CN219538309U - Blood sugar detection circuit and blood sugar detection system - Google Patents

Abstract

The application relates to a blood sugar detection circuit and a blood sugar detection system, wherein the blood sugar detection circuit comprises a driving module, a selection module, a signal amplification module, a control module and a plurality of light detection modules, each light detection module comprises a light emitting unit and a light receiving unit, the driving module is connected with the light emitting unit, the selection module is connected with the light receiving unit, the signal amplification module is connected with the selection module, and the control module is connected with the signal amplification module. The light receiving units in different light detection modules receive the detection light emitted by the light emitting units in different receiving modes to obtain initial detection signals, the signal amplifying unit receives the initial detection signals obtained by the detection light received in at least one receiving mode under the action of the selection module and amplifies the initial detection signals to generate target amplified signals, and the control module analyzes the target amplified signals to obtain blood glucose information of a detection part, so that the reliability and accuracy of noninvasive blood glucose detection are improved.

Description

Blood sugar detection circuit and blood sugar detection system

Technical Field

The application relates to the technical field of blood sugar detection, in particular to a blood sugar detection circuit and a blood sugar detection system.

Background

With the development of blood glucose detection technology, blood glucose can be detected through multiple ways, including an electrochemical method, a reverse iontophoresis method, a human body fluid method, an impedance method, an optical method and the like. Among them, the optical method is the most main method at present, it has advantages such as non-invasive, fast, easy to operate, green pollution-free.

The principle of blood sugar detection by an optical method is that an infrared light source irradiates a human body sampling part, an infrared sensor array is used for receiving optical signals and carrying out photoelectric conversion, an electric signal is subjected to processing means such as amplification sampling and the like and then is subjected to data calculation by a microprocessor or an upper computer, and finally, data storage and output are carried out, so that the aim of accurately detecting the blood sugar of the human body is finally achieved. However, the existing detection scheme mainly has two defects, namely high sensitivity and high dynamic range cannot be considered, so that full-range high-precision detection cannot be achieved; secondly, the surface layer of human skin, fat, protein, moisture, capillary vessel wall and other tissue structures have different structures, so that the measurement position is deviated or the accuracy can not meet the requirement after the human body state is changed. Therefore, the conventional noninvasive blood glucose detection device has a disadvantage in terms of key judgment indexes of accuracy.

Disclosure of Invention

Accordingly, it is necessary to provide a blood glucose detection circuit and a blood glucose detection system for solving the problem of low detection accuracy of the noninvasive detection apparatus.

In a first aspect, the present utility model provides a blood glucose detection circuit comprising:

a plurality of light detection modules, each of which includes a light emitting unit and a light receiving unit; the light emitting unit is used for emitting detection light to a detection part so as to detect the detection part; the light receiving unit is used for receiving the detection light to acquire an initial detection signal; the light receiving units in the light detection modules receive the detection light in an unused receiving mode;

the driving module is connected with the light emitting units of the light detection modules and is used for outputting driving signals to drive the light emitting units to emit driving light so as to detect detection parts;

a selection module connected to each of the light receiving units, for receiving an initial detection signal detected by each of the light receiving units and selectively outputting at least one of a plurality of the initial detection signals;

the signal amplification module is connected with the selection module and is used for amplifying the initial detection signal output by the selection module to generate a target amplified signal;

The control module is connected with the driving module and the signal amplification module and is used for controlling the driving module to output the driving signal, receiving the target amplified signal and analyzing the target amplified signal to acquire the blood sugar information of the detection part.

In one embodiment, the number of the light detection modules is two, and the two light detection modules share one light emitting unit;

the two light receiving units are respectively connected with the selection module, one light receiving unit is used for generating one initial detection signal according to the reflected light of the detection part, and the other light receiving unit is used for generating the other initial detection signal according to the transmitted light of the detection part.

In one embodiment, the selection module includes:

the two input ends of the switch circuit are respectively and correspondingly connected with the two light receiving units, the output end of the switch circuit is connected with the signal amplifying module, and the control end of the switch circuit is connected with the control module;

the control module is used for controlling the switch circuit to conduct a signal transmission path between at least one light receiving unit and the signal amplifying module.

In one embodiment, the blood glucose detection circuit further comprises a power module connected with the signal amplification module and used for outputting a power supply voltage signal to the signal amplification module; the signal amplification module includes:

the signal conversion unit is connected with the selection module and used for converting the initial detection signal from a current signal to a voltage signal so as to output a detection voltage signal;

the reverse amplification unit is connected with the signal conversion unit and is used for carrying out reverse linear amplification on the detection voltage signal so as to generate a forward amplification signal;

and the low-pass filtering unit is respectively connected with the reverse amplifying unit and the control module and is used for carrying out filtering processing on the target amplified signal so as to generate and output the target amplified signal.

In one embodiment, the signal conversion unit includes:

the inverting input end of the first operational amplifier is connected with the output end of the selection module; the non-inverting input end of the first operational amplifier is connected with a reference voltage; the output end of the first operational amplifier is connected with the reverse amplifying unit through a first resistor; the positive power supply end of the first operational amplifier is connected with the power supply module; the negative power supply end of the first operational amplifier is connected with the grounding end;

The two ends of the first capacitor are respectively connected with the output end of the first operational amplifier and the inverting input end of the first operational amplifier;

the second resistor is connected with the first capacitor in parallel;

and two ends of the third resistor are respectively connected with the non-inverting input end and the grounding end of the first operational amplifier.

In one embodiment, the reverse amplifying unit includes:

the inverting input end of the second operational amplifier is connected with the first resistor of the signal conversion unit; the output end of the second operational amplifier is sequentially connected with the low-pass filtering unit through a fourth resistor and a fifth resistor; the positive power supply end of the second operational amplifier is connected with the power supply module; the negative power supply end of the second operational amplifier is connected with the grounding end;

the second capacitor is respectively connected with the output end of the second operational amplifier and the reverse input end of the second operational amplifier;

a sixth resistor connected in parallel with the second capacitor;

a seventh resistor connected with the non-inverting input end of the second operational amplifier and the reference voltage respectively;

The eighth resistor is respectively connected with the non-inverting input end and the grounding end of the second operational amplifier;

and the third capacitor is connected with the eighth resistor in parallel.

