Fluorescence detection circuit, device and fluorescence detection method

Abstract

The application provides a fluorescence detection circuit, device and method, and relates to the field of electronic power. The fluorescence detection circuit comprises a photosensitive device, a photoelectric conversion circuit and a control circuit. The photosensitive device is used for detecting a photoelectric current corresponding to fluorescence emitted by a to-be-detected substance. The photoelectric conversion circuit is connected with the photosensitive device. The photoelectric conversion circuit comprises a plurality of resistance feedback paths. The photoelectric conversion circuit is used for determining a voltage value according to the photoelectric current and a gated resistance feedback path. The control circuit is connected with the photoelectric conversion circuit. The control circuit is used for determining a target resistance feedback path from the plurality of resistance feedback paths according to the voltage value, and controlling the photoelectric conversion circuit to gate the target resistance feedback path, so as to detect the fluorescence emitted by the to-be-detected substance through the target resistance feedback path. The embodiments of the application aim to conveniently switch resistance feedback paths corresponding to different resistance values, so as to accurately detect the fluorescence emitted by the to-be-detected substance.

Description

Technical Field

[0001] This application relates to the field of electronics and power, and in particular to a fluorescence detection circuit, fluorescence detection device, and fluorescence detection method. Background Technology

[0002] Fluorescence refers to the emission of cold light by substances with structures that absorb and excite electromagnetic radiation. Typically, the fluorescence emitted by a substance has a lower frequency, longer wavelength, and lower photon energy than the light that excited the substance. Unlike phosphorescence, the substance stops emitting fluorescence almost immediately upon the excitation light disappearing.

[0003] Existing fluorescence detection circuits use photomultiplier tubes (PMTs) with special filters for detection. Because PMTs are pre-built modules, their components are relatively fixed due to size limitations, resulting in low design freedom. Therefore, they can only use fixed-value resistor feedback paths for fluorescence detection, making it difficult to easily and quickly switch between different resistance values. This leads to low convenience and accuracy in fluorescence detection. Summary of the Invention

[0004] The main objective of this application is to provide a fluorescence detection circuit, a fluorescence detection device, and a fluorescence detection method, which aims to conveniently switch the resistance feedback path corresponding to different resistance values ​​in order to accurately detect the fluorescence emitted by the substance to be tested.

[0005] In a first aspect, this application provides a fluorescence detection circuit, comprising a photosensitive device, a photoelectric conversion circuit, and a control circuit. The photosensitive device is used to detect the photocurrent corresponding to the fluorescence emitted by the analyte. The photoelectric conversion circuit is connected to the photosensitive device and includes multiple resistance feedback paths. The photoelectric conversion circuit is used to determine a voltage value based on the photocurrent and the selected resistance feedback path. The control circuit is connected to the photoelectric conversion circuit and is used to determine a target resistance feedback path from the multiple resistance feedback paths based on the voltage value, and control the photoelectric conversion circuit to select the target resistance feedback path so as to detect the fluorescence emitted by the analyte through the target resistance feedback path.

[0006] Secondly, this application also provides a fluorescence detection method, which uses the fluorescence detection circuit described above, the method comprising:

[0007] The photoelectric conversion circuit is controlled to select a preset resistance feedback path and acquire the voltage and photocurrent values ​​corresponding to the preset resistance feedback path; a target resistance feedback path is determined from multiple resistance feedback paths based on the voltage and photocurrent values; the photoelectric conversion circuit is controlled to select the target resistance feedback path so as to detect the fluorescence emitted by the analyte through the target resistance feedback path.

[0008] Thirdly, this application also provides a fluorescence detection device, including the fluorescence detection circuit as described above.

[0009] This application provides a fluorescence detection circuit, a fluorescence detection device, and a fluorescence detection method. The fluorescence detection circuit includes a photosensitive device, a photoelectric conversion circuit, and a control circuit. The photosensitive device detects the photocurrent corresponding to the fluorescence emitted by the analyte. The photoelectric conversion circuit is connected to the photosensitive device and includes multiple resistance feedback paths. The photoelectric conversion circuit determines a voltage value based on the photocurrent and the selected resistance feedback path. The control circuit is connected to the photoelectric conversion circuit and determines a target resistance feedback path from the multiple resistance feedback paths based on the voltage value. The control circuit then controls the photoelectric conversion circuit to select the target resistance feedback path to detect the fluorescence emitted by the analyte through the target resistance feedback path. The fluorescence detection circuit of this application can easily switch between resistance feedback paths corresponding to different resistance values ​​and determine the target resistance feedback path based on the voltage value, thereby accurately detecting the fluorescence emitted by the analyte and improving the user experience. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A schematic block diagram of a fluorescence detection circuit provided in an embodiment of this application;

[0012] Figure 2 This is a schematic diagram of the structure of a fluorescence detection device provided in an embodiment of this application;

[0013] Figure 3 A circuit diagram of a driving circuit provided in an embodiment of this application;

[0014] Figure 4 A circuit diagram of another driving circuit provided in an embodiment of this application;

[0015] Figure 5 A circuit diagram of a temperature detection circuit provided in an embodiment of this application;

[0016] Figure 6 A circuit diagram of a photoelectric conversion circuit provided in an embodiment of this application;

[0017] Figure 7 A circuit diagram of another photoelectric conversion circuit provided in an embodiment of this application;

[0018] Figure 8 A circuit diagram of an environmental sensing circuit provided in an embodiment of this application;

[0019] Figure 9 A schematic block diagram of a fluorescence detection device provided in this application embodiment;

[0020] Figure 10 A schematic diagram of the flow steps of a fluorescence detection method provided in an embodiment of this application;

[0021] Figure label:

[0022] 1000. Fluorescence detection equipment; 100. Fluorescence detection circuit; 10. Photosensitive device; 20. Photoelectric conversion circuit; 30. Control circuit; 40. Light emission device; 50. Driving circuit; 60. Thermistor; 70. Temperature detection circuit; 80. Environmental sensing circuit. Detailed Implementation

[0023] 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 some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] With the deepening research on fluorescence phenomena, specific applications have emerged in fields such as petrochemicals, minerals, medicine, and biology. Although the purposes and scenarios of these applications vary, such as detecting oils, screening minerals, and labeling proteins, the basic operation process can be summarized as follows: a light source illuminates the substance, the substance emits fluorescence, and a photosensor detects the fluorescence.

