A voltage acquisition circuit and a gas sensor

Abstract

This invention discloses a voltage acquisition circuit and a gas sensor. The circuit includes an adjustable load module, a control module, and a voltage acquisition module. The adjustable load module includes multiple first-type resistors, each with its first terminal connected to a first terminal of the gas sensor. The first terminals of these resistors are also connected to multiple first-type ports of the control module. The control module sends a control signal to the adjustable load module according to the type of the gas sensor, controlling at least a portion of the first-type resistors to ground their second terminals. The first terminal of the voltage acquisition module is connected to the first terminal of the gas sensor, and its second terminal is connected to the first terminal of the control module. The technical solution provided by this invention allows for flexible adjustment of the load resistor value based on the gas sensor's ID, enabling users to quickly replace the gas sensor without changing the circuit configuration.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a voltage acquisition circuit and a gas sensor. Background Technology

[0002] Combustible gas detectors play a vital role in industrial and home safety, and their detection accuracy directly impacts the effectiveness of safety protection. Therefore, selecting a suitable gas sensor and its matching load resistor is crucial.

[0003] Existing technology achieves the required load resistance value by connecting multiple resistors in parallel, which can meet the needs of different gas detection requirements. However, since different ID gas sensors correspond to different load resistor values, if a different ID gas sensor needs to be replaced, a resistor with the corresponding resistance value must also be replaced. In other words, the existing technology has the drawback of difficulty in flexibly adjusting the load resistor value when replacing a gas sensor of the same model but different ID. Summary of the Invention

[0004] This invention provides a voltage acquisition circuit and a gas sensor to solve the problem that the resistance value of the load resistor is difficult to adjust flexibly when replacing gas sensors of the same model but different IDs.

[0005] According to one aspect of the present invention, a voltage acquisition circuit is provided for acquiring a gas concentration signal at a first end of a gas sensor, comprising: an adjustable load module, a control module, and a voltage acquisition module;

[0006] The adjustable load module includes a plurality of first-type resistors, the first ends of which are all connected to the first end of the gas sensor, and the first ends of the plurality of first-type resistors are respectively connected to a plurality of first-type ports of the control module; the control module sends a control signal to the adjustable load module according to the type of the gas sensor, and controls at least a portion of the first-type resistors to ground their second ends.

[0007] The first end of the voltage acquisition module is connected to the first end of the gas sensor, and the second end of the voltage acquisition module is connected to the first end of the control module. The voltage acquisition module is used to transmit the gas concentration signal output by the gas sensor to the control module.

[0008] Optionally, the resistance values ​​of the plurality of first-type resistors are not necessarily equal.

[0009] Optionally, the adjustable load module further includes: a first resistor and a first capacitor;

[0010] The first resistor is connected between the first terminal of the gas sensor and the ground terminal, and the first capacitor is connected in parallel with the first resistor.

[0011] Optionally, the voltage acquisition module includes: a buffer unit and a protection unit;

[0012] The first end of the buffer unit is connected to the first end of the gas sensor; the power supply end of the buffer unit is connected to the first DC voltage source.

[0013] The first end of the protection unit is connected to the second end of the buffer unit, and the second end of the protection unit is connected to the first end of the control module. The protection unit is used to limit the voltage input to the input terminal of the control module when the gas concentration signal is greater than a first preset voltage; or to clamp the voltage at the input terminal of the control module to a third preset voltage when the voltage output at the first end of the gas sensor is greater than or equal to a second preset voltage; wherein the second preset voltage is greater than the first preset voltage.

[0014] Optionally, the buffer unit includes: a first operational amplifier;

[0015] The first input terminal of the first operational amplifier is connected to the first terminal of the gas sensor, the second input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, the first power supply terminal of the first operational amplifier is connected to the first DC voltage source, and the second power supply terminal of the first operational amplifier is connected to the ground terminal.

[0016] Optionally, the protection unit includes: a second resistor and a first diode;

[0017] The second resistor is connected between the second end of the buffer unit and the ground terminal;

[0018] The first end of the first diode is connected to the first end of the control module, and the second end of the first diode is connected to the second DC voltage source.

[0019] Optionally, it may also include: a first filtering module, a second filtering module, and a third filtering module;

[0020] The first filtering module is connected to the second end of the gas sensor, and the first filtering module is used to filter the signal input to the second end of the gas sensor.

