Human body impedance detection device and method capable of self-adapting to detection range, medium and product

Abstract

The invention discloses a human body impedance detection device and method capable of self-adapting to a detection range, a medium and a product. For an impedance detection device, an impedance converter circuit is connected with a signal conditioning circuit to send a sampling signal, and the signal conditioning circuit amplifies the sampling signal; a sampling signal selectively enters the adjustable calibration impedance circuit or the impedance measurement circuit through the selection circuit, then is input into the I-V conversion circuit to be processed and then is transmitted back to the impedance converter circuit; when a sampling signal is input into the adjustable calibration impedance circuit, the impedance converter circuit calculates and records a gain coefficient of the impedance converter circuit, and the impedance converter circuit calculates the gain coefficient at least once before impedance measurement is carried out each time; when a sampling signal is input into the impedance measurement circuit, the impedance converter circuit calculates the amplitude and the phase of the impedance to be measured through the measured gain coefficient. The sampling precision of the impedance converter can be effectively improved, and the sampling range of the impedance converter is expanded.

Description

Technical Field

[0001] This application relates to the field of human body detection, and specifically relates to a human body impedance detection device, method, medium and product with an adaptive detection range. Background Art

[0002] An intraoperative nerve detector is a medical device that monitors the integrity of nerve function in real time during surgery. It evaluates the nerve conduction state through electrophysiological techniques to help surgeons avoid nerve damage and improve surgical safety. When using an intraoperative nerve detector, it is necessary to ensure the connection effectiveness of the signal acquisition path and collect the impedance value of the signal path (human body) in real time, as Figure 1 shown.

[0003] The impedance converter is an effective means for collecting human body impedance. Due to reasons such as measurement conditions, tissue types, and individual differences, the human body impedance value is an unknown impedance within a relatively large range, which can range from hundreds to dozens of kiloohms. The impedance converter can achieve the conversion between different impedance systems and perform measurements. It outputs a constant current signal of a certain frequency, and after flowing through the signal path, it collects the returned signal. By analyzing the amplitude and phase change amount between the output signal and the returned signal, the impedance value of the signal path is calculated.

[0004] In practical applications, there are many problems with directly applying the impedance converter to human body impedance collection.

[0005] Firstly, before measuring an unknown impedance using an impedance converter, it is necessary to calculate the gain coefficient by measuring a calibration impedance with a known impedance value, and then measure and calculate the unknown impedance to be measured through the gain coefficient. The conventional method of measuring the gain coefficient before using the impedance converter cannot adapt to the large range of human body impedance values. Only within a specific narrow range of impedance, this gain coefficient is accurate, enabling the impedance converter to perform high-precision sampling. Once the human body impedance value deviates from this range, it will cause the gain coefficient to experience range failure, resulting in the sampled impedance value obtained through the gain coefficient deviating significantly from the true value.

[0006] Secondly, although the impedance converter has a certain ability to adapt to different impedance systems, due to the large impedance range of the human body, directly applying the impedance converter to the human body will still result in the problem of difficulty in matching the human body impedance value with the sampling system of the impedance converter. For example, if the actual human body impedance value is less than the range of the impedance converter, it will cause the sampling current to be too large, resulting in cut-off distortion of the subsequent signal collection and amplification circuit. This greatly limits the detection range of the impedance converter for human body impedance. Summary of the Invention

[0007] The purpose of this application is to overcome the deficiencies of the prior art and provide a human body impedance detection device, method, medium and product with an adaptive detection range, which can effectively improve the sampling accuracy of the impedance converter and expand the sampling range of the impedance converter.

[0008] In a first aspect, a human body impedance detection device with an adaptive detection range provided by this application adopts the following technical solution: The human body impedance detection device includes an impedance converter circuit and an impedance measurement circuit, and also includes a signal conditioning circuit, a selection circuit, an adjustable calibration impedance circuit and an I-V conversion circuit; The impedance converter circuit is connected to the signal conditioning circuit and sends a sampling signal to the signal conditioning circuit. The signal conditioning circuit amplifies the sampling signal. The sampling signal selectively enters the adjustable calibration impedance circuit or the impedance measurement circuit through the selection circuit, and then is input into the I-V conversion circuit to be converted into a voltage signal, amplified and then sent back to the impedance converter circuit; When the sampling signal is input into the adjustable calibration impedance circuit, the impedance converter circuit calculates and records the gain coefficient of the impedance converter circuit based on the amplitude change amount between the sent sampling signal and the received signal. The impedance converter circuit calculates the gain coefficient at least once before each impedance measurement; when the sampling signal is input into the impedance measurement circuit, the impedance converter circuit calculates the amplitude and phase of the impedance to be measured based on the amplitude and phase change amounts between the sent sampling signal and the received signal and the gain coefficient.

[0009] By adopting the above technical solution, by setting a signal conditioning circuit in front of the impedance measurement circuit and the adjustable calibration impedance circuit to regulate the voltage amplitude of the sampling signal output by the impedance converter circuit, the sampling signal can be reliably adapted when facing the adjustable calibration impedance circuit or the impedance measurement circuit with different impedance ranges, avoiding the cut-off of the rear-end I-V conversion circuit caused by excessive sampling current; by setting an adjustable calibration impedance circuit and an impedance measurement circuit with selectable inputs, the convenient switching between gain coefficient measurement and impedance measurement can be realized. At the same time, since the calibration impedance of the adjustable calibration impedance circuit is adjustable, according to the actual value of the impedance to be measured, a gain coefficient accurately adapted to the impedance to be measured can be obtained, expanding the sampling range and improving the sampling accuracy.

