Optical sensor and light intensity control circuit of light source thereof

Abstract

The utility model provides an optical sensor and a light intensity control circuit of a light source thereof, the optical sensor is provided with a light source and a photoelectric detector, the circuit comprises a master control circuit used for outputting a control signal to control a light source control circuit; the light source control circuit is used for outputting a signal to enable a loop where the light source is located to form current and receiving a feedback signal of the light intensity feedback circuit so as to adjust the output signal of the light source to enable the light intensity of the light source to be kept unchanged. And the light intensity feedback circuit is used for processing the current signal converted by the photoelectric detector and feeding back the current signal to the light source control circuit. The light source of the optical sensor is controlled according to the feedback of the light intensity signal currently received by the photoelectric detector, so that the light intensity control of the light source of the optical sensor is more accurate, the light intensity change of the light source caused by various factors can be more effectively responded, and the stability and the consistency of the final light intensity output of the light source of the optical sensor are ensured.

Description

Technical Field

[0001] This utility model relates to the field of optical sensor control technology, and in particular to an optical sensor and its light intensity control circuit. Background Technology

[0002] An optical sensor is a device that converts light signals into electrical signals for processing. The light signal can be infrared, visible, or ultraviolet radiation, or it can be laser light, fiber optic light, or other forms of light waves. Optical sensors can detect and measure various physical quantities, such as light intensity, illuminance, temperature, pressure, displacement, velocity, acceleration, shape, and color, thereby enabling the monitoring and control of target objects or the environment.

[0003] Generally, a complete optical sensor system consists of three parts: a light source, a detector, and a signal processing circuit. Among them:

[0004] A light source is used to emit light of a specific wavelength and intensity to illuminate a target object or environment. Common light sources include light-emitting diodes (LEDs), laser diodes (LDs), and infrared emitting diodes (IRLEDs).

[0005] Detectors are used to receive reflected or transmitted light and convert it into corresponding electrical signals. Common detectors include various types of photosensitive elements (such as phototubes, photomultiplier tubes, photoresistors, etc.) and image sensors (such as CCDs, CMOS, etc.).

[0006] Signal processing circuits are used to amplify, filter, modulate, demodulate, encode, and decode the electrical signals output by the detector in order to obtain the required information or control signals.

[0007] Controlling the light intensity emitted by an optical sensor is a crucial technical challenge in spectral sampling and analysis applications, as it determines the quantitative analysis of the incident light source size. Related technologies control the current of the optical sensor's light source, using current control to replace light intensity control. However, in practical use, this method cannot compensate for changes in the light source's operating state caused by factors such as temperature and prolonged operation.

[0008] Therefore, it is necessary to provide a new approach to solve the aforementioned technical problems. Utility Model Content

[0009] To achieve the above-mentioned objectives and other advantages of this utility model, the first objective of this utility model is to provide a light intensity control circuit for an optical sensor light source, wherein the optical sensor is configured with a light source and a photodetector, comprising:

[0010] The main control circuit is used to output control signals to control the light source control circuit.

[0011] The light source control circuit is used to output a signal to generate a current in the circuit where the light source is located, and to receive a feedback signal from the light intensity feedback circuit to adjust its output signal so that the light intensity of the light source remains constant.

[0012] The light intensity feedback circuit is used to process the current signal converted by the photodetector and feed it back to the light source control circuit.

[0013] Furthermore, the main control circuit includes:

[0014] The main controller is used to output digital signals.

[0015] Furthermore, the light source control circuit includes:

[0016] A digital-to-analog converter is used to receive the digital signal output by the main controller and output an analog voltage with reference to an external reference voltage.

[0017] A driving circuit is used to output a driving signal to turn on the light source.

[0018] Furthermore, the driving circuit includes a comparator and an NMOS transistor. The inverting input terminal and the output terminal of the internal output operational amplifier of the digital-to-analog converter are connected to the non-inverting input terminal of the comparator via a resistor. The inverting input terminal of the comparator is connected to the light intensity feedback circuit. The output terminal of the comparator is connected to the gate of the NMOS transistor. The drain of the NMOS transistor is connected to the negative terminal of the light source. The positive terminal of the light source is connected to the power supply. The source of the NMOS transistor is grounded via a voltage divider resistor.

[0019] Furthermore, the light intensity feedback circuit includes:

[0020] A transimpedance amplifier circuit is used to convert the current signal converted by the photodetector into a voltage signal and feed it back to the comparator;

[0021] A non-inverting amplifier circuit is used to amplify the voltage signal output by the transimpedance amplifier circuit and feed it back to the main controller.