[0026] The light source is typically chosen to be a specific wavelength within the ultraviolet spectrum. This wavelength of ultraviolet light was previously obtained using xenon lamps with special filters. Substances exhibiting fluorescence emit fluorescence at a specific wavelength after absorbing ultraviolet light. This wavelength depends on the substance's inherent properties and varies from substance to substance. The spectral range typically extends from the near-ultraviolet region to the visible green region. The fluorescence disappears almost simultaneously with the elimination of ultraviolet light.

[0027] The choice of photosensor is related to the fluorescence wavelength emitted by the analyte. Because the energy of ultraviolet light is not entirely concentrated on the material, and due to factors such as reflection, refraction, and absorption of fluorescence by optical devices, as well as the attenuation of fluorescence with optical path length, the intensity of fluorescence is usually very weak. Fluorescence detection has traditionally been performed using photomultiplier tubes with specially designed filters.

[0028] Existing fluorescence detection circuits use photomultiplier tubes (PMTs) with special filters for detection. Because PMTs are pre-built modules, their components are relatively fixed due to size limitations, resulting in low design freedom. Therefore, they can only use fixed-value resistor feedback paths for fluorescence detection, making it difficult to easily and quickly switch between different resistance values. This leads to low convenience and accuracy in fluorescence detection.

[0029] To address the aforementioned issues, this application provides a fluorescence detection circuit, a fluorescence detection device, and a fluorescence detection method. This allows for convenient switching of resistance feedback paths corresponding to different resistance values, and the determination of the target resistance feedback path through voltage values. Consequently, it enables accurate detection of the fluorescence emitted by the substance under test, thereby improving the user experience.

[0030] Please refer to Figure 1 , Figure 1 A schematic block diagram of a fluorescence detection circuit provided for an embodiment of this application.

[0031] like Figure 1 As shown, the fluorescence detection circuit 100 includes a photosensitive device 10, a photoelectric conversion circuit 20, and a control circuit 30. The photosensitive device 10 is used to detect the photocurrent corresponding to the fluorescence emitted by the analyte. The photoelectric conversion circuit 20 is connected to the photosensitive device 10 and includes multiple resistance feedback paths. The photoelectric conversion circuit 20 is used to determine a voltage value based on the photocurrent and the selected resistance feedback path. The control circuit 30 is connected to the photoelectric conversion circuit 20 and is used to determine a target resistance feedback path from the multiple resistance feedback paths based on the voltage value, and control the photoelectric conversion circuit 20 to select the target resistance feedback path so as to detect the fluorescence emitted by the analyte through the target resistance feedback path.

[0032] The photosensitive device 10 receives the fluorescence emitted by the substance to be tested, detects the intensity of the fluorescence, and converts it into a corresponding photocurrent value for subsequent voltage calculation. The photoelectric conversion circuit 20 includes multiple resistance feedback paths, each with a different resistance value. Therefore, the voltage value is determined by the resistance value of the selected resistance feedback path and the magnitude of the photocurrent. The target resistance feedback path is the one that ensures the calculated voltage value falls within the optimal voltage range.

[0033] For example, if the photocurrent remains constant, the voltage value is determined by the resistance value corresponding to the resistive feedback path; if the resistance value corresponding to the resistive feedback path remains constant, the voltage value is determined by the photocurrent.

[0034] Specifically, the photosensitive device 10 detects the photocurrent corresponding to the fluorescence emitted by the substance under test. The photoelectric conversion circuit 20 determines the voltage value corresponding to this path based on the photocurrent and the pre-selected resistance feedback path. The control circuit 30 determines whether the voltage value corresponding to this path is within the optimal voltage range. If not, it determines the target resistance feedback path from multiple resistance feedback paths and controls the photoelectric conversion circuit 20 to select the target resistance feedback path so as to detect the fluorescence emitted by the substance under test through the target resistance feedback path. This enables accurate detection of the fluorescence emitted by the substance under test and improves the user experience.

[0035] like Figure 2 As shown, in some embodiments, the fluorescence detection circuit 100 further includes a light-emitting device 40 and a driving circuit 50. The light-emitting device 40 is disposed on a substrate, and the photosensitive device 10 is used to emit ultraviolet light to irradiate the substance to be tested, so that the substance to be tested emits fluorescence. The driving circuit 50 is connected to the light-emitting device 40 and the control circuit 30, and the driving circuit 50 is used to drive the light-emitting device 40 to emit ultraviolet light at a preset power. The control circuit 30 is also used to determine a target power based on a voltage value and control the driving circuit 50 to drive the light-emitting device 40 to emit ultraviolet light at the target power.

[0036] The light-emitting device 40 can be a light-emitting diode (LED) that emits ultraviolet light. The preset power can be the maximum power of the LED. Since the intensity of fluorescence is usually very weak, the light-emitting device 40 is first driven to emit ultraviolet light at its maximum power, and then the power of the light-emitting device 40 is adjusted according to the actual situation. The target power is the power that makes the fluorescence detection parameters (such as voltage and temperature values) fall within the optimal range.