[0010] Preferably, it further includes a main controller, which is respectively connected to the impedance converter circuit, the signal conditioning circuit, the selection circuit, the adjustable calibration impedance circuit and the I-V conversion circuit. The main controller controls the impedance converter circuit to send a sampling signal, reads the impedance to be measured measured by the impedance converter circuit, controls the amplification factor of the signal conditioning circuit, controls the selection direction of the selection circuit, sets the calibration impedance of the adjustable calibration impedance circuit, and controls the amplification factor of the I-V conversion circuit.

[0011] Preferably, the main controller is connected to the adjustable calibration impedance circuit through an isolated bus driver, connected to the impedance converter circuit through an isolated bus driver, connected to the signal conditioning circuit through an optocoupler, connected to the selection circuit through an optocoupler, and connected to the I-V conversion circuit through an optocoupler.

[0012] By adopting the above technical solutions, the adjustment and control of the amplification factor of the signal conditioning circuit are realized, the selection control of the adjustable calibration impedance circuit and the impedance measurement circuit is realized, the adjustment and control of the amplification factor of the I-V conversion circuit are realized, and the controllability of the human impedance detection device in different scenarios is improved.

[0013] In a second aspect, a human impedance detection method with an adaptive detection range provided by the present application includes the following steps: S100, turn on the human impedance detection device and initialize the main controller; S200, enter the calibration step, switch to the adjustable calibration impedance circuit path, sequentially set the calibration impedance values for the adjustable calibration impedance circuit according to the preset impedance values, and for each set calibration impedance value, calculate and save the gain coefficient of the impedance converter circuit once; S300, enter the sampling step, switch to the impedance measurement circuit path, set the calibration impedance value as the current calibration impedance value, set the gain coefficient corresponding to the current calibration impedance value as the current gain coefficient, measure the impedance to be measured, calculate the pending impedance to be measured, and compare the pending impedance to be measured with the current calibration impedance value. If the deviation between the two exceeds the set value, it is determined that the pending impedance to be measured does not meet the requirements, and a new calibration impedance value is replaced as the current calibration impedance value until the deviation between the pending impedance to be measured and the current calibration impedance value meets the requirements. Record the pending impedance to be measured that meets the requirements as the sampling impedance, and record the corresponding current gain coefficient as the sampling gain coefficient; S400, complete the sampling process, and continuously collect the human impedance with the parameters set in the sampling process.

[0014] Preferably, the calibration step of S200 specifically includes: S210, switch to the adjustable calibration impedance circuit path; S220, according to the preset impedance value, set the lowest preset calibration impedance value as the calibration impedance value; S230, set the current amplification factor of the corresponding signal conditioning circuit according to the set calibration impedance value; S240, set the current amplification factor of the corresponding I-V conversion circuit according to the set calibration impedance value; S250, the impedance converter circuit sends a sampling signal to calculate the gain coefficient of the impedance converter circuit; S260, save the calibrated impedance values and the measured gain coefficients in a corresponding manner; S270, adjust the calibrated impedance value upward according to the preset impedance value, return to S230, and repeat the above steps until the gain coefficients corresponding to all the preset impedance values have been calculated and saved.

[0015] Preferably, the sampling step of S300 specifically includes: S310, switch to the impedance measurement circuit path; S320, set the lowest calibrated impedance value as the current calibrated impedance value; S330, retrieve the gain coefficient corresponding to the current calibrated impedance value and set it as the current gain coefficient; S340, set the current amplification factor of the corresponding signal conditioning circuit according to the current calibrated impedance value; S350, set the current amplification factor of the corresponding I-V conversion circuit according to the current calibrated impedance value; S360, the impedance converter circuit sends out a sampling signal to measure the impedance to be measured, and calculates the impedance to be determined to be measured through the current gain coefficient; S370, compare the impedance to be determined to be measured with the current calibrated impedance value. If the deviation between the two exceeds the set value, it is determined that the impedance to be determined to be measured does not meet the requirements. Increase the calibrated impedance value by one level as the current calibrated impedance value, return to S330, and repeat the above steps until the deviation between the impedance to be determined to be measured and the current calibrated impedance value meets the requirements; S380, record the impedance to be determined to be measured that meets the requirements as the sampling impedance, and record the corresponding current gain coefficient as the sampling gain coefficient.

[0016] Through the above technical solution, the calculation and saving of the gain coefficients for the calibrated impedances with different impedance values are realized. Then, when sampling an unknown impedance, the measured impedance to be determined to be measured is compared with the corresponding current calibrated impedance value. If the deviation is too large, it indicates that there is a large error in measuring the unknown impedance using the gain coefficient obtained with this current calibrated impedance value, and it needs to be replaced until a situation where the current calibrated impedance value is relatively close to the impedance to be determined to be measured is found. At this time, the sampling value will not deviate greatly, the impedance to be determined to be measured is close to the true value of the unknown impedance, and the accuracy and reliability of the impedance measurement value can be improved.