[0022] Furthermore, the light intensity feedback circuit also includes:

[0023] The first filtering circuit is used to filter the output of the transimpedance amplifier circuit;

[0024] The second filtering circuit is used to filter the output of the non-inverting amplifier circuit.

[0025] Furthermore, the transimpedance amplifier circuit includes a first operational amplifier, a first resistor, a first capacitor, a second resistor, and a third resistor. The first resistor and the first capacitor are connected in parallel between the inverting input terminal and the output terminal of the first operational amplifier. The negative terminal of the photodetector is connected to the inverting input terminal of the first operational amplifier, and the positive terminal of the photodetector is grounded. The second resistor and the third resistor are connected in series between the non-inverting input terminal of the first operational amplifier and ground. The output terminal of the first operational amplifier is connected to the inverting input terminal of the comparator via a resistor.

[0026] Furthermore, the non-inverting amplifier circuit includes a second operational amplifier, a fourth resistor, a fifth resistor, and a sixth resistor. The output terminal of the first operational amplifier is connected to the non-inverting input terminal of the second operational amplifier via the fourth resistor. The fifth resistor is connected between the inverting input terminal and the output terminal of the second operational amplifier. The sixth resistor is connected between the inverting input terminal and ground of the second operational amplifier. The output terminal of the second operational amplifier is connected to the ADC sampling unit of the main controller.

[0027] Furthermore, the first filter circuit includes a first filter resistor and a second filter capacitor. The first filter resistor is connected between the output terminal of the first operational amplifier and the fourth resistor. One end of the second filter capacitor is connected between the first filter resistor and the fourth resistor, and the other end of the second filter capacitor is grounded.

[0028] Furthermore, the second filtering circuit includes a second filtering resistor and a third filtering capacitor. The second filtering resistor is connected between the output terminal of the second operational amplifier and the ADC sampling unit of the main controller. One end of the third filtering capacitor is connected between the second filtering resistor and the ADC sampling unit of the main controller, and the other end of the third filtering capacitor is grounded.

[0029] The second objective of this invention is to provide an optical sensor that uses the aforementioned control circuit to control the light intensity of its light source.

[0030] Furthermore, the light source and photodetector within the optical sensor are encapsulated within the same photosensitive chip.

[0031] Compared with the prior art, the beneficial effects of this utility model are:

[0032] This invention provides an optical sensor and its light intensity control circuit for a light source. The optical sensor is equipped with a light source and a photodetector. The circuit includes: a main control circuit for outputting control signals to control a light source control circuit; a light source control circuit for outputting signals to generate current in the circuit containing the light source and receiving feedback signals from a light intensity feedback circuit to adjust its output signal to keep the light intensity of the light source constant; and a light intensity feedback circuit for processing the current signal converted by the photodetector and feeding it back to the light source control circuit. This invention controls the light source of the optical sensor based on the feedback of the light intensity signal currently received by the photodetector, making the light intensity control of the optical sensor light source more precise. It can more effectively respond to changes in light intensity caused by various factors, ensuring the stability and consistency of the final light intensity output of the optical sensor light source. By controlling the light intensity of the optical sensor light source in real time with precision, it can maintain the consistency of the optical sensor measurement results and meet the measurement needs of different scenarios.

[0033] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it according to the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. The specific implementation methods of this utility model are given in detail in the following embodiments and their accompanying drawings. Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0035] Figure 1 A schematic diagram of the light intensity control circuit for an optical sensor light source;

[0036] Figure 2 This is a schematic diagram of the light source control circuit;

[0037] Figure 3 This is a schematic diagram of a light intensity feedback circuit;

[0038] Figure 4 This is a schematic diagram of the light intensity control circuit for an optical sensor light source.

[0039] Figure 5 This is a circuit diagram for controlling the light intensity of an optical sensor light source.

[0040] Figure 6 This is a schematic diagram of an optical sensor;

[0041] Figure 7 This is a schematic diagram of a photosensitive chip. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0043] In the accompanying drawings, shapes and dimensions may be enlarged for clarity, and the same reference numerals will be used in all figures to indicate the same or similar parts.

[0044] In the following description, terms such as center, thickness, height, length, front, back, rear, left, right, top, bottom, upper, and lower are defined relative to the structure shown in the accompanying drawings. In particular, "height" corresponds to the dimension from top to bottom, "width" corresponds to the dimension from left to right, and "depth" corresponds to the dimension from front to back. These are relative concepts and may vary depending on their location and usage. Therefore, these or other orientations should not be interpreted as restrictive terms.