In one embodiment, the low-pass filtering unit includes:

the inverting input end of the third operational amplifier is connected with the output end of the third operational amplifier; the output end of the third operational amplifier is connected with the control module through a ninth resistor; the positive power supply end of the third operational amplifier is connected with the power supply module; the negative power supply end of the third operational amplifier is connected with the grounding end;

the fourth capacitor is respectively connected with the inverting input end of the third operational amplifier and one end of the fifth resistor connected with the fourth resistor;

and the fifth capacitor is respectively connected with the non-inverting input end and the grounding end of the third operational amplifier.

In one embodiment, the signal conversion unit includes:

the inverting input end of the fourth operational amplifier is connected with the output end of the selection module; the output end of the fourth operational amplifier is sequentially connected with the reverse amplifying unit through a sixth capacitor and a tenth resistor; one end of the sixth capacitor, which is connected with the tenth resistor, is connected with one end of the eleventh resistor; the other end of the eleventh resistor is connected with the grounding end; the positive power supply end of the fourth operational amplifier is connected with the power supply module; the negative power supply end of the fourth operational amplifier is connected with the power supply module to receive a negative pressure signal in the power supply voltage signal;

A seventh capacitor connected with the output end of the fourth operational amplifier and the inverting input end of the fourth operational amplifier respectively;

a twelfth resistor connected in parallel with the seventh capacitor;

and the thirteenth resistor is respectively connected with the non-inverting input end and the grounding end of the fourth operational amplifier.

In one embodiment, the reverse amplifying unit includes:

the inverting input end of the fifth operational amplifier is connected with the tenth resistor of the signal conversion unit; the output end of the fifth operational amplifier is sequentially connected with the low-pass filter unit through a fourteenth resistor and a fifteenth resistor; the positive power supply end of the fifth operational amplifier is connected with the power supply module; the negative power supply end of the fifth operational amplifier is connected with the power supply module to receive a negative pressure signal in the power supply voltage signal;

an eighth capacitor connected to the output terminal of the fifth operational amplifier and the inverting input terminal of the fifth operational amplifier, respectively;

a sixteenth resistor connected in parallel with the eighth capacitor;

seventeenth resistor is connected to the non-inverting input terminal and the ground terminal of the fifth operational amplifier.

In one embodiment, the low-pass filtering unit includes:

the inverting input end of the sixth operational amplifier is connected with the output end of the sixth operational amplifier; the output end of the sixth operational amplifier is connected with the control module through an eighteenth resistor; the positive power supply end of the sixth operational amplifier is connected with the power supply module; the negative power supply end of the sixth operational amplifier is connected with the power supply module;

a ninth capacitor connected to the inverting input terminal of the sixth operational amplifier and one end of the fourteenth resistor connected to the fifteenth resistor, respectively;

and the tenth capacitor is respectively connected with the non-inverting input end and the grounding end of the sixth operational amplifier.

In one embodiment, the control module includes:

the ADC sampling chip is connected with the signal amplifying module and is used for carrying out analog-to-digital conversion on the target amplified signal in the form of an analog signal;

and the MCU chip is connected with the driving module and the ADC sampling chip and is used for controlling the driving module to output the driving signal and analyzing the target amplified signal in the form of a digital signal so as to acquire the blood sugar information of the detection part.

In one embodiment, the supply voltage signal comprises a first positive voltage signal, a negative voltage signal, and a second positive voltage signal; the power module includes:

the voltage source is used for outputting an original voltage signal;

the slow start circuit is connected with the voltage source and used for protecting the power supply module and buffering an original voltage signal so as to output a buffered voltage signal;

the boost circuit is connected with the slow start circuit, the driving module, the control module and the signal amplification module and is used for boosting the buffer voltage signal so as to output the first positive voltage signal to the driving module, the control module and the signal amplification module respectively;

the negative pressure circuit is connected with the boost circuit and the signal amplification module and is used for outputting the negative pressure signal to the signal amplification module;

the step-down circuit is connected with the slow start circuit, the driving module and the control module and is used for reducing the voltage of the buffer voltage signal so as to output the second positive voltage signal to the driving module and the control module;

and the voltage regulating circuit is connected with the voltage reducing circuit and the driving module and is used for outputting an adjustable voltage signal to the driving module.

In one embodiment, the blood glucose detection circuit further comprises:

and the man-machine interaction module is connected with the control module and is used for receiving detection indication signals output by external equipment and transmitting the detection indication signals to the control module so that the control module can respectively control each light detection module to detect the detection part.

In a second aspect, the present application also provides a blood glucose detection system comprising:

the blood glucose detection circuit according to any one of the above embodiments, wherein the blood glucose detection circuit is further configured to output blood glucose information of the detection location through a human-computer interaction module;

the data processing terminal is connected with the man-machine interaction module of the blood sugar detection circuit and used for controlling the blood sugar detection circuit to detect the detection part and obtaining a blood sugar detection result of a user according to blood sugar information of the detection part output by the blood sugar detection circuit.

The blood sugar detection circuit comprises a plurality of detection module light detection modules, wherein each light detection module comprises a light emitting unit and a light receiving unit, and the light emitting unit is used for emitting detection light to a detection part so as to detect the detection part; the light receiving unit is used for receiving the detection light, and the plurality of detection modules are used for respectively detecting the detection parts by the light detection modules of the detection modules so as to obtain a plurality of initial detection signals; the light receiving units in the light detection modules receive the detection light in an unused receiving mode; the driving module is connected with the light emitting units of the light detection modules to output driving signals to drive the light emitting units, so that the light emitting units are driven to emit detection light to detect the detection parts; the selection module is respectively connected with the light detection module receiving units of the detection modules and is used for respectively receiving the initial detection signals detected by the light receiving units and selectively outputting at least one of the initial detection signals; the signal amplification module is connected with the selection module and is used for amplifying the initial detection signal output by the selection module to generate a target amplified signal; the control module is connected with the driving module and the signal amplification module and is used for controlling the driving module to output the driving signal, receiving the target amplified signal and analyzing the target amplified signal to acquire the blood sugar information of the detection part. Because the blood sugar detection information acquired by the control module of the blood sugar detection circuit is acquired based on at least one mode of receiving detection light, the reliability and the accuracy of noninvasive blood sugar detection can be improved.