[0017] Preferably, in S370, the formula for determining that the deviation between the impedance to be determined to be measured and the current calibrated impedance value meets the requirements is specifically: where, R 待 is the impedance to be determined to be measured, and R 当前 is the current calibrated impedance value.

[0018] Through the above technical solution, the judgment basis for the deviation between the impedance to be determined and the current calibrated impedance value to meet the requirements is clarified. And this basis can be used as a judgment condition to be input into the main controller to realize the automatic determination and automatic selection of whether the gain coefficient of the human impedance detection device is appropriate, and realize the intelligent adaptive detection of the human impedance detection device.

[0019] In a third aspect, a computer-readable storage medium provided by the present application stores a computer program thereon, and when the computer program is executed by a processor, the steps of the human impedance detection method within the above-mentioned adaptive detection range are performed.

[0020] In a fourth aspect, a computer program product provided by the present application includes a computer program or instruction, which enables the computer program or instruction to implement the steps of the human impedance detection method within the above-mentioned adaptive detection range.

[0021] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application can switch between the adjustable calibration impedance circuit and the impedance measurement circuit, which is convenient for measuring the gain coefficient before each impedance measurement, and simplifies the preparation process of the human impedance detection device.

[0022] 2. Through the adjustable calibration impedance, the present application can measure and record the gain coefficients corresponding to the calibration impedances with different impedance values. When dealing with a large range of human impedance, the present application proposes a standard for judging the measurement accuracy of the impedance to be measured, and can adaptively select the corresponding gain coefficient to measure the impedance to be measured, expanding the sampling range of the impedance converter and improving the sampling accuracy of the impedance converter.

[0023] 3. The present application can adjust the amplification factor of the signal conditioning circuit and the amplification factor of the I-V conversion circuit, and the amplification factor is adapted to the calibration impedance or the impedance to be measured, which can effectively avoid the distortion of the sampling value.

[0024] 4. The present application can automatically calculate and record the gain coefficient, and can automatically screen the gain coefficient adapted to the unknown impedance, realizing the adaptive detection range and intelligent detection of the human impedance detection, and improving the detection efficiency. Description of the Drawings

[0025] Figure 1 It is a schematic diagram for collecting human impedance; Figure 2 It is a functional circuit connection block diagram of the human impedance detection device with an adaptive detection range according to an embodiment of the present application; Figure 3 It is a top-level design diagram of the human impedance detection device with an adaptive detection range according to an embodiment of the present application; Figure 4 Circuit diagram of impedance converter circuit 2 of the human body impedance detection device with an adaptive detection range according to an embodiment of the present application; Figure 5 Circuit diagram of signal conditioning circuit connection 3 of the human body impedance detection device with an adaptive detection range according to an embodiment of the present application; Figure 6 Circuit diagram of selection circuit 4 and I-V conversion circuit 7 of the human body impedance detection device with an adaptive detection range according to an embodiment of the present application; Figure 7 Circuit diagram of adjustable calibration impedance circuit 5 of the human body impedance detection device with an adaptive detection range according to an embodiment of the present application; Figure 8 Circuit diagram of impedance measurement circuit 6 of the human body impedance detection device with an adaptive detection range according to an embodiment of the present application; Figure 9 Flowchart of the human body impedance detection method with an adaptive detection range according to an embodiment of the present application; Figure 10 Flowchart of S200 calibration step of the human body impedance detection method with an adaptive detection range according to an embodiment of the present application; Figure 11 Flowchart of S300 sampling step of the human body impedance detection method with an adaptive detection range according to an embodiment of the present application. Detailed implementation manners

[0026] This specific embodiment is only an interpretation of the present application and does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment as needed after reading this specification, but as long as it is within the scope of the present application, it is protected by the patent law.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application. It should be noted that in the optional embodiments of this application, for relevant data such as object information, when the embodiments in this application are applied to specific products or technologies, permission or consent from the object needs to be obtained, and the collection, use, and processing of relevant data need to comply with the relevant laws, regulations, and standards of the relevant countries and regions. That is to say, if the embodiments of this application involve data related to an object, it needs to be obtained under the authorization and consent of the object, the authorization and consent of the relevant department, and compliance with the relevant laws, regulations, and standards of the relevant countries and regions. In the embodiments, if personal information is involved, the acquisition of all personal information requires the consent of the individual. If sensitive information is involved, the separate consent of the information subject needs to be obtained, and the embodiments also need to be implemented under the authorization and consent of the object.

[0028] The following further describes the embodiments of this application in detail with reference to the accompanying drawings of the specification.

[0029] In one embodiment, please refer to Figure 2 , a human body impedance detection device with an adaptive detection range in this application includes a main controller 1, an impedance converter circuit 2, a signal conditioning circuit 3, a selection circuit 4, an adjustable calibration impedance circuit 5, an impedance measurement circuit 6, and an I-V conversion circuit 7. The combination of the impedance converter circuit 2, the signal conditioning circuit 3, the selection circuit 4, the adjustable calibration impedance circuit 5, the impedance measurement circuit 6, and the I-V conversion circuit 7 forms an impedance collector 8.

