Infrared gas detection circuit, signal adjustment method and infrared gas sensor

Abstract

The application discloses an infrared gas detection circuit, a signal adjusting method and an infrared gas sensor, and particularly relates to the technical field of environment detection. The method comprises a light source module for emitting light with a preset flickering frequency; a detection module for collecting a target signal passing through the light and a reference signal passing through the light; an adjusting module for adjusting the concentration of the target signal to obtain a first gas signal and adjusting a signal irrelevant to the concentration in the reference signal to obtain a second gas signal; and a control module for controlling the light source module to emit the light, receiving the first gas signal and the second gas signal to calculate the concentration of a target gas and determining the target gas. The detection module and the adjusting module are arranged to detect and adjust the target signal and the reference signal to output the first gas signal and the second gas signal, the gas concentration is calculated according to the first gas signal and the second gas signal, and the target gas is determined, so that the production cost of the infrared gas sensor is reduced.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring technology, specifically to an infrared gas detection circuit, a signal adjustment method, and an infrared gas sensor. Background Technology

[0002] In production and living environments, it is frequently necessary to detect flammable or toxic gases. For example, gas sensors are installed in industrial sites, pipe corridors, and well sites to detect gases in the environment and prevent leaks that could endanger lives. However, existing gas sensors use pyroelectric sensors as the detection element, resulting in high costs. Furthermore, to ensure the proper functioning of the pyroelectric detection element, designers often complicate the sensor's circuitry, which in turn contributes to high production costs. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide an infrared gas detection circuit, device, and method to solve the problem of high production cost of infrared gas sensors.

[0004] According to a first aspect, embodiments of the present invention provide an infrared gas detection circuit, the circuit comprising:

[0005] The light source module is used to emit light at a preset flashing frequency;

[0006] The detection module is used to acquire the target signal and the reference signal that have passed through the light.

[0007] An adjustment module, connected to the detection module, is used to adjust the concentration of the target signal to obtain a first gas signal, and to adjust the concentration-independent signal in the reference signal to obtain a second gas signal;

[0008] The control module is connected to the adjustment module and the light source module respectively. It is used to control the light source module to emit the light and to receive the first gas signal and the second gas signal to calculate the concentration of the target gas and determine the target gas.

[0009] Optionally, the detection module includes:

[0010] A target detection element is used to receive the light and collect the target signal from the light. A first end of the target detection element is used to receive the light, and a second end of the target detection element is connected to the adjustment module. The second end of the target detection element is used to output the target signal.

[0011] A reference detection element is used to receive the light and collect the reference signal from the light. The first end of the reference detection element is used to receive the light, and the second end of the reference detection element is connected to the adjustment module. The second end of the reference detection element is used to output the reference signal.

[0012] Optionally, the detection module further includes:

[0013] A temperature sensing element is used to collect the temperature signal of the current environment; the first end of the temperature sensing element is used to collect the temperature signal of the current environment; the second end of the temperature sensing element is connected to the adjustment module, and the second end of the temperature sensing element is used to output the temperature signal.

[0014] Optionally, the adjustment module includes:

[0015] An offset voltage adjustment unit is used to receive an offset voltage adjustment signal sent by the control module, adjust the offset voltage of the target signal and the reference signal, and output the adjusted target signal and the adjusted reference signal; the first terminal of the offset voltage adjustment unit is connected to the control module, and the second terminal of the offset voltage adjustment unit is used to output an offset voltage adjustment signal to adjust the target signal and the reference signal;

[0016] A signal gain adjustment unit is used to receive an adjusted target signal, an adjusted reference signal, and a signal gain adjustment signal sent by the control module. Based on the signal gain adjustment signal, the unit adjusts the gain of the adjusted target signal and the adjusted reference signal, and outputs a first gas signal and a second gas signal. The first and second terminals of the signal gain adjustment unit are connected to the control module. The third terminal of the signal gain adjustment unit is used to receive the adjusted target signal. The fourth terminal of the signal gain adjustment unit is used to receive the adjusted reference signal. The fifth terminal of the signal adjustment unit is used to output the first gas signal, and the sixth terminal of the signal adjustment unit is used to output the second gas signal.