Drawings

FIG. 1 is a block diagram schematically illustrating a structure of a blood glucose detection circuit in one embodiment;

FIG. 2 is a block diagram schematically illustrating the structure of a light detection module in one embodiment;

FIG. 3 is a schematic diagram of a switch circuit configuration in one embodiment;

FIG. 4 is a schematic diagram of a signal amplifying module in one embodiment;

FIG. 4 (a) is a second schematic diagram of a signal amplifying module in one embodiment;

FIG. 4 (b) is a third schematic diagram of the signal amplifying module in one embodiment;

FIG. 5 is a block diagram illustrating a control module in one embodiment;

FIG. 6 is a block diagram of a power module in one embodiment;

fig. 7 is a block diagram schematically illustrating the structure of a blood glucose detection system according to an embodiment.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

The blood sugar detection circuit and the blood sugar detection system are both used for noninvasive blood sugar detection. The noninvasive blood glucose detection mainly detects the glucose content in the blood vessels of the dermis layer of the detected object in real time, the energy signal representing the blood glucose is transmitted by being superposed on the peak-peak value of the pulse, and the interference energy signals of other tissues, muscles, capillary walls, water, proteins, fat and the like are inevitably introduced in the process, so that the blood glucose signal acquired in the blood glucose detection only accounts for 1% of the output signal. Therefore, it is required that the dynamic range that can be detected by the blood glucose detection circuit is as large as possible, and the accuracy and sensitivity of the detection are as high as possible.

When the detected object is a human body, the heart rate range of the human body is basically 30-240 times/min, about 0.5 Hz-4 Hz, and the blood sugar signal superimposed on the heart rate range is the same frequency as the heart rate, so that the signal to be detected belongs to a low frequency band and is greatly interfered by the environment, and the bandwidth range of the detection circuit is required to be reasonably set at the moment so as to ensure the filtering efficiency; in addition, to amplify current signals of the nanoampere level to be detectable, a large Scale Factor (Scale Factor) is required, taking into account the signal-to-noise ratio (SNR, signal Noise Rate) problem while taking care to avoid self-oscillation. Because the human body belongs to a complex time-varying system, the pulse wave crest-peak detection can bring variability and instability. The blood sugar detection circuit needs to keep high stability and reliability in the blood sugar signal acquisition process of different acquisition time, different complexity acquisition environments and different batches so as to ensure blood sugar. To this end, the present application provides a blood glucose test circuit and a blood glucose test system capable of enhancing blood glucose test accuracy.

In one embodiment, as shown in one of the schematic block diagrams of the blood glucose detection circuit shown in fig. 1, the blood glucose detection circuit 100 provided by the present application includes a plurality of light detection modules 110 (only two of which are shown in fig. 1), a driving module 120, a selecting module 130, a signal amplifying module 140, and a control module 150; each of the light detection modules 110 includes a light emitting unit 1110 and a light receiving unit 1120, wherein the light emitting unit 1110 is configured to emit detection light to the detection site 160 to detect the detection site 160 and the light receiving unit 1120 is configured to receive the detection light to acquire an initial detection signal; the light receiving units 1120 in the plurality of light detecting modules 110 receive the detection light using an unused receiving manner; the driving module 120 is connected to the light emitting units 1110 in the light detecting modules 110, and is configured to output a driving signal to drive the light emitting units 1110 to detect the detection sites 160; the selection module 130 is connected to each light detection module 110, and is configured to receive the initial detection signals detected by each light detection module 110, and select and output at least one of the plurality of initial detection signals; the signal amplifying module 140 is connected to the selecting module 130, and is configured to amplify the initial detection signal output by the selecting module 130 to generate a target amplified signal; the control module 150 is connected to the driving module 120 and the signal amplifying module 140, and is configured to control the driving module 120 to output a driving signal, receive a target amplified signal, and analyze the target amplified signal to obtain blood glucose information of the detection site.

The detection portion 160 includes an arm, a finger, an abdomen, a wrist, an earlobe, a tiger's mouth between an index finger and a thumb, a fingertip, a lip, or the like.

The driving signal is used to control the on-off of the light emitting unit 1110, the light emitting unit 1110 outputs detection light with different light intensities and wavelengths, and the operation mode of the light emitting unit 1110, for example, a single-aspect operation mode is adopted in a certain temperature and circuit range.

The light emitting unit 1110 may be a laser diode or a vertical cavity surface emitting laser. The light emitting unit 1110 generally adopts one wavelength, and in order to improve the accuracy of blood glucose test, a plurality of wavelengths may be used, and the wavelength band of the plurality of wavelengths should include the near infrared region of the frequency doubling vibration and the frequency combining vibration of glucose molecules, and the wavelength is preferably in the range of 800nm to 2600nm. The wavelength band should contain a wavelength which does not conform to the absorption band of glucose molecules, so as to contrast, and further improve the blood glucose detection accuracy.

In this embodiment, the blood glucose test circuit 100 operates normally after power is turned on. The control module 150 controls the operation of the whole blood glucose detecting circuit 100, specifically, controls the driving module to output different driving signals according to different detecting positions 160 and detecting environments so that the light emitting unit 1110 of the light detecting module 110 outputs detecting light with different light intensities and wavelengths and adopts different working modes. The light detection module 110 in the above blood glucose detection circuit includes a plurality of light detection modules 110, and under the action of the selection module 130, the initial detection signal of the detection site obtained by at least one light detection module 110 can be analyzed to obtain the blood glucose information of the detection site. For example, when the initial detection signal acquired by one light detection module 110 can already analyze the blood glucose information of the detection site, the selection module 130 may select to output the initial detection signal acquired by the light detection module 110; when the difficulty of blood glucose detection on a certain detection part is high, the selection module 130 can be used for selecting to acquire initial detection signals output by the two light detection modules 110 simultaneously in a detection period, and the positions of the two light detection modules 110 are locked in the detection period, so that errors of the positions on detection results can be eliminated, and the reliability of blood glucose detection is ensured. Since the initial detection signal directly obtained from the detection part 160 is a very weak current signal, in order to obtain more clear and accurate blood glucose information, the initial detection signal is output to the signal amplifying module 140 to generate a target amplified signal which can be analyzed and processed by the control module 150, so that the control module further analyzes the target amplified signal, and finally obtains the blood glucose detection information of the detection part. Since the initial detection signals detected by the two light detection modules 110 are simultaneously acquired, the control module 150 can acquire more accurate blood glucose information by comparing and analyzing the initial detection signals detected by the two light detection modules 110. The light detection modules 110 are adopted to detect blood sugar at the detection part, so that noninvasive blood sugar detection can be realized, the light receiving units 1120 in the plurality of light detection modules 110 acquire detection light in different receiving modes, initial detection signals with different accuracies can be obtained, more accurate blood sugar information can be obtained based on the initial detection signals selected and output by the selection module 130, and the reliability and accuracy of noninvasive blood sugar detection are improved.