[0021] The second filtering module is connected between the third terminal of the buffer unit and the first DC voltage source, and the second filtering module is used to filter out the noise of the first DC voltage source;

[0022] The first end of the third filtering module is connected to the second end of the buffer unit, and the second end of the third filtering module is connected to the first end of the protection unit. The third filtering module is used to filter the signal output by the buffer unit.

[0023] Optionally, the first filtering module includes:

[0024] The system comprises a first magnetic bead assembly, a second capacitor, and a third capacitor; a first terminal of the first magnetic bead assembly is connected to a third DC voltage source, and a second terminal of the first magnetic bead assembly is connected to a second terminal of the gas sensor; the second capacitor is connected between the second terminal of the first magnetic bead assembly and a ground terminal; and the third capacitor is connected in parallel with the second capacitor.

[0025] Optionally, the second filtering module includes:

[0026] The second magnetic bead assembly, the fourth capacitor, and the fifth capacitor; the first end of the second magnetic bead assembly is connected to the third end of the buffer unit, and the second end of the second magnetic bead assembly is connected to the first DC voltage source; the fourth capacitor is connected between the first end of the second magnetic bead assembly and the ground terminal; the fifth capacitor is connected between the second end of the second magnetic bead assembly and the ground terminal.

[0027] Optionally, the third filtering module includes: a third resistor and a sixth capacitor;

[0028] The third resistor is connected between the second end of the buffer unit and the first end of the protection unit; the sixth capacitor is connected between the first end of the protection unit and the grounding end.

[0029] The technical solution of this invention controls different first-type resistors in the adjustable load module to be grounded according to the different IDs of the gas sensors, thereby adjusting the resistance value of the adjustable module. This ensures that the first terminals of gas sensors with different IDs can output gas concentration signals within a reasonable threshold range. The technical solution provided by this invention allows for flexible adjustment of the load resistor value based on the gas sensor ID, enabling users to quickly replace gas sensors without changing the circuit configuration. Furthermore, this technical solution does not require individually matching load resistors for each gas sensor with a different ID, significantly improving production efficiency and reducing costs. In addition, this technical solution can adapt to new ID sensors that may emerge in the future, exhibiting good scalability and compatibility.

[0030] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a voltage acquisition circuit provided in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] Figure 1This is a schematic diagram of a voltage acquisition circuit provided in an embodiment of the present invention. This embodiment is applicable to situations where a gas sensor acquires gas concentration. Figure 1 As shown, the voltage acquisition circuit includes: an adjustable load module 110, and a control module ( Figure 1 (Not shown in the image) and voltage acquisition module 130. Adjustable load module 110 includes multiple first-type resistors 111, the first ends of which are all connected to the first end of the gas sensor. The first ends of the multiple first-type resistors 111 are respectively connected to multiple first-type ports of the control module. The control module sends a control signal to the adjustable load module 110 according to the type of gas sensor, controlling at least some of the first-type resistors 111 to ground their second ends. The first end of voltage acquisition module 130 is connected to the first end of the gas sensor, and the second end of voltage acquisition module 130 is connected to the first end of the control module. Voltage acquisition module 130 is used to transmit the gas concentration signal output by the gas sensor to the control module.

[0040] For example, the gas sensor is electrically connected to the voltage acquisition circuit through the gas sensor interface 140, and the various pins of the gas sensor are brought out. Specifically, the first end of the gas sensor interface 140 is electrically connected to the first end of the gas sensor, and the first end of the gas sensor interface 140 transmits the signal RS-. Therefore, the first ends of the plurality of first-class resistors 111 and the first end of the voltage acquisition module are connected to the first end of the gas sensor through the first end of the gas sensor interface 140.

[0041] Specifically, a gas sensor is a device used to detect the composition and concentration of gases, and is widely used in environmental monitoring, safety protection, and other fields. A gas concentration signal is a voltage signal generated by the gas sensor, representing the concentration of a specific gas, and is usually related to the physical and chemical properties of the gas. The voltage acquisition module 130 is the component responsible for acquiring the gas concentration signal from the gas sensor and converting it into a data format suitable for subsequent processing.

