calibrating the circuit; the multiplexing module is connected to the calibration module;

[0014] Wherein: the output end of the operational amplifier module is connected to the microcontroller for analog-to-digital acquisition; the multiplexing module is connected to the microcontroller to receive the digital signal of the microcontroller.

[0015] Preferably, the connection method of the measuring circuit specifically includes:

[0016] The bias elimination module includes at least a transistor Q5 and a transistor Q6; the operational amplifier module includes at least an operational amplifier U6, an operational amplifier U7 and an operational amplifier U9B;

[0017] Wherein: a +9V voltage is input to the first end of the resistor R100, and the second end of the resistor R100 is connected to the first end of the resistor R35, the collector and base of the transistor Q5, the emitter of the transistor Q6 and the first end of the capacitor C100; the second end of the capacitor C100, the collector and base of the transistor Q6, the emitter of the transistor Q5 and the first end of the resistor R40 are connected to the measuring point; the second end of the resistor R40 is connected to the positive input terminal of the operational amplifier U6, the negative input terminal of the operational amplifier U6 and the output terminal of the operational amplifier U6 are both connected to the first end of the resistor R38, the positive power supply input terminal of the operational amplifier U6 is connected to 12V and the 12V is connected to a capacitor and then connected to GND, and the negative power supply input terminal of the operational amplifier U6 is connected to GND; the second end of the resistor R38 and the first end of the capacitor C30 are both connected to the first end of the resistor R39; the second end of the capacitor C30, the negative input terminal of the operational amplifier U7 and the output terminal of the operational amplifier U7 are all connected to the first end of the resistor R37 The second end of the resistor R37 and the first end of the resistor R42 are both connected to the negative input terminal of the operational amplifier U9B, the other end of the resistor R35 and one end of the resistor R41 are both connected to the positive input terminal of the operational amplifier U9B; the second end of the resistor R41 and the first end of the capacitor C32 are both connected to GND; the output terminal of the operational amplifier U9B and the second end of the resistor R42 are both connected to the first end of the resistor R36; the second end of the resistor R36, the second end of the resistor C32 and the anode of a diode are all connected to the microcontroller and used for ADC-PORT acquisition, and the cathode of the diode is connected to +3.3V.

[0018] Preferably, the connection mode of the multiplexing circuit specifically includes:

[0019] The gating module includes an analog multiplexer U8; the calibration module includes at least a plurality of resistors;

[0020] Wherein: the first end of resistor R28 and the first end of resistor R32 are both connected to GND, the second end of resistor R28 is connected to pin 1 of analog multiplexer U8, the second end of resistor R32 is connected to the first end of resistor R33, the second end of resistor R33 is connected to pin 5 of analog multiplexer U8, pins 7 and 8 of analog multiplexer U8 are grounded; the VDD pin of analog multiplexer U8 is connected to +9V; the Y2 pin of analog multiplexer U8 is connected to the first end of resistor R26; resistor R26 The second end of the analog multiplexer U8 is connected to the first end of the resistor R27, and the second end of the resistor R27 is connected to GND; the Y1 pin of the analog multiplexer U8 is connected to the first end of the resistor R29, the Y0 pin of the analog multiplexer U8 is connected to the first end of the resistor R30, the Y3 pin of the analog multiplexer U8 is connected to the first end of the resistor R31, and the second end of the resistor R29, the second end of the resistor R30 and the second end of the resistor R31 are all connected to GND; the four ports on the first side of the four-way resistor RN1 are all connected to +9V The four ports on the second side of the four-way resistor RN1 are connected to the collector of transistor Q7, the collector of transistor Q8, the collector of transistor Q9 and the collector of transistor Q10 respectively; the collector of transistor Q7 is also connected to pin 6 of analog multiplexer U8; the collector of transistor Q8 is also connected to pin A2 of analog multiplexer U8; the collector of transistor Q9 is also connected to pin A1 of analog multiplexer U8; the collector of transistor Q10 is also connected to pin A0 of analog multiplexer U8. The emitter of the transistor Q7, the emitter of the transistor Q8, the emitter of the transistor Q9, and the emitter of the transistor Q10 are all connected to GDN; the four ports on the first side of the four-way resistor RN2 are respectively connected to the microcontroller and correspondingly connected to the four GPIOs, and the four ports on the second side of the four-way resistor RN2 are respectively connected to the base of the transistor Q7, the base of the transistor Q8, the base of the transistor Q9, and the base of the transistor Q10; the analog multiplexer U8 is connected to the measurement point.

