Driving circuit of spectrograph and spectrum detection system

Abstract

The embodiment of the invention discloses a drive circuit of a spectrometer and a spectrum detection system, and the drive circuit comprises an oscillation circuit which receives a first control signal and generates a first signal according to the first control signal, and the first signal is a sine wave signal; the shaping circuit receives the second control signal and the first signal and generates a second signal according to the first signal, the frequency of the first signal is equal to that of the second signal, and the second signal is a square wave signal with a preset duty ratio; the amplitude modulation circuit receives the third control signal and the second signal and generates a third signal according to the second signal, and the amplitude of the third signal is different from that of the second signal; and the buffer circuit receives the third signal and generates a driving signal according to the third signal, and the driving current of the driving signal is determined based on the amplitude of the third signal. Based on the control signal, the signal generated by the oscillation circuit is processed by the shaping circuit and the amplitude modulation circuit, and the driving signal with the preset duty ratio and adjustable frequency and amplitude is output.

Description

Technical Field

[0001] This application relates to the field of spectrometer driving technology, and in particular to a spectrometer driving circuit and a spectral detection system. Background Technology

[0002] There are many non-invasive methods for blood glucose testing, among which optical methods are currently the most prevalent. Optical methods estimate blood glucose levels by detecting the specific response of light waves to glucose concentrations within the body. Among these, Raman spectroscopy, based on the Raman scattering effect, can quantitatively analyze glucose concentration. Its principle is that different molecules produce scattered light of different frequencies at specific laser light sources. By analyzing the Raman spectrum of the scattered light, the types of molecules in the blood are identified, thereby estimating the blood glucose concentration.

[0003] However, current blood glucose testing devices that use Raman spectroscopy have shortcomings in their spectrometer drive circuits, such as unstable drive signals, slow rise times, poor load capacity, narrow signal amplitude adjustment range, and insufficient signal frequency accuracy, making it difficult to meet the needs of accurate blood glucose testing. Summary of the Invention

[0004] This application provides a driving circuit and a spectral detection system for a spectrometer, aiming to solve the problems of difficulty in accurately adjusting signal frequency and amplitude and poor signal stability in the driving circuits of spectrometers used for blood glucose detection in the prior art.

[0005] According to a first aspect of this application, this application provides a driving circuit for a spectrometer. The driving circuit provides a driving signal to drive the spectrometer, and an external control circuit generates a first control signal, a second control signal, and a third control signal based on the optical signal output by the spectrometer. The driving circuit includes: an oscillation circuit that receives the first control signal and generates a first signal based on the first control signal, wherein the first signal is a sine wave signal; a shaping circuit that receives the second control signal and the first signal and generates a second signal based on the first signal, wherein the first signal and the second signal have the same frequency, and the second signal is a square wave signal with a preset duty cycle; an amplitude modulation circuit that receives the third control signal and the second signal and generates a third signal based on the second signal, wherein the amplitude of the third signal is different from the amplitude of the second signal; and a buffer circuit that receives the third signal and generates a driving signal based on the third signal, wherein the driving current of the driving signal is determined based on the amplitude of the third signal.

[0006] Further, the oscillation circuit includes: a first operational amplifier, the first input terminal of which is coupled to a reference ground, the second input terminal of which is coupled to the first terminal of a positive feedback branch, and the output terminal of which is coupled to the shaping circuit to provide the first signal; a positive feedback branch, the second terminal of which is coupled to the output terminal of the first operational amplifier, the positive feedback branch being used to generate a sine wave of a fixed frequency through self-excited oscillation and output it to the second input terminal of the first operational amplifier; and a negative feedback branch, the first terminal of which is coupled to the first input terminal of the first operational amplifier, the second terminal of which is coupled to the output terminal of the first operational amplifier, the negative feedback branch being used to maintain the frequency and amplitude of the first signal unchanged.

[0007] Further, the positive feedback branch includes: a first potentiometer coupled between a second input terminal of the first operational amplifier and a reference ground; a second capacitor connected in parallel with the first potentiometer; a second potentiometer, with a first terminal coupled to the second input terminal of the first operational amplifier and a second terminal coupled to the first capacitor; and a first capacitor coupled between the second potentiometer and the output terminal of the first operational amplifier; wherein the resistance values ​​of the first potentiometer and the second potentiometer are determined based on the first control signal, and the frequency of the first signal is related to the resistance values ​​of the first potentiometer and the second potentiometer.

[0008] Further, the negative feedback branch includes: a second resistor, the first end of which is coupled to the first input terminal of the first operational amplifier, and the second end of which is coupled to the output terminal of the first operational amplifier; a third resistor, the first end of which is coupled to the first input terminal of the first operational amplifier, and the second end of which is coupled to the positive terminal of a first diode; a first diode, the negative terminal of which is coupled to the output terminal of the first operational amplifier; and a second diode, the negative terminal of which is coupled to the positive terminal of the first diode, and the positive terminal of which is coupled to the output terminal of the first operational amplifier; when the amplitude of the first signal is greater than or equal to a preset threshold, the first diode or the second diode is turned on.