[0042] The adjustable load module 110 refers to a component in the voltage acquisition circuit, comprising multiple first-type resistors 111. The adjustable load module 110 can match the corresponding load resistance value according to the gas sensor's identification (ID) to meet the requirements of different ID gas sensors. The first-type resistor 111 refers to the type of resistor used in the adjustable load module 110. In this embodiment, the control module can send a low level to one or more of its first-type ports, which is equivalent to controlling one or more first-type resistors 111 connected to its first-type ports to ground, thereby adjusting the resistance value of the adjustable load module. The control module refers to the module responsible for managing and adjusting the operating state of the entire voltage acquisition circuit. For example, the control module can adjust the resistance value of the adjustable load module 110 to ensure that the voltage acquisition circuit can adjust accordingly based on changes in the gas concentration signal; the control module can also receive the voltage signal acquired by the voltage acquisition module 130 and transmit it to the host computer. For example, the control module is a microcontroller unit (MCU).

[0043] In this embodiment of the invention, the second end of the gas sensor is connected to the third DC voltage source 153 via the gas sensor interface 140, and the first end of the gas sensor is connected to the adjustable load module 110. The control module controls one or more resistors of the adjustable load module 110 to be grounded according to the ID of different gas sensors, thereby adjusting the resistance value of the adjustable load module 110. For example, the gas sensor can be equivalent to a resistor; that is, the second end of the resistor is connected to the third DC voltage source 153, and the first end of the resistor is connected to the adjustable load module 110. The adjustable load module 110 includes multiple first-type resistors 111. By controlling the number of grounded first-type resistors 111, the magnitude of the voltage obtained by voltage division at the first end of the gas sensor can be adjusted. That is, this embodiment of the invention adjusts the voltage value of the gas concentration signal output from the first end of the gas sensor by adjusting the resistance value of the adjustable load module 110, ensuring that the gas concentration signals output by gas sensors with different IDs are within a reasonable threshold range. The voltage acquisition module 130 is responsible for further processing the gas concentration signal and transmitting it to the control module.

[0044] The technical solution of this invention controls different first-type resistors in the adjustable load module to be grounded according to the different IDs of the gas sensors, thereby adjusting the resistance value of the adjustable module. This ensures that the first terminals of gas sensors with different IDs can output gas concentration signals within a reasonable threshold range. The technical solution provided by this invention allows for flexible adjustment of the load resistor value based on the gas sensor ID, enabling users to quickly replace gas sensors without changing the circuit configuration. Furthermore, this technical solution does not require individually matching load resistors for each gas sensor with a different ID, significantly improving production efficiency and reducing costs. In addition, this technical solution can adapt to any type of ID sensor, exhibiting good scalability and compatibility.

[0045] Based on the above embodiments, optionally, the resistance values ​​of the plurality of first-type resistors 111 are not completely equal.

[0046] For example, let's take a scenario where there are four Class I resistors 111. When the adjustable load module 110 contains four Class I resistors 111 with unequal resistance values, 16 different resistance values ​​can be obtained. However, since each gas sensor ID requires a specific load resistor value, and some of the 16 values ​​are close to each other while others are too large or too small, only a portion can be adapted to the gas sensor. Furthermore, depending on the selected gas sensor ID, eight more suitable resistance values ​​can be selected from the 16 resistance values ​​as backups. Additionally, if necessary, several resistors can be added appropriately, thereby selecting load resistor values ​​suitable for more different gas sensor IDs from the combined 32 or even 64 resistance values.

[0047] It should be noted that the embodiments of the present invention are only illustrated by using four first-class resistors 111 as examples, and do not constitute a limitation on the number of first-class resistors 111.

[0048] Figure 2 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention. Based on the above embodiments, alternatively, such as... Figure 2 As shown, the adjustable load module 110 also includes a first resistor 112 and a first capacitor 113; the first resistor 112 is connected between the first end of the gas sensor and the ground end, and the first capacitor 113 is connected in parallel with the first resistor 112.

[0049] In this embodiment of the invention, the first resistor 112 serves as the base load resistor. The first resistor 112 is a non-adjustable load. When the first type of resistor 111 in the control module is grounded, the first resistor 112 is effectively connected in parallel with this first type of resistor 111, which can effectively stabilize the gas concentration signal output by the gas sensor. In addition, the first capacitor 113 and the first resistor 112 are connected in parallel to form an RC filter, thereby smoothing the signal output by the gas sensor and filtering out high-frequency noise.