[0021] Preferably, when the circuit is used to measure the ESD resistance of a measurement object, the measurement object includes a calibration resistor and an actual ESD resistance to be measured, the calibration resistor is used for parameter calibration, and the actual ESD resistance to be measured is the actual ESD resistance to be measured.

[0022] Preferably, when the circuit is used to measure the ESD resistance of a measurement object, the following steps are performed:

[0023] S1: The microcontroller controls the analog multiplexer through GPIO to select the calibration resistor so that it is connected to the measurement point. After performing impedance transformation, filtering and amplification on the voltage at the measurement point, the microcontroller samples the voltage signal of the calibration resistor through ADC-PORT to perform parameter calibration and establish a resistance-voltage logarithmic relationship model.

[0024] S2: The microcontroller switches the analog multiplexer to select the actual ESD resistor to be measured, connects the actual ESD resistor to be measured to the measurement point, performs the same signal conditioning as in step S1 on the voltage at the measurement point, and the microcontroller samples the voltage signal of the actual ESD resistor to be measured through the ADC-PORT;

[0025] S3: The microcontroller substitutes the voltage signal of the actual ESD resistor to be measured sampled in step S2 into the resistance-voltage logarithmic relationship model, calculates the resistance value of the actual ESD resistor to be measured, and outputs it.

[0026] Beneficial effects: The ESD resistance measurement circuit of the present application realizes high-precision measurement with a large dynamic range through real-time interaction between the measurement circuit and the multiplexing circuit based on the measurement point; the design of the reverse-parallel transistor in the measurement circuit eliminates the voltage bias caused by the reverse bias current, so that the resistance value of the resistor to be measured is directly proportional to the measurement voltage in the logarithmic space, and the measurement range is extended to 100KΩ to 100MΩ, which solves the nonlinear error problem of the traditional circuit; the multiplexing circuit switches the calibration resistor and the resistor to be measured through an analog multiplexer, and combines the ADC sampling and calculation of the microcontroller to realize self-calibration to improve the measurement consistency and accuracy; the impedance conversion, filtering and amplification functions in the circuit ensure signal stability and adapt to the acquisition requirements of the microcontroller; the circuit has a simple structure and low cost. Through the combination of hardware design and calibration mechanism, it not only meets the rapid measurement requirements of large-span resistance values ​​such as human body ESD resistance in the production of electronic equipment, but also further improves the accuracy, and is suitable for efficient detection in electrostatic sensitive places. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a structural block diagram of the ESD resistance measurement circuit provided in an embodiment of the present application;

[0029] Figure 2 The circuit principle of the ESD resistance measurement circuit provided in the embodiment of the present application Figure 1 ;

[0030] Figure 3 The circuit principle of the ESD resistance measurement circuit provided in the embodiment of the present application Figure 2 ;

[0031] Figure 4This is a flowchart of a measurement method for an ESD resistance measurement circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] In this document, the term "comprising" is intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0034] In order to achieve high-precision real-time measurement in a large dynamic range while taking into account calibration convenience and cost control, this embodiment discloses the following Figure 1 An ESD resistance measurement circuit shown includes a measurement circuit, a multiplexing circuit, and a measurement point, wherein the measurement circuit and the multiplexing circuit are both connected to the measurement point, and the measurement point is connected to the ESD resistance of the measurement object;

[0035] The measurement circuit includes: a bias elimination module for eliminating reverse bias, and an operational amplifier module for impedance conversion, filtering, and signal amplification; the input end of the bias elimination module is connected to the power supply, and the output end of the bias elimination module is connected to the input end of the operational amplifier module;

[0036] The multiplexing circuit includes a multiplexing module for analog multiplexing and a calibration module for calibrating the circuit; the multiplexing module is connected to the calibration module;

[0037] Among them: the output end of the operational amplifier module is connected to the microcontroller for analog-to-digital acquisition; the multiplexing module is connected to the microcontroller to receive the digital signal of the microcontroller.