[0017] Optionally, the signal gain adjustment unit further includes:

[0018] First amplifier, second amplifier and signal gain adjustment subunit;

[0019] The first terminal of the first amplifier is used to acquire the adjusted target signal, the second terminal of the second amplifier is used to acquire the signal gain adjustment signal, and the second terminal of the first amplifier is connected to the signal gain adjustment subunit; the third terminal of the first amplifier is connected to the control module, and the third terminal of the first amplifier is used to output a first gas signal to the control module.

[0020] The first terminal of the second amplifier is used to acquire the adjusted reference signal, the second terminal of the second amplifier is used to acquire the signal gain adjustment signal, the second terminal of the first amplifier is connected to the signal gain adjustment subunit, the third terminal of the second amplifier is connected to the control module, and the third terminal of the second amplifier is used to output a second gas signal to the control module.

[0021] The first terminal of the signal gain adjustment subunit is connected to the second terminal of the first amplifier and the first terminal of the second amplifier, and the second terminal of the signal gain adjustment subunit is connected to the control module.

[0022] Optionally, the infrared gas detection circuit further includes:

[0023] A digital interface is provided, with its first end connected to the control module, and its second end connected to the second end of the signal gain adjustment subunit and the second end of the offset voltage adjustment unit. The digital interface is used to transmit the signal gain adjustment signal and the offset voltage adjustment signal sent by the control module.

[0024] According to a first aspect, embodiments of the present invention provide a signal adjustment method, the signal adjustment method being applicable to the infrared gas detection circuit described above, for adjusting the target signal and the reference signal, and outputting a first gas signal and a second gas signal, the signal adjustment method comprising:

[0025] Acquire the offset voltage adjustment signal and the signal gain adjustment signal;

[0026] According to the offset voltage adjustment signal and the signal gain adjustment signal, the target signal and the reference signal are adjusted until the adjusted target signal and the reference signal meet the preset voltage value range of the target signal and the preset voltage value range of the reference signal. The voltage value of the adjusted target signal that meets the voltage value range is output as the first gas signal and the voltage value of the adjusted reference signal that meets the voltage value range is output as the second gas signal.

[0027] Based on the first gas signal and the second gas signal, the target gas concentration and the target gas are determined.

[0028] Optionally, the voltage value of the target signal that meets the voltage range after output adjustment is used as the first gas signal, and the voltage value of the reference signal that meets the voltage range after output adjustment is used as the second gas signal, including:

[0029] Obtain the maximum and minimum voltage values ​​of the target signal that, after adjustment, satisfy the voltage value range;

[0030] Calculate the average value of the target signal based on its maximum and minimum voltage values;

[0031] The average value of the target signal is determined as the first gas signal;

[0032] And obtain the maximum and minimum voltage values ​​of the reference signal that, after adjustment, satisfy the voltage value range;

[0033] Calculate the maximum voltage value and the minimum voltage value of the reference signal, and calculate the average value of the reference signal.

[0034] The average value of the reference signal is determined as the second gas signal.

[0035] Optionally, determining the target gas concentration and target gas based on the first gas signal and the second gas signal further includes:

[0036] The absorption coefficient of the target gas is calculated based on the voltage values ​​of the first gas signal and the second gas signal.

[0037] Based on the absorption coefficient, the concentration of the target gas is calculated using the calibration algorithm, zero-point compensation algorithm, and temperature compensation algorithm.

[0038] According to a third aspect, embodiments of the present invention provide an infrared gas sensor, including a housing, wherein an infrared gas detection circuit provided in the first aspect is disposed within the housing, and the infrared gas detection circuit performs the gas concentration determination method described in the second aspect.