[0030] The impedance converter circuit 2 is connected to the signal conditioning circuit 3 and sends a sampling signal to the signal conditioning circuit 3. A constant current sine wave signal with a certain frequency is usually used as the sampling signal. Before the sampling signal is input into the adjustable calibration impedance circuit 5 or the impedance measurement circuit 6, the signal conditioning circuit 3 needs to amplify the sampling signal. For example, before sampling a small impedance, the signal conditioning circuit 3 needs to reduce the voltage amplitude of the output sine wave signal to avoid cutoff of the backend I-V conversion circuit 7 caused by an excessive sampling current, and the amplification factor of the signal conditioning circuit 3 is less than 1. The sampling signal amplified by the signal conditioning circuit 3 selectively enters the adjustable calibration impedance circuit 5 or the impedance measurement circuit 6 through the selection circuit 4, and then is input into the I-V conversion circuit 7 to be converted into a voltage signal, amplified, and then sent back to the impedance converter circuit 2.

[0031] When a sampling signal is input to the adjustable calibration impedance circuit 5, the impedance converter circuit 2 calculates and records the gain coefficient of the impedance converter circuit 5 based on the amplitude change between the sine wave signal it emits and the received sine wave signal. Before each impedance measurement, the impedance converter circuit 2 calculates the gain coefficient at least once.

[0032] In practical applications, technicians found that the error of the gain coefficient is related to the difference between the calibration impedance and the actual impedance to be measured. That is, the closer the calibration impedance is to the actual impedance value of the impedance to be measured, the higher the accuracy of the gain coefficient measured through the calibration impedance when applied to the detection of the impedance to be measured. Therefore, by using the adjustable calibration impedance circuit 5, the impedance value of the adjustable calibration circuit 5 can be adjusted, and the gain coefficients corresponding to the calibration impedances with different impedance values can be obtained through multiple measurements. Each gain coefficient corresponds to an interval range of unknown impedance, which is used to measure the unknown impedance within this interval range.

[0033] When a sampling signal is input to the impedance measurement circuit 6, the impedance converter circuit 2 calculates the amplitude and phase of the impedance to be measured based on the amplitude and phase changes between the emitted sampling signal and the received signal, as well as the gain coefficient. Since the impedance value of the impedance to be measured is an unknown interval range, the impedance value of the impedance to be measured calculated once is not necessarily an accurate value and needs to be temporarily listed as a pending impedance to be measured. By comparing the pending impedance to be measured with the calibration impedance corresponding to the adopted gain coefficient, if the difference between the two is small, it can be considered that the pending impedance to be measured is accurate.

[0034] The main controller 1 is respectively connected to the impedance converter circuit 2, the signal conditioning circuit 3, the selection circuit 4, the adjustable calibration impedance circuit 5, and the I-V conversion circuit 7, and is used to achieve the comprehensive control of the system. The main controller 1 controls the impedance converter circuit 2 to emit a sampling signal, reads the impedance to be measured measured by the impedance converter circuit 2, controls the amplification factor of the signal conditioning circuit 3, controls the selection direction of the selection circuit 4, sets the calibration impedance of the adjustable calibration impedance circuit 5, and controls the amplification factor of the I-V conversion circuit 7. In other embodiments, the main controller 1 further includes an input module, a display module, and a storage module. The input module enables the user to input control instructions to set and control the impedance collector 8; the display module is used to display the status information of the impedance collector 8 and display it in real time after reading the measured impedance value to be measured; the storage module is used to store the corresponding relationship between each measured calibration impedance and the gain coefficient, and can store the measured impedance to be measured.

[0035] In another embodiment, the main controller 1 is connected to the adjustable calibration impedance circuit 5 through an isolated bus driver, connected to the impedance converter circuit 2 through an isolated bus driver, connected to the signal conditioning circuit 3 through an optocoupler, connected to the selection circuit 4 through an optocoupler, and connected to the I-V conversion circuit 7 through an optocoupler. The above technical solution is used to achieve electrical isolation between the human body detection loop and the circuit and ensure reliable signal transmission.

[0036] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the above division of each functional circuit is used as an example. In actual applications, the above functions can be allocated to different functional circuits, units, and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above.

[0037] In another embodiment, please refer to Figure 3 , the top-level design of an application example of a human impedance detection device with an adaptive detection range. Through the control bus and control ports of the main controller 1, an impedance collector 8 with an adjustable impedance range is controlled to collect the resistance value to be detected, and the sampling range of the impedance converter is adjusted in real time according to the actual resistance value collected to ensure the sampling accuracy. Specifically, please refer to Figures 4 to 8 , the design circuit embodiment of the impedance collector 8.

[0038] Please refer to Figure 4 , the impedance converter circuit 2 includes an impedance converter D3. The impedance converter D3 outputs a set of constant-current sine signals with adjustable frequencies to the signal conditioning circuit 3 through the pin Vout. The impedance converter D3 receives the signal returned from the I-V conversion circuit 7 through the pin Vin. If it is in the calibration mode at this time, the gain coefficient is calculated; if it is in the impedance measurement mode at this time, the unknown impedance is measured.