[0037] Current technology typically uses xenon lamps with specialized filters to emit ultraviolet light. However, with advancements in materials science and the maturation of LED manufacturing processes in recent years, LEDs can now emit ultraviolet light within a narrower wavelength range in the deep ultraviolet region. Compared to xenon lamps, LEDs have a higher energy conversion efficiency from electrical energy to light at specific wavelengths, resulting in greater energy savings under the same light intensity. LEDs are also smaller and require less heat dissipation space, making it easier to integrate them into the overall design. In some applications, LEDs do not require filters, simplifying the optical path design. Furthermore, LEDs can be mass-produced on a larger scale, resulting in lower material costs. Therefore, in certain applications, LEDs are well-suited to replace xenon lamps as the excitation source.

[0038] Specifically, the fluorescence detection circuit 100 may also include a power supply circuit, a temperature detection circuit 70, an environmental sensing circuit 80, a memory circuit, a relay circuit, a communication circuit, and so on. All of the above circuits are connected to the control circuit 30 and are all mounted on the main circuit board.

[0039] The main circuit board is connected to the substrate via a wiring harness. The main circuit board is also connected to the photodiode via pin soldering, and to external interfaces via a wiring harness. The photodiode should be soldered directly onto the substrate to prevent heat generated during operation from being rapidly conducted through the board and affecting the normal operation of other circuits. The model of the photodiode should be selected based on the actual application scenario of the circuit. Key parameters include the ultraviolet wavelength range, emission angle, forward voltage, and full-load current.

[0040] Specifically, the driving circuit 50 first drives the light-emitting device 40 to emit ultraviolet light at a preset power to irradiate the substance to be tested. The photosensitive device 10 detects the photocurrent corresponding to the fluorescence emitted by the substance to be tested. The photoelectric conversion circuit 20 determines the voltage value corresponding to this path based on the photocurrent and the pre-selected resistance feedback path. Then, it selects the target resistance feedback path from multiple resistance feedback paths and controls the photoelectric conversion circuit 20 to select the target resistance feedback path, obtains the voltage value corresponding to the target resistance feedback path, determines the target power based on the voltage value corresponding to the target resistance feedback path, and controls the driving circuit 50 to drive the light-emitting device 40 to emit ultraviolet light at the target power. This enables accurate detection of the fluorescence emitted by the substance to be tested, improving the user experience.

[0041] For example, the driving circuit 50 first drives the light-emitting device 40 to emit ultraviolet light at the highest power to irradiate the substance to be tested. The photosensitive device 10 detects the photocurrent corresponding to the fluorescence emitted by the substance to be tested. The photoelectric conversion circuit 20 determines the voltage value corresponding to the path based on the photocurrent and the resistance feedback path corresponding to the minimum resistance value selected in advance. If the voltage value is not less than the first voltage value threshold, the path is used as the target resistance feedback path. If the voltage value is less than the first voltage value threshold, the photoelectric conversion circuit 20 is controlled to select the resistance feedback path corresponding to the larger resistance value until the voltage value of the corresponding path is greater than the first voltage value threshold, and the path is used as the target resistance feedback path.

[0042] The photoelectric conversion circuit 20 selects the target resistor feedback path and obtains the voltage value corresponding to the target resistor feedback path. If the voltage value is not greater than the second voltage threshold, the preset power is used as the target power. If the voltage value is greater than the second voltage threshold, the driving circuit 50 drives the light-emitting device 40 to reduce the power until the voltage value of the corresponding power is less than the second voltage threshold. The power at this time is used as the target power, so that the fluorescence emitted by the substance to be tested can be accurately detected, improving the user experience.

[0043] Wherein, the first voltage threshold is the lower limit of the optimal voltage range, and the second voltage threshold is the upper limit of the optimal voltage range. The specific values ​​of the first voltage threshold and the second voltage threshold can be any values, and no specific limitation is made here.

[0044] like Figure 3 As shown, in some embodiments, the driving circuit 50 includes a driver U1, the input of which is connected to the control circuit 30, and the output of which is connected to the light-emitting device 40. The driver U1 is used to control the light-emitting device 40 to emit ultraviolet light according to the light-emitting command issued by the control circuit 30.

[0045] Specifically, the driver U1 is connected to the pulse width modulation (PWM) signal output terminal of the control circuit 30 through the CTRL terminal, so that it can control the corresponding light-emitting device 40 to emit ultraviolet light according to the light-emitting command issued by the control circuit 30.

[0046] Specifically, the driving circuit 50 also includes a first capacitor C1, a first resistor R1, a second interface J2, a first inductor, and a first diode D1. The VIN terminal of driver U1 is connected to the first terminal of the first capacitor C1, the 5V power supply output from the power supply circuit, and the first terminal of the first resistor R1. The second terminal of the first capacitor C1 is grounded. The SET terminal of driver U1 is connected to the second terminal of the first resistor R1 and the first pin of the second interface J2. The SW terminal of driver U1 is connected to the first terminal of the first inductor and the anode of the first diode D1. The second terminal of the first inductor is connected to the second pin of the second interface J2. The cathode of the first diode D1 is connected to the 5V power supply output from the power supply circuit. The ground (GND) terminal and the exposed pad (EP) terminal of driver U1 are both connected to the GND terminal of the power supply circuit. The anode of the light-emitting diode is connected to the first pin of the second interface J2. The cathode of the light-emitting diode is connected to the second pin of the second interface J2.