[0038] Through the aforementioned real-time interaction between the measurement circuit and the multiplexing circuit based on the measurement points, high-precision ESD resistance measurement over a wide dynamic range is achieved. The collaborative design of the measurement and multiplexing circuits allows for switching measurement objects and calibration via the multiplexing circuit. Combined with the measurement circuit's real-time measurement capabilities, this eliminates the nonlinear errors of traditional circuits and expands the measurement range to 100kΩ-100mΩ. The hardware architecture also simplifies the calibration process, reducing costs and meeting the demands for fast, high-precision testing in ESD-sensitive scenarios.

[0039] Furthermore, the measurement circuit adopts a specific topology to achieve accurate measurement, specifically including a combined connection of resistors, transistors, capacitors and operational amplifiers.

[0040] Specifically, such as Figure 2 As shown in the figure, the connection method of the measurement circuit includes:

[0041] The bias elimination module includes at least transistor Q5 and transistor Q6; the operational amplifier module includes at least operational amplifier U6, operational amplifier U7 and operational amplifier U9B;

[0042] Wherein: a +9V voltage is input to the first end of resistor R100, a second end of resistor R100 is connected to the first end of resistor R35, the collector and base of transistor Q5, the emitter of transistor Q6, and the first end of capacitor C100; the second end of capacitor C100, the collector and base of transistor Q6, the emitter of transistor Q5, and the first end of resistor R40 are connected to the measuring point; the second end of resistor R40 is connected to the positive input of operational amplifier U6, the negative input of operational amplifier U6 and the output of operational amplifier U6 are both connected to the first end of resistor R38, the positive power supply input of operational amplifier U6 is connected to 12V, and the 12V is connected to a capacitor and then to GND, and the negative power supply input of operational amplifier U6 is connected to GND; the second end of resistor R38 and the first end of capacitor C30 are both connected to the first end of resistor R39; the second end of capacitor C30, the negative input of operational amplifier U7, and the output of operational amplifier U7 are all connected to the first end of resistor R37, The second end of resistor R39 and the first end of capacitor C33 are both connected to the positive input terminal of operational amplifier U7, and the second end of capacitor C33 is connected to GND. The positive power supply input terminal of operational amplifier U7 is connected to 12V, and the 12V is connected to a capacitor and then connected to GND. The negative power supply input terminal of operational amplifier U7 is connected to -5, and the -5 is connected to capacitor C34 and then connected to GND; the second end of resistor R37 and the first end of resistor R42 are both connected to the negative input terminal of operational amplifier U9B, the other end of resistor R35 and one end of resistor R41 are both connected to the positive input terminal of operational amplifier U9B; the second end of resistor R41 and the first end of capacitor C32 are both connected to GND; the output terminal of operational amplifier U9B and the second end of resistor R42 are both connected to the first end of resistor R36; the second end of resistor R36, the second end of resistor C32 and the positive electrode of a diode are all connected to the microcontroller and used for ADC-PORT acquisition, and the cathode of the diode is connected to +3.3V.

[0043] It should be noted that the ADC-PORT acquisition in this embodiment is the digital-to-analog acquisition performed by the existing microcontroller.

[0044] Through the above, the measurement circuit eliminates reverse bias current through anti-parallel transistors, and cooperates with the impedance transformation, filtering and multi-stage amplification of the operational amplifier to linearize the logarithmic relationship between the resistance to be measured and the voltage, so that the measurement range is extended to 100KΩ~100MΩ, and the signal stability is high. It is suitable for microcontroller ADC sampling, which improves measurement accuracy and anti-interference ability.

[0045] Furthermore, the multiplexing circuit implements the switching of the measurement object through specific connections between the analog multiplexer and the transistors and resistors, which specifically includes the connection relationship between the analog multiplexer U8 and related peripheral components.

[0046] Specifically, such as Figure 3 As shown, the connection method of the multiplexing circuit specifically includes:

[0047] The gating module includes an analog multiplexer U8; the calibration module includes at least a plurality of resistors;