[0045] Terms involving attachment, connection, etc. (e.g., “connection” and “attachment”) refer to the relationship in which these structures are directly or indirectly fixed or attached to each other through an intermediate structure, as well as movable or rigid attachments or relationships, unless otherwise explicitly stated.

[0046] An optical sensor is a sensor that measures based on optical principles. Typically, a complete optical sensor system consists of three parts: a light source, a detector, and a signal processing circuit. Among them:

[0047] A light source is used to emit light of a specific wavelength and intensity to illuminate a target object or environment. Common light sources include light-emitting diodes (LEDs), laser diodes (LDs), and infrared emitting diodes (IRLEDs).

[0048] Detectors are used to receive reflected or transmitted light and convert it into corresponding electrical signals. Common detectors include various types of photosensitive elements (such as phototubes, photomultiplier tubes, photoresistors, etc.) and image sensors (such as CCDs, CMOS, etc.).

[0049] Signal processing circuits are used to amplify, filter, modulate, demodulate, encode, and decode the electrical signals output by the detector in order to obtain the required information or control signals.

[0050] Optical sensors have advantages such as non-contact and non-destructive measurement, minimal interference, high-speed transmission, and remote measurement and control capabilities, and are widely used in fields such as automation control, industrial inspection, security monitoring, and smart homes.

[0051] For example, in water quality testing, optical sensors are mainly used to measure turbidity, color, and the concentration of certain chemicals in water. These sensors utilize optical principles, calculating water quality parameters by measuring the scattering and absorption of light in water. TOC sensors are one such example; they can quickly and accurately measure the total organic carbon content in a water sample, thereby assessing the degree of organic pollution in the water.

[0052] Optical detection technology in water quality testing mainly utilizes the interaction between light and water samples to obtain water quality information. Its principles and application advantages are as follows:

[0053] Spectrophotometry: When light of a specific wavelength passes through a water sample, certain substances in the water absorb some of the light. The degree to which a substance absorbs light is related to its concentration and the wavelength of the light. According to the Lambert-Beer law, absorbance is related to the concentration of the substance. By measuring the transmittance or absorbance of light, the concentration of a specific substance in the water sample can be determined. For example, when detecting iron ions in water, a specific wavelength of light can be selected to illuminate the water sample. Iron ions will absorb light of that wavelength. After the instrument measures the absorbance, the concentration of iron ions can be calculated based on a standard curve.

[0054] Fluorescence method: Substances fluoresce when exposed to excitation light. Different substances have different fluorescence characteristics, including fluorescence intensity and wavelength. By measuring the fluorescence intensity, specific components in a water sample can be analyzed. For example, some organic pollutants in water fluoresce under specific conditions when exposed to excitation light; by detecting the fluorescence intensity, the presence and concentration of these organic pollutants can be determined.

[0055] Colorimetric method: This method utilizes the differences in absorption, scattering, or transmission of light at specific wavelengths by a substance solution, and detects the substance based on a colorimetric reaction. First, a specific colorimetric reagent is added to the water sample, causing it to react with the analyte to form a colored compound. Then, the sample is illuminated with a light source, and a detector measures the intensity of the light transmitted through the water sample. By comparing the color intensity with that of a standard solution, the concentration of the analyte in the water sample is determined.

[0056] Scattering method: When a beam of light passes through a water sample, the particles in the sample scatter the light. The intensity and angle of the scattered light are related to factors such as the size, shape, and concentration of the particles. By measuring the intensity and characteristics of the scattered light, information such as the turbidity of the water sample can be obtained, thereby determining the water quality.

[0057] This invention uses the optical sensor as a TOC sensor as an example for illustration, and should not be construed as a limitation on the type of optical sensor.

[0058] TOC sensors are primarily based on ultraviolet (UV) absorption. Specifically, many organic compounds dissolved in water absorb UV light of specific wavelengths (e.g., 254 nm). Therefore, by measuring the degree of UV absorption by these organic compounds, the total amount of organic pollutants in the water can be indirectly measured. Furthermore, for more accurate measurements, some TOC sensors employ dual-beam technology, simultaneously using UV and infrared light (e.g., 850 nm) to automatically compensate for light path attenuation and turbidity effects, ensuring stable and reliable measurements.