[0009] Further, the shaping circuit includes: a second operational amplifier, the first input terminal of which is coupled to a reference ground, the second input terminal of which is coupled to the output terminal of the oscillation circuit to receive the first signal, and the output terminal of which is coupled to the amplitude modulation circuit to output the second signal; and a third potentiometer, the first terminal of which is coupled to the second input terminal of the second operational amplifier, and the second terminal of which is coupled to the output terminal of the second operational amplifier; wherein the resistance value of the third potentiometer is determined based on the second control signal.

[0010] Furthermore, during a first preset time period when the shaping circuit receives the first signal, the resistance value of the third function potentiometer is a first preset value; during a second preset time period when the shaping circuit receives the first signal, the resistance value of the third function potentiometer is a second preset value.

[0011] Furthermore, the shaping circuit also includes a limiting circuit, which is coupled between the output of the second operational amplifier and a reference ground. When the amplitude of the second signal exceeds a preset amplitude range, the limiting circuit is turned on to clamp the amplitude of the second signal within the preset amplitude range.

[0012] Furthermore, the limiting circuit includes: a third diode, the positive terminal of which is coupled to the output terminal of the second operational amplifier, and the negative terminal of which is coupled to the negative terminal of a fourth diode; and a fourth diode, the positive terminal of which is coupled to a reference ground.

[0013] Furthermore, the amplitude modulation circuit includes: a fourth function potentiometer, the first terminal of which is coupled to the shaping circuit to receive the second signal, and the second terminal of which is coupled to the buffer circuit to output a third signal, wherein the resistance value of the fourth function potentiometer is determined based on the control signal, and the amplitude of the third signal is related to the resistance value of the fourth function potentiometer.

[0014] Furthermore, the buffer circuit includes: a third operational amplifier, the first input terminal of which is coupled to the amplitude modulation circuit to receive the third signal, and the second input terminal of which is coupled to the spectrometer to output the driving signal, wherein the amplitude and frequency of the driving signal are the same as those of the third signal.

[0015] According to a second aspect of this application, a spectral detection system is provided, comprising: a control circuit that provides a control signal; a driving circuit as shown in any of the first aspects above, the driving circuit receiving the control signal and generating a driving signal based on the control signal, and outputting it to a spectrometer; and a spectrometer that receives the driving signal and determines the light intensity and wavelength of an output light signal based on the driving signal; wherein the driving circuit has an input terminal coupled to the control circuit to receive the control signal, the driving circuit has an output terminal coupled to the spectrometer to provide the driving signal, the driving circuit generating the driving signal based on the control signal to control the light intensity and wavelength of the light signal output by the spectrometer, and wherein the control signal includes a first control signal, a second control signal, and a third control signal.

[0016] Furthermore, the control circuit includes: a photodetector that generates a detection signal based on the scattered light of the optical signal; a signal amplification circuit having an input terminal coupled to the photodetector, receiving the detection signal, and generating an amplified signal based on the detection signal; and a microcontroller circuit having an input terminal coupled to the signal amplification circuit, receiving the amplified signal, and generating the control signal based on the amplified signal.

[0017] Through one or more embodiments of the above-described embodiments in this application, at least the following technical effects can be achieved: The driving circuit provided in the embodiments of this application includes an oscillation circuit, a shaping circuit, an amplitude modulation circuit, and a buffer circuit. The oscillation circuit generates a first signal under the control of a first control signal; the shaping circuit generates a second signal based on the first signal under the control of a second control signal; the amplitude modulation circuit generates a third signal based on the second signal under the control of a third control signal; and the buffer circuit generates a driving signal based on the third signal. The first, second, and third control signals are determined based on the optical signal output by the spectrometer driven by the driving circuit. Through this driving circuit, the driving effect of the driving circuit on the spectrometer can be adjusted according to the feedback of the optical signal from the spectrometer, enhancing the driving accuracy and stability of the driving circuit. Attached Figure Description

[0018] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0019] Figure 1 A schematic diagram of the drive system of a spectrometer according to an embodiment of this application is provided;

[0020] Figure 2 A schematic diagram of the circuit structure of an oscillation circuit according to an embodiment of this application is provided;

[0021] Figure 3 A schematic diagram of the circuit structure of a shaping circuit according to an embodiment of this application is provided;

[0022] Figure 4 A schematic diagram of the circuit structure of an amplitude modulation circuit according to an embodiment of this application is provided;

[0023] Figure 5 A schematic diagram of the circuit structure of a buffer circuit according to an embodiment of this application is provided;

[0024] Figure 6 A schematic diagram of the control circuit in a drive system according to an embodiment of this application is provided. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0027] Figure 1 A schematic diagram of the structure of a spectral detection system according to an embodiment of this application is provided. Figure 1 As shown, the spectral detection system 100 includes a control circuit 10, a drive circuit 20, and a spectrometer 30.