[0039] This application provides an infrared gas detection circuit that emits light at a preset flashing frequency through a light source module. Before being detected by the detection module, the light absorbs a target gas and a reference gas. The detection module then collects the light that has absorbed the target and reference gases to determine the target signal and the reference signal. To ensure that the control module can accurately detect the target and reference signals, the target and reference signals are sent to an adjustment module for voltage and signal gain adjustment. By setting the detection module and the adjustment module to detect and adjust the target and reference signals, a first gas signal and a second gas signal are output. The gas concentration is calculated based on the first and second gas signals to determine the target gas, thereby reducing the production cost of the infrared gas sensor. Attached Figure Description

[0040] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0041] Figure 1 This paper shows a structural block diagram of an infrared gas detection circuit provided in an embodiment of this application;

[0042] Figure 2 A circuit diagram of an infrared gas detection circuit provided in an optional embodiment of this application is shown;

[0043] Figure 3 A circuit diagram of an infrared gas detection circuit provided in an optional embodiment of this application is shown;

[0044] Figure 4 A flowchart of a signal adjustment method provided in an embodiment of this application is shown;

[0045] Figure 5 The diagram shows a waveform before signal adjustment in a signal adjustment method provided in this application embodiment.

[0046] Figure 6 The diagram shows a waveform after signal adjustment in a signal adjustment method provided in an embodiment of this application.

[0047] Figure 7 A schematic diagram of the structure of an infrared gas sensor provided in an embodiment of this application is shown.

[0048] Figure Labels

[0049] 1-Light source module; 2-Detection module; 3-Adjustment module; 4-Control module; 5-Housing; 31-Offset voltage adjustment unit; 32-Signal gain adjustment unit; 33-Digital interface; U1-First amplifier; U2-Second amplifier. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] like Figure 1 The diagram shows an infrared gas detection circuit provided in this application, which can be used to detect harmful gases. Specifically, the circuit may include: a light source module 1, a detection module 2, an adjustment module 3, and a control module 4. The control module 4 is connected to both the adjustment module 3 and the light source control module 1, and the detection module 2 is connected to the adjustment module 3.

[0052] The light source module 1 is used to emit light at a preset flashing frequency.

[0053] The detection module 2 is used to collect the target signal and the reference signal that have passed through the light.

[0054] The adjustment module 3 is used to adjust the concentration signal in the target signal to obtain the first gas signal, and to adjust the signal in the reference signal that is unrelated to concentration to obtain the second gas signal.

[0055] The control module 4 is used to control the light emitted by the light source module 1, and to receive the first gas signal and the second gas signal to calculate the concentration of the target gas and determine the target gas. In this embodiment, the light source module 1 emits light at a preset flashing frequency. Before being detected by the detection module 2, the light absorbs the target gas and the reference gas. Then, the detection module 2 collects the light that has absorbed the target gas and the reference gas to determine the target signal and the reference signal. To ensure that the control module 4 can accurately detect the target signal and the reference signal, the target signal and the reference signal need to be sent to the adjustment module 3 for voltage and signal gain adjustment. By setting the detection module 2 and the adjustment module 3 to detect and adjust the target signal and the reference signal, the first gas signal and the second gas signal are output. The gas concentration is calculated based on the first gas signal and the second gas signal to determine the target gas, thereby reducing the production cost of the infrared gas sensor.

[0056] Optionally, the light source module 1 can be an incandescent lamp or an infrared lamp. In this embodiment, the light emitted by the incandescent lamp includes infrared light. Because incandescent lamps are relatively cheaper than infrared lamps, it is preferable to use an incandescent lamp for the light source module.

[0057] Optionally, in this embodiment, the light source module 1 will emit light with a regularly changing flashing frequency of 1Hz to 4Hz to facilitate the detection of the target gas.

[0058] Optionally, an optical path is also provided between the light transmission and the detection device. This optical path consists of the upper and lower parts of the gas chamber. The upper and lower parts combine to form the gas chamber, where infrared light emitted from the light source is continuously emitted and eventually reaches the detection element. It should be noted that the gas chamber is not sealed; it has an air vent at the top. The target gas to be detected enters the gas chamber through the air vent and resonates / absorbs with the infrared light along the optical path. The resonant / absorbed light is then sent to the detection module 2 for detection, thereby achieving gas detection.

[0059] Optionally, the light source module 1 can emit at least two beams of light, one beam for absorbing the target gas and the other beam for absorbing the reference gas.

[0060] Optionally, the detection module 2 may include a target detection element and a reference detection element.

[0061] The target detection element is used to receive light and collect target signals from the light. The first end of the target detection element receives light, and the second end is connected to the adjustment module and outputs the target signal.