[0039] Please refer to Figure 5 , the signal conditioning circuit 3 includes an adjustable inverting amplifier composed of a first operational amplifier D1A and an adjustable feedback resistor. After the constant-current sine signal filters out the DC signal through the filtering DC capacitor C2, it is input to the inverting input terminal of the first operational amplifier D1A through the input resistor R2. The adjustable feedback resistor is respectively connected to the inverting input terminal and the output terminal of the first operational amplifier D1A, and the output terminal of the first operational amplifier D1A is connected to the selection circuit 4. The feedback magnification formula of the adjustable inverting amplifier is: Among them, V out is the output signal of the adjustable inverting amplifier, V in is the input signal of the adjustable inverting amplifier, R f is the resistance value of the adjustable feedback resistor, and R in is the resistance value of the input resistor.

[0040] More specifically, in a preferred embodiment, the adjustable feedback resistor is composed of a digital-to-analog switch D2, a first feedback resistor R4, a second feedback resistor R3, and a third feedback resistor R6. The pin D1_in of the digital-to-analog switch D2 is connected to the output terminal of the operational amplifier D1A, and the pin D2_out of the digital-to-analog switch D2 is connected to the selection circuit 4. Through the path control of the digital-to-analog switch D2, the adjustable feedback resistor can select multiple modes, such as the first feedback resistor R4, the first feedback resistor R4 in parallel with the second feedback resistor R3, the first feedback resistor R4 in parallel with the third feedback resistor R6, and the first feedback resistor R4 in parallel with the second feedback resistor R3 in parallel with the third feedback resistor R6. By changing the resistance value of the adjustable feedback resistor, the amplification factor of the adjustable inverting amplifier can be changed. Set the input resistor R2 to 20K ohms, the first feedback resistor R4 to 20K ohms, the second feedback resistor R3 to 20K ohms, and the third feedback resistor R6 to 10K ohms. When the first feedback resistor R4 is selected, R f is 20K ohms, and at this time, the signal amplitude magnification of the signal conditioning circuit 3 remains unchanged at 1:1; when the first feedback resistor R4 is in parallel with the second feedback resistor R3, R f is 10K ohms, and at this time, the signal amplitude magnification of the signal conditioning circuit 3 is 1 / 2; when the first feedback resistor R4 is in parallel with the third feedback resistor R6, R f is 6.67K ohms, and at this time, the signal amplitude magnification of the signal conditioning circuit 3 is 1 / 3; when the first feedback resistor R4 is in parallel with the second feedback resistor R3 in parallel with the third feedback resistor R6, R f is 5k ohms, and at this time, the signal amplitude magnification of the signal conditioning circuit 3 is 1 / 4. If more signal amplitude magnifications of the signal conditioning circuit 3 need to be selected, more optional feedback resistor impedances can be added, and the number of channels of the digital-to-analog switch D2 can be increased.

[0041] Please refer to Figure 6 , the selection circuit 4 includes a digital-to-analog switch D4. The pin D2_in of the digital-to-analog switch D4 is connected to the output terminal of the signal conditioning circuit 3, the pin S2A of the digital-to-analog switch D4 is connected to the impedance measurement circuit 6, and the pin S2B of the digital-to-analog switch D4 is connected to the adjustable calibration impedance circuit 5.

[0042] Please refer to Figure 7 , the adjustable calibration impedance circuit 5 includes a jumper V, a calibration fixed-value resistor R16, and a calibration digital variable resistor D5. The pin V2 of the jumper V is connected to the selection circuit 4, the pin V1 of the jumper V is connected to the calibration fixed-value resistor R16, and the pin V3 of the jumper V is connected to the calibration digital variable resistor D5. The output terminals of the calibration fixed-value resistor R16 and the calibration digital variable resistor D5 are connected to the I-V conversion circuit 7. Through the jumper V, the calibration fixed-value resistor R16 and the calibration digital variable resistor D5 can be selectively connected.

[0043] Among them, in a preferred embodiment, the resistance value of the calibrated fixed resistor R16 is 20 kΩ, and the resistance adjustment gradient of the calibrated digital variable resistor D5 is: 500 Ω, 1 kΩ, 2 kΩ, 4 kΩ, 8 kΩ, 16 kΩ, and 20 kΩ. The basis for setting the resistance values of the calibrated fixed resistor R16 and the calibrated digital variable resistor D5 is the human body impedance range, and the accurate standard for the gain coefficient is that the deviation between the to-be-detected impedance and the current calibrated impedance value is less than 150%. For example, when the gain coefficient is measured using a calibrated resistor of 2 kΩ, if the measured to-be-detected impedance exceeds 3000 Ω, the gain coefficient measured using a calibrated resistor adjusted to 4 kΩ needs to be used for the to-be-detected impedance measurement.

[0044] When calculating the gain coefficient of the impedance converter circuit 2 at different impedance values of the corresponding adjustable calibrated impedance circuit 5, the jumper is first switched to pin V3, the calibrated digital variable resistor D5 is adjusted to different resistance values in ascending order, and the gain coefficient for each resistance value is calculated. Then, it is switched to pin V1, and the gain coefficient when using the calibrated fixed resistor R16 is calculated.