In one embodiment, reference is made to the schematic block diagram of the light detection module structure shown in FIG. 2; the number of the light detection modules is two—a first light detection module 111 and a second light detection module 112, the first light detection module 111 and the second light detection module 112 share one common light emission unit 1111, the first light detection module 111 includes a first light reception unit 1112, and the second light detection module 112 includes a second light reception unit 1113; the first light receiving unit 1112 and the second light receiving unit 1113 are respectively connected to the selection module 130, the second light receiving unit 1113 is configured to generate one initial detection signal according to the reflected light of the detection light from the detection portion 160, and the first light receiving unit 1112 is configured to generate another initial detection signal according to the transmitted light of the detection light from the detection portion 160.

The second light receiving unit 1113 may be a reflective detector, and may be a low dark current, large target surface, and high sensitivity photodetector, and may be configured to receive the light emitted from the detection portion 160 to the detection light; the first light receiving unit 1112 may be a transmission type detector, which uses a low dark current, large target surface, high sensitivity photodetector, and is capable of receiving the transmission light of the detection light from the detection portion 160; the detection part 160 may select different parts according to different principles of the light receiving unit receiving the detection light, for example, since the first light receiving unit 1112 is configured to generate an initial detection signal according to the transmission light of the detection light by the detection part 160, the detection part 160 may be a position of a tiger mouth between an earlobe, an index finger and a thumb, a fingertip, a lip, or the like; the second light receiving unit 1113 generates another initial detection signal according to the reflection of the detection light by the detection portion 160, where the detection portion 160 may be a portion of an arm, a second or third joint of a finger, an abdomen, or a wrist.

In this embodiment, the blood glucose detection circuit operates normally after the power is turned on. The provision of the light detection module 110 including the first light reception unit 1112 and the second light reception unit 1113, and one common light emission unit 1111 enables the detection light emitted by the common light emission unit 1111 to be received by at least one reception means to obtain an initial detection signal, since the first light reception unit 1112 is an initial detection signal generated by the transmission light of the detection light by the detection section 160 and the second light reception unit 1113 is an initial detection signal generated by the reflection light of the detection light by the detection section 160, since the accuracy of the initial detection signal generated by the reception light of the detection light and the transmission light differs at different detection sections 160, the provision of the two light reception units enables the selection of the initial detection signal from which the two light reception units receive the reflection light or the transmission light of the detection light to be output by the selection module 130 at different detection sections 160, ensuring the accuracy of the initial detection signal obtained from the different detection sections 160.

In one embodiment, the blood glucose detection circuit includes a plurality of light detection modules, one light detection module includes a light emitting unit and a plurality of light receiving units, the plurality of light receiving units receive detection light emitted by the light emitting units in the same light detection module through different receiving modes (for example, transmission or reflection), the plurality of light emitting units in the plurality of light detection modules emit detection light at different detection positions at the same time, so that the plurality of light receiving units in each light detection module can obtain initial detection signals of different detection positions at the same time, and the selection module can select and output the initial detection signals obtained by at least one light receiving unit in the different detection modules in a time sharing manner, so that blood glucose information of different detection positions can be obtained in one detection period, and the detection efficiency of blood glucose is improved.

In one embodiment, the selection module 130 includes a switch circuit 1310, and referring to the schematic diagram of the switch circuit shown in fig. 3, two input terminals A1 and A2 of the switch circuit 1310 are respectively connected to the first light receiving unit 1111 and the second light receiving unit 1112. An output end COM of the switch circuit 1310 is connected with the signal amplifying module 140, and a control end SEL of the switch circuit 1310 is connected with the control module 150; the control module 150 is further configured to control the switch circuit 1310 to conduct a signal transmission path between the at least one light receiving unit and the signal amplifying module 140.

The switch circuit 1310 is a high-speed and low-loss dual-channel bidirectional program-controlled analog switch (Single Pole Double Throw, SPDT), wherein the switch circuit 1310 includes an input terminal A1, an input terminal A2, a control terminal SEL, an output terminal COM, a positive power supply access terminal B, a negative power supply access terminal C, an eleventh capacitor C11, a twelfth capacitor C12, and a nineteenth resistor R19, the input terminal A1 is connected to the first light receiving unit 1111, the input terminal A2 is connected to the second light receiving unit 1112, the control terminal SEL is connected to the control module 150 in this embodiment, the output terminal COM is connected to the signal amplifying module 140, the positive power supply input terminal B is added with a positive voltage signal VCC, the eleventh capacitor C11 is connected to the positive power supply input terminal B and the ground terminal GND, the negative power supply input terminal C is connected to the ground terminal GND, the two ends of the twelfth capacitor C12 are connected to the output terminal COM and the ground terminal GND, the nineteenth resistor R19 is connected in parallel to the twelfth capacitor C12, the on-resistance of the switch circuit 1310 is set to 4.7Ω, the on-time period is set to 5ns, and the off-time period is set to 5ns. In a specific application, the control terminal SEL may also be connected to a logic input chip or a crystal oscillator.

In this embodiment, the blood glucose detection circuit operates normally after the power is turned on. According to actual needs, the blood sugar detection circuit can be controlled by the control module 150 to realize three blood sugar light detection modules-1) reflection type blood sugar detection modes: under the control of the control module 150, the switch circuit 1310 turns on the signal transmission paths of the input terminal A1 and the output terminal COM, that is, the signal transmission path between the first light receiving unit 1111 and the signal amplifying circuit 140 is turned on, and the switch circuit 1310 outputs a reflective initial detection signal to the signal amplifying circuit 140; 2) Transmission type blood sugar detection mode: the connection between the input terminal A2 and the output terminal COM is turned on under the control of the control module 150, that is, the signal transmission path between the second light receiving unit 1112 and the signal amplifying circuit 140 is turned on, and the switch circuit 1310 outputs a transmission type initial detection signal to the signal amplifying circuit 140; 3) Reflection + transmission type blood glucose detection mode: the switch circuit 1310 is controlled by the control module 150 to conduct the signal transmission lines between the input end A1 and the input end A2 and the output end COM of the switch circuit 1310 in a time-sharing manner, that is, the signal amplifying module 140 can receive the reflective initial detection signal and the transmissive initial detection signal in one detection period, so as to realize synchronous detection of the reflective blood glucose detection and the transmissive blood glucose detection. In practical application, the selection module may also be a multiplexer or other modules capable of implementing one-out-of-two and two-out-of-two functions. In a specific application process, different light receiving units can be adopted according to different detection positions so as to obtain more accurate initial detection signals. It should be noted that, in this embodiment, the switch circuit 1310 is configured as a dual-channel bidirectional program-controlled analog switch, and in practical application, the switch circuit 1310 may also be configured as a multiplexer, and the present application does not specifically limit the switch circuit 1310, and may be any electronic device or circuit capable of implementing the functions described in this embodiment. In this embodiment, the switching circuit 1310 is set to be a high-speed and low-loss dual-channel bidirectional program-controlled analog switch, so that the circuit loss can be reduced, and the utilization rate of electric energy can be improved.