[0062] The reference detection element is used to receive light and collect a reference signal from the light. The first end of the reference detection element is used to receive light, and the second end of the reference detection element is connected to the adjustment module 3 and is used to output the reference signal.

[0063] Optionally, to save costs, in this embodiment, the target detection element and the reference detection element are thermopile elements. The target detection element and the reference detection element include a detection channel and a narrowband filter. In the target detection element, only infrared light at the resonant frequency of the target gas can pass through. This part of the infrared energy will change according to the concentration of the target gas. The reference detection element can only pass through infrared light that does not resonate with the target gas. This part of the energy is independent of the concentration of the target gas and will be used as a reference signal.

[0064] Optionally, the detection module 2 also includes a temperature detection element for acquiring the temperature signal of the current environment; the first end of the temperature detection element is used to acquire the temperature signal of the current environment; the second end of the temperature detection element is connected to the adjustment module 3, and the second end of the temperature detection element is used to output the temperature signal.

[0065] The temperature detection element can be a temperature sensor, used to detect the temperature of the infrared gas detection circuit to prevent inaccurate detection results due to excessively high ambient temperature.

[0066] like Figure 2 The diagram illustrates an infrared gas detection circuit provided in this application. This infrared gas detection circuit includes a light source module 1, a detection module 2, an adjustment module 3, and a control module 4 as described in the above embodiments. The detection module may further include:

[0067] The offset voltage adjustment unit 31 is used to receive the offset voltage adjustment signal sent by the control module 4, adjust the offset voltage of the target signal and the reference signal, and output the adjusted target signal and the adjusted reference signal. The first end of the offset voltage adjustment unit is connected to the control module 4, and the second end of the offset voltage adjustment unit 31 is used to output the offset voltage adjustment signal for adjusting the target signal and the reference signal.

[0068] The signal gain adjustment unit 32 is used to receive the adjusted target signal, the adjusted reference signal, and the signal gain adjustment signal sent by the control module 4. Based on the signal gain adjustment signal, it adjusts the gain of the adjusted target signal and the adjusted reference signal, and outputs a first gas signal and a second gas signal. The first and second terminals of the signal gain adjustment unit 32 are connected to the control module 4. The third terminal of the signal gain adjustment unit 32 is used to receive the adjusted target signal. The fourth terminal of the signal gain adjustment unit 32 is used to receive the adjusted reference signal. The fifth terminal of the signal adjustment unit is used to output the first gas signal, and the sixth terminal of the signal adjustment unit is used to output the second gas signal.

[0069] Optionally, the signal gain adjustment unit 32 further includes:

[0070] First amplifier U1, second amplifier U2, and signal gain adjustment subunit;

[0071] The first terminal of the first amplifier U1 is used to acquire the adjusted target signal, the second terminal of the first amplifier U1 is used to acquire the signal gain adjustment signal, and the second terminal of the first amplifier U1 is connected to the signal gain adjustment subunit; the third terminal of the first amplifier U1 is connected to the control module, and the third terminal of the first amplifier U1 is used to output the first gas signal to the control module.

[0072] The first terminal of the second amplifier U2 is used to acquire the adjusted reference signal, and the second terminal of the second amplifier U2 is used to acquire the signal gain adjustment signal. The second terminal of the first amplifier U2 is connected to the signal gain adjustment subunit. The third terminal of the second amplifier U2 is connected to the control module and is used to output the second gas signal to the control module.

[0073] The first end of the signal gain adjustment subunit is connected to the second end of the first amplifier U1 and the first end of the second amplifier U2, and the second end of the signal gain adjustment subunit is connected to the control module 4.

[0074] Optional, such as Figure 3 As shown, the infrared gas detection circuit provided in this application further includes:

[0075] Digital interface 33, the first end of the digital interface is connected to the control module, the second end of the digital interface is connected to the second end of the signal gain adjustment subunit and the second end of the offset voltage adjustment unit, and the digital interface is used to transmit the signal gain adjustment signal and the offset voltage adjustment signal sent by the control module.

[0076] Optionally, in this embodiment, the detection module can be a signal conditioning circuit, which can dynamically adjust the DC bias voltage and amplification gain by the control module, that is, amplify the target signal and the reference signal, so that the control module can quickly detect the target gas.