[0047] It should be noted that the capacitance value of the first capacitor C1 needs to be set according to the specific characteristics of the LED model, the PWM signal frequency, and other circuit parameters. The capacitance value is generally 4.7μF or higher, and no specific limit is set here. However, it is essential to ensure that the rated voltage of capacitor C1 is at least twice the output voltage of the power supply circuit.

[0048] The resistance value of the first resistor R1 varies depending on the specific LED model and the current required at full load; no specific limit is imposed here. To reduce control errors, the first resistor R1 should be a device with high nominal resistance accuracy, low temperature drift coefficient, and large package size.

[0049] The second interface J2 can be selected from different models depending on the application scenario, and no limitation is made here. However, the second interface J2 must include at least two independent pins. The rated current parameter of the second interface J2 must be greater than the maximum output current parameter set by the driver U1. The pin spacing of the second interface J2 must ensure that it will not be broken down by the voltage drop across the LED under the aforementioned maximum current conditions.

[0050] The inductance value of the first inductor needs to be set according to the specific characteristics of the LED model, the resistance value of the first resistor R1, and other circuit parameters. The inductance value is generally between 33μH and 100μH, and is not limited here. However, it must be ensured that the saturation current parameter of the first inductor exceeds the aforementioned maximum current. Furthermore, a fully shielded metal-cased package is preferred to reduce electromagnetic radiation interference to surrounding circuits.

[0051] The type of the first diode D1 depends on the characteristics of other parts of the circuit and is not limited here. However, the rated peak current parameter of the first diode D1 should be greater than the peak current of the first inductor. The rated continuous current parameter should be greater than the maximum output current parameter set by the driver U1. The reverse breakdown voltage parameter should be twice or more the output voltage value of the power supply circuit. The driver U1 can be any type of hysteresis-mode DC-DC buck converter.

[0052] like Figure 4 As shown, for example, the light-emitting device 40 may include a plurality of light-emitting diodes.

[0053] The light-emitting device 40 can be composed of three identical ultraviolet light-emitting diodes connected in series. Therefore, Figure 4 The required drive voltage at both ends of the second interface J2 is Figure 3 Three times that of the standard. Accordingly, the output voltage of the power supply circuit should also be increased. Furthermore, if more ultraviolet light-emitting diodes of the same specification are connected in series in the same circuit, only the output voltage of the power supply circuit needs to be increased. However, it cannot exceed the minimum of the maximum output voltage of the power supply circuit, the maximum input voltage of the driver U1, and the voltage parameters of the other aforementioned components.

[0054] and Figure 3 and Figure 4 Unlike other implementations, the light-emitting device 40 can also consist of two or more light-emitting diodes of the same specification connected in parallel. To achieve the same full-load current for each light-emitting diode in the parallel circuit as a single ultraviolet light-emitting diode circuit, the power supply circuit needs to output a larger current while simultaneously reducing the resistance value of the first resistor R1. For example, if the light source consists of four... Figure 3 If the ultraviolet light-emitting diodes shown are connected in parallel, then the resistance value of the first resistor R1 should be set to one-quarter of the original value.

[0055] Furthermore, the light-emitting device 40 can also be configured as a circuit combination of multiple light-emitting diodes connected in series and then in parallel or in parallel and then in series.

[0056] like Figure 2 As shown, in some embodiments, the fluorescence detection circuit 100 further includes a thermistor 60 and a temperature detection circuit 70. The thermistor 60 is disposed on the substrate. The temperature detection circuit 70 is connected to the thermistor 60 and the control circuit 30. The temperature detection circuit 70 is used to obtain the resistance value of the thermistor 60. The control circuit 30 is also used to determine the temperature of the substrate based on the resistance value of the thermistor 60, adjust the preset power based on the temperature of the substrate, and control the driving circuit 50 to drive the light-emitting device 40 to emit ultraviolet light at the adjusted preset power.

[0057] The resistance of the thermistor 60 increases with temperature and has a fixed resistance value at a fixed temperature. Since both the thermistor 60 and the light-emitting diode (LED) are mounted on the substrate, the temperature of the LED can be reflected by the thermistor 60.

[0058] Specifically, the light-emitting device 40 is controlled to emit ultraviolet light at a preset power. At this time, the resistance value of the thermistor 60 is obtained, and the temperature of the substrate is determined based on the resistance value of the thermistor 60. If the temperature of the substrate exceeds the preset temperature threshold, the driving circuit 50 is controlled to reduce the power, and the light-emitting device 40 is driven to emit ultraviolet light at the reduced power until the temperature of the substrate does not exceed the preset temperature threshold.

[0059] like Figure 5 As shown, in some embodiments, the temperature detection circuit 70 includes a first interface J1 and a first amplifier U2. The first pin of the first interface J1 is connected to the first end of the thermistor 60, the second pin of the first interface J1 is connected to the first end of the thermistor 60 and the control circuit 30, the third pin of the first interface J1 is connected to the second end of the thermistor 60 and the control circuit 30, and the fourth pin of the first interface J1 is connected to the second end of the thermistor 60. The first input terminal of the first amplifier U2 is grounded, the second input terminal of the first amplifier U2 is connected to the fourth pin of the first interface J1, and the output terminal of the first amplifier U2 is connected to the first pin of the first interface J1.

