Multi-channel multi-gear amplification factor-adjustable human body impedance measuring circuit

Abstract

The utility model discloses a multi-channel multi-gear amplification factor-adjustable human body impedance measuring circuit, which is in communication connection with a multi-channel analog switch module, an impedance conversion module and a singlechip microcontroller, and the multi-channel analog switch module is used for switching a plurality of measurement input channels to realize acquisition of human body impedance measurement data. Meanwhile, different amplification factors are switched through the multi-channel analog switch module, the amplification effect of different factors is accurately achieved, the human body electrical impedance measuring circuit is designed by adopting a single high-frequency and high-precision impedance conversion chip in a module integration mode, the manufacturing cost of the human body electrical impedance measuring circuit is greatly reduced, and the human body electrical impedance measuring circuit is suitable for large-scale popularization and application. The impedance conversion module transmits the obtained electrical impedance measurement data to the single-chip microcomputer microcontroller for storage, and the electrical impedance measurement data is retrieved as required and displayed through the man-machine display module, so that great convenience is brought to the use of a user.

Description

Technical Field

[0001] The utility model relates to the technical field of human body electrical impedance measurement, in particular to a multi-channel multi-gear adjustable amplification human body electrical impedance measurement circuit. Background Art

[0002] Bioimpedance is the result of the viscous medium and narrow channels hindering the movement of electrolyte ions in the intracellular and extracellular fluids when they move in an electric field. Bioimpedance analysis is an indirect method for evaluating the health risk status of human tissues and organs. By comparing with the normal resistance value of human tissues and organs, it can be determined whether the organs and tissues of the current user being tested have health risks.

[0003] However, the existing human body impedance measurement is mostly single-channel impedance measurement, and it cannot effectively realize multi-channel measurement in non-invasive diagnostic fields such as impedance tomography and blood flow mapping. The existing multi-channel impedance measuring instrument needs to use multiple high-frequency and high-precision impedance conversion chips, and in terms of multi-channel measurement, it only copies multiple sets of the same single-channel impedance measurement circuit, which causes the problem of complex circuits, limited measurement accuracy and high production cost, which is not convenient for widespread promotion and use. Therefore, it is urgent to design a multi-channel multi-speed adjustable magnification human body impedance measurement circuit, which is a problem that needs to be solved at present. Summary of the invention

[0004] The utility model provides a multi-channel multi-gear adjustable magnification human body electrical impedance measurement circuit to overcome the above technical problems.

[0005] In order to achieve the above purpose, the technical solution of the utility model is:

[0006] A multi-channel, multi-speed, adjustable magnification human body impedance measurement circuit, comprising an impedance conversion module, a single-chip microcontroller, a communication module, a power supply module, a multi-channel analog switch module and a human-machine display module;

[0007] The power supply module is connected with the impedance conversion module, the single-chip microcontroller, the communication module, the human-machine display module and the multi-channel analog switch module to provide power;

[0008] The multi-channel analog switch module includes an analog switch module and a plurality of measurement input channels, wherein the analog switch module is used to shift each measurement input channel to receive a feedback voltage signal of human tissue to realize multi-channel measurement of human body electrical impedance;

[0009] The multi-channel analog switch module is connected to the impedance conversion module, and a signal amplifier is provided between the multi-channel analog switch module and the impedance conversion module, and the signal amplifier is used to amplify the feedback voltage signal;

[0010] The impedance conversion module is used to obtain electrical impedance measurement data according to the feedback voltage signal after the received signal amplification processing, and transmit the electrical impedance measurement data to the single-chip microcontroller for storage;

[0011] The human-machine display module is communicatively connected with the single-chip microcontroller via a communication module, and the human-machine display module is used to send a data call signal to the single-chip microcontroller, and the single-chip microcontroller is used to feed back the stored electrical impedance measurement data to the human-machine display module to realize data display according to the received data call signal.