[0048] Wherein: the first end of resistor R28 and the first end of resistor R32 are both connected to GND, the second end of resistor R28 is connected to pin 1 of analog multiplexer U8, the second end of resistor R32 is connected to the first end of resistor R33, the second end of resistor R33 is connected to pin 5 of analog multiplexer U8, pins 7 and 8 of analog multiplexer U8 are grounded; the VDD pin of analog multiplexer U8 is connected to +9V; the Y2 pin of analog multiplexer U8 is connected to the first end of resistor R26; resistor R2 The second end of pin 6 is connected to the first end of resistor R27, and the second end of resistor R27 is connected to GND; the Y1 pin of analog multiplexer U8 is connected to the first end of resistor R29, the Y0 pin of analog multiplexer U8 is connected to the first end of resistor R30, the Y3 pin of analog multiplexer U8 is connected to the first end of resistor R31, and the second end of resistor R29, the second end of resistor R30 and the second end of resistor R31 are all connected to GND; the four ports on the first side of four-way resistor RN1 are all connected to +9V The four ports on the second side of the four-way resistor RN1 are connected to the collector of the transistor Q7, the collector of the transistor Q8, the collector of the transistor Q9 and the collector of the transistor Q10 respectively; the collector of the transistor Q7 is also connected to the 6th pin of the analog multiplexer U8; the collector of the transistor Q8 is also connected to the A2 pin of the analog multiplexer U8; the collector of the transistor Q9 is also connected to the A1 pin of the analog multiplexer U8; the collector of the transistor Q10 is also connected to the A 0 pin; the emitters of transistors Q7, Q8, Q9 and Q10 are all connected to GDN; the four ports on the first side of the four-way resistor RN2 are respectively connected to the microcontroller and correspondingly connected to the four GPIOs, and the four ports on the second side of the four-way resistor RN2 are respectively connected to the bases of transistors Q7, Q8, Q9 and Q10; the analog multiplexer U8 is connected to the measurement point.

[0049] It should be noted that the GPIO of this embodiment is the input / output port of the aforementioned microcontroller, thereby obtaining a digital signal corresponding to the microcontroller.

[0050] To solve the calibration problem of the ESD resistance measurement circuit, this embodiment designs a corresponding calibration module including a calibration resistor in the ESD resistance measurement circuit.

[0051] Specifically, when the circuit is used to measure the ESD resistance of a measurement object, the measurement object includes a calibration resistor and an actual ESD resistance to be measured. The calibration resistor is used for parameter calibration, and the actual ESD resistance to be measured is the actual ESD resistance to be measured. In this embodiment, the calibration resistor is resistors R26 to R34.

[0052] Based on the ESD resistance measurement circuit of this embodiment, this embodiment is designed with a corresponding ESD resistance measurement method.

[0053] Specifically, such as Figure 4 When this circuit is used to measure the ESD resistance of a measurement target, the following steps are performed:

[0054] S1: The microcontroller controls the analog multiplexer through GPIO to select the calibration resistor, connecting it to the measurement point. After performing impedance transformation, filtering, and amplification on the voltage at the measurement point, the microcontroller samples the voltage signal of the calibration resistor through the ADC-PORT to perform parameter calibration and establish a resistance-voltage logarithmic relationship model.

[0055] S2: The microcontroller switches the analog multiplexer to select the actual ESD resistor to be measured, connects the actual ESD resistor to be measured to the measurement point, performs the same signal conditioning on the voltage at the measurement point as in step S1, and samples the voltage signal of the actual ESD resistor to be measured through the ADC-PORT of the microcontroller;

[0056] S3: The microcontroller substitutes the voltage signal of the actual ESD resistor to be measured sampled in step S2 into the resistance-voltage logarithmic relationship model, calculates the resistance value of the actual ESD resistor to be measured, and outputs it.

[0057] In a simple example, the on / off and channel selection of the analog multiplexer U8 are controlled by the GPIO port signal of the microcontroller, which is connected to the measurement point in the measurement circuit, and each channel is connected to each calibration resistor and the external measurement port. When it is turned on, the analog multiplexer will connect the corresponding channel to the measurement point according to the selection signal. When it is turned off, all channels are in a high-impedance state; resistors R26 to R34 are calibration resistor elements, one end of which is connected to the channel of the analog multiplexer and the other end is grounded. When the corresponding channel in the analog multiplexing is selected, the corresponding calibration resistor or external port is connected to the measurement circuit; resistor R36 and capacitor C32 are input RC filter resistors and capacitors, which are connected between the op amp transmission circuit and the microcontroller ADC sampling pin to filter the collected voltage information of the measurement point.

[0058] When performing precise ESD resistance measurement, it will be divided into two implementation steps: when the measurement circuit wants to measure the ESD resistance of the external port, it will first select the corresponding channel through the analog multiplexer U8, and use the microcontroller to perform ADC sampling to obtain the approximate resistance range; then it will further compare the calibration resistor within the range, and again fit the relationship between the resistance to be measured and the voltage at the measurement point in this interval, and perform a secondary calculation to obtain the precise resistance value.