[0059] Controlling the light intensity emitted by an optical sensor is a crucial technical challenge in spectral sampling and analysis applications, as it determines the quantitative analysis of the incident light source size. Related technologies control the current of the optical sensor's light source, using current control to replace light intensity control. However, in practical use, this method cannot compensate for changes in the light source's operating state caused by factors such as temperature and prolonged operation.

[0060] Therefore, controlling the light intensity of the light source of the optical sensor is of great significance in ensuring the stability and consistency of the final light intensity output of the optical sensor.

[0061] For ease of description, this utility model uses an example where the TOC sensor uses a light-emitting diode (LED) as its light source and a photodetector uses a photodiode, and should not be construed as a limitation on the type of optical sensor.

[0062] Example 1

[0063] An optical sensor light source intensity control circuit, such as Figure 6 As shown, the optical sensor 1 is equipped with a light source 200 and a photodetector 300, such as Figure 1 As shown, the light intensity control circuit 100 of the optical sensor light source includes:

[0064] The main control circuit 110 is used to output control signals to control the light source control circuit;

[0065] The light source control circuit 120 is used to output a signal to generate a current in the circuit where the light source is located, and to receive a feedback signal from the light intensity feedback circuit to adjust its output signal so that the light intensity of the light source remains constant.

[0066] The LED light source of the TOC sensor is turned on by the light source control circuit 120, and a current is formed in the loop.

[0067] When the control voltage signal issued by the main control circuit 110 remains unchanged, if the light intensity of the LED light source of the TOC sensor changes due to certain factors such as temperature and aging, the feedback signal of the light intensity feedback circuit will also change accordingly. Since it is connected to the feedback terminal of the light source control circuit 120, the output signal of the light source control circuit 120 will also be adjusted to control the state of the light source 200, so that the voltage signal after the magnitude of the induced photocurrent on the photodetector 300 is amplified and remains consistent with the magnitude of the control signal of the main control circuit 110. That is, the magnitude of the control voltage signal issued by the main control circuit 110 determines the magnitude of the voltage signal after the induced current signal on the feedback photodetector 300 is converted, which means that the light intensity of the light source 200 of the optical sensor 1 remains unchanged.

[0068] The light intensity feedback circuit 130 is used to process the current signal converted by the photodetector and feed it back to the light source control circuit.

[0069] After the LED light source of the TOC sensor is turned on by the light source control circuit 120, the photodetector of the TOC sensor can detect the light intensity signal of the LED light source and convert the light intensity of the LED light source into a current signal in real time. When the light intensity of the LED light source changes, the light intensity signal detected by the photodetector will also change accordingly. At this time, the feedback signal of the light intensity feedback circuit will also change accordingly. Since it is connected to the feedback terminal of the light source control circuit 120, the output signal of the light source control circuit 120 will also be adjusted to control the state of the light source 200, so that the voltage signal after the amplification of the induced photocurrent on the photodetector 300 is consistent with the control signal of the main control circuit 110, that is, the light intensity of the light source 200 of the optical sensor 1 is considered to remain constant.

[0070] It should be noted that, Figure 1 The dashed line with an arrowhead represents a ray of light.

[0071] In some embodiments, such as Figure 2 , Figure 3 , Figure 4 As shown, the main control circuit 110 includes:

[0072] The main controller 111 is used to output digital signals.

[0073] Optionally, the main controller 111 adopts a microcontroller unit (MCU), also known as a single-chip microcomputer or single-chip microcomputer. An MCU is a chip that integrates functions such as a microprocessor core, memory and peripheral interfaces.

[0074] In the initial state, a precise digital signal is output based on the initial voltage value of the MCU.

[0075] In some embodiments, such as Figure 2 , Figure 4 As shown, the light source control circuit 120 includes:

[0076] The digital-to-analog converter 121 is used to receive the digital signal output by the main controller and output an analog voltage with reference to an external reference voltage.

[0077] To achieve automatic control of the LED light source of the TOC sensor, the digital signal output by the MCU needs to be converted into an analog signal based on a standard (or reference) quantity. The input of the digital-to-analog converter 121 (DAC) is connected to the output of the MCU. The DAC receives the digital signal from the MCU and then performs the conversion. To obtain a more accurate conversion result, the DAC can input a reference voltage VREF through a pin, and the DAC outputs a voltage based on an external reference voltage.