[0060] Specifically, the temperature detection circuit 70 also includes a second capacitor C2, a third capacitor C3, and a second resistor R2. The non-inverting input of the first amplifier U2 is connected to the 2.5V output of the power supply circuit and the first terminal of the second capacitor C2, with the second terminal of the second capacitor C2 grounded. The inverting input of the first amplifier U2 is connected to the fourth pin of the first interface J1 and the first terminal of the second resistor R2, with the second terminal of the second resistor R2 grounded. The output of the first amplifier U2 is connected to the first pin of the first interface J1. The positive power supply input of the first amplifier U2 is connected to the 5V output of the power supply circuit and the first terminal of the third capacitor C3, with the second terminal of the third capacitor C3 grounded. The negative power supply input of the first amplifier U2 is connected to the GND terminal of the power supply circuit.

[0061] The second capacitor C2 and the third capacitor C3 serve as high-frequency decoupling capacitors. Their values ​​must be determined based on the noise generated by the actual circuit at this point and the acceptable noise level for the application. Generally, a value of 100nF or higher is used, without specific limitation. However, the rated voltage of the capacitors must be 1.5 times or more the output voltage of the power supply circuit.

[0062] It should be noted that the first amplifier U2 can be an operational amplifier. The resistance value of the second resistor R2 is set according to the specific type of thermistor 60 and the required current, and is not limited here.

[0063] In some embodiments, the photosensitive device 10 is a photodiode.

[0064] The choice of photosensor is related to the fluorescence wavelength emitted by the substance being tested. Because the energy of ultraviolet light is not entirely concentrated on the material, and due to factors such as reflection, refraction, and absorption of fluorescence by optical devices, as well as fluorescence attenuation with optical path length, the fluorescence intensity is usually very weak. Fluorescence detection was previously performed using photomultiplier tubes with special filters. However, in recent years, with the maturation of photodiode manufacturing processes, its optical window surface, after special treatment, can exhibit better selectivity for specific wavelengths. Furthermore, with the development of analog circuit technology, it has become possible to amplify the photodiode signal at high rates through signal conditioning circuits. Compared to photomultiplier tubes, photodiodes have a simpler structure, making it easier to improve the overall design integration. Photodiodes are passive devices, resulting in simpler circuit design. Photodiodes have a larger production scale and lower material costs. Therefore, in certain applications, photodiodes are very suitable as replacements for photomultiplier tubes as photosensing devices.

[0065] It should be noted that the model of a photodiode depends on the application scenario, and key parameters include the optical window area, spectral range, dark current, light intensity and photocurrent conversion efficiency, etc.

[0066] like Figure 6 As shown, in some embodiments, the photoelectric conversion circuit 20 includes a second amplifier U3 and a first multiplexer U4; the first input terminal of the second amplifier U3 is grounded, and the second input terminal of the second amplifier U3 is connected to the photosensitive device 10; the input terminal of the first multiplexer U4 is connected to the output terminal of the second amplifier U3, the output terminal of the first multiplexer U4 is connected to the control circuit 30, and the output terminal of the first multiplexer U4 is also connected to the second terminal of the second amplifier U3 to form multiple resistive feedback paths.

[0067] Specifically, the resistive feedback path includes a resistive element and a capacitive element. The first end of the resistive element is connected to the second end of the second amplifier U3, and the second end of the resistive element is connected to the output end of the first multiplexer U4. The capacitive element is connected in parallel with the resistive element.

[0068] For example, the photoelectric conversion circuit 20 includes a first multiplexer U4 and a second multiplexer U5, and both the first multiplexer U4 and the second multiplexer U5 include 8 source terminals (i.e., 8 resistive feedback paths).

[0069] like Figure 6As shown, since there are 8 resistor feedback paths, the resistor elements can include the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the tenth resistor R10, and the capacitor elements include the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, the ninth capacitor C9, the tenth capacitor C10 and the eleventh capacitor C11.

[0070] For example, the third resistor R3 and the fourth capacitor C4 form a resistive feedback path, the fourth resistor R4 and the fifth capacitor C5 form a resistive feedback path, and so on. The capacitors are compensation capacitors for the resistive elements connected to their ends, and are used to establish an AC signal path in high-frequency fluorescent current signals. Their compensation capacitance values ​​need to be determined based on the signal frequency and the paired feedback resistor values, typically ranging from a few pF to tens of pF.

[0071] Specifically, the non-inverting input of the second amplifier U3 is connected to the GND terminal of the power supply circuit. The inverting input of the second amplifier U3 is connected to the cathode of the photodiode, the first terminal of the resistor, and the first terminal of the capacitor. The second terminals of the resistor and the second terminals of the capacitor are connected sequentially to the corresponding source terminals of the second multiplexer U5. The positive power supply input of the second amplifier U3 is connected to the first terminal of the twelfth capacitor C12 and the 5V power supply output from the power supply circuit, and the second terminal of the twelfth capacitor C12 is grounded. The negative power supply input of the second amplifier U3 is connected to the GND terminal of the power supply circuit. The output of the second amplifier U3 is connected to the common drain terminal of the first multiplexer U4. Pins 2 and 7 of the second amplifier U3 are guard ring output pins, connected to the GND terminal of the power supply circuit. Pin 8 of the second amplifier U3 is an internal connection (IC) pin, connected to the GND terminal of the power supply circuit. The anode of the photodiode is connected to the GND terminal of the power supply circuit.

[0072] The positive power input terminal of the second multiplexer U5 is connected to the first terminal of the thirteenth capacitor C13 and the 5V power supply output from the power supply circuit, while the second terminal of the thirteenth capacitor C13 is grounded. The negative power input terminal of the second multiplexer U5 is connected to the GND terminal of the power supply circuit. The reference ground terminal of the second multiplexer U5 is connected to the GND terminal of the power supply circuit. The common drain terminal of the second multiplexer U5 is connected to the single-ended voltage analog signal acquisition channel VS1 of the analog-to-digital converter. Similarly, the positive power input terminal of the third multiplexer is connected to the first terminal of the fourteenth capacitor C14 and the 5V power supply output from the power supply circuit, while the second terminal of the fourteenth capacitor C14 is grounded. The control circuit 30 is connected to the SPI signal terminal of the analog-to-digital converter through the first serial peripheral interface (SPI) signal terminal.