[0012] Furthermore, the circuit of the impedance conversion module includes an impedance conversion chip U4; the signal amplifier input signal amplifier U6.1 and the output signal amplifier U6.2;

[0013] Pin 4 of the impedance conversion chip U4 is connected to one end of a thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected to one end of a fourteenth resistor R14 and pin 5 of the impedance conversion chip U4, the other end of the fourteenth resistor R14 is connected to pin 1 of the input signal amplifier U6.1 and pin 2 of the third wiring terminal P3, pin 4 of the input signal amplifier U6.1 is connected to the VCC3V3 wiring terminal, pin 8 of the input signal amplifier U6.1 is grounded, and pin 2 of the input signal amplifier U6.1 is connected to pin 1 of the third wiring terminal P3 and pin 2 of the second wiring terminal P2, pin 3 of the input signal amplifier U6.1 is connected to one end of a fifth resistor R5 and one end of a sixth resistor R6, and the other end of the fifth resistor R5 is connected to the VCC3V3 wiring terminal, and the other end of the sixth resistor R6 is grounded;

[0014] Pin 6 of the impedance conversion chip U4 is connected to one end of the first capacitor C16, the other end of the first capacitor C16 is connected to one end of the seventh resistor R7, one end of the eighth resistor R8 and pin 5 of the output signal amplifier U6.2, and the other end of the seventh resistor R7 is connected to the VCC3V3 terminal, the other end of the eighth resistor R8 is grounded, pin 6 of the output signal amplifier U6.2 is connected to pin 7 of the output signal amplifier U6.2 and pin 1 of the second terminal P2, pin 8 of the impedance conversion chip U4 is connected to the second crystal oscillator Y2, pin 9 of the impedance conversion chip U4 is connected to one end of the third capacitor C13 and one end of the second inductor L2, and the other end of the third capacitor C13 is grounded, the other end of the second inductor L2 is connected to one end of the fourth capacitor C14, one end of the second capacitor C12, pin 10 of the impedance conversion chip U4, and the impedance conversion Pin 11 of chip U4 is connected to the VCC3V3 terminal, and the other end of the fourth capacitor C14 and the other end of the second capacitor C12 are grounded, pin 12 of the impedance conversion chip U4 is connected to one end of the first inductor L1, the other end of the first inductor L1 is grounded to pin 13 of the impedance conversion chip U4 and pin 14 of the impedance conversion chip U4, pin 15 of the impedance conversion chip U4 is connected to one end of the twelfth resistor R12 and one end of the tenth resistor R10, pin 16 of the impedance conversion chip U4 is connected to one end of the eleventh resistor R11 and one end of the ninth resistor R9, and the other end of the ninth resistor R9 is connected to the other end of the tenth resistor R10 and the VCC3V3 terminal, the other end of the twelfth resistor R12 is connected to pin 43 of the control chip U5 of the single-chip microcontroller, and the other end of the eleventh resistor R11 is connected to pin 42 of the control chip U5.

[0015] Furthermore, the circuit of the single-chip microcontroller includes a control chip U5, a first crystal oscillator Y1 and a switch RS;

[0016] Pin 1 of the control chip U5 is connected to the VDD_3.3 terminal, pin 5 of the control chip U5 is connected to one end of the first crystal oscillator Y1 and one end of the fifth capacitor C17, pin 6 of the control chip U5 is connected to the other end of the first crystal oscillator Y1 and one end of the sixth capacitor C18, and the other end of the fifth capacitor C17 and the other end of the sixth capacitor C18 are grounded, pin 7 of the control chip U5 is connected to one end of the switch RS, one end of the third resistor R3 and one end of the seventh capacitor C19, pin 8 of the control chip U5 is grounded, and the other end of the seventh capacitor C19 is connected to the other end of the switch RS and grounded;

[0017] Pin 9 of the control chip U5 is connected to one end of the diode D3 and the VDD_3.3 terminal, the other end of the diode D3 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to pin 10 of the control chip U5, pin 20 of the control chip U5 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is grounded to pin 35 of the control chip U5 and pin 47 of the control chip U5, pin 36 of the control chip U5 is connected to pin 48 of the control chip U5 and the VDD_3.3 terminal, pin 44 of the control chip U5 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded.