[0077] Optionally, the control module can be a controller with analog-to-digital conversion capabilities, such as a microcontroller or a programmable logic device. In this embodiment, the control module can control the light source module to flash at a preset frequency. The analog-to-digital conversion function in the control module can convert the collected voltage information of the target gas or the voltage information or temperature information of the reference gas into digital signals. The control module then calculates the concentration of the target gas according to a calculation method preset within the control module, thus determining the target gas. Optionally, the magnitude of the DC offset voltage and the gain can both be adjusted by the control module.

[0078] Optionally, a digital interface is used to send the signal gain adjustment signal and the offset voltage adjustment signal to the control module through a single connection port, thereby avoiding the use of multiple control ports.

[0079] Additionally, it should be noted that the detection device used in the detection module of this application is a thermopile. A thermopile is a component that can convert temperature difference and electrical energy into each other. It can be composed of multiple thermocouples connected in series. The thermoelectric potentials output by each thermocouple are superimposed. When a temperature difference occurs on both sides of the thermopile, a current will be generated.

[0080] When using a thermopile to measure temperature changes, the drawback of a single thermocouple being too small to measure can be overcome, thus avoiding the need for expensive high-precision operational amplifiers.

[0081] Furthermore, the thermopile sensor used in this application incorporates both sensitive and non-sensitive filters for the target gas. It can simultaneously detect both the infrared signal of the target gas and the reference infrared signal. This dual-channel simultaneous detection eliminates signal variations caused by optical path contamination and light source degradation.

[0082] In this invention, the thermopile sensor also has a temperature detection sensor, which can detect the temperature inside the sensor and perform zero-point tracking and temperature compensation.

[0083] Thermopile sensors have the advantages of being easy to manufacture and inexpensive. However, they have disadvantages such as relatively high output impedance, small signal strength, and a large temperature coefficient. Therefore, to overcome these shortcomings, an adjustment module and a gas concentration determination method are used, thus reducing the manufacturing cost of infrared gas sensors.

[0084] Optionally, the DC offset can be determined by the control module acquiring the voltage values ​​of the target gas signal and the reference gas signal, determining the maximum and minimum values ​​of the input signal, and then calculating the average value to determine the DC offset of the input signal.

[0085] like Figure 4 As shown, this application provides a signal adjustment method applied to an infrared gas detection circuit. By adjusting a target signal and a reference signal, a first gas signal and a second gas signal are output. The method includes the following steps:

[0086] S1, acquire the offset voltage adjustment signal and the signal gain adjustment signal.

[0087] In this embodiment, the control module controls the signal gain adjustment unit and the offset voltage adjustment unit to output the offset voltage adjustment signal and the signal gain adjustment signal. The signal gain adjustment unit can be composed of a logic unit or a signal amplifier, and the offset voltage adjustment unit can be composed of an adjustable voltage source.

[0088] S2, adjust the target signal and reference signal according to the offset voltage adjustment signal and the signal gain adjustment signal until the adjusted target signal and reference signal meet the preset voltage value range of the target signal and the preset voltage value range of the reference signal. Output the voltage value of the adjusted target signal that meets the voltage value range as the first gas signal and output the voltage value of the adjusted reference signal that meets the voltage value range as the second gas signal.

[0089] In this embodiment, the maximum and minimum voltage values ​​of the target signal that meet the voltage range after adjustment are obtained;

[0090] Calculate the average value of the target signal based on its maximum and minimum voltage values;

[0091] The average value of the target signal is determined as the first gas signal;

[0092] And obtain the maximum and minimum voltage values ​​of the reference signal that meets the voltage range after adjustment;

[0093] Calculate the average value of the reference signal for its maximum and minimum voltage values;

[0094] The average value of the reference signal is used as the second gas signal.

[0095] In this embodiment, the control module can acquire the voltage values ​​of the target signal and the reference signal, determine the maximum and minimum values ​​of the target signal and the reference signal, and then calculate the average value to obtain the result. Figure 5The signal waveform diagram shown is provided, where 3.1V is the upper limit voltage, 0.2V is the lower limit voltage, and k is the average value of the signal before adjustment.