[0073] It should be noted that, as Figure 6 In the illustrated embodiment, there are a total of eight resistive feedback paths, so one eight-channel multiplexer can be used on each side, or one sixteen-channel multiplexer can be used on each side, or two four-channel multiplexers can be used on each side, or four single-pole double-throw switches can be used on each side. Considering material cost, package size, wiring difficulty, and control convenience, using one eight-channel multiplexer on each side is optimal.

[0074] Specifically, the photocurrent I generated when fluorescence shines on the photodiode L Feedback resistance value R F The voltage VS at the source terminal of the second multiplexer U5 has the following relationship.

[0075] V S =I L ×R F

[0076] Due to the device characteristics of a photodiode, the photocurrent flows from the cathode to the anode, and the anode of the photodiode is connected to the GND of the power supply circuit. S It is a positive voltage relative to GND.

[0077] As shown in the above formula, the selection of the feedback resistor value is related to the photocurrent intensity generated when fluorescence irradiates the photodiode in the application scenario. However, in practical applications, the photocurrent is often difficult to predict and can fluctuate within a range of several orders of magnitude. This embodiment can adapt to different photocurrent intensities by selecting different feedback paths.

[0078] like Figure 7 As shown, in some embodiments, the photosensitive device 10 may consist of multiple (e.g., four) photodiodes of the same specification connected in parallel. Furthermore, the second multiplexer U5 is omitted, and each source terminal of the first multiplexer U4 is directly connected to a single-ended analog voltage acquisition channel of the analog-to-digital converter.

[0079] When the conversion efficiency of a single photodiode is insufficient to provide the required photocurrent, or when multiple photodiodes are needed for other technical reasons, they can be connected in parallel. The photocurrent I generated when fluorescence illuminates each photodiode is... L1 I L2 I L3 I L4 Feedback resistance value R S The voltage V at the source terminal of the first multiplexer U4 S The following relationship exists.

[0080] V S =(I L1 +I L2 +IL3 +I L4 )×R F

[0081] When the selected analog-to-digital converter has enough analog voltage acquisition channels, a multi-channel multiplexer can be omitted. This reduces material costs, package size, wiring complexity, and improves control convenience.

[0082] In some embodiments, the photoelectric conversion circuit 20 further includes an analog-to-digital converter (ADC), which is connected to the output of the first multiplexer U4 and the control circuit 30. The ADC is used to convert the analog voltage output of the first multiplexer U4 into a digital voltage.

[0083] For example, the voltage value calculated and output by the first multiplexer U4 or the second multiplexer U5 is an analog voltage quantity, which needs to be converted from analog to digital before it can be received and used by the control circuit 30. Therefore, the analog voltage quantity output by the first multiplexer U4 can be converted into a digital voltage quantity by an analog-to-digital converter and output to the control circuit 30.

[0084] like Figure 8 As shown, in some embodiments, the fluorescence detection circuit 100 further includes an environmental sensing circuit 80, which includes an environmental sensor U6, a fifteenth capacitor C15, and a sixteenth capacitor C16. The environmental sensor U6 is connected to the control circuit 30 via a 4-wire SPI signal interface. The digital input / output power supply VDDIO terminal of the environmental sensor U6 is connected to the first terminal of the fifteenth capacitor C15 and the 3.3V output terminal of the power supply circuit, while the second terminal of the fifteenth capacitor C15 is grounded. The digital power supply VDD terminal of the environmental sensor U6 is connected to the first terminal of the sixteenth capacitor C16 and the 3.3V output terminal of the power supply circuit, while the second terminal of the sixteenth capacitor C16 is grounded. Pins 1 and 7 of the environmental sensor U6 are connected to the GND of the power supply circuit.

[0085] Specifically, the environmental sensor U6 can detect environmental parameters such as ambient temperature and ambient humidity, and send them to the control circuit 30 to save the environmental parameters such as ambient temperature and ambient humidity.

[0086] In one embodiment, please refer to Figure 9 , Figure 9 This is a schematic block diagram of one embodiment of the fluorescence detection device 1000 provided in the present application.

[0087] like Figure 9 As shown, the fluorescence detection device 1000 includes a fluorescence detection circuit 100.

[0088] The fluorescence detection circuit 100 can be referred to as follows: Figures 1 to 8Examples of settings can be used, such as the fluorescence detection device 1000 including the photosensitive device 10, photoelectric conversion circuit 20 and control circuit 30 described in the above embodiments. The specific setting of the fluorescence detection circuit 100 can be referred to the corresponding embodiment described in this application specification, which will not be repeated here.

[0089] Please refer to Figure 10 , Figure 10 This is a schematic flowchart of a fluorescence detection method provided for an embodiment of this application. Specifically, the fluorescence detection method is applied in the fluorescence detection circuit 100 or fluorescence detection device 1000 as described above.

[0090] S101. Control the photoelectric conversion circuit to select a preset resistor feedback path and obtain the voltage value and photocurrent value corresponding to the preset resistor feedback path.

[0091] The preset resistance feedback path can be the resistance feedback path corresponding to the minimum resistance value.