[0028] The input terminal of the drive circuit 20 is coupled to the control circuit 10, and the output terminal is coupled to the spectrometer 30. The drive circuit 20 is used to generate a drive signal VDS according to the control signal provided by the control circuit 10, so as to control the light intensity and wavelength of the light signal output by the spectrometer 30. The control signal provided by the control circuit 10 includes a first control signal VCS1, a second control signal VCS2, and a third control signal VCS3.

[0029] exist Figure 1 In the embodiment shown, the driving circuit 20 includes an oscillation circuit 21, a shaping circuit 22, an amplitude modulation circuit 23, and a buffer circuit 24.

[0030] Oscillating circuit 21 receives a first control signal VCS1 and generates a first signal SIG1, which is a sinusoidal signal. Shaping circuit 22 receives a second control signal VCS2 and the first signal SIG1, and generates a second signal SIG2 based on the first signal SIG1. The first signal SIG1 and the second signal SIG2 have the same frequency, and the second signal SIG2 is a square wave signal with a preset duty cycle. Amplitude modulation circuit 23 receives a third control signal VCS3 and the second signal SIG2, and generates a third signal SIG3 based on the second signal SIG2. The amplitude of the third signal SIG3 is different from the amplitude of the second signal SIG2. A buffer circuit 24 receives the third signal SIG3 and generates a drive signal VDS based on the third signal SIG3, wherein the drive current of the drive signal is determined based on the amplitude of the third signal.

[0031] Figure 2 A schematic diagram of the circuit structure of an oscillation circuit according to an embodiment of this application is provided. The oscillation circuit 21 includes a first operational amplifier U1, a positive feedback branch 211, and a negative feedback branch 212.

[0032] The first operational amplifier U1 has its first input terminal coupled to the first terminal of the negative feedback branch 212, its second input terminal coupled to the first terminal of the positive feedback branch 211, and its output terminal coupled to the shaping circuit 22. The first operational amplifier U1 amplifies the signal input from the second input terminal to activate the oscillation circuit 21 and provide the first signal SIG1. In one embodiment, the power supply voltage range of the first operational amplifier U1 is 3V-36V, and its unity-gain bandwidth is greater than or equal to 500kHz. The second terminal of the positive feedback branch 211 is coupled to the output terminal of the first operational amplifier U1. The positive feedback branch 211 generates a sine wave of a fixed frequency through self-excited oscillation and outputs it to the second input terminal of the first operational amplifier U1. The first terminal of the negative feedback branch 212 is coupled to the first input terminal of the first operational amplifier U1, and its second terminal is coupled to the output terminal of the first operational amplifier U1. The negative feedback branch 212 maintains the frequency and amplitude of the first signal unchanged.

[0033] exist Figure 2 In the embodiment shown, the oscillation circuit 21 further includes a first resistor R1, and the first input terminal of the first operational amplifier U1 is connected in series with the first resistor R1 and coupled to the reference ground.

[0034] exist Figure 2 In the embodiment shown, the positive feedback branch 211 includes a first function potentiometer P441, a second function potentiometer P442, a first capacitor C1, and a second capacitor C2.

[0035] A first potentiometer P441 is coupled between the second input terminal of the first operational amplifier U1 and a reference ground. A second capacitor C2 is connected in parallel with the first potentiometer P441. A first terminal of the second potentiometer P442 is coupled to the second input terminal of the first operational amplifier U1, and a second terminal of the second potentiometer P442 is coupled to the first capacitor C1. The first capacitor C1 is coupled between the second potentiometer P442 and the second input terminal of the first operational amplifier U1. The resistance values ​​of the first potentiometer P441 and the second potentiometer P442 are determined based on a first control signal VCS1. For example, the first potentiometer P441 and the second potentiometer P442 can be multi-channel programmable digital potentiometers. A digital potentiometer is an electronic device whose resistance value can be controlled by a digital signal and set through a digital interface. The first control signal VCS1 is a digital signal. When the first potentiometer P441 and the second potentiometer P442 receive the first control signal VCS1, they determine their own resistance values ​​based on its digital value. The frequency of the first signal SIG1 is related to the resistance values ​​of the first function potentiometer P441 and the second function potentiometer P442. In one embodiment, the first function potentiometer P441 and the second function potentiometer P442 are a set of dual synchronous potentiometers, and their resistance values ​​are always kept consistent.