[0018] Furthermore, the analog switch module includes a plurality of channel selection switch modules and a plurality of multiple amplification switch modules;

[0019] The circuit of the multiple amplification switch module includes a first switch chip U10, a fifteenth resistor R19, a sixteenth resistor R20, a seventeenth resistor R21 and an eighteenth resistor R22;

[0020] Pin 1 of the first switch chip U10 is connected to one end of the fifteenth resistor R19, pin 3 of the first switch chip U10 is connected to one end of the sixteenth resistor R20, pin 8 of the first switch chip U10 is connected to one end of the eighteenth resistor R22, pin 11 of the first switch chip U10 is connected to one end of the seventeenth resistor R21, and the other end of the fifteenth resistor R19, the other end of the sixteenth resistor R20, the other end of the seventeenth resistor R21 and the other end of the eighteenth resistor R22 are connected to the circuit of the impedance conversion module through the FB terminal, pin 14 of the first switch chip U10 is connected to one end of the eighth capacitor C6 and the VCC3V3 terminal, and the other end of the eighth capacitor C6 is grounded;

[0021] The circuit of the channel selection switch module includes a second switch chip U12, a first input port P6, a second input port P7, a third input port P8 and a fourth input port P9;

[0022] Pin 1 of the second switch chip U12 is connected to terminal 2 of the first input port P6, pin 3 of the second switch chip U12 is connected to terminal 2 of the second input port P7, pin 11 of the second switch chip U12 is connected to terminal 1 of the third input port P8, and pin 8 of the second switch chip U12 is connected to terminal 1 of the fourth input port P9;

[0023] And pin 5, pin 6, pin 12 and pin 13 of the second switch chip U12 are respectively connected to pin 19, pin 40, pin 18 and pin 39 of the control chip U5, and terminal 1 of the first input port P6, terminal 1 of the second input port P7, terminal 2 of the third input port P8 and terminal 2 of the fourth input port P9 are connected to the circuit of the impedance conversion module.

[0024] Furthermore, the impedance conversion chip U4 adopts AD5933YRSZ;

[0025] The input signal amplifier U6.1 and the output signal amplifier U6.2 both use AD8606ARZ-REEL7;

[0026] The control chip U5 adopts STM32F103C8T6;

[0027] The first switch chip U10 and the second switch chip U12 both adopt TS3A4751PWR.

[0028] Further, the communication module includes a wired communication module or a wireless communication module;

[0029] The wired communication module uses UART to USB serial port communication to connect the single-chip microcontroller with the human-machine display module;

[0030] The wireless communication module adopts Lora wireless communication circuit and is connected to the single-chip microcontroller through the SPI interface;

[0031] The human-machine display module includes but is not limited to any one of a host computer, a computer or a smart phone, and is used to establish two-way communication with the single-chip microcontroller to realize the control and display of electrical impedance measurement data.

[0032] Beneficial effects: The utility model provides a multi-channel, multi-speed, adjustable-magnification human body impedance measurement circuit, which communicates and connects a multi-channel analog switch module, an impedance conversion module, and a single-chip microcontroller. The multi-channel analog switch module is used to switch multiple measurement input channels to realize the collection of human body impedance measurement data, and different magnifications are switched through the multi-channel analog switch module at the same time, and different magnifications are accurately achieved. By adopting a single high-frequency and high-precision impedance conversion chip and designing the human body impedance measurement circuit in a module integration manner, the production cost of the human body impedance measurement circuit is greatly reduced. The impedance conversion module is used to transmit the acquired impedance measurement data to the single-chip microcontroller for storage, and the impedance measurement data is retrieved as needed and displayed through the human-machine display module, which brings great convenience to users. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 It is a schematic diagram of the structure of the human body electrical impedance measurement circuit with multi-channel, multi-speed and adjustable amplification factor of the utility model;

[0035] Figure 2 Schematic diagram of the connection of the human body impedance measurement circuit in this embodiment;

[0036] Figure 3 is a circuit schematic diagram of the impedance conversion module in this embodiment;

[0037] Figure 4 is a circuit schematic diagram of the signal amplifier in this embodiment;

[0038] Figure 5 1 is a circuit schematic diagram of a single-chip microcontroller in this embodiment;

[0039] Figure 6 is a circuit schematic diagram of the multiple amplification switch module in this embodiment;

[0040] Figure 7 is a circuit schematic diagram of the channel selection switch module in this embodiment;

[0041] Figure 8 is a circuit schematic diagram of the wired communication module in this embodiment;

[0042] Fig. 9 is a circuit schematic diagram of the wireless communication module in this embodiment;

[0043] Fig.10 Schematic diagram of the circuit of the power module in this embodiment. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0045] This embodiment provides a multi-channel multi-speed adjustable amplification human body electrical impedance measurement circuit, such as Figure 1 to Figure 2 As shown, it includes an impedance conversion module, a single-chip microcontroller, a communication module, a power module, a multi-channel analog switch module and a human-machine display module;