[0092] Specifically, the photosensitive device 10 detects the photocurrent corresponding to the fluorescence emitted by the substance to be tested, and the photoelectric conversion circuit 20 determines the voltage value corresponding to this path based on the photocurrent and the resistance feedback path corresponding to the minimum resistance value selected in advance.

[0093] In some embodiments, before the photoelectric conversion circuit 20 selects the preset resistor feedback path, the resistance value of the thermistor 60 is obtained, and the temperature of the substrate is determined based on the resistance value of the thermistor 60; if the temperature of the substrate exceeds a preset temperature threshold, the preset power of the light-emitting device 40 is adjusted, and the driving circuit 50 is controlled to drive the light-emitting device 40 to emit ultraviolet light at the adjusted preset power.

[0094] Specifically, the light-emitting device 40 is controlled to emit ultraviolet light at a preset power. At this time, the resistance value of the thermistor 60 is obtained, and the temperature of the substrate is determined based on the resistance value of the thermistor 60. If the temperature of the substrate exceeds the preset temperature threshold, the driving circuit 50 is controlled to reduce the power, and the light-emitting device 40 is driven to emit ultraviolet light at the reduced power until the temperature of the substrate does not exceed the preset temperature threshold.

[0095] For example, if the preset temperature threshold is 60°, the light-emitting device 40 is controlled to emit ultraviolet light at the highest power. At this time, the resistance value of the thermistor 60 is obtained, and the temperature of the substrate is determined according to the resistance value of the thermistor 60. If the temperature of the substrate exceeds 60°, the driving circuit 50 is controlled to reduce the power, and the light-emitting device 40 is driven to emit ultraviolet light at the reduced power until the temperature of the substrate does not exceed the preset temperature threshold, and the reduced power is used as the preset power.

[0096] S102. Determine the target resistance feedback path from multiple resistance feedback paths based on the voltage value and the photocurrent value.

[0097] The output terminal of the first multiplexer U4 is connected to the second terminal of the second amplifier U3 to form multiple resistance feedback paths. The target resistance feedback path is the resistance feedback path that makes the calculated voltage value fall within the optimal voltage range.

[0098] In some embodiments, it is determined whether the voltage value corresponding to the preset resistance feedback path is less than a first voltage value threshold; if the voltage value is less than the first voltage value threshold, a target resistance feedback path is determined based on the resistance value corresponding to each resistance feedback path and the photocurrent value.

[0099] Specifically, it is determined whether the voltage value corresponding to the preset resistance feedback path is less than a first voltage value threshold; if the voltage value is not less than the first voltage value threshold, the photoelectric conversion circuit 20 is controlled to select the resistance feedback path corresponding to the larger resistance value, and this path is used as the target resistance feedback path; if the voltage value is less than the first voltage value threshold, the photoelectric conversion circuit 20 is controlled to select the resistance feedback path corresponding to the larger resistance value until the voltage value of the corresponding path is greater than the first voltage value threshold, and this path is used as the target resistance feedback path.

[0100] For example, if the first voltage threshold is 1V, it is determined whether the voltage value corresponding to the resistance feedback path a is less than 1V. If the voltage value corresponding to the resistance feedback path a is not less than 1V, then the resistance feedback path a is taken as the target resistance feedback path. If the voltage value is less than the first voltage threshold, then the photoelectric conversion circuit 20 is controlled to select the resistance feedback path corresponding to the larger resistance value (such as resistance feedback path b) until the voltage value of its corresponding path is greater than 1V. For example, if the voltage value of the path corresponding to resistance feedback path c is greater than 1V, then the resistance feedback path c is taken as the target resistance feedback path.

[0101] In some embodiments, after determining the target resistance feedback path from multiple resistance feedback paths based on the voltage value and the photocurrent value, it is determined whether the voltage value corresponding to the target resistance feedback path is greater than a second voltage value threshold; if the voltage value corresponding to the target resistance feedback path is greater than the second voltage value threshold, the target power of the light-emitting device 40 is determined based on the voltage value, and the driving circuit 50 is controlled to drive the light-emitting device 40 to emit ultraviolet light at the target power.

[0102] Specifically, the photoelectric conversion circuit 20 selects the target resistor feedback path, obtains the voltage value corresponding to the target resistor feedback path, and determines whether the voltage value corresponding to the target resistor feedback path is greater than a second voltage threshold. If the voltage value is not greater than the second voltage threshold, the preset power is used as the target power. If the voltage value is greater than the second voltage threshold, the driving circuit 50 drives the light-emitting device 40 to reduce its power until the voltage value of its corresponding power is less than the second voltage threshold, and the power at this time is used as the target power. This enables accurate detection of the fluorescence emitted by the substance to be tested, improving the user experience.

[0103] For example, if the second voltage threshold is 3V and the preset power is 3W, determine whether the voltage value corresponding to the target resistor feedback path is greater than 3V; if the voltage value is not greater than 3V, then the preset power is used as the target power, which is 3W; if the voltage value is greater than 3V, then control the driving circuit 50 to drive the light-emitting device 40 to reduce the power until the voltage value of its corresponding power is less than 3V, for example, when the power is 2W, the corresponding voltage value is less than 3V, and 2W is used as the target power.

[0104] S103. Control the photoelectric conversion circuit to select the target resistance feedback path so as to detect the fluorescence emitted by the substance to be tested through the target resistance feedback path.

[0105] Specifically, the control drive circuit 50 first drives the light-emitting device 40 to emit ultraviolet light at a target power to irradiate the substance under test, thereby enabling the photosensitive device 10 to detect the photocurrent corresponding to the fluorescence emitted by the substance under test. Then, the control photoelectric conversion circuit 20 selects the target resistance feedback path to detect the fluorescence emitted by the substance under test through the target resistance feedback path. This allows for accurate detection of the fluorescence emitted by the substance under test, improving the user experience.