[0050] The technical solution of this invention uses multiple first-type resistors, a first resistor, and a first capacitor to form the load resistor of the gas sensor, which avoids excessive resistors occupying circuit board area and saves costs to a certain extent. Furthermore, the load resistor value can be automatically and flexibly set according to the gas sensor ID, avoiding the existence of multiple versions of the circuit board. When purchasing gas sensors, there is no limitation to a specific sensor ID, reducing the procurement cycle and minimizing stockout pressure. During after-sales maintenance, even if a gas sensor with a different ID is selected for replacement, it is not necessary to resolder the circuit board load resistor. In short, the technical solution of this invention significantly improves the application range and flexibility of gas sensors and reduces maintenance costs.

[0051] Figure 3 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention. Based on the above embodiments, alternatively, such as... Figure 3 As shown, the voltage acquisition module 130 includes a buffer unit 131 and a protection unit 132. The first end of the buffer unit 131 is connected to the first end of the gas sensor; the power supply terminal of the buffer unit 131 is connected to the first DC voltage source 151. The first end of the protection unit 132 is connected to the second end of the buffer unit 131, and the second end of the protection unit 132 is connected to the first end of the control module. The protection unit 132 is used to limit the voltage input to the control module when the gas concentration signal is greater than a first preset voltage; or to clamp the voltage at the input of the control module to a third preset voltage when the voltage output from the first end of the gas sensor is greater than or equal to a second preset voltage; wherein the second preset voltage is greater than the first preset voltage.

[0052] Specifically, buffer unit 131 is a component used to isolate the output of the gas sensor from subsequent circuits, ensuring signal transmission stability and preventing load from affecting the sensor's output. Protection unit 132 is a component responsible for protecting the control module from excessively high voltage input. The protection module has two ports: one connected to the output of buffer unit 131, and the other connected to the input of the control module, ensuring that the input voltage is limited or clamped under specific conditions. The first preset voltage refers to a set first voltage threshold. When the gas concentration signal exceeds the first preset voltage, protection unit 132 limits the input voltage of the control module to prevent overload. The second preset voltage refers to a set second voltage threshold, higher than the first preset voltage. When the output voltage of the gas sensor reaches or exceeds the second preset voltage, protection unit 132 clamps the input voltage of the control module to a third preset voltage.

[0053] In this embodiment of the invention, a gas sensor detects the gas concentration and outputs the corresponding gas concentration signal to a buffer unit 131. The buffer unit 131 isolates and amplifies the input signal to prevent the load from affecting the gas sensor output. The output signal of the buffer unit 131 is transmitted to a protection unit 132. The protection unit 132 monitors the signal voltage. When the gas concentration signal exceeds a first preset voltage, the protection unit 132 limits the input voltage of the control module to prevent overload. If the output voltage of the gas sensor reaches or exceeds a second preset voltage, the protection unit 132 clamps the input voltage of the control module at a third preset voltage to ensure that the control module is not affected by excessively high voltage. The buffered and protected gas concentration signal is then transmitted to the control module for further processing and analysis, thereby achieving the monitoring and control of the gas concentration.

[0054] The technical solution of this invention effectively collects, stabilizes, and protects the output signal of the gas sensor through a buffer module and a protection module, significantly improving the safety and reliability of the voltage acquisition circuit.

[0055] Figure 4 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention. Based on the above embodiments, alternatively, such as... Figure 4 As shown, the buffer unit 131 includes: a first operational amplifier 133; the first input terminal of the first operational amplifier 133 is connected to the first terminal of the gas sensor, the second input terminal of the first operational amplifier 133 is connected to the output terminal of the first operational amplifier 133, the first power supply terminal of the first operational amplifier 133 is connected to the first DC voltage source 151, and the second power supply terminal of the first operational amplifier 133 is connected to the ground terminal.

[0056] Specifically, the first operational amplifier 133 refers to an electronic component used to amplify input signals. The first operational amplifier 133 includes two input terminals, namely a non-inverting input terminal and an inverting input terminal, and also includes an output terminal, which can realize signal gain and processing.

[0057] In this embodiment of the invention, connecting the first input terminal of the first operational amplifier 133 to the output of the gas sensor allows for direct acquisition of the sensor's voltage signal. The connection between the second input terminal and the output terminal of the first operational amplifier 133 forms a feedback loop, enhancing circuit stability and ensuring that the relationship between the output signal and the input signal is amplified at a set gain. Connecting the first power supply terminal of the first operational amplifier 133 to a DC voltage source ensures sufficient voltage for signal processing; grounding the second power supply terminal provides a stable reference voltage.

[0058] Based on the above embodiments, optionally, the protection unit 132 includes: a second resistor 134 and a first diode 135. The second resistor 134 is connected between the second end of the buffer unit 131 and the ground end; the first end of the first diode 135 is connected to the first end of the control module, and the second end of the first diode 135 is connected to the second DC voltage source 152.