[0046] The power supply module is connected with the impedance conversion module, the single-chip microcontroller, the communication module, the human-machine display module and the multi-channel analog switch module to provide power;

[0047] The multi-channel analog switch module includes an analog switch module and a plurality of measurement input channels, each of the measurement input channels is connected to an electrode that can be attached to the surface of human skin, and the analog switch module is used to shift each measurement input channel to receive feedback voltage signals of human tissue to realize multi-channel measurement of human body electrical impedance;

[0048] The multi-channel analog switch module is connected to the impedance conversion module, and a signal amplifier is provided between the multi-channel analog switch module and the impedance conversion module, and the signal amplifier is used to amplify the feedback voltage signal; the impedance conversion module is used to obtain electrical impedance measurement data according to the received feedback voltage signal after signal amplification, and transmit the electrical impedance measurement data to the single-chip microcontroller for storage;

[0049] The human-machine display module is communicatively connected with the single-chip microcontroller via a communication module, and the human-machine display module is used to send a data call signal to the single-chip microcontroller, and the single-chip microcontroller is used to feed back the stored electrical impedance measurement data to the human-machine display module to realize data display according to the received data call signal.

[0050] The human body impedance tester based on the multi-channel multi-speed adjustable magnification human body impedance measurement circuit in this embodiment is used for applications such as digital impedance blood flow graph detection and electrical impedance tomography analysis, and can assist in the diagnosis of the following types of diseases:

[0051] Pulmonary system: lung cancer, pulmonary edema;

[0052] Cardiovascular system: postoperative effusion;

[0053] Circulatory system: intravascular volume, hyponatremia, hydration;

[0054] Renal system: hemodialysis, assessment of dry weight;

[0055] Nervous system: Alzheimer's disease, anorexia nervosa;

[0056] Muscular system: changes in body composition during training;

[0057] Immune system: HIV infection assessment, cancer patient assessment for dengue fever;

[0058] This embodiment realizes the collection of human body impedance measurement data by communicating with a multi-channel analog switch module, an impedance conversion module and a single-chip microcontroller, and uses the multi-channel analog switch module to switch multiple measurement input channels. At the same time, different magnification factors are switched by the multi-channel analog switch module to accurately achieve different magnification effects. By adopting a single high-frequency and high-precision impedance conversion chip and designing a human body impedance measurement circuit in a module integration manner, the production cost of the human body impedance measurement circuit is greatly reduced. The impedance conversion module transmits the acquired impedance measurement data to the single-chip microcontroller for storage, and the impedance measurement data is retrieved as needed for display through the human-machine display module, which brings great convenience to users. It is suitable for low-cost and miniaturized testing and is convenient for the popularization of health detection equipment.

[0059] In a specific embodiment, Figure 3 to Figure 4 As shown, the circuit of the impedance conversion module includes an impedance conversion chip U4, the signal amplifier input signal amplifier U6.1 and the output signal amplifier U6.2; and the impedance conversion chip U4 adopts AD5933YRSZ, and the input signal amplifier U6.1 and the output signal amplifier U6.2 both adopt AD8606ARZ-REEL7; the pin 4 of the impedance conversion chip U4 is connected to one end of the thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14 and the pin 5 of the impedance conversion chip U4, and the other end of the fourteenth resistor R14 is connected to the pin 6 of the impedance conversion chip U4. The end is connected to pin 1 of the input signal amplifier U6.1 and pin 2 of the third wiring terminal P3, pin 4 of the input signal amplifier U6.1 is connected to the VCC3V3 wiring terminal, pin 8 of the input signal amplifier U6.1 is grounded, and pin 2 of the input signal amplifier U6.1 is connected to pin 1 of the third wiring terminal P3 and pin 2 of the second wiring terminal P2, pin 3 of the input signal amplifier U6.1 is connected to one end of the fifth resistor R5 and one end of the sixth resistor R6, and the other end of the fifth resistor R5 is connected to the VCC3V3 wiring terminal, and the other end of the sixth resistor R6 is grounded;