[0036] The second capacitor C2 and the first potentiometer P441 form a parallel resonant circuit. The first capacitor C1 and the second potentiometer P442 form a series resonant circuit. The series and parallel resonant circuits together form the positive feedback branch 211, which also serves as the frequency selection network for the oscillation circuit 21. The first potentiometer P441 and the second potentiometer P442 are dual potentiometers with the same resistance value, i.e., the resistance R of the first potentiometer P441 is... P441 Equal to the resistance R of the second function potentiometer P442 P442 The first capacitor C1 and the second capacitor C2 have the same capacitance value, with C1 equal to C2. Ideally, when the positive feedback branch 211 and the negative feedback branch 212 of the first operational amplifier U1 are in balance, that is, when the oscillation generated by the positive feedback obtains a stable output frequency under the limitation of the negative feedback, the oscillation circuit 21 will continue to work stably. The frequency calculation formula for the first signal SIG1 at this time is as follows:

[0037]

[0038] Where f0 is the frequency of the first signal SIG1. When R P441 =R P442 =R p And when C1=C2=C, the value of f0 is As can be seen from the above formula, changing the values ​​of Rp and C can change the frequency of the output first signal SIG1. The first capacitor C1 and the second capacitor C2 are pre-selected capacitors with constant capacitance values. The frequency of the first signal SIG1 can be changed by altering the resistance values ​​of P441 and P442. The frequency of the first signal SIG1 can be determined based on the spectrometer 30 coupled to the drive circuit 20. Different spectrometers 30 output optical signals with different wavelengths, requiring different frequency and amplitude drive signals VDS for driving depending on the wavelength. By adjusting the resistance values ​​of the first potentiometer P441 and the second potentiometer P442 to adjust the frequency of the first signal SIG1, drive signals VDS adapted to different wavelengths of the spectrometer 30 can be output, achieving better driving effects and ensuring the universality of the drive circuit 20. In one embodiment, the amplitude of the first signal SIG1 is 12V with an accuracy of 0.1V.

[0039] exist Figure 2 In the illustrated embodiment, the oscillation circuit 21 further includes a negative feedback branch 212. In the oscillation circuit 21, the positive feedback branch 211 is crucial for initiating and maintaining oscillation. However, if only the positive feedback branch exists, the oscillation amplitude of the first signal SIG1 output by the oscillation circuit 21 will increase indefinitely until the oscillation circuit 21 is overloaded or damaged. The function of the negative feedback branch 212 is to limit this unlimited increase by adjusting the gain of the first operational amplifier U1 to control the amplitude of the first signal SIG1 output by the oscillation circuit 21. The first terminal of the negative feedback branch 212 is coupled to the first input terminal of the first operational amplifier U1, and the second terminal of the negative feedback branch 212 is coupled to the output terminal of the first operational amplifier U1. The negative feedback branch 212 includes a second resistor R2, a third resistor R3, a first diode D1, and a second diode D2.

[0040] The first terminal of the second resistor R2 is coupled to the first input terminal of the first operational amplifier U1, and the second terminal of the second resistor R2 is coupled to the output terminal of the first operational amplifier U1. The first terminal of the third resistor R3 is coupled to the first input terminal of the first operational amplifier U1, and the second terminal of the third resistor R3 is coupled to the positive terminal of the first diode D1. The negative terminal of the first diode D1 is coupled to the output terminal of the first operational amplifier U1. The negative terminal of the second diode D2 is coupled to the positive terminal of the first diode D1, and the positive terminal of the second diode D2 is coupled to the output terminal of the first operational amplifier U1.

[0041] In one embodiment, when the amplitude and frequency of the first signal SIG1 output by the oscillation circuit 21 are stable, the amplification factor of the oscillation circuit 21 remains at a first preset value, and the amplitude of the first signal SIG1 remains at a second preset value. When the oscillation circuit 21 starts oscillating, the amplitude of the first signal SIG1 is less than the second preset value, the first diode D1 and the second diode D2 are both turned off, and the third resistor R3 is not connected to the circuit, that is, the negative feedback branch 212 is not connected to the circuit, thus there is no limitation on the signal amplification factor by the negative feedback branch 212, making the amplification factor greater than the first preset value. When the oscillation circuit 21 starts oscillating, its amplification factor needs to be greater than the first preset value so that the initial excitation signal can be amplified and gradually increased until the output signal tends to stabilize. Therefore, not connecting the negative feedback branch in the early stage, so that the amplification factor is greater than the first preset value, can solve the problem of the oscillation circuit starting when the first signal SIG1 is relatively small. When the amplitude of the first signal SIG1 is greater than or equal to the preset threshold, the first diode D1 or the second diode D2 is turned on, and the second resistor R2 and the third resistor R3 are connected in parallel. Specifically, the first signal SIG1 is a sinusoidal signal. According to the periodic change of the signal, the first diode D1 and the second diode D2 are turned on at different periods. However, whether the second resistor R2 is turned on or the third resistor R3 is turned on, the third resistor R3 is connected in parallel with the second resistor R2, and the amplification factor is less than the first preset value, thereby limiting the maximum amplitude of the first signal SIG1 oscillation and avoiding clipping distortion of the waveform of the first signal SIG1.