In one embodiment, reference is made to one of the schematic structural diagrams of the signal amplification module shown in fig. 4; the blood sugar detection circuit further comprises a power supply module 170, wherein the power supply module 170 is connected with the signal amplification module 140 and is used for outputting a power supply voltage signal to the signal amplification module 140; the signal amplification module 140 includes a signal conversion unit 1410, an inverse amplification unit 1420, and a low pass filtering unit 1430; the signal conversion unit 1410 is connected to the selection module 130, and is configured to convert the initial detection signal from a current signal to a voltage signal to output a detection voltage signal; the inverse amplifying unit 1420 is connected to the signal converting unit 1410, and is configured to perform inverse linear amplification on the detection voltage signal to generate a forward amplified signal; the low pass filtering unit 1430 is connected to the inverse amplifying unit 1420 and the control module 150, respectively, for filtering the target amplified signal to generate and output the target amplified signal.

In this embodiment, the signal amplifying module 140 is composed of a signal converting unit 1410, an inverting amplifying unit 1420 and a low-pass filtering unit 1430, where the signal converting unit 1410 is connected to the selecting module 130 and is capable of receiving the initial detection signal output from the selecting module 130. Since the initial detection signal is a blood glucose signal from a human body, the initial detection signal is very tiny and has a very low signal frequency, the signal conversion unit 1410 converts the initial detection signal which is originally tiny and is a photocurrent signal into a voltage signal to output a detection voltage signal, and since the detection voltage signal output by the signal conversion unit 1410 of the initial detection signal at this time is inverted compared with the initial detection signal, the detection voltage signal at this time is inversely proportional amplified by the inverse amplification unit 1420 to obtain an inverse amplification signal, and the inverse amplification signal is subjected to filtering processing on a portion higher than the human body photoplethysmogram signal (Programmable Pulse Generator, PPG) in the inverse amplification signal by the low-pass filtering unit 1430 to obtain a target amplification signal which can be recognized and processed by the control module 150.

In one embodiment, reference is made to the second schematic diagram of the signal amplification module shown in fig. 4 (a); the signal conversion unit 1410 includes a first operational amplifier U1, a first capacitor C1, a second resistor R2, and a third resistor R3; the inverting input end of the first operational amplifier U1 is connected with the output end of the selection module; the non-inverting input end of the first operational amplifier U1 is connected with a reference voltage; the output end of the first operational amplifier U1 is connected with the reverse amplifying unit 1420 through a first resistor R1; the positive power supply end of the first operational amplifier U1 is connected with the power module 170; the negative power supply end of the first operational amplifier U1 is connected with the ground end GND; two ends of the first capacitor C1 are respectively connected with the output end of the first operational amplifier U1 and the inverting input end of the first operational amplifier U1; the second resistor R2 is connected with the first capacitor C1 in parallel; both ends of the third resistor R3 are connected to the non-inverting input terminal of the first operational amplifier U1 and the ground terminal GND, respectively. The inverting amplification unit 1420 includes a second operational amplifier U2, a second capacitor C2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a third capacitor C3; the inverting input terminal of the second operational amplifier U2 is connected to the first resistor R1 of the signal conversion unit 1410; the output end of the second operational amplifier U2 is sequentially connected with the low-pass filtering unit 1430 through a fourth resistor R4 and a fifth resistor R5; the positive power supply end of the second operational amplifier U2 is connected with the power module 170; the negative power supply end of the second operational amplifier U2 is connected with the ground end GND; the second capacitor C2 is respectively connected with the output end of the second operational amplifier U2 and the reverse input end of the second operational amplifier U2; the sixth resistor R6 is connected with the second capacitor C2 in parallel; the seventh resistor R7 is respectively connected with the non-inverting input end of the second operational amplifier U2 and the reference voltage; the eighth resistor R8 is respectively connected with the non-inverting input end of the second operational amplifier U2 and the ground end GND; the third capacitor C3 is connected in parallel with the eighth resistor R8. The low-pass filtering unit 1430 includes a third operational amplifier U3, and an inverting input terminal of the third operational amplifier U3 is connected to an output terminal of the third operational amplifier U3; the output end of the third operational amplifier U3 is connected with the control module 150 through a ninth resistor R9; the positive power supply end of the third operational amplifier U3 is connected with the power module 170; the negative power supply end of the third operational amplifier U3 is connected with the ground end GND; the fourth capacitor C4 is respectively connected with the inverting input end of the third operational amplifier U3 and one end of the fifth resistor R5 connected with the fourth resistor R4; the fifth capacitor C5 is connected to the non-inverting input terminal of the third operational amplifier U3 and the ground terminal GND, respectively.

In this embodiment, the initial detection signal is converted into a detection voltage signal (reverse voltage signal) with bias through a first operational amplifier U1 (charge amplifier), amplified and converted into a forward amplified signal through a second operational amplifier U2 (reverse amplifier), filtered to remove the interference signal through a third operational amplifier U3 (second order butterworth low pass filter), and output. The signal amplifying module 140 maintains the dc signal property of the initial detection signal, and maintains the weak initial detection signal as a positive voltage signal all the time by providing a fixed reference voltage dc bias at the non-inverting input terminals of the first operational amplifier U1 and the second operational amplifier. The low-pass filtering unit 1430 is connected with the control module 150, the control module 150 can directly sample the target amplified signal finally output by the signal amplifying module 140, and the control module 150 analyzes the parameters contained in the obtained blood glucose information more accurately because the target amplified signal retains the direct current signal attribute of the initial detection signal, and the blood glucose detection circuit has higher requirement on the analysis capability of the control module 150 and can be used in the medical field.