[0060] Pin 6 of the impedance conversion chip U4 is connected to one end of the first capacitor C16, the other end of the first capacitor C16 is connected to one end of the seventh resistor R7, one end of the eighth resistor R8 and pin 5 of the output signal amplifier U6.2, and the other end of the seventh resistor R7 is connected to the VCC3V3 terminal, the other end of the eighth resistor R8 is grounded, pin 6 of the output signal amplifier U6.2 is connected to pin 7 of the output signal amplifier U6.2 and pin 1 of the second terminal P2, pin 8 of the impedance conversion chip U4 is connected to the second crystal oscillator Y2, pin 9 of the impedance conversion chip U4 is connected to one end of the third capacitor C13 and one end of the second inductor L2, and the other end of the third capacitor C13 is grounded, the other end of the second inductor L2 is connected to one end of the fourth capacitor C14, one end of the second capacitor C12, pin 10 of the impedance conversion chip U4, and the impedance conversion Pin 11 of chip U4 is connected to the VCC3V3 terminal, and the other end of the fourth capacitor C14 and the other end of the second capacitor C12 are grounded, pin 12 of the impedance conversion chip U4 is connected to one end of the first inductor L1, the other end of the first inductor L1 is grounded to pin 13 of the impedance conversion chip U4 and pin 14 of the impedance conversion chip U4, pin 15 of the impedance conversion chip U4 is connected to one end of the twelfth resistor R12 and one end of the tenth resistor R10, pin 16 of the impedance conversion chip U4 is connected to one end of the eleventh resistor R11 and one end of the ninth resistor R9, and the other end of the ninth resistor R9 is connected to the other end of the tenth resistor R10 and the VCC3V3 terminal, the other end of the twelfth resistor R12 is connected to pin 43 of the control chip U5 of the single-chip microcontroller, and the other end of the eleventh resistor R11 is connected to pin 42 of the control chip U5.

[0061] The impedance conversion module described in this embodiment is used as the core circuit of the human body impedance measurement circuit, and the impedance of the object to be measured is calculated through the impedance conversion chip of the impedance conversion module to realize high-frequency and high-precision impedance measurement and acquisition, wherein the calculation method of the impedance of the object to be measured is an existing known technical means, not the invention point of this application, and will not be repeated here. The impedance conversion module directly uses the AD5933 chip of AD Company, and outputs the acquisition result data through the IIC interface, and combined with the physical characteristics of the human body, the impedance measurement range is 1kΩ~10MΩ, and the measurement accuracy is 12Bit; the input signal amplifier U6.1 is used to amplify the input signal of the AD5933 impedance conversion chip, and at the same time, between the FB terminal and the IN terminal, the multi-channel analog switch module is controlled by a preset programming program to switch the size of the negative feedback resistor to adjust the amplification factor; the output signal amplifier U6.2 is used to amplify the output signal of the AD5933 impedance conversion chip to improve the load capacity of the output signal and increase the current output.

[0062] In a specific embodiment, Figure 5 As shown, the circuit of the single-chip microcontroller includes a control chip U5, a first crystal oscillator Y1 and a switching switch RS, and the control chip U5 adopts STM32F103C8T6; Pin 1 of the control chip U5 is connected to the VDD_3.3 terminal, Pin 5 of the control chip U5 is connected to one end of the first crystal oscillator Y1 and one end of the fifth capacitor C17, Pin 6 of the control chip U5 is connected to the other end of the first crystal oscillator Y1 and one end of the sixth capacitor C18, and the other end of the fifth capacitor C17 and the other end of the sixth capacitor C18 are grounded, Pin 7 of the control chip U5 is connected to one end of the switching switch RS, one end of the third resistor R3 and one end of the seventh capacitor C19, Pin 8 of the control chip U5 is grounded, and the other end of the seventh capacitor C19 is connected to the other end of the switching switch RS and grounded;

[0063] Pin 9 of the control chip U5 is connected to one end of the diode D3 and the VDD_3.3 terminal, the other end of the diode D3 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to pin 10 of the control chip U5, pin 20 of the control chip U5 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is grounded to pin 35 of the control chip U5 and pin 47 of the control chip U5, pin 36 of the control chip U5 is connected to pin 48 of the control chip U5 and the VDD_3.3 terminal, pin 44 of the control chip U5 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded.