[0045] Please refer to Figure 8 , the impedance measurement circuit 6 includes a first path electrode P1, a second path electrode P2, a first current-limiting resistor R14, a second current-limiting resistor R15, a first TVS tube TVS1, and a second TVS tube TVS2. The input end of the impedance measurement circuit 6 is connected to the selection circuit 4 and leads to the first path electrode P1 through the second current-limiting resistor R15; the second path electrode P2 is connected to the first current-limiting resistor R14, and the output end of the impedance measurement circuit 6 is connected to the I-V conversion circuit 7. The first path electrode P1 and the second path electrode P2 are lapped at both ends of the to-be-detected impedance (the position of the human body to be detected). The first TVS tube TVS1 is connected in parallel between the equipotential and the signal input line, and the second TVS tube TVS2 is connected in parallel between the equipotential and the signal output line.

[0046] Please refer to Figure 6 , the I-V conversion circuit 7 includes an adjustable inverting amplifier composed of a second operational amplifier D1B and an adjustable feedback resistor. The output signal of the adjustable calibrated impedance circuit 5 or the impedance measurement circuit 6 is input to the inverting input end of the second operational amplifier D1B. The adjustable feedback resistor is respectively connected to the inverting input end and the output end of the first operational amplifier D1A, and the output end of the second operational amplifier D1B is connected to the impedance converter circuit 2.

[0047] More specifically, the adjustable feedback resistor consists of a digital-to-analog switch D4, a fourth feedback resistor R10, and a fifth feedback resistor R13. The pin D1_out of the digital-to-analog switch D4 is connected to the inverting input terminal of the operational amplifier D1B. Through the path control of the digital-to-analog switch D2, the adjustable feedback resistor can select to be connected to the output terminal of the second operational amplifier D1B through the fourth feedback resistor R10 or the fifth feedback resistor R13, thereby changing the amplification factor of the I-V conversion circuit. The I-V conversion circuit controls two amplification factor gears through the fourth feedback resistor R10 or the fifth feedback resistor R13. In a preferred embodiment, considering that the human body impedance detection range is usually 200 - 20K ohms, R10 is set to 1K ohm and R13 is set to 10K ohms.

[0048] Those skilled in the art can understand that the circuit structure in the above embodiments is only one implementation manner of the part related to the solution of the present application, and does not constitute a limitation on the circuit components and electronic devices to which the solution of the present application is applied. The specific circuit components and electronic devices may include more or fewer components than those shown in the figure, or use other components with the same functions, or combine certain components, or have different component arrangements. Unless otherwise specified, the pins (such as the power supply pin VCC, the ground pin GND, the enable pin EN, etc.) and components not clearly described in the circuit diagrams of the present application are connected in the usual manner of those skilled in the art, and such connections do not constitute a limitation on the technical solution of the present invention.

[0049] In another embodiment, please refer to Figure 9 , an adaptive detection range human body impedance detection method of the present application, which applies the adaptive detection range human body impedance detection device described above, specifically includes the following steps: S100, turn on the human body impedance detection device and initialize the main controller.

[0050] Collectively, the content of initializing the main controller specifically includes: setting the frequency and voltage amplitude of the sampling signal of the impedance converter circuit to initial values, setting the calibration impedance value to an initial value (switching to a fixed-value resistor), setting the amplification factor of the signal conditioning circuit to an initial value, setting the amplification factor of the I-V conversion circuit to an initial value, and clearing the previously saved gain coefficient.

[0051] S200, enter the calibration step, switch to the adjustable calibration impedance circuit path, and sequentially set the calibration impedance value of the adjustable calibration impedance circuit according to the preset impedance value. For each set calibration impedance value, calculate and save the gain coefficient of the impedance converter circuit once.

[0052] Specifically, please refer to Figure 10 , the S200 calibration step includes: S210, switch to the adjustable calibration impedance circuit path.

[0053] S220, set the lowest preset impedance value as the calibration impedance value according to the preset impedance value. In principle, the default lowest preset impedance value is the lowest adjustable calibration impedance value, so as to calculate the gain coefficient for each calibration impedance value of the adjustable calibration circuit respectively; if the operator is experienced and can accurately judge the range of the impedance to be measured of the target human tissue, a specific range of calibration impedance values can also be selected as the section of the preset impedance value, and the calculation of the gain coefficient can start from the lowest preset impedance value in this section.

[0054] S230, set the amplification factor of the corresponding signal conditioning circuit according to the calibration impedance value. Each calibration impedance value is preset with a corresponding amplification factor of the signal conditioning circuit.

[0055] S240, set the amplification factor of the corresponding I-V conversion circuit according to the calibration impedance value. Each calibration impedance value is preset with a corresponding amplification factor of the I-V conversion circuit.

[0056] S250, the impedance converter circuit sends out a sampling signal to calculate the gain coefficient of the impedance converter circuit.

[0057] S260, save the calibration impedance value and the measured gain coefficient in a corresponding manner.

[0058] S270, adjust the preset impedance value upward to the calibration impedance value according to the preset impedance value, return to S230, and repeat the above steps until the gain coefficients corresponding to all preset impedance values have been calculated and saved.

[0059] S300, enter the sampling step, switch to the impedance measurement circuit path, set the calibration impedance value as the current calibration impedance value, set the gain coefficient corresponding to the current calibration impedance value as the current gain coefficient, measure the impedance to be measured, calculate the pending impedance to be measured, and compare the pending impedance to be measured with the current calibration impedance value. If the deviation between the two exceeds the set value, it is determined that the pending impedance to be measured does not meet the requirements, and a new calibration impedance value is replaced as the current calibration impedance value until the deviation between the pending impedance to be measured and the current calibration impedance value meets the requirements. Record the pending impedance to be measured that meets the requirements as the sampling impedance, and record the corresponding current gain coefficient as the sampling gain coefficient.