[0059] Based on the above, the multiplexing circuit realizes automatic switching between the calibration resistor and the resistor to be measured by analog multiplexer U8 and transistor level conversion. Combined with the microcontroller GPIO control, a self-calibration model is established to eliminate circuit errors, expand the measurement range to 100KΩ~100MΩ, and improve measurement consistency and real-time performance.

[0060] In summary, the ESD resistance measurement circuit of this embodiment realizes high-precision measurement with a large dynamic range through real-time interaction between the measurement circuit and the multiplexing circuit based on the measurement point; the design of the reverse parallel transistor in the measurement circuit eliminates the voltage bias caused by the reverse bias current, so that the resistance value of the resistor to be measured is directly proportional to the measurement voltage in the logarithmic space, and the measurement range is extended to 100KΩ to 100MΩ, which solves the nonlinear error problem of the traditional circuit; the multiplexing circuit switches the calibration resistor and the resistor to be measured through an analog multiplexer, and combines the ADC sampling and calculation of the microcontroller to realize self-calibration to improve measurement consistency and accuracy; the impedance conversion, filtering and amplification functions in the circuit ensure signal stability and adapt to the acquisition requirements of the microcontroller; the circuit has a simple structure and low cost. Through the combination of hardware design and calibration mechanism, it not only meets the rapid measurement requirements of large-span resistance values ​​such as human body ESD resistance in electronic equipment production, but also further improves the accuracy, and is suitable for efficient detection in electrostatic sensitive places.

[0061] In the embodiments provided herein, it should be understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, code, or any appropriate combination thereof. For hardware implementation, the processor can be implemented in one or more of the following units: an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microcontroller, a microprocessor, other electronic units designed to implement the functions described herein, or a combination thereof. For software implementation, part or all of the processes of the embodiments can be completed by instructing the relevant hardware through a computer program. When implemented, the above program can be stored in a computer-readable storage medium or transmitted as one or more instructions or codes on a computer-readable storage medium. Computer-readable storage media include computer storage media and communication media, wherein the communication media include any medium that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that a computer can access. The computer-readable storage medium can include, but is not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer.

[0062] Finally, it should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An ESD resistance measurement circuit, characterized in that: The device comprises a measuring circuit, a multiplexing circuit and a measuring point, wherein the measuring circuit and the multiplexing circuit are both connected to the measuring point, and the measuring point is connected to the ESD resistance of the measurement object; The measurement circuit includes: a bias elimination module for eliminating reverse bias, and an operational amplifier module for impedance transformation, filtering, and signal amplification; the input end of the bias elimination module is connected to a power supply, and the output end of the bias elimination module is connected to the input end of the operational amplifier module; The multiplexing circuit includes a multiplexing module for analog multiplexing and a calibration module for calibrating the circuit; the multiplexing module is connected to the calibration module; Wherein: the output end of the operational amplifier module is connected to the microcontroller for analog-to-digital acquisition; the multiplexing module is connected to the microcontroller to receive the digital signal of the microcontroller.

2. The ESD resistance measurement circuit according to claim 1, wherein: The connection method of the measuring circuit specifically includes: The bias elimination module includes at least a transistor Q5 and a transistor Q6; the operational amplifier module includes at least an operational amplifier U6, an operational amplifier U7 and an operational amplifier U9B; Wherein: a +9V voltage is input to the first end of the resistor R100, and the second end of the resistor R100 is connected to the first end of the resistor R35, the collector and base of the transistor Q5, the emitter of the transistor Q6 and the first end of the capacitor C100; the second end of the capacitor C100, the collector and base of the transistor Q6, the emitter of the transistor Q5 and the first end of the resistor R40 are connected to the measuring point; the second end of the resistor R40 is connected to the positive input terminal of the operational amplifier U6, the negative input terminal of the operational amplifier U6 and the output terminal of the operational amplifier U6 are both connected to the first end of the resistor R38, the positive power supply input terminal of the operational amplifier U6 is connected to 12V and the 12V is connected to a capacitor and then connected to GND, and the negative power supply input terminal of the operational amplifier U6 is connected to GND; the second end of the resistor R38 and the first end of the capacitor C30 are both connected to the first end of the resistor R39; the second end of the capacitor C30, the negative input terminal of the operational amplifier U7 and the output terminal of the operational amplifier U7 are all connected to the first end of the resistor R37 The second end of the resistor R37 and the first end of the resistor R42 are both connected to the negative input terminal of the operational amplifier U9B, the other end of the resistor R35 and one end of the resistor R41 are both connected to the positive input terminal of the operational amplifier U9B; the second end of the resistor R41 and the first end of the capacitor C32 are both connected to GND; the output terminal of the operational amplifier U9B and the second end of the resistor R42 are both connected to the first end of the resistor R36; the second end of the resistor R36, the second end of the resistor C32 and the anode of a diode are all connected to the microcontroller and used for ADC-PORT acquisition, and the cathode of the diode is connected to +3.3V.