[0096] The waveform was then adjusted by the adjustment module to obtain the following result: Figure 6 The signal waveform diagram shown indicates that 3.1V is the upper limit voltage, 0.2V is the lower limit voltage, and K is the average value after signal adjustment. By setting the adjustment module, the detection range of the infrared gas sensor can be widened, further improving the accuracy of infrared gas sensor detection.

[0097] S3, based on the first gas signal and the second gas signal, determine the target gas concentration and the target gas.

[0098] In this embodiment, it may also include:

[0099] The absorption coefficient of the target gas is calculated based on the voltage values ​​of the first gas signal and the second gas signal.

[0100] Based on the absorption coefficient, the concentration of the target gas is calculated using calibration algorithms, zero-point compensation algorithms, and temperature compensation algorithms.

[0101] In this embodiment, the DC offset voltage is adjusted by the control module to achieve automatic gain adjustment, preventing inaccurate gas detection caused by excessively large or large signals.

[0102] like Figure 7 As shown, this application provides an infrared gas sensor, including: a housing 5, and an infrared gas detection circuit provided in the above embodiments is disposed inside the housing 5, wherein the infrared detection circuit performs the signal adjustment method provided in the above embodiments.

[0103] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An infrared gas detection circuit, characterized in that, include: The light source module is used to emit light with a preset flashing frequency that varies regularly from 1Hz to 4Hz; wherein, the light source module emits at least two beams of light, one beam is used to absorb the target gas, and the other beam is used to absorb the reference gas. The detection module is used to acquire the target signal and the reference signal of the light passing through it; wherein, the detection module is a thermopile sensor with a sensitive filter and a non-sensitive filter for the target gas, and simultaneously detects the infrared signal of the target gas and the infrared signal of the reference; the thermopile sensor also has a temperature detection sensor for acquiring the temperature signal of the current environment, and performing zero-point tracking and temperature compensation. An adjustment module, connected to the detection module, is used to adjust the concentration signal in the target signal by offset voltage and gain to obtain a first gas signal, and to adjust the signal in the reference signal that is unrelated to concentration by offset voltage and gain to obtain a second gas signal. The control module is connected to the adjustment module and the light source module respectively. It is used to control the light source module to emit light and to receive the first gas signal and the second gas signal to calculate the concentration of the target gas and determine the target gas. The absorption coefficient of the target gas is calculated based on the voltage values ​​of the first gas signal and the second gas signal. The concentration of the target gas is calculated based on the absorption coefficient using a calibration algorithm, a zero-point compensation algorithm and a temperature compensation algorithm. The detection module includes a target detection element and a reference detection element. The target detection element can only transmit infrared light at the resonant frequency of the target gas. This portion of infrared energy varies depending on the concentration of the target gas. The reference detection element can only transmit infrared light that does not resonate with the target gas. This portion of energy is independent of the concentration of the target gas and serves as a reference signal.

2. The infrared gas detection circuit according to claim 1, characterized in that, The detection module includes: A target detection element is used to receive the light and collect the target signal from the light. A first end of the target detection element is used to receive the light, and a second end of the target detection element is connected to the adjustment module. The second end of the target detection element is used to output the target signal. A reference detection element is used to receive the light and collect the reference signal from the light. The first end of the reference detection element is used to receive the light, and the second end of the reference detection element is connected to the adjustment module. The second end of the reference detection element is used to output the reference signal.

3. The infrared gas detection circuit according to claim 2, characterized in that, The detection module also includes: A temperature sensing element is used to collect the temperature signal of the current environment; the first end of the temperature sensing element is used to collect the temperature signal of the current environment; the second end of the temperature sensing element is connected to the adjustment module, and the second end of the temperature sensing element is used to output the temperature signal.