[0059] In this embodiment of the invention, the second resistor 134 is a reserved voltage divider resistor used to divide the voltage output from the first terminal of the gas sensor when, under certain special conditions (such as high temperature and humidity or high concentration of gas), it exceeds the voltage acquisition limit of the analog-to-digital converter (ADC) of the control module. The ADC voltage acquisition limit of the control module is the first preset voltage. For example, the first preset voltage is 3.3 volts. The first diode 135 is a clamping diode used to protect the GPIO port of the control module. If the gas sensor pin is connected incorrectly, the output voltage at its first terminal may exceed the second preset voltage. At this time, the first diode 135 conducts, which can limit the voltage input to the first terminal of the control module to within the voltage output of the second DC voltage source 152 and the voltage drop of the first diode 135. That is, the third preset voltage is the sum of the voltage output of the second DC voltage source 152 and the voltage drop of the first diode 135. For example, the third preset voltage is 3.6 volts.

[0060] The technical solution of this invention protects the input interface of the control module through a protection module, ensuring that the control module operates within a safe range, thereby improving the overall stability of the voltage acquisition circuit.

[0061] Figure 5 This is a schematic diagram of another voltage acquisition circuit provided in an embodiment of the present invention. Based on the above embodiments, alternatively, such as... Figure 5 As shown, the voltage acquisition circuit further includes a first filtering module 160, a second filtering module 170, and a third filtering module 180. The first filtering module 160 is connected to the second terminal of the gas sensor and is used to filter the signal input from the second terminal of the gas sensor. The second filtering module 170 is connected between the third terminal of the buffer unit 131 and the first DC voltage source 151, and is used to filter out noise from the first DC voltage source 151. The first terminal of the third filtering module 180 is connected to the second terminal of the buffer unit 131, and the second terminal of the third filtering module 180 is connected to the first terminal of the protection unit 132, and is used to filter the signal output from the buffer unit 131.

[0062] Specifically, the first filtering module 160 is a component connected to the second terminal of the gas sensor, responsible for filtering the signal from the gas sensor. The first filtering module 160 removes high-frequency noise and interference input from the second terminal of the gas sensor, ensuring the stability and accuracy of the voltage signal input to the gas sensor from the third DC voltage source 153. The second filtering module 170 is a component connected between the third terminal of the buffer unit 131 and the first DC voltage source 151. The second filtering unit is mainly used to filter out noise from the first DC voltage source 151, ensuring a stable power signal for subsequent circuits. The third filtering unit is a filtering component connected between the second terminal of the buffer unit 131 and the first terminal of the protection unit 132. The third filtering unit is mainly used to filter the signal output from the buffer unit 131 to further improve the stability and accuracy of the signal input to the control module.

[0063] In this embodiment of the invention, by configuring the first filtering module 160, the second filtering module 170 and the third filtering module 180, the voltage acquisition circuit can effectively remove interference signals and improve the overall signal quality, thereby ensuring the accuracy and reliability of the data.

[0064] Based on the above embodiments, optionally, the first filtering module 160 includes: a first magnetic bead assembly 161, a second capacitor 162, and a third capacitor 163. A first terminal of the first magnetic bead assembly 161 is connected to a third DC voltage source 153, and a second terminal of the first magnetic bead assembly 161 is connected to a second terminal of the gas sensor; the second capacitor 162 is connected between the second terminal of the first magnetic bead assembly 161 and a ground terminal; the third capacitor 163 is connected in parallel with the second capacitor 162.

[0065] Specifically, the first magnetic bead assembly 161 refers to an inductive element used to suppress high-frequency noise. When the gas sensor outputs a signal, the signal may contain high-frequency noise. The first magnetic bead assembly 161, through its inductive characteristics, can effectively suppress this high-frequency noise and prevent it from passing through.

[0066] In this embodiment of the invention, the voltage signal from the third DC voltage source 153 passes through the first ferrite bead assembly 161 and then enters the second capacitor 162. The connection between the second capacitor 162 and the ground terminal forms a low-pass filter, which can filter out high-frequency components in the signal and retain only low-frequency signals. The third capacitor 163 is connected in parallel with the second capacitor 162, increasing the total capacitance value of the filter. This can further improve the filtering effect, making the signal output by the third DC voltage source 153 smoother and reducing fluctuations.