[0042] Figure 3 A schematic diagram of the circuit structure of a shaping circuit according to an embodiment of this application is provided. The shaping circuit 22 includes a second operational amplifier U2, a third function potentiometer P443, a fourth resistor R4, a fifth resistor R5, and a limiting circuit 221.

[0043] The first input terminal of the second operational amplifier U2 is connected in series with the fourth resistor R4 and coupled to reference ground. The second input terminal of the second operational amplifier U2 is connected in series with the fifth resistor R5 and coupled to the output terminal of the oscillation circuit 21, receiving the first signal SIG1. The output terminal of the second operational amplifier U2 is connected in series with the sixth resistor R6 and coupled to the amplitude modulation circuit 23, outputting the second signal SIG2. The second operational amplifier U2 is used to compare the first signal SIG1 with the value of the threshold voltage, and generate the second signal SIG2 based on the comparison result.

[0044] The first terminal of the third function potentiometer P443 is coupled to the second input terminal of the second operational amplifier U2. The second terminal of the third function potentiometer P443 is coupled to the output terminal of the second operational amplifier U2. The resistance value of the third function potentiometer P443 is determined based on the second control signal VCS2. The third function potentiometer P443 is used to adjust the threshold voltage of the second operational amplifier U2.

[0045] The shaping circuit 22 is a Schmitt trigger, exemplarily having a positive threshold voltage and a negative threshold voltage. When the rising edge of the input signal is greater than the positive threshold voltage, the output signal flips to a logic high level and remains at a logic high level. When the falling edge of the input signal is less than the negative threshold voltage, the output signal flips to a logic low level and remains at a logic low level. This characteristic makes the Schmitt trigger suitable for use as the shaping circuit 22 to convert a sine wave signal into a square wave signal. The shaping circuit 22 converts the first signal SIG1 into a second signal SIG2 with a preset duty cycle. The square wave signal output by the shaping circuit has the same frequency as the sine wave signal output by the oscillation circuit; therefore, the preset duty cycle is a fixed 50% duty cycle.

[0046] In some embodiments, a liquid crystal micro-spectrometer is selected as the spectrometer, whose driving characteristics dictate that the driving signal must be a square wave signal with a 50% duty cycle, alternating positive and negative phases, and equal amplitude. The driving circuit in the embodiments of this application has multiple circuit designs to prevent distortion of the driving signal waveform, and is capable of outputting a driving signal with a standard 50% duty cycle.

[0047] The hysteresis window of a Schmitt trigger refers to the difference between the positive and negative threshold voltages. The hysteresis window needs to be matched to the signal; if the hysteresis window is too narrow, when the upper and lower limits of the signal are very close, the Schmitt trigger will repeatedly switch between the two thresholds. Figure 3 In the embodiment shown, when the upper and lower extreme values ​​of the first signal SIG1 are close, if the shaping circuit 22 has a narrow hysteresis window, the glitches of the first signal SIG1 will cause the second signal SIG2 output by the shaping circuit 22 to produce undesirable continuous jumps, i.e., generate a "ringing effect". The ringing effect will cause signal distortion, incorrect data reading, additional electromagnetic interference (EMI), and possible hardware damage.

[0048] The threshold voltage adjustment circuit, composed of the fifth resistor R5 and the third function potentiometer P443, can solve the "ringing effect" problem. Assuming the positive feedback coefficient of the second operational amplifier U2 is K, its calculation formula is as follows:

[0049]

[0050] In the formula, R5 is the resistance value of the fifth resistor R5, R P443 The resistance value of the third function potentiometer P443 is K. The closer the K value is to 1, the stronger the positive feedback and the wider the hysteresis window. The farther the K value is from 1, the weaker the positive feedback and the narrower the hysteresis window.