[0060] Specifically, please refer to Figure 11 , the sampling step of S300 includes: S310, switch to the impedance measurement circuit path.

[0061] S320, set the lowest calibration impedance value as the current calibration impedance value. This lowest calibration impedance value is the lowest calibration impedance value in the preset impedance value range.

[0062] S330, retrieve the gain coefficient corresponding to the current calibration impedance value and set it as the current gain coefficient.

[0063] S340, set the current amplification factor of the corresponding signal conditioning circuit according to the current calibration impedance value. Each current calibration impedance value is preset to correspond to a signal conditioning circuit amplification factor.

[0064] S350, set the current amplification factor of the corresponding I-V conversion circuit according to the current calibration impedance value. Each current calibration impedance value is preset to correspond to a signal conditioning circuit amplification factor.

[0065] S360, the impedance converter circuit issues a sampling signal to measure the impedance to be measured, and calculates the to-be-determined impedance to be measured through the current gain coefficient.

[0066] S370, compare the to-be-determined impedance to be measured with the current calibration impedance value. If the deviation between the two exceeds the set value, it is determined that the to-be-determined impedance to be measured does not meet the requirements. Increase the calibration impedance value by one level as the current calibration impedance value, and return to S330 to repeat the above steps until the deviation between the to-be-determined impedance to be measured and the current calibration impedance value meets the requirements.

[0067] More specifically, in S370, the formula for determining that the deviation between the to-be-determined impedance to be measured and the current calibration impedance value meets the requirements is specifically: where, R 待 is the to-be-determined impedance to be measured, and R 当前 is the current calibration impedance value.

[0068] For example, if the 1k ohm gear of the calibration digital variable resistor D5 is used as the calibration impedance value, the to-be-determined impedance to be measured not exceeding 1.5k ohm can be considered to meet the requirements; once the to-be-determined impedance to be measured exceeds 1.5k ohm, such as 1.7k ohm, it is considered not to meet the requirements, the gain coefficient is inaccurate, and the gain coefficient corresponding to the calibration impedance value (2k ohm) one level higher needs to be used. When the to-be-determined impedance to be measured exceeds 20k ohm, the gain coefficient measured by the calibration fixed-value resistor R16 is used.

[0069] S380, record the to-be-determined impedance to be measured that meets the requirements as the sampled impedance, and record the corresponding current gain coefficient as the sampled gain coefficient.

[0070] S400, complete the sampling process, and continuously collect the human impedance with the parameters set in the sampling process. When the continuously collected human impedance significantly deviates from the sampled impedance, trigger a sampling alarm.

[0071] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not imply the order of execution. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0072] In another embodiment, a computer-readable storage medium of the present application stores a computer program thereon, and when the computer program is executed by a processor, the steps of the above-described human body impedance detection method with an adaptive detection range are implemented.

[0073] In another embodiment, a computer program product of the present application includes a computer program or instruction, and causes the computer program or instruction to be able to implement the steps of the above-described human body impedance detection method with an adaptive detection range.

[0074] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working process of the above-described human body impedance detection method with an adaptive detection range can refer to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0075] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line) or a wireless manner (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid-state drive), etc.

[0076] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by relevant hardware instructed by a computer program. This program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above method embodiments. The aforementioned storage medium includes various media that can store program codes, such as ROM, random access memory (RAM), magnetic disks, or optical discs.

[0077] Unless otherwise defined, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those of ordinary skill in the art to which this application belongs. The terms "first", "second", "third", and similar words used in the specification and claims of this application do not denote any order, quantity, or importance, but are only used to distinguish different components. Words such as "a" or "an" do not denote a quantity limitation, but mean that there is at least one. The words "comprising" or "including" and similar words mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, and do not exclude other elements or items. The terms "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A human body impedance detection device with an adaptive detection range, comprising an impedance converter circuit and an impedance measurement circuit, characterized in that, It also includes a signal conditioning circuit, a selection circuit, an adjustable calibration impedance circuit, and an I-V conversion circuit; The impedance converter circuit is connected to the signal conditioning circuit and sends a sampling signal to the signal conditioning circuit. The signal conditioning circuit amplifies the sampling signal. The sampling signal selectively enters the adjustable calibration impedance circuit or the impedance measurement circuit through the selection circuit, and then is input into the I-V conversion circuit to be converted into a voltage signal, amplified, and then sent back to the impedance converter circuit; When the sampling signal is input into the adjustable calibration impedance circuit, the impedance converter circuit calculates and records the gain coefficient of the impedance converter circuit based on the amplitude change amount between the sent sampling signal and the received signal. The impedance converter circuit calculates the gain coefficient at least once before each impedance measurement; when the sampling signal is input into the impedance measurement circuit, the impedance converter circuit calculates the amplitude and phase of the impedance to be measured based on the amplitude and phase change amounts between the sent sampling signal and the received signal, as well as the gain coefficient.