[0064] In a specific embodiment, the analog switch module includes a plurality of channel selection switch modules and a plurality of multiple amplification switch modules; Figure 6As shown, the circuit of the multiple amplification switch module includes a first switch chip U10, a fifteenth resistor R19, a sixteenth resistor R20, a seventeenth resistor R21 and an eighteenth resistor R22; the first switch chip U10 adopts TS3A4751PWR, pin 1 of the first switch chip U10 is connected to one end of the fifteenth resistor R19, pin 3 of the first switch chip U10 is connected to one end of the sixteenth resistor R20, pin 8 of the first switch chip U10 is connected to one end of the eighteenth resistor R22, pin 11 of the first switch chip U10 is connected to one end of the seventeenth resistor R21, and the other end of the fifteenth resistor R19, the other end of the sixteenth resistor R20, the other end of the seventeenth resistor R21 and the other end of the eighteenth resistor R22 are connected to the circuit of the impedance conversion module through the FB terminal, pin 14 of the first switch chip U10 is connected to one end of the eighth capacitor C6 and the VCC3V3 terminal, and the other end of the eighth capacitor C6 is grounded;

[0065] The fifteenth resistor R19, the sixteenth resistor R20, the seventeenth resistor R21 and the eighteenth resistor R22 are variable resistors, and the resistance values ​​of the fifteenth resistor R19, the sixteenth resistor R20, the seventeenth resistor R21 and the eighteenth resistor R22 in the circuit of the multiple amplification switch module are adjusted to obtain multiple circuits of different multiple amplification switch modules; multiple circuits of multiple amplification switch modules with different resistance values ​​can also be connected in parallel at the same time, such as the nineteenth resistor R23, the twentieth resistor R24, the twenty-first resistor R21 and the twenty-second resistor R26, to increase the gear of the multiple amplification switch;

[0066] like Figure 7 As shown, the circuit of the channel selection switch module includes a second switch chip U12, a first input port P6, a second input port P7, a third input port P8 and a fourth input port P9, and the switch chip U12 adopts TS3A4751PWR; pin 1 of the second switch chip U12 is connected to the terminal 2 of the first input port P6, pin 3 of the second switch chip U12 is connected to the terminal 2 of the second input port P7, pin 11 of the second switch chip U12 is connected to the terminal 1 of the third input port P8, and pin 8 of the second switch chip U12 is connected to the terminal 1 of the fourth input port P9;

[0067] And pin 5, pin 6, pin 12 and pin 13 of the second switch chip U12 are respectively connected to pin 19, pin 40, pin 18 and pin 39 of the control chip U5, and terminal 1 of the first input port P6, terminal 1 of the second input port P7, terminal 2 of the third input port P8 and terminal 2 of the fourth input port P9 are connected to the circuit of the impedance conversion module.

[0068] In this embodiment, since the high-frequency and high-precision impedance conversion chip is expensive, in order to achieve multi-channel acquisition, this embodiment adopts the time division multiplexing principle and designs the circuit to be multi-channel switchable, that is, the input signal is switched through a multi-channel analog switch. Figure 6 to Figure 7 As shown, if a group of 4-channel analog switches is used, 4-channel signal acquisition can be achieved; if two groups of 4-channel analog switches are used, 8-channel signal acquisition can be achieved, and so on, more signal acquisition channels can be expanded. The amplification of each channel signal is achieved through an operational amplifier circuit. In order to accurately achieve different magnification effects, multi-channel analog switches are also used, with a total of 8 channels, to achieve the switching of the amplification feedback resistors, thereby achieving 8 different gears of amplification.

[0069] In a specific embodiment, Figures 8 to 9 As shown, the communication module includes a wired communication module or a wireless communication module; the wired communication module uses UART to USB serial communication to connect the single-chip microcontroller with the human-machine display module; the wireless communication module uses Lora wireless communication circuit and is connected to the single-chip microcontroller through the SPI interface; the human-machine display module includes but is not limited to any one of a host computer, a computer or a smart phone, which is used to establish two-way communication with the single-chip microcontroller to realize the control and display of electrical impedance measurement data. Fig.10 The figure shows the circuit schematic of the power module, which is a 5V to 3.3V power supply circuit.