[0051] In some embodiments, during a first preset time period when the shaping circuit 22 receives the first signal SIG1, the resistance value R of the third function potentiometer P443 is...P443 The first preset value is used. During the second preset time period when the shaping circuit 22 receives the first signal SIG1, the resistance value R of the third function potentiometer P443 is... P443 This is the second preset value. The first preset time period is the oscillation stage of the first signal SIG1. During the oscillation stage, the upper and lower extreme values ​​of the first signal SIG1 are relatively close, which easily leads to ringing effects and requires a wider hysteresis window. The second preset time period is the stable stage of the first signal SIG1. During the stable stage, the upper and lower extreme values ​​of the first signal SIG1 differ significantly, which is less likely to lead to ringing effects and allows for the application of a narrower hysteresis window. Therefore, within the first preset time period, the upper and lower extreme values ​​of the first signal SIG1 are extremely close, and the resistance value R of the third function potentiometer P443 is adjusted. P443 The first preset value is used to widen the hysteresis window of the shaping circuit 22 and avoid ringing effects. During the second preset time period after the first signal SIG1 output by the oscillation circuit 21 reaches stability, the resistance value R of the third function potentiometer P443 is adjusted. P443 The second preset value is greater than the first preset value, so as to narrow the hysteresis window of the shaping circuit 22 and obtain a better signal shaping effect.

[0052] For example, the first preset time period and the second preset time period can be set based on the power-on time of the first oscillation circuit 21 and the time from the start of oscillation to stabilization of the first signal SIG1. The second control signal VCS2 is a pulse signal set based on the power-on time and the time from the start of oscillation to stabilization.

[0053] The limiting circuit 221 is coupled between the output of the second operational amplifier U2 and the reference ground, and includes a third diode D3 and a fourth diode D4. The positive terminal of the third diode D3 is coupled to the output of the second operational amplifier U2, the negative terminal of the third diode D3 is coupled to the negative terminal of the fourth diode D4, and the positive terminal of the fourth diode D4 is coupled to the reference ground.

[0054] In some embodiments, the third diode D3 and the fourth diode D4 are both Zener diodes, connected in reverse series between the output of the shaping circuit 22 and the reference ground. Their breakdown voltages are set based on the forward and negative threshold voltages of the shaping circuit 22. The Zener diodes' voltage regulation characteristics in the reverse breakdown region are used to limit the voltage amplitude of the signal in the circuit, thereby improving the response speed.

[0055] In this embodiment, the limiting circuit 221, composed of a third diode D3 in reverse series with a fourth diode D4, simultaneously functions as signal limiting and improved response speed. Since the shaping circuit 22 is essentially a Schmitt trigger, the output saturation voltage of the second operational amplifier U2 determines the upper and lower limits of the second signal SIG2. This output saturation voltage is related to the positive and negative supply voltages of the second operational amplifier U2. Since the absolute values ​​of the positive and negative supply voltages cannot be exactly equal, a circuit with limiting function is needed to obtain a stable, known voltage window, thereby precisely controlling the upper and lower limits of the output signal SIG2 of the shaping circuit 22. In some embodiments, the theoretical values ​​of the positive and negative supply voltages are ±15V, with a certain deviation between the actual and theoretical values. In the limiting circuit 221 composed of a third diode D3 in reverse series with a fourth diode D4, a Zener diode with a rated voltage of 12V is selected to limit the positive voltage to +12V and the negative voltage to -12V, resulting in a precise ±12V square wave output voltage.

[0056] Specifically, the third diode, D3, is a positive limiting Zener diode. During the positive half-cycle of the square wave, when the positive voltage exceeds +12V, D3 enters the reverse breakdown state. At this time, the current can vary within a wide range, but the positive voltage is limited and stabilized at +12V. The fourth diode, D4, is a negative limiting Zener diode. During the negative half-cycle of the square wave, when the negative voltage exceeds -12V, D4 enters the reverse breakdown state. At this time, the current can vary within a wide range, but the negative voltage is limited and stabilized at -12V.

[0057] When the voltage of the first signal SIG1 input to the shaping circuit 22 exceeds the positive threshold voltage of the shaping circuit 22, the third function potentiometer P443, through the stable voltage provided by the third diode D3 and the fourth diode D4, keeps the second signal SIG2 at a high level through signal limiting. Conversely, when the first signal SIG1 drops below the negative threshold voltage of the shaping circuit 22, the voltage provided by the third diode D3 and the fourth diode D4 is insufficient to maintain the high level of the second signal SIG1, causing the second signal SIG1 to drop rapidly. This effectively improves the comparator's response speed and stability.

[0058] Figure 4 A schematic diagram of the circuit structure of an amplitude modulation circuit according to an embodiment of this application is provided, as follows: Figure 4 As shown, the amplitude modulation circuit 23 includes a fourth function potentiometer P444.

[0059] The first terminal of the fourth potentiometer P444 is coupled to the shaping circuit 22 to receive the second signal SIG2. The second terminal of the fourth potentiometer P444 is coupled to the buffer circuit 24 to output the third signal SIG3. The resistance value of the fourth potentiometer P444 is determined based on the control signal, and the amplitude of the third signal SIG3 is related to the resistance value of the fourth potentiometer P444.

[0060] Figure 5 A schematic diagram of the circuit structure of a buffer circuit according to an embodiment of this application is provided. The buffer circuit 24 includes a third operational amplifier U3 and a seventh resistor R7.