2. The human body impedance detection device with an adaptive detection range according to claim 1, characterized in that It also includes a main controller, which is respectively connected to the impedance converter circuit, the signal conditioning circuit, the selection circuit, the adjustable calibration impedance circuit, and the I-V conversion circuit. The main controller controls the impedance converter circuit to send a sampling signal, reads the impedance to be measured measured by the impedance converter circuit, controls the amplification factor of the signal conditioning circuit, controls the selection direction of the selection circuit, sets the calibration impedance setting of the adjustable calibration impedance circuit, and controls the amplification factor of the I-V conversion circuit.

3. The human body impedance detection device with an adaptive detection range according to claim 2, characterized in that, The main controller is connected to the adjustable calibration impedance circuit through an isolation bus driver, connected to the impedance converter circuit through an isolation bus driver, connected to the signal conditioning circuit through an optocoupler, connected to the selection circuit through an optocoupler, and connected to the I-V conversion circuit through an optocoupler.

4. A method for detecting human body impedance with an adaptive detection range, which applies the device for detecting human body impedance with an adaptive detection range according to claim 2, characterized in that, It includes the following steps: S100, turn on the human impedance detection device and initialize the main controller; S200, enter the calibration step, switch to the adjustable calibration impedance circuit path, sequentially set the calibration impedance value of the adjustable calibration impedance circuit according to the preset impedance value, calculate and save the gain coefficient of the impedance converter circuit respectively for each set calibration impedance value; S300, enter the sampling step, switch to the impedance measurement circuit path, set the calibration impedance value as the current calibration impedance value, set the gain coefficient corresponding to the current calibration impedance value as the current gain coefficient, measure the impedance to be measured, calculate the pending impedance to be measured, and compare the pending impedance to be measured with the current calibration impedance value. If the deviation between the two exceeds the set value, it is determined that the pending impedance to be measured does not meet the requirements, and a new calibration impedance value is replaced as the current calibration impedance value until the deviation between the pending impedance to be measured and the current calibration impedance value meets the requirements. Record the pending impedance to be measured that meets the requirements as the sampling impedance, and record the corresponding current gain coefficient as the sampling gain coefficient; S400, complete the sampling process and continuously collect the human impedance with the parameters set in the sampling process.

5. The method for detecting human body impedance with an adaptive detection range according to claim 4, characterized in that, In S100, the specific content of initializing the main controller includes: setting the frequency and voltage amplitude of the sampling signal of the impedance converter circuit to initial values, setting the calibrated impedance value to the initial value, setting the amplification factor of the signal conditioning circuit to the initial value, setting the amplification factor of the I-V conversion circuit to the initial value, and clearing the previously saved gain coefficient.

6. The method for detecting human body impedance with an adaptive detection range according to claim 4, wherein The calibration steps in S200 specifically include: S210, switching to the adjustable calibration impedance circuit path; S220, setting the lowest preset impedance value as the calibration impedance value according to the preset impedance value; S230, setting the corresponding amplification factor of the signal conditioning circuit according to the calibration impedance value; S240, setting the corresponding amplification factor of the I-V conversion circuit according to the calibration impedance value; S250, the impedance converter circuit sends out a sampling signal to calculate the gain coefficient of the impedance converter circuit; S260, saving the calibration impedance value and the measured gain coefficient in a corresponding manner; S270, adjusting the preset impedance value upward as the calibration impedance value according to the preset impedance value, returning to S230, and repeating the above steps until the gain coefficients corresponding to all preset impedance values have been calculated and saved.

7. The method for detecting human body impedance with an adaptive detection range according to claim 4, wherein The sampling steps in S300 specifically include: S310, switching to the impedance measurement circuit path; S320, setting the lowest calibrated impedance value as the current calibration impedance value; S330, retrieving the gain coefficient corresponding to the current calibration impedance value as the current gain coefficient; S340, setting the current amplification factor of the corresponding signal conditioning circuit according to the current calibration impedance value; S350, setting the current amplification factor of the corresponding I-V conversion circuit according to the current calibration impedance value; S360, the impedance converter circuit sends out a sampling signal to measure the impedance to be measured, and calculates the impedance to be measured to be determined through the current gain coefficient; S370, comparing the impedance to be measured to be determined with the current calibration impedance value. If the deviation between the two exceeds the set value, it is determined that the impedance to be measured to be determined does not meet the requirements. The calibrated impedance value of the next higher level is adjusted as the current calibration impedance value, and return to S330. Repeat the above steps until the deviation between the impedance to be measured to be determined and the current calibration impedance value meets the requirements; S380, recording the impedance to be measured to be determined that meets the requirements as the sampling impedance, and recording the corresponding current gain coefficient as the sampling gain coefficient.

8. The method for detecting human body impedance with an adaptive detection range according to claim 7, characterized in that, In S370, the formula for determining that the deviation between the impedance to be measured to be determined and the current calibration impedance value meets the requirements is specifically: Among them, R 待 is the impedance to be measured and determined, and R 当前 is the current calibration impedance value.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the human impedance detection method with an adaptive detection range described in any one of claims 4 to 8.

10. A computer program product, characterized in that, The computer program product includes a computer program or instruction, enabling the computer program or instruction to implement the steps of the human impedance detection method with an adaptive detection range described in any one of claims 4 to 8.

Images