In one embodiment, reference is made to the third schematic diagram of the signal amplification module shown in fig. 4 (b); the signal conversion unit 1410 may include a fourth operational amplifier U4, a seventh capacitor C7, a twelfth resistor R12, and a thirteenth resistor R13, where an inverting input terminal of the fourth operational amplifier U4 is connected to an output terminal of the selection module; the output end of the fourth operational amplifier U4 is sequentially connected with the reverse amplifying unit 1420 through a sixth capacitor C6 and a tenth resistor R10; one end of the sixth capacitor C6 connected with the tenth resistor R10 is connected with one end of the eleventh resistor R11; the other end of the eleventh resistor R11 is connected with the ground end GND; the positive power supply end of the fourth operational amplifier U4 is connected with the power module 170; the negative power supply end of the fourth operational amplifier U4 is connected to the power module 170 to receive the negative voltage signal VEE in the power supply voltage signal; the seventh capacitor C7 is respectively connected with the output end of the fourth operational amplifier U4 and the inverting input end of the fourth operational amplifier U4; the twelfth resistor R12 is connected in parallel with the seventh capacitor C7; the thirteenth resistor R13 is connected to the non-inverting input terminal of the fourth operational amplifier U4 and the ground terminal GND, respectively. The inverting amplification unit 1420 may include a fifth operational amplifier U5, an eighth capacitor C8, a sixteenth resistor R16, and a seventeenth resistor R17, the inverting input terminal of the fifth operational amplifier U5 being connected to the tenth resistor R10 of the signal conversion unit 1410; the output end of the fifth operational amplifier U5 is sequentially connected with the low-pass filtering unit 1430 through a fourteenth resistor R14 and a fifteenth resistor R15; the positive power supply end of the fifth operational amplifier U5 is connected with the power module 170; the negative power supply end of the fifth operational amplifier U5 is connected to the power module 170 to receive the negative voltage signal VEE in the power supply voltage signal; two ends of the eighth capacitor C8 are respectively connected with the output end of the fifth operational amplifier U5 and the inverting input end of the fifth operational amplifier U5; the sixteenth resistor R16 is connected in parallel with the eighth capacitor C8; both ends of the seventeenth resistor R17 are connected to the non-inverting input terminal of the fifth operational amplifier U5 and the ground terminal GND, respectively. The low pass filtering unit 1430 may include a sixth operational amplifier U6, a ninth capacitor C9 and a tenth capacitor C10, an inverting input terminal of the sixth operational amplifier U6 being connected to an output terminal of the sixth operational amplifier U6; the output end of the sixth operational amplifier U6 is connected with the control module 150 through an eighteenth resistor R18; the positive power supply end of the sixth operational amplifier U6 is connected with the power module 170; the negative power supply end of the sixth operational amplifier U6 is connected with a negative voltage source; two ends of the ninth capacitor C9 are respectively connected with an inverting input end of the sixth operational amplifier U6 and one end of the fourteenth resistor R14 connected with the fifteenth resistor R15; both ends of the tenth capacitor C10 are connected to the non-inverting input terminal of the sixth operational amplifier U6 and the ground terminal GND, respectively.

In this embodiment, the initial detection signal is converted from a current signal to a reverse voltage signal through a fourth operational amplifier U4 (charge amplifier), then a direct current component is filtered through a first-order RC high-pass filter (1 st order RC High Pass Fitter), only an alternating current signal component containing blood glucose information is remained, at this time, the detection voltage signal is output, the detection voltage signal is amplified and converted into a forward amplified signal through a fifth operational amplifier U5 (reverse amplifier), and finally a target amplified signal is output after an interference signal is filtered through a sixth operational amplifier U6, namely a second-order butterworth low-pass filter (2 nd order Butterworth Low Pass Fitter). The signal amplification module adopts a first-order RC high-pass filter with cutoff frequency of 0.01Hz-0.3Hz to perform DC blocking treatment on the reverse voltage signal reversely amplified by the fifth operational amplifier U5. The ac component of the initial detection signal has a negative voltage portion after filtering the dc bias, so that the power supply to the fourth operational amplifier U4, the fifth operational amplifier U5 and the sixth operational amplifier U6 must be changed from single power supply to dual power supply, and the negative voltage signal VEE is increased. In addition, the output of the signal amplifying module 140 also does not include dc bias, and the target amplified signal cannot be directly sampled, so an eighteenth resistor R18 for boosting is added to perform sampling preprocessing before the low-pass filtering unit 1430 finally outputs the target amplified signal. Because the target amplified signal does not contain direct current bias at this time, that is, parameters contained in the blood glucose information acquired by the final control module 150 based on the target amplified signal are more simplified, the requirement of the blood glucose detection circuit on the analysis capability of the control module 150 at this time is lower, and the method can be used for devices such as a smart watch, which need to acquire the blood glucose detection result quickly.

In one embodiment, reference is made to the block diagram of the control module shown in FIG. 5; the control module 150 includes an ADC sampling chip 1510 and an MCU chip 1520; the ADC sampling chip 1510 is connected to the signal amplifying module 140, and is configured to perform analog-to-digital conversion on a target amplified signal in the form of an analog signal; the MCU chip 1520 is connected to the driving module 120 and the ADC sampling chip 1510, and is used for controlling the driving module 120 to output a driving signal, and analyzing a target amplified signal in the form of a digital signal to obtain blood glucose information of a detection site.

In this embodiment, the ADC sampling chip 1510 is connected to the signal amplifying module 140, and is capable of performing analog-to-digital conversion on the target amplified signal in the form of an analog signal, and the MCU chip 1520 is capable of analyzing the target amplified signal in the form of a digital signal to obtain blood glucose information of the detection site, and meanwhile, the MCU chip 1520 is capable of obtaining the relative variation curves of the light absorption degrees received under different wavelengths and light intensities, so that no initial state is needed, and no light absorption degree measured each time is needed, and the indirectly obtained blood glucose detection result can be obtained as long as the relative variation curves of the received light intensities under different wavelengths and light intensities are obtained.

In one embodiment, reference is made to the block schematic diagram of the power module shown in FIG. 6; the power module 170 is connected to all of the light detection modules (only one of the light detection modules 110 is shown in fig. 6), the driving module 120, the control module 150, and the signal amplifying module 140, respectively, for providing a supply voltage signal to all of the light detection modules 110, the driving module 120, the control module 150, and the signal amplifying module 140. The power supply voltage signal comprises a first positive voltage signal, a negative voltage signal and a second positive voltage signal; the power supply module 170 includes a voltage source 1710, a boost circuit 1720, a negative voltage circuit 1730, a buck circuit 1740, a voltage regulator circuit 1750, and a soft start circuit 1760; the voltage source 1710 is configured to output an original voltage signal; the slow start circuit 1760 is connected to the voltage source 1710, and is used for protecting the power module 170 and buffering the original voltage signal to output a buffered voltage signal; the boost circuit 1720 is connected to the slow start circuit 1760, the driving module 120, the control module 150, and the signal amplifying module 140, and is configured to boost the buffered voltage signal to output a first positive voltage signal to the driving module 120, the control module 150, and the signal amplifying module 140, respectively; the negative voltage circuit 1730 is connected to the boost circuit 1720 and the signal amplifying module 140, and is configured to output a negative voltage signal to the signal amplifying module 140; the step-down circuit 1740 is connected to the slow start circuit 1760, the driving module 120, and the control module 150, and is configured to step down the buffered voltage signal to output a second positive voltage signal to the voltage source 1710, the driving module 120, and the control module 150; the voltage regulator circuit 1750 is coupled to the step-down circuit 1740 and the driver module 120 for outputting an adjustable voltage signal to the driver module 120.