4. The infrared gas detection circuit according to claim 1, characterized in that, The adjustment module includes: An offset voltage adjustment unit is used to receive an offset voltage adjustment signal sent by the control module, adjust the offset voltage of the target signal and the reference signal, and output the adjusted target signal and the adjusted reference signal; the first terminal of the offset voltage adjustment unit is connected to the control module, and the second terminal of the offset voltage adjustment unit is used to output an offset voltage adjustment signal to adjust the target signal and the reference signal; A signal gain adjustment unit is used to receive an adjusted target signal, an adjusted reference signal, and a signal gain adjustment signal sent by the control module. Based on the signal gain adjustment signal, the unit adjusts the gain of the adjusted target signal and the adjusted reference signal, and outputs a first gas signal and a second gas signal. The first and second terminals of the signal gain adjustment unit are connected to the control module. The third terminal of the signal gain adjustment unit is used to receive the adjusted target signal. The fourth terminal of the signal gain adjustment unit is used to receive the adjusted reference signal. The fifth terminal of the signal adjustment unit is used to output the first gas signal, and the sixth terminal of the signal adjustment unit is used to output the second gas signal.

5. The infrared gas detection circuit according to claim 4, characterized in that, The signal gain adjustment unit further includes: First amplifier, second amplifier and signal gain adjustment subunit; The first terminal of the first amplifier is used to acquire the adjusted target signal, the second terminal of the second amplifier is used to acquire the signal gain adjustment signal, and the second terminal of the first amplifier is connected to the signal gain adjustment subunit; the third terminal of the first amplifier is connected to the control module, and the third terminal of the first amplifier is used to output a first gas signal to the control module. The first terminal of the second amplifier is used to acquire the adjusted reference signal, the second terminal of the second amplifier is used to acquire the signal gain adjustment signal, the second terminal of the first amplifier is connected to the signal gain adjustment subunit, the third terminal of the second amplifier is connected to the control module, and the third terminal of the second amplifier is used to output a second gas signal to the control module. The first terminal of the signal gain adjustment subunit is connected to the second terminal of the first amplifier and the first terminal of the second amplifier, and the second terminal of the signal gain adjustment subunit is connected to the control module.

6. The infrared gas detection circuit according to claim 5, characterized in that, The infrared gas detection circuit further includes: A digital interface is provided, with its first end connected to the control module, and its second end connected to the second end of the signal gain adjustment subunit and the second end of the offset voltage adjustment unit. The digital interface is used to transmit the signal gain adjustment signal and the offset voltage adjustment signal sent by the control module.

7. A signal adjustment method, characterized in that, The signal adjustment method is applicable to the infrared gas detection circuit as described in claim 1, and is used to adjust the target signal and the reference signal to output a first gas signal and a second gas signal. The signal adjustment method includes: Acquire the offset voltage adjustment signal and the signal gain adjustment signal; According to the offset voltage adjustment signal and the signal gain adjustment signal, the target signal and the reference signal are adjusted until the adjusted target signal and the reference signal meet the preset voltage value range of the target signal and the preset voltage value range of the reference signal. The voltage value of the adjusted target signal that meets the voltage value range is output as the first gas signal and the voltage value of the adjusted reference signal that meets the voltage value range is output as the second gas signal. Based on the first gas signal and the second gas signal, the target gas concentration and the target gas are determined.

8. The signal adjustment method according to claim 7, characterized in that, The voltage value of the target signal, which meets the voltage range after output adjustment, is used as the first gas signal, and the voltage value of the reference signal, which meets the voltage range after output adjustment, is used as the second gas signal, including: Obtain the maximum and minimum voltage values ​​of the target signal that, after adjustment, satisfy the voltage value range; Calculate the average value of the target signal based on its maximum and minimum voltage values; The average value of the target signal is determined as the first gas signal; And obtain the maximum and minimum voltage values ​​of the reference signal that, after adjustment, satisfy the voltage value range; Calculate the maximum voltage value and the minimum voltage value of the reference signal, and calculate the average value of the reference signal. The average value of the reference signal is determined as the second gas signal.

9. The signal adjustment method according to claim 7, characterized in that, The step of determining the target gas concentration and the target gas based on the first gas signal and the second gas signal further includes: The absorption coefficient of the target gas is calculated based on the voltage values ​​of the first gas signal and the second gas signal. Based on the absorption coefficient, the concentration of the target gas is calculated using the calibration algorithm, zero-point compensation algorithm, and temperature compensation algorithm.

10. An infrared gas sensor, characterized in that, The device includes a housing, within which is disposed an infrared gas detection circuit as described in any one of claims 1-6, the infrared gas detection circuit performing the signal adjustment method as described in any one of claims 7-9.

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