[0061] The first input terminal of the third operational amplifier U3 is coupled to the amplitude modulation circuit 23, receiving the third signal SIG3. The second input terminal of the third operational amplifier U3 is coupled to the spectrometer 30, outputting the drive signal VDS. The third operational amplifier U3 is used to isolate the third signal SIG3 and the drive signal VDS, stabilizing the output of the drive signal VDS. The amplitude and frequency of the drive signal VDS are the same as those of the third signal SIG3. The seventh resistor R7 is coupled between the output terminal of the third operational amplifier U3 and the reference ground, in parallel with the subsequent load. In practical applications, the resistance value of the seventh resistor R7 can be adjusted according to the size of the subsequent load. Based on the principle of parallel resistors, by reasonably configuring the resistance value of the seventh resistor R7, the output current of the drive signal VDS can be controlled within a very small fluctuation range, avoiding excessive current disturbance.

[0062] Figure 6 A schematic diagram of the control circuit 10 in a drive system according to an embodiment of this application is provided. The control circuit 10 includes a photodetector 11, a signal amplification circuit 12, and a microcontroller circuit 13.

[0063] After the object under test receives the light signal, the photodetector 11 generates a detection signal based on the scattered light from the light signal. The scattered light signal is the light reflected or transmitted by the object after the light signal enters it. The input terminal of the signal amplification circuit 12 is coupled to the photodetector 11, receives the detection signal, and generates an amplified signal based on the detection signal. The input terminal of the microcontroller circuit 13 is coupled to the signal amplification circuit 12, receives the amplified signal, and generates a control signal based on the amplified signal.

[0064] In this embodiment, the driving circuit includes an oscillation circuit, a shaping circuit, an amplitude modulation circuit, and a buffer circuit. The oscillation circuit generates a first signal under the control of a first control signal, the shaping circuit generates a second signal based on the first signal under the control of a second control signal, the amplitude modulation circuit generates a third signal based on the second signal under the control of a third control signal, and the buffer circuit generates a driving signal based on the third signal. The first, second, and third control signals are determined based on the optical signal output by the spectrometer driven by the driving circuit. Through this driving circuit, a driving signal with a preset duty cycle, adjustable frequency, and adjustable amplitude is output. The driving signal output by the driving circuit is adjusted by feedback from the first to the third control signals, thereby improving the driving effect of the driving circuit on the spectrometer. While enhancing driving stability, it also meets the requirement of rapid and accurate signal adjustment based on the optical signal output of the spectrometer.

[0065] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional circuits and modules is merely an example. In practical applications, the above functions can be assigned to different functional circuits and modules as needed, that is, the internal structure of the device can be divided into different functional circuits or modules to complete all or part of the functions described above. The functional circuits and modules in the embodiments can be integrated into one processing circuit, or each circuit can exist physically separately, or two or more circuits can be integrated into one circuit. The integrated circuit can be implemented in hardware or software. Furthermore, the specific names of the functional circuits and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the circuits and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0066] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A driving circuit for a spectrometer, characterized in that, The driving circuit provides a driving signal to drive the spectrometer, and the external control circuit generates a first control signal, a second control signal, and a third control signal based on the light signal output by the spectrometer. The driving circuit includes: An oscillation circuit receives a first control signal and generates a first signal based on the first control signal, wherein the first signal is a sine wave signal. The shaping circuit receives a second control signal and a first signal, and generates a second signal based on the first signal. The first signal and the second signal have the same frequency, and the second signal is a square wave signal with a preset duty cycle. An amplitude modulation circuit receives a third control signal and a second signal, and generates a third signal based on the second signal, wherein the amplitude of the third signal is different from the amplitude of the second signal; and A buffer circuit receives a third signal and generates a drive signal based on the third signal, wherein the drive current of the drive signal is determined based on the amplitude of the third signal.

2. The driving circuit according to claim 1, characterized in that, The oscillation circuit includes a first operational amplifier, a positive feedback branch, and a negative feedback branch; The first input terminal of the first operational amplifier is coupled to the first terminal of the negative feedback branch, the second input terminal is coupled to the first terminal of the positive feedback branch, and the output terminal is coupled to the shaping circuit. The first operational amplifier is used to amplify the signal according to the signal input at the second input terminal, so as to start the oscillation circuit to provide the first signal. The second end of the positive feedback branch is coupled to the output end of the first operational amplifier. The positive feedback branch is used to generate a sine wave of a fixed frequency through self-excited oscillation and output it to the second input end of the first operational amplifier. The first end of the negative feedback branch is coupled to the first input terminal of the first operational amplifier, and the second end is coupled to the output terminal of the first operational amplifier. The negative feedback branch is used to maintain the frequency and amplitude of the first signal unchanged.