[0070] This embodiment designs two transmission modes, wired and wireless, for data transmission. Data can be visualized on the host computer. When Bluetooth wireless transmission is used, a mobile phone can be used as the host computer system, which brings great convenience to users.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A multi-channel, multi-speed, adjustable amplification human body impedance measurement circuit, characterized in that: It includes an impedance conversion module, a single-chip microcontroller, a communication module, a power module, a multi-channel analog switch module and a human-machine display module; The power supply module is connected with the impedance conversion module, the single-chip microcontroller, the communication module, the human-machine display module and the multi-channel analog switch module to provide power; The multi-channel analog switch module includes an analog switch module and a plurality of measurement input channels, wherein the analog switch module is used to shift each measurement input channel to receive a feedback voltage signal of human tissue to realize multi-channel measurement of human body electrical impedance; The multi-channel analog switch module is connected to the impedance conversion module, and a signal amplifier is provided between the multi-channel analog switch module and the impedance conversion module, and the signal amplifier is used to amplify the feedback voltage signal; The impedance conversion module is used to obtain electrical impedance measurement data according to the feedback voltage signal after the received signal amplification processing, and transmit the electrical impedance measurement data to the single-chip microcontroller for storage; The human-machine display module is communicatively connected with the single-chip microcontroller via a communication module, and the human-machine display module is used to send a data call signal to the single-chip microcontroller, and the single-chip microcontroller is used to feed back the stored electrical impedance measurement data to the human-machine display module to realize data display according to the received data call signal.

2. The multi-channel multi-speed adjustable amplification human body electrical impedance measurement circuit according to claim 1, characterized in that: The circuit of the impedance conversion module includes an impedance conversion chip U4; the signal amplifier input signal amplifier U6.1 and the output signal amplifier U6.2; Pin 4 of the impedance conversion chip U4 is connected to one end of a thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected to one end of a fourteenth resistor R14 and pin 5 of the impedance conversion chip U4, the other end of the fourteenth resistor R14 is connected to pin 1 of the input signal amplifier U6.1 and pin 2 of the third wiring terminal P3, pin 4 of the input signal amplifier U6.1 is connected to the VCC3V3 wiring terminal, pin 8 of the input signal amplifier U6.1 is grounded, and pin 2 of the input signal amplifier U6.1 is connected to pin 1 of the third wiring terminal P3 and pin 2 of the second wiring terminal P2, pin 3 of the input signal amplifier U6.1 is connected to one end of a fifth resistor R5 and one end of a sixth resistor R6, and the other end of the fifth resistor R5 is connected to the VCC3V3 wiring terminal, and the other end of the sixth resistor R6 is grounded; Pin 6 of the impedance conversion chip U4 is connected to one end of the first capacitor C16, the other end of the first capacitor C16 is connected to one end of the seventh resistor R7, one end of the eighth resistor R8 and pin 5 of the output signal amplifier U6.2, and the other end of the seventh resistor R7 is connected to the VCC3V3 terminal, the other end of the eighth resistor R8 is grounded, pin 6 of the output signal amplifier U6.2 is connected to pin 7 of the output signal amplifier U6.2 and pin 1 of the second terminal P2, pin 8 of the impedance conversion chip U4 is connected to the second crystal oscillator Y2, pin 9 of the impedance conversion chip U4 is connected to one end of the third capacitor C13 and one end of the second inductor L2, and the other end of the third capacitor C13 is grounded, the other end of the second inductor L2 is connected to one end of the fourth capacitor C14, one end of the second capacitor C12, pin 10 of the impedance conversion chip U4, and the impedance conversion Pin 11 of chip U4 is connected to the VCC3V3 terminal, and the other end of the fourth capacitor C14 and the other end of the second capacitor C12 are grounded, pin 12 of the impedance conversion chip U4 is connected to one end of the first inductor L1, the other end of the first inductor L1 is grounded to pin 13 of the impedance conversion chip U4 and pin 14 of the impedance conversion chip U4, pin 15 of the impedance conversion chip U4 is connected to one end of the twelfth resistor R12 and one end of the tenth resistor R10, pin 16 of the impedance conversion chip U4 is connected to one end of the eleventh resistor R11 and one end of the ninth resistor R9, and the other end of the ninth resistor R9 is connected to the other end of the tenth resistor R10 and the VCC3V3 terminal, the other end of the twelfth resistor R12 is connected to pin 43 of the control chip U5 of the single-chip microcontroller, and the other end of the eleventh resistor R11 is connected to pin 42 of the control chip U5.