[0078] The MCU sends a drive digital signal to the DAC, which then converts it into a stable analog signal. For example... Figure 5 As shown, based on the DAC reference chip U16, a precise digital signal of the initial voltage value emitted by the MCU is received. The voltage output is referenced to an external 1.25V power supply and is input to the comparator terminal of U16 via resistor R46. Specifically, the DIN, SCLK, and SYNC pins of U16 are connected to the MOSI, SCLK, and SYNC pins of the MCU, respectively. The GND pin of U16 is grounded, the VDD pin is connected to a 3.3V power supply and grounded via C35, the VREF pin is connected to a 1.25V power supply, and the VFB and #OUT pins of U16 are connected to the driver circuit 122 via resistor R46.

[0079] It should be noted that, Figure 4 The dashed line with an arrowhead represents a ray of light. Figure 4 The solid line with an arrowhead represents an electrical signal. Figure 4 A solid line without an arrowhead represents a conductor.

[0080] The driving circuit 122 is used to output a driving signal to turn on the light source;

[0081] The MCU sends a digital drive signal to the DAC, which then converts it into a stable analog signal. A comparator controls the current on the MOSFET. The comparator then compares the DAC drive signal with the amplifier's feedback signal and adjusts the MOSFET current accordingly to maintain a constant feedback light intensity signal. Figure 4 , Figure 5As shown, the driving circuit includes a comparator U15 and an NMOS transistor Q2. The inverting input terminal (i.e., the VFB pin of U16) and the output terminal (i.e., the #OUT pin of U16) of the internal output operational amplifier of the digital-to-analog converter U16 are connected to the non-inverting input terminal of the comparator U15 via resistor R46. The inverting input terminal of the comparator U15 is connected to the light intensity feedback circuit 130. The output terminal of the comparator U15 is connected to the gate of the NMOS transistor Q2 via parallel C38 and R27. C38 and R27 are connected in parallel and then grounded via R41. Pin 2 of the comparator U15 is grounded, and pin 5 is connected to VCC. The drain of the NMOS transistor Q2 is connected to the negative terminal of the light source UV. The positive terminal of the light source UV is connected to the power supply 9V. The source of the NMOS transistor Q2 is grounded via voltage divider resistor R50.

[0082] The comparator U15 outputs a drive signal to control the NMOS transistor Q2 to conduct, turning on the LED light source and forming a current in the circuit.

[0083] In some embodiments, such as Figure 3 As shown, the light intensity feedback circuit 130 includes:

[0084] The transimpedance amplifier circuit 131 is used to convert the current signal converted by the photodetector into a voltage signal and feed it back to the comparator;

[0085] The non-inverting amplifier circuit 132 is used to amplify the voltage signal output by the transimpedance amplifier circuit and feed it back to the main controller.

[0086] When the LED light source emits light differently, the signal received by the photodetector (PD) changes, and this change is processed by the operational amplifier and fed back to the comparator U15. For example... Figure 4 , Figure 5 As shown, the transimpedance amplifier circuit includes a first operational amplifier U14, a first resistor R15, a first capacitor C34, a second resistor R48, and a third resistor R49. The first resistor R15 and the first capacitor C34 are connected in parallel between the inverting input terminal and the output terminal of the first operational amplifier U14. The negative terminal of the photodetector PD is connected to the inverting input terminal of the first operational amplifier U14, and the positive terminal of the photodetector PD is grounded. The second resistor R48 and the third resistor R49 are connected in series between the non-inverting input terminal of the first operational amplifier U14 and ground. The output terminal of the first operational amplifier U14 is connected to the inverting input terminal of the comparator U15 via resistor R43.

[0087] like Figure 4 , Figure 5As shown, the non-inverting amplifier circuit includes a second operational amplifier U12, a fourth resistor R45, a fifth resistor R37, and a sixth resistor R40. The output terminal of the first operational amplifier U14 is connected to the non-inverting input terminal of the second operational amplifier U12 via resistor R43 and the fourth resistor R45. The fifth resistor R37 is connected between the inverting input terminal and the output terminal of the second operational amplifier U12. The sixth resistor R40 is connected between the inverting input terminal of the second operational amplifier U12 and ground. The output terminal of the second operational amplifier U12 is connected to the ADC sampling unit (PD_SG) of the main controller.

[0088] Optionally, such as Figure 5 , Figure 7 As shown, the UV and IR light sources and the photodetector PD are packaged in the same photosensitive chip U5, which can effectively reduce environmental interference and the impact on chip consistency.