In this embodiment, the first positive voltage signal is a +5v voltage signal, the second positive voltage signal is a +3.3v voltage signal, the negative voltage signal is a-5V voltage signal, and the adjustable voltage signal is a 0.6V to +3.3v voltage signal. The power module 170 is capable of providing the first positive voltage signal of +5v, the second positive voltage signal of +3.3v, and the adjustable voltage signal of 0.6V to +3.3v to the driving module 120, providing the first positive voltage signal of +5v and the negative voltage signal of-5V to the fourth operational amplifier U4, the fifth operational amplifier U5, and the sixth operational amplifier U6 in the signal amplifying module 140, and simultaneously providing the first positive voltage signal of +5v to the first operational amplifier U1, the second operational amplifier U2, and the third operational amplifier U3, and providing the first positive voltage signal of +5v and the second positive voltage signal of +3.3v to the control module 150; the slow start circuit 1760 is connected with the voltage source 1710, and can slow down the power supply voltage jitter, sag and intense electromagnetic radiation caused by larger impact current generated by the charging of the capacitor when the power supply is electrified and instantaneously jumps, thereby protecting the normal work of the power supply module.

In one embodiment, the blood glucose detection circuit further comprises a man-machine interaction module, wherein the man-machine interaction module is connected with the control module and used for receiving detection indication signals output by external equipment and transmitting the detection indication signals to the control module, so that the control module drives each light detection module to detect a detection part respectively.

In this embodiment, specifically, the man-machine interaction module may include wired and wireless interaction modes. The wired interaction can be realized through a USB interface or an RS232 standard interface, the instruction of the data processing terminal is transmitted to the MCU chip, and the data processed by the MCU chip is transmitted to the external equipment so as to realize man-machine interaction. The wireless interaction mode can be realized through a Bluetooth module, a WiFi module or radio frequency identification (Radio Frequency Identification, RFID), and various detection signals, blood glucose information and detection indication signals between external equipment and a blood glucose detection circuit can be interacted through a wireless transmission mode.

In one embodiment, referring to the schematic block diagram of the blood glucose detection system shown in fig. 7, the blood glucose detection system 10 includes the blood glucose detection circuit 100 and the data processing terminal 200 of any of the above embodiments, where the blood glucose detection circuit 100 is further capable of outputting blood glucose information of a detection site through the human-computer interaction module 710; the data processing terminal 200 is connected to the man-machine interaction module of the blood glucose detection circuit 100, and is capable of controlling the blood glucose detection circuit 100 to detect a detection site and acquiring a blood glucose detection result of a user according to blood glucose information of the detection site output by the blood glucose detection circuit 100.

In this embodiment, the data processing terminal 200 can identify data processing and algorithm with higher performance requirements of the processor, the data processing terminal 200 can be a computer or a smart phone, and the like, and the blood glucose detection result can be obtained more accurately by depending on the high performance processor of the smart device, so that the expansion of artificial intelligence deep learning in future is more convenient; in addition, the application does not need an extra memory chip, and the preprocessed blood glucose signals are directly transmitted to the data processing terminal 200 in a wired or wireless mode, so that the real-time monitoring of the measured blood glucose information by related personnel is facilitated.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims (14)

1. A blood glucose testing circuit, the testing circuit comprising:

a plurality of light detection modules, each of which includes a light emitting unit and a light receiving unit; the light emitting unit is used for emitting detection light to a detection part so as to detect the detection part; the light receiving unit is used for receiving the detection light to acquire an initial detection signal; the light receiving units in the light detection modules receive the detection light in an unused receiving mode;

the driving module is connected with the light emitting unit and is used for outputting a driving signal to drive the light emitting unit to emit detection light so as to detect a detection part;

a selection module connected to each of the light receiving units, for receiving the initial detection signals detected by each of the light detecting modules and selectively outputting at least one of the plurality of initial detection signals;

the signal amplification module is connected with the selection module and is used for amplifying the initial detection signal output by the selection module to generate a target amplified signal;

the control module is connected with the driving module and the signal amplification module and is used for controlling the driving module to output the driving signal, receiving the target amplified signal and analyzing the target amplified signal to acquire the blood sugar information of the detection part.

2. The blood glucose test circuit of claim 1, wherein the circuit comprises a circuit for detecting blood glucose,

the number of the light detection modules is two, and the two light detection modules share one light emitting unit;

the two light receiving units are respectively connected with the selection module, one light receiving unit is used for generating one initial detection signal according to the reflected light of the detection part, and the other light receiving unit is used for generating the other initial detection signal according to the transmitted light of the detection part.

3. The blood glucose detection circuit of claim 2, wherein the selection module comprises:

the two input ends of the switch circuit are respectively and correspondingly connected with the two light receiving units, the output end of the switch circuit is connected with the signal amplifying module, and the control end of the switch circuit is connected with the control module;

the control module is used for controlling the switch circuit to conduct a signal transmission path between at least one light receiving unit and the signal amplifying module.

4. The blood glucose detection circuit of claim 1, further comprising a power module coupled to the signal amplification module for outputting a supply voltage signal to the signal amplification module; the signal amplification module includes:

The signal conversion unit is connected with the selection module and used for converting the initial detection signal from a current signal to a voltage signal so as to output a detection voltage signal;

the reverse amplification unit is connected with the signal conversion unit and is used for carrying out reverse linear amplification on the detection voltage signal so as to generate a forward amplification signal;

and the low-pass filtering unit is respectively connected with the reverse amplifying unit and the control module and is used for carrying out filtering processing on the target amplified signal so as to generate and output the target amplified signal.