3. The ESD resistance measurement circuit according to claim 1, wherein: The connection method of the multiplexing circuit specifically includes: The gating module includes an analog multiplexer U8; the calibration module includes at least a plurality of resistors; Wherein: the first end of resistor R28 and the first end of resistor R32 are both connected to GND, the second end of resistor R28 is connected to pin 1 of analog multiplexer U8, the second end of resistor R32 is connected to the first end of resistor R33, the second end of resistor R33 is connected to pin 5 of analog multiplexer U8, pins 7 and 8 of analog multiplexer U8 are grounded; the VDD pin of analog multiplexer U8 is connected to +9V; the Y2 pin of analog multiplexer U8 is connected to the first end of resistor R26; resistor R26 The second end of the analog multiplexer U8 is connected to the first end of the resistor R27, and the second end of the resistor R27 is connected to GND; the Y1 pin of the analog multiplexer U8 is connected to the first end of the resistor R29, the Y0 pin of the analog multiplexer U8 is connected to the first end of the resistor R30, the Y3 pin of the analog multiplexer U8 is connected to the first end of the resistor R31, and the second end of the resistor R29, the second end of the resistor R30 and the second end of the resistor R31 are all connected to GND; the four ports on the first side of the four-way resistor RN1 are all connected to +9V The four ports on the second side of the four-way resistor RN1 are connected to the collector of transistor Q7, the collector of transistor Q8, the collector of transistor Q9 and the collector of transistor Q10 respectively; the collector of transistor Q7 is also connected to pin 6 of analog multiplexer U8; the collector of transistor Q8 is also connected to pin A2 of analog multiplexer U8; the collector of transistor Q9 is also connected to pin A1 of analog multiplexer U8; the collector of transistor Q10 is also connected to pin A0 of analog multiplexer U8. The emitter of the transistor Q7, the emitter of the transistor Q8, the emitter of the transistor Q9, and the emitter of the transistor Q10 are all connected to GDN; the four ports on the first side of the four-way resistor RN2 are respectively connected to the microcontroller and correspondingly connected to the four GPIOs, and the four ports on the second side of the four-way resistor RN2 are respectively connected to the base of the transistor Q7, the base of the transistor Q8, the base of the transistor Q9, and the base of the transistor Q10; the analog multiplexer U8 is connected to the measurement point.

4. The ESD resistance measurement circuit according to claim 1, wherein: When the circuit is used to measure the ESD resistance of a measurement object, the measurement object includes a calibration resistor and an actual ESD resistance to be measured. The calibration resistor is used for parameter calibration, and the actual ESD resistance to be measured is the actual ESD resistance to be measured.

5. The ESD resistance measurement circuit according to claim 4, wherein: When this circuit is used to measure the ESD resistance of a measurement target, the following steps are performed: S1: The microcontroller controls the analog multiplexer through GPIO to select the calibration resistor so that it is connected to the measurement point. After performing impedance transformation, filtering and amplification on the voltage at the measurement point, the microcontroller samples the voltage signal of the calibration resistor through ADC-PORT to perform parameter calibration and establish a resistance-voltage logarithmic relationship model. S2: The microcontroller switches the analog multiplexer to select the actual ESD resistor to be measured, connects the actual ESD resistor to be measured to the measurement point, performs the same signal conditioning as in step S1 on the voltage at the measurement point, and the microcontroller samples the voltage signal of the actual ESD resistor to be measured through the ADC-PORT; S3: The microcontroller substitutes the voltage signal of the actual ESD resistor to be measured sampled in step S2 into the resistance-voltage logarithmic relationship model, calculates the resistance value of the actual ESD resistor to be measured, and outputs it.

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