[0089] In order to suppress high-frequency noise and interference and improve signal quality, in some embodiments, the optical intensity feedback circuit further includes:

[0090] The second filtering circuit is used to filter the output of the transimpedance amplifier circuit;

[0091] The third filtering circuit is used to filter the output of the non-inverting amplifier circuit.

[0092] like Figure 5 As shown, the second filter circuit includes a first filter resistor R44 and a second filter capacitor C39. The first filter resistor R44 is connected between the resistor R43 connected to the output terminal of the first operational amplifier U14 and the fourth resistor R45. One end of the second filter capacitor C39 is connected between the first filter resistor R44 and the fourth resistor R45, and the other end of the second filter capacitor C39 is grounded.

[0093] like Figure 5 As shown, the third filter circuit includes a second filter resistor R42 and a third filter capacitor C29. The second filter resistor R42 is connected between the output terminal of the second operational amplifier U12 and the ADC sampling unit of the main controller. One end of the third filter capacitor C29 is connected between the second filter resistor R42 and the ADC sampling unit of the main controller, and the other end of the third filter capacitor C29 is grounded.

[0094] The photodetector PD receives the light intensity of the LED light source in real time and converts it into a current signal. The current signal is then converted into a voltage signal by the cross-group amplifier circuit. After being filtered by R44 and C39, the voltage signal is amplified by the subsequent non-inverting amplifier circuit, filtered by R42 and C29, and then enters the ADC acquisition unit of the MCU. On the other hand, the signal is fed back to the inverting input of the comparator U15 for feedback adjustment.

[0095] When the voltage signal of the control current sent by the MCU remains unchanged, if the state of the LED light source is affected by certain factors such as temperature aging, the light intensity changes. At this time, the output voltage signal of the cross-group amplifier circuit will change accordingly. Since it is connected to the feedback terminal of comparator U15, the output signal of comparator U15 will also be adjusted to control the conduction state of the MOS transistor, so that the magnitude of the voltage signal after the induced photocurrent on the PD is amplified by the cross-group amplifier remains consistent with the magnitude of the MCU control signal. That is, the magnitude of the voltage signal sent by the MCU determines the magnitude of the voltage signal after the induced current signal on the feedback PD is converted. In other words, the light intensity of the LED in the circuit is considered to remain unchanged.

[0096] This embodiment provides a light intensity control circuit for an optical sensor light source. The optical sensor is equipped with a light source and a photodetector. The circuit includes: a main control circuit for outputting control signals to control a light source control circuit; a light source control circuit for outputting signals to generate current in the circuit containing the light source and receiving feedback signals from a light intensity feedback circuit to adjust its output signal to keep the light intensity of the light source constant; and a light intensity feedback circuit for processing the current signal converted by the photodetector and feeding it back to the light source control circuit. This embodiment controls the light source of the optical sensor based on the feedback of the light intensity signal currently received by the photodetector, making the light intensity control of the optical sensor light source more precise. It can more effectively respond to changes in light intensity caused by various factors, ensuring the stability and consistency of the final light intensity output of the optical sensor light source. By performing real-time and precise control of the light intensity of the optical sensor light source, the consistency of the optical sensor measurement results can be maintained, and the measurement requirements of different scenarios can be met.

[0097] Example 2

[0098] like Figure 6 As shown, an optical sensor 1 uses the light intensity control circuit 100 of the aforementioned optical sensor light source to control the light intensity of its light source 200. A detailed description of the light intensity control circuit 100 of the optical sensor light source can be found in the corresponding description in the above-described control circuit embodiments, and will not be repeated here. In some embodiments, the optical sensor 1 can be used as a TOC sensor, while in other embodiments it can be used as other optical sensors that utilize a light source for spectral sampling and analysis.

[0099] Optionally, such as Figure 7 As shown, the light source 200 and photodetector 300 in the optical sensor 1 are packaged in the same photosensitive chip 400, which can effectively reduce environmental interference and the impact on chip consistency.

[0100] The light intensity control circuit 100 of the optical sensor light source in this embodiment may include:

[0101] The main control circuit is used to output control signals to control the light source control circuit.

[0102] The light source control circuit is used to output a signal to generate a current in the circuit where the light source is located, and to receive a feedback signal from the light intensity feedback circuit to adjust its output signal so that the light intensity of the light source remains constant.

[0103] The light intensity feedback circuit is used to process the current signal converted by the photodetector and feed it back to the light source control circuit.

[0104] Based on the technical solutions of the above embodiments, optionally, the main control circuit includes:

[0105] The main controller is used to output digital signals.