3. The driving circuit according to claim 2, characterized in that, The positive feedback branch includes: A first function potentiometer is coupled between the second input terminal of the first operational amplifier and a reference ground. The second capacitor is connected in parallel with the first function potentiometer; A second potentiometer, the first terminal of which is coupled to the second input terminal of the first operational amplifier, and the second terminal of which is coupled to the first capacitor; and The first capacitor is coupled between the second function potentiometer and the output terminal of the first operational amplifier; The resistance values ​​of the first and second potentiometers are determined based on the first control signal, and the frequency of the first signal is related to the resistance values ​​of the first and second potentiometers.

4. The driving circuit according to claim 2, characterized in that, The negative feedback branch includes: The second resistor has a first end coupled to the first input terminal of the first operational amplifier and a second end coupled to the output terminal of the first operational amplifier. The third resistor has a first end coupled to the first input terminal of the first operational amplifier and a second end coupled to the positive terminal of the first diode. A first diode, the negative terminal of which is coupled to the output of the first operational amplifier; and The second diode has its negative terminal coupled to the positive terminal of the first diode, and its positive terminal coupled to the output terminal of the first operational amplifier. When the amplitude of the first signal is greater than or equal to a preset threshold, the first diode or the second diode is turned on.

5. The driving circuit according to claim 1, characterized in that, The shaping circuit includes: The second operational amplifier has a first input terminal coupled to a reference ground and a second input terminal coupled to the output terminal of the oscillation circuit to receive the first signal. The output terminal of the second operational amplifier is coupled to the amplitude modulation circuit to output the second signal. The second operational amplifier is used to compare the first signal with the value of the threshold voltage and generate the second signal based on the comparison result. A third potentiometer, wherein the first terminal of the third potentiometer is coupled to the second input terminal of the second operational amplifier, and the second terminal of the third potentiometer is coupled to the output terminal of the second operational amplifier, and the third potentiometer is used to adjust the threshold voltage of the second operational amplifier; The resistance value of the third function potentiometer is determined based on the second control signal.

6. The driving circuit according to claim 5, characterized in that, During a first preset time period when the shaping circuit receives the first signal, the resistance value of the third function potentiometer is a first preset value; during a second preset time period when the shaping circuit receives the first signal, the resistance value of the third function potentiometer is a second preset value.

7. The driving circuit according to claim 5, characterized in that, The shaping circuit also includes a limiting circuit, which is coupled between the output of the second operational amplifier and a reference ground. When the amplitude of the second signal exceeds a preset amplitude range, the limiting circuit is turned on to clamp the amplitude of the second signal within the preset amplitude range.

8. The driving circuit according to claim 7, characterized in that, The limiting circuit includes: The third diode, the positive terminal of which is coupled to the output terminal of the second operational amplifier, and the negative terminal of which is coupled to the negative terminal of the fourth diode; A fourth diode, the positive terminal of which is coupled to a reference ground.

9. The driving circuit according to claim 1, characterized in that, The amplitude modulation circuit includes: A fourth potentiometer, wherein a first terminal of the fourth potentiometer is coupled to the shaping circuit to receive the second signal, and a second terminal of the fourth potentiometer is coupled to the buffer circuit to output a third signal, wherein the resistance value of the fourth potentiometer is determined based on the third control signal, and the amplitude of the third signal is related to the resistance value of the fourth potentiometer.

10. The driving circuit according to claim 1, characterized in that, The buffer circuit includes: A third operational amplifier has its first input terminal coupled to the amplitude modulation circuit to receive the third signal, and its second input terminal coupled to the spectrometer to output the driving signal. The third operational amplifier is used to isolate the third signal and the driving signal to achieve stable output of the driving signal. The amplitude and frequency of the driving signal are the same as those of the third signal.

11. A spectral detection system, characterized in that, The spectral detection system includes: Control circuit, which provides control signals; The driving circuit as described in any one of claims 1 to 10, wherein the driving circuit receives the control signal, generates a driving signal according to the control signal, and outputs it to the spectrometer; A spectrometer that receives the driving signal and determines the light intensity and wavelength of the output light signal based on the driving signal; The driving circuit has an input terminal coupled to a control circuit to receive a control signal, and an output terminal coupled to a spectrometer to provide a driving signal. The driving circuit generates a driving signal according to the control signal to control the light intensity and wavelength of the light signal output by the spectrometer. The control signal includes a first control signal, a second control signal, and a third control signal.

12. The spectral detection system according to claim 11, characterized in that, The control circuit includes: A photodetector that generates a detection signal based on the scattered light from the optical signal; A signal amplification circuit has an input terminal coupled to the photodetector, receives the detection signal, and generates an amplified signal based on the detection signal; A microcontroller circuit, the input terminal of which is coupled to the signal amplification circuit, receives the amplified signal and generates the control signal based on the amplified signal.

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