[0106] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, and they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0107] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0108] The foregoing disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described above. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0109] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] The above embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of protection of this application. Any non-substantial changes and substitutions made by those skilled in the art based on this application shall fall within the scope of protection claimed by this application.

Claims

1. A fluorescence detection circuit, characterized in that, The fluorescence detection circuit includes: A photosensitive device, wherein the photosensitive device is used to detect the photocurrent corresponding to the fluorescence emitted by the substance to be tested; A photoelectric conversion circuit, connected to the photosensitive device, includes a second amplifier and a first multiplexer. The first input terminal of the second amplifier is grounded, and the second input terminal of the second amplifier is connected to the photosensitive device. The input terminal of the first multiplexer is connected to the output terminal of the second amplifier, and the output terminal of the first multiplexer is connected to the second terminal of the second amplifier to form multiple resistive feedback paths. The photoelectric conversion circuit is used to determine the voltage value based on the photocurrent and the pre-selected resistive feedback paths. A control circuit is connected to the output terminal of the first multiplexer. The control circuit is used to determine the target resistance feedback path from multiple resistance feedback paths according to the voltage value, and control the photoelectric conversion circuit to select the target resistance feedback path so as to detect the fluorescence emitted by the substance to be tested through the target resistance feedback path. A light-emitting device is disposed on a substrate, and the photosensitive device is used to emit ultraviolet light to irradiate the substance to be tested, so that the substance to be tested emits fluorescence. A driving circuit is connected to the light-emitting device and the control circuit. The driving circuit is used to drive the light-emitting device to emit ultraviolet rays at a preset power. The control circuit is further configured to determine the target power based on the voltage value corresponding to the target resistor feedback path, and control the driving circuit to drive the light-emitting device to emit ultraviolet light at the target power.

2. The fluorescence detection circuit according to claim 1, characterized in that, The driving circuit includes: A driver, the input of which is connected to the control circuit, and the output of which is connected to the light-emitting device, is used to control the light-emitting device to emit ultraviolet light according to the light-emitting command issued by the control circuit.

3. The fluorescence detection circuit according to claim 1, characterized in that, The fluorescence detection circuit also includes: A thermistor is disposed on the substrate; A temperature detection circuit is connected to the thermistor and the control circuit, and the temperature detection circuit is used to obtain the resistance value of the thermistor. The control circuit is further configured to determine the temperature of the substrate based on the resistance value of the thermistor, adjust the preset power based on the temperature of the substrate, and control the driving circuit to drive the light-emitting device to emit ultraviolet light at the adjusted preset power.

4. The fluorescence detection circuit according to claim 3, characterized in that, The temperature detection circuit includes: A first interface, wherein a first pin of the first interface is connected to a first end of the thermistor, a second pin of the first interface is connected to the first end of the thermistor and the control circuit, a third pin of the first interface is connected to the second end of the thermistor and the control circuit, and a fourth pin of the first interface is connected to the second end of the thermistor. The first amplifier has a first input terminal grounded, a second input terminal connected to the fourth pin of the first interface, and an output terminal connected to the first pin of the first interface.

5. The fluorescence detection circuit according to claim 1, characterized in that, The resistance feedback path includes: A resistor element, wherein a first end of the resistor element is connected to a second end of the second amplifier, and a second end of the resistor element is connected to the output end of the first multiplexer; A capacitor element, wherein the capacitor element is connected in parallel with the resistor element.

6. The fluorescence detection circuit according to any one of claims 1-5, characterized in that, The photosensitive device is a photodiode.

7. A fluorescence detection method, characterized in that, The method, using the fluorescence detection circuit as described in any one of claims 1-6, comprises: The photoelectric conversion circuit is controlled to select a preset resistor feedback path, and the voltage value and photocurrent value corresponding to the preset resistor feedback path are obtained. The target resistance feedback path is determined from multiple resistance feedback paths based on the voltage value and the photocurrent value; The photoelectric conversion circuit is controlled to select the target resistance feedback path so as to detect the fluorescence emitted by the substance to be tested through the target resistance feedback path.

8. The fluorescence detection method according to claim 7, characterized in that, The step of determining the target resistance feedback path from multiple resistance feedback paths based on the voltage value and the photocurrent value includes: Determine whether the voltage value is less than a first voltage threshold; If the voltage value is less than the first voltage value threshold, then the target resistance feedback path is determined based on the resistance value corresponding to each resistance feedback path and the photocurrent value.

9. The fluorescence detection method according to claim 7, characterized in that, After determining the target resistance feedback path from multiple resistance feedback paths based on the voltage value and the photocurrent value, the method further includes: Determine whether the voltage value corresponding to the target resistor feedback path is greater than the second voltage threshold; If the voltage value corresponding to the target resistor feedback path is greater than the second voltage threshold, the target power of the light-emitting device is determined based on the voltage value, and the driving circuit is controlled to drive the light-emitting device to emit ultraviolet light at the target power.

10. The fluorescence detection method according to claim 7, characterized in that, Before the photoelectric conversion circuit selects the preset resistor feedback path, the following steps are included: Obtain the resistance value of the thermistor, and determine the temperature of the substrate based on the resistance value of the thermistor; If the temperature of the substrate exceeds a preset temperature threshold, the preset power of the light-emitting device is adjusted, and the driving circuit is controlled to drive the light-emitting device to emit ultraviolet light at the adjusted preset power.

11. A fluorescence detection device, characterized in that, Includes the fluorescence detection circuit as described in any one of claims 1-6.

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