[0106] Based on the technical solutions of the above embodiments, optionally, the light source control circuit includes:

[0107] A digital-to-analog converter is used to receive the digital signal output by the main controller and output an analog voltage with reference to an external reference voltage.

[0108] A driving circuit is used to output a driving signal to turn on the light source.

[0109] Based on the technical solutions of the above embodiments, optionally, the driving circuit includes a comparator and an NMOS transistor. The inverting input terminal and the output terminal of the internal output operational amplifier of the digital-to-analog converter are connected to the non-inverting input terminal of the comparator via a resistor. The inverting input terminal of the comparator is connected to the light intensity feedback circuit. The output terminal of the comparator is connected to the gate of the NMOS transistor. The drain of the NMOS transistor is connected to the negative terminal of the light source. The positive terminal of the light source is connected to the power supply. The source of the NMOS transistor is grounded via a voltage divider resistor.

[0110] Based on the technical solutions of the above embodiments, optionally, the light intensity feedback circuit includes:

[0111] A transimpedance amplifier circuit is used to convert the current signal converted by the photodetector into a voltage signal and feed it back to the comparator;

[0112] A non-inverting amplifier circuit is used to amplify the voltage signal output by the transimpedance amplifier circuit and feed it back to the main controller.

[0113] Based on the technical solutions of the above embodiments, optionally, the light intensity feedback circuit further includes:

[0114] The first filtering circuit is used to filter the output of the transimpedance amplifier circuit;

[0115] The second filtering circuit is used to filter the output of the non-inverting amplifier circuit.

[0116] Based on the technical solutions of the above embodiments, optionally, the transimpedance amplifier circuit includes a first operational amplifier, a first resistor, a first capacitor, a second resistor, and a third resistor. The first resistor and the first capacitor are connected in parallel between the inverting input terminal and the output terminal of the first operational amplifier. The negative terminal of the photodetector is connected to the inverting input terminal of the first operational amplifier, and the positive terminal of the photodetector is grounded. The second resistor and the third resistor are connected in series between the non-inverting input terminal of the first operational amplifier and ground. The output terminal of the first operational amplifier is connected to the inverting input terminal of the comparator via a resistor.

[0117] Based on the technical solutions of the above embodiments, optionally, the non-inverting amplifier circuit includes a second operational amplifier, a fourth resistor, a fifth resistor, and a sixth resistor. The output terminal of the first operational amplifier is connected to the non-inverting input terminal of the second operational amplifier via the fourth resistor. The fifth resistor is connected between the inverting input terminal and the output terminal of the second operational amplifier. The sixth resistor is connected between the inverting input terminal and ground of the second operational amplifier. The output terminal of the second operational amplifier is connected to the ADC sampling unit of the main controller.

[0118] Based on the technical solutions of the above embodiments, optionally, the first filter circuit includes a first filter resistor and a second filter capacitor. The first filter resistor is connected between the output terminal of the first operational amplifier and the fourth resistor. One end of the second filter capacitor is connected between the first filter resistor and the fourth resistor, and the other end of the second filter capacitor is grounded.

[0119] Based on the technical solution of the above embodiments, optionally, the second filtering circuit includes a second filtering resistor and a third filtering capacitor. The second filtering resistor is connected between the output terminal of the second operational amplifier and the ADC sampling unit of the main controller. One end of the third filtering capacitor is connected between the second filtering resistor and the ADC sampling unit of the main controller, and the other end of the third filtering capacitor is grounded.

[0120] This embodiment provides an optical sensor that uses the aforementioned control circuit to control the light intensity of its light source. This embodiment controls the light source of the optical sensor based on feedback from the light intensity signal currently received by the photodetector, making the light intensity control of the optical sensor light source more precise. This allows for a more effective response to changes in light intensity caused by various factors, ensuring the stability and consistency of the final light intensity output of the optical sensor light source. By precisely controlling the light intensity of the optical sensor light source in real time, the consistency of the optical sensor's measurement results can be maintained, and the measurement requirements of different scenarios can be met.

[0121] The number of devices and processing scale described herein are for the purpose of simplifying the description of this utility model. Applications, modifications, and variations of this utility model will be readily apparent to those skilled in the art.

[0122] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

[0123] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0124] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0125] The above description is merely an embodiment of this specification and is not intended to limit the scope of one or more embodiments of this specification. Various modifications and variations can be made to one or more embodiments of this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of one or more embodiments of this specification should be included within the scope of the claims of one or more embodiments of this specification.