3. A multi-channel, multi-speed, adjustable magnification human body electrical impedance measurement circuit according to claim 2, characterized in that: The circuit of the single-chip microcontroller includes a control chip U5, a first crystal oscillator Y1 and a switch RS; Pin 1 of the control chip U5 is connected to the VDD_3.3 terminal, pin 5 of the control chip U5 is connected to one end of the first crystal oscillator Y1 and one end of the fifth capacitor C17, pin 6 of the control chip U5 is connected to the other end of the first crystal oscillator Y1 and one end of the sixth capacitor C18, and the other end of the fifth capacitor C17 and the other end of the sixth capacitor C18 are grounded, pin 7 of the control chip U5 is connected to one end of the switch RS, one end of the third resistor R3 and one end of the seventh capacitor C19, pin 8 of the control chip U5 is grounded, and the other end of the seventh capacitor C19 is connected to the other end of the switch RS and grounded; Pin 9 of the control chip U5 is connected to one end of the diode D3 and the VDD_3.3 terminal, the other end of the diode D3 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to pin 10 of the control chip U5, pin 20 of the control chip U5 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is grounded to pin 35 of the control chip U5 and pin 47 of the control chip U5, pin 36 of the control chip U5 is connected to pin 48 of the control chip U5 and the VDD_3.3 terminal, pin 44 of the control chip U5 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded.

4. The multi-channel multi-speed adjustable amplification human body electrical impedance measurement circuit according to claim 3, characterized in that: The analog switch module includes a plurality of channel selection switch modules and a plurality of multiple amplification switch modules; The circuit of the multiple amplification switch module includes a first switch chip U10, a fifteenth resistor R19, a sixteenth resistor R20, a seventeenth resistor R21 and an eighteenth resistor R22; Pin 1 of the first switch chip U10 is connected to one end of the fifteenth resistor R19, pin 3 of the first switch chip U10 is connected to one end of the sixteenth resistor R20, pin 8 of the first switch chip U10 is connected to one end of the eighteenth resistor R22, pin 11 of the first switch chip U10 is connected to one end of the seventeenth resistor R21, and the other end of the fifteenth resistor R19, the other end of the sixteenth resistor R20, the other end of the seventeenth resistor R21 and the other end of the eighteenth resistor R22 are connected to the circuit of the impedance conversion module through the FB terminal, pin 14 of the first switch chip U10 is connected to one end of the eighth capacitor C6 and the VCC3V3 terminal, and the other end of the eighth capacitor C6 is grounded; The circuit of the channel selection switch module includes a second switch chip U12, a first input port P6, a second input port P7, a third input port P8 and a fourth input port P9; Pin 1 of the second switch chip U12 is connected to terminal 2 of the first input port P6, pin 3 of the second switch chip U12 is connected to terminal 2 of the second input port P7, pin 11 of the second switch chip U12 is connected to terminal 1 of the third input port P8, and pin 8 of the second switch chip U12 is connected to terminal 1 of the fourth input port P9; And pin 5, pin 6, pin 12 and pin 13 of the second switch chip U12 are respectively connected to pin 19, pin 40, pin 18 and pin 39 of the control chip U5, and terminal 1 of the first input port P6, terminal 1 of the second input port P7, terminal 2 of the third input port P8 and terminal 2 of the fourth input port P9 are connected to the circuit of the impedance conversion module.

5. The multi-channel multi-speed adjustable amplification human body electrical impedance measurement circuit according to claim 4, characterized in that: The impedance conversion chip U4 adopts AD5933YRSZ; The input signal amplifier U6.1 and the output signal amplifier U6.2 both use AD8606ARZ-REEL7; The control chip U5 adopts STM32F103C8T6; The first switch chip U10 and the second switch chip U12 both adopt TS3A4751PWR.

6. The multi-channel multi-speed adjustable amplification human body electrical impedance measurement circuit according to claim 4, characterized in that: The communication module includes a wired communication module or a wireless communication module; The wired communication module uses UART to USB serial port communication to connect the single-chip microcontroller with the human-machine display module; The wireless communication module adopts Lora wireless communication circuit and is connected to the single-chip microcontroller through the SPI interface; The human-machine display module includes but is not limited to any one of a host computer, a computer or a smart phone, and is used to establish two-way communication with the single-chip microcontroller to realize the control and display of electrical impedance measurement data.

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