5. The blood glucose detection circuit of claim 4, wherein the signal conversion unit comprises:

the inverting input end of the first operational amplifier is connected with the output end of the selection module; the non-inverting input end of the first operational amplifier is connected with a reference voltage; the output end of the first operational amplifier is connected with the reverse amplifying unit through a first resistor; the positive power supply end of the first operational amplifier is connected with the power supply module; the negative power supply end of the first operational amplifier is connected with the grounding end;

the two ends of the first capacitor are respectively connected with the output end of the first operational amplifier and the inverting input end of the first operational amplifier;

The second resistor is connected with the first capacitor in parallel;

and two ends of the third resistor are respectively connected with the non-inverting input end and the grounding end of the first operational amplifier.

6. The blood glucose detection circuit of claim 5, wherein the reverse amplification unit comprises:

the inverting input end of the second operational amplifier is connected with the first resistor of the signal conversion unit; the output end of the second operational amplifier is sequentially connected with the low-pass filtering unit through a fourth resistor and a fifth resistor; the positive power supply end of the second operational amplifier is connected with the power supply module; the negative power supply end of the second operational amplifier is connected with the grounding end;

the second capacitor is respectively connected with the output end of the second operational amplifier and the reverse input end of the second operational amplifier;

a sixth resistor connected in parallel with the second capacitor;

a seventh resistor connected with the non-inverting input end of the second operational amplifier and the reference voltage respectively;

the eighth resistor is respectively connected with the non-inverting input end and the grounding end of the second operational amplifier;

and the third capacitor is connected with the eighth resistor in parallel.

7. The blood glucose detection circuit of claim 6, wherein the low pass filtering unit comprises:

the inverting input end of the third operational amplifier is connected with the output end of the third operational amplifier; the output end of the third operational amplifier is connected with the control module through a ninth resistor; the positive power supply end of the third operational amplifier is connected with the power supply module; the negative power supply end of the third operational amplifier is connected with the grounding end;

the fourth capacitor is respectively connected with the inverting input end of the third operational amplifier and one end of the fifth resistor connected with the fourth resistor;

and the fifth capacitor is respectively connected with the non-inverting input end and the grounding end of the third operational amplifier.

8. The blood glucose detection circuit of claim 4, wherein the signal conversion unit comprises:

the inverting input end of the fourth operational amplifier is connected with the output end of the selection module; the output end of the fourth operational amplifier is sequentially connected with the reverse amplifying unit through a sixth capacitor and a tenth resistor; one end of the sixth capacitor, which is connected with the tenth resistor, is connected with one end of the eleventh resistor; the other end of the eleventh resistor is connected with the grounding end; the positive power supply end of the fourth operational amplifier is connected with the power supply module; the negative power supply end of the fourth operational amplifier is connected with the power supply module to receive a negative pressure signal in the power supply voltage signal;

A seventh capacitor connected with the output end of the fourth operational amplifier and the inverting input end of the fourth operational amplifier respectively;

a twelfth resistor connected in parallel with the seventh capacitor;

and the thirteenth resistor is respectively connected with the non-inverting input end and the grounding end of the fourth operational amplifier.

9. The blood glucose detection circuit of claim 8, wherein the reverse amplification unit comprises:

the inverting input end of the fifth operational amplifier is connected with the tenth resistor of the signal conversion unit; the output end of the fifth operational amplifier is sequentially connected with the low-pass filter unit through a fourteenth resistor and a fifteenth resistor; the positive power supply end of the fifth operational amplifier is connected with the power supply module; the negative power supply end of the fifth operational amplifier is connected with the power supply module to receive a negative pressure signal in the power supply voltage signal;

an eighth capacitor connected to the output terminal of the fifth operational amplifier and the inverting input terminal of the fifth operational amplifier, respectively;

a sixteenth resistor connected in parallel with the eighth capacitor;

seventeenth resistor is connected to the non-inverting input terminal and the ground terminal of the fifth operational amplifier.

10. The blood glucose detection circuit of claim 9, wherein the low pass filtering unit comprises:

the inverting input end of the sixth operational amplifier is connected with the output end of the sixth operational amplifier; the output end of the sixth operational amplifier is connected with the control module through an eighteenth resistor; the positive power supply end of the sixth operational amplifier is connected with the power supply module; the negative power supply end of the sixth operational amplifier is connected with the power supply module;

a ninth capacitor connected to the inverting input terminal of the sixth operational amplifier and one end of the fourteenth resistor connected to the fifteenth resistor, respectively;

and the tenth capacitor is respectively connected with the non-inverting input end and the grounding end of the sixth operational amplifier.

11. The blood glucose detection circuit of claim 1, wherein the control module comprises:

the ADC sampling chip is connected with the signal amplifying module and is used for carrying out analog-to-digital conversion on the target amplified signal in the form of an analog signal;

and the MCU chip is connected with the driving module and the ADC sampling chip and is used for controlling the driving module to output the driving signal and analyzing the target amplified signal in the form of a digital signal so as to acquire the blood sugar information of the detection part.

12. The blood glucose detection circuit of claim 4, wherein the supply voltage signal comprises a first positive voltage signal, a negative voltage signal, and a second positive voltage signal; the power module includes:

the voltage source is used for outputting an original voltage signal;

the slow start circuit is connected with the voltage source and used for protecting the power supply module and buffering an original voltage signal so as to output a buffered voltage signal;

the boost circuit is connected with the slow start circuit, the driving module, the control module and the signal amplification module and is used for boosting the buffer voltage signal so as to output the first positive voltage signal to the driving module, the control module and the signal amplification module respectively;

the negative pressure circuit is connected with the boost circuit and the signal amplification module and is used for outputting the negative pressure signal to the signal amplification module;

the step-down circuit is connected with the slow start circuit, the driving module and the control module and is used for reducing the voltage of the buffer voltage signal so as to output the second positive voltage signal to the driving module and the control module;

and the voltage regulating circuit is connected with the voltage reducing circuit and the driving module and is used for outputting an adjustable voltage signal to the driving module.

13. The blood glucose detection circuit of any one of claims 1 to 12, further comprising:

and the man-machine interaction module is connected with the control module and is used for receiving detection indication signals output by external equipment and transmitting the detection indication signals to the control module so that the control module can respectively control each light detection module to detect the detection part.

14. A blood glucose testing system, the blood glucose testing system comprising:

the blood glucose testing circuit of claim 13, further configured to output blood glucose information of the test site via a human-machine interaction module;

the data processing terminal is connected with the man-machine interaction module of the blood sugar detection circuit and used for controlling the blood sugar detection circuit to detect the detection part and obtaining a blood sugar detection result of a user according to blood sugar information of the detection part output by the blood sugar detection circuit.