Claims

1. A light intensity control circuit for an optical sensor light source, wherein the optical sensor is equipped with a light source and a photodetector, characterized in that, include: The main control circuit is used to output control signals to control the light source control circuit. The light source control circuit is used to output a signal to generate a current in the circuit where the light source is located, and to receive a feedback signal from the light intensity feedback circuit to adjust its output signal so that the light intensity of the light source remains constant. The light intensity feedback circuit is used to process the current signal converted by the photodetector and feed it back to the light source control circuit.

2. The light intensity control circuit for an optical sensor light source as described in claim 1, characterized in that, The main control circuit includes: The main controller is used to output digital signals.

3. The light intensity control circuit for an optical sensor light source as described in claim 2, characterized in that, The light source control circuit includes: A digital-to-analog converter is used to receive the digital signal output by the main controller and output an analog voltage with reference to an external reference voltage. A driving circuit is used to output a driving signal to turn on the light source.

4. The light intensity control circuit for an optical sensor light source as described in claim 3, characterized in that: The driving circuit includes a comparator and an NMOS transistor. The inverting input and output of the internal output operational amplifier of the digital-to-analog converter are connected to the non-inverting input of the comparator via a resistor. The inverting input of the comparator is connected to the light intensity feedback circuit. The output of the comparator is connected to the gate of the NMOS transistor. The drain of the NMOS transistor is connected to the negative terminal of the light source. The positive terminal of the light source is connected to the power supply. The source of the NMOS transistor is grounded via a voltage divider resistor.

5. The light intensity control circuit for an optical sensor light source as described in claim 4, characterized in that: The light intensity feedback circuit includes: A transimpedance amplifier circuit is used to convert the current signal converted by the photodetector into a voltage signal and feed it back to the comparator; A non-inverting amplifier circuit is used to amplify the voltage signal output by the transimpedance amplifier circuit and feed it back to the main controller.

6. The light intensity control circuit for an optical sensor light source as described in claim 5, characterized in that, The light intensity feedback circuit also includes: The first filtering circuit is used to filter the output of the transimpedance amplifier circuit; The second filtering circuit is used to filter the output of the non-inverting amplifier circuit.

7. The light intensity control circuit for an optical sensor light source as described in claim 6, characterized in that, The transimpedance amplifier circuit includes a first operational amplifier, a first resistor, a first capacitor, a second resistor, and a third resistor. The first resistor and the first capacitor are connected in parallel between the inverting input terminal and the output terminal of the first operational amplifier. The negative terminal of the photodetector is connected to the inverting input terminal of the first operational amplifier, and the positive terminal of the photodetector is grounded. The second resistor and the third resistor are connected in series between the non-inverting input terminal of the first operational amplifier and ground. The output terminal of the first operational amplifier is connected to the inverting input terminal of the comparator via a resistor.

8. The light intensity control circuit for an optical sensor light source as described in claim 7, characterized in that, The non-inverting amplifier circuit includes a second operational amplifier, a fourth resistor, a fifth resistor, and a sixth resistor. The output terminal of the first operational amplifier is connected to the non-inverting input terminal of the second operational amplifier via the fourth resistor. The fifth resistor is connected between the inverting input terminal and the output terminal of the second operational amplifier. The sixth resistor is connected between the inverting input terminal and ground. The output terminal of the second operational amplifier is connected to the ADC sampling unit of the main controller.

9. The light intensity control circuit for an optical sensor light source as described in claim 8, characterized in that, The first filter circuit includes a first filter resistor and a second filter capacitor. The first filter resistor is connected between the output terminal of the first operational amplifier and the fourth resistor. One end of the second filter capacitor is connected between the first filter resistor and the fourth resistor, and the other end of the second filter capacitor is grounded.

10. The light intensity control circuit for an optical sensor light source as described in claim 8, characterized in that, The second filtering circuit includes a second filtering resistor and a third filtering capacitor. The second filtering resistor is connected between the output terminal of the second operational amplifier and the ADC sampling unit of the main controller. One end of the third filtering capacitor is connected between the second filtering resistor and the ADC sampling unit of the main controller, and the other end of the third filtering capacitor is grounded.

11. An optical sensor, characterized in that, The light intensity of the light source is controlled by the control circuit described in any one of claims 1 to 10.

12. An optical sensor as described in claim 11, characterized in that: The light source and photodetector in the optical sensor are encapsulated in the same photosensitive chip.

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