[0067] Based on the above embodiments, optionally, the second filtering module 170 includes: a second ferrite bead assembly 171, a fourth capacitor 173, and a fifth capacitor 172. The first end of the second ferrite bead assembly 171 is connected to the third end of the buffer unit 131, and the second end of the second ferrite bead assembly 171 is connected to the first DC voltage source 151; the fourth capacitor 173 is connected between the first end of the second ferrite bead assembly 171 and the ground terminal; the fifth capacitor 172 is connected between the second end of the second ferrite bead assembly 171 and the ground terminal. The third filtering module 180 includes: a third resistor 181 and a sixth capacitor 182. The third resistor 181 is connected between the second end of the buffer unit 131 and the first end of the protection unit 132; the sixth capacitor 182 is connected between the first end of the protection unit 132 and the ground terminal.

[0068] Specifically, the second ferrite bead assembly 171 refers to another inductive element used to suppress high-frequency noise. Through its inductive characteristics, the second ferrite bead assembly 171 can effectively suppress high-frequency noise from the first DC voltage source 151, preventing it from interfering with the signal output by the buffer unit 131.

[0069] In this embodiment of the invention, the second ferrite bead assembly 171, the fourth capacitor 173, and the fifth capacitor 172 form a low-pass filter, which can filter out high-frequency components in the signal output from the first DC voltage source 151, ensuring signal stability. The third resistor 181 and the sixth capacitor 182 form an RC filter. The combination of RC filters allows low-frequency signals to pass through while suppressing high-frequency noise. The RC filter helps eliminate high-frequency interference that may be introduced during signal transmission, ensuring the quality of the output signal.

[0070] Based on the above embodiments, optionally, the gas sensor interface 140 includes 6 pins: pin 1 is the second terminal of the gas sensor interface, transmitting signal RS+; pin 2 is the third terminal of the gas sensor interface, transmitting signal RH+; pin 3 is the fourth terminal of the gas sensor interface, transmitting signal RH-; pin 1 is the first terminal of the gas sensor interface, transmitting signal RS-; pin 5 is the fifth terminal of the gas sensor interface, connected to the ground terminal; and pin 6 is the sixth terminal of the gas sensor interface, connected to the ground terminal.

[0071] This invention also provides a gas sensor, which is connected to the voltage acquisition circuit provided in any embodiment of this invention via a gas sensor interface, and has corresponding beneficial effects.

[0072] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0073] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A voltage acquisition circuit, characterized in that, The system is used to acquire the gas concentration signal at the first end of the gas sensor, and includes: an adjustable load module, a control module, and a voltage acquisition module. The adjustable load module includes a plurality of first-type resistors, the first ends of which are all connected to the first end of the gas sensor, and the first ends of the plurality of first-type resistors are respectively connected to a plurality of first-type ports of the control module; the control module sends a control signal to the adjustable load module according to the type of the gas sensor, and controls at least a portion of the first-type resistors to ground their second ends. The first terminal of the voltage acquisition module is connected to the first terminal of the gas sensor, and the second terminal of the voltage acquisition module is connected to the first terminal of the control module. The voltage acquisition module is used to transmit the gas concentration signal output by the gas sensor to the control module. The resistance values ​​of the plurality of first-class resistors are not all equal; The adjustable load module further includes: a first resistor and a first capacitor; The first resistor is connected between the first terminal of the gas sensor and the ground terminal, and the first capacitor is connected in parallel with the first resistor; The voltage acquisition module includes: a buffer unit and a protection unit; The first end of the buffer unit is connected to the first end of the gas sensor; the power supply end of the buffer unit is connected to the first DC voltage source. The first end of the protection unit is connected to the second end of the buffer unit, and the second end of the protection unit is connected to the first end of the control module. The protection unit is used to limit the voltage input to the input terminal of the control module when the gas concentration signal is greater than a first preset voltage; or to clamp the voltage at the input terminal of the control module to a third preset voltage when the voltage output at the first end of the gas sensor is greater than or equal to a second preset voltage; wherein the second preset voltage is greater than the first preset voltage.

2. The voltage acquisition circuit according to claim 1, characterized in that, The buffer unit includes: a first operational amplifier; The first input terminal of the first operational amplifier is connected to the first terminal of the gas sensor, the second input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, the first power supply terminal of the first operational amplifier is connected to the first DC voltage source, and the second power supply terminal of the first operational amplifier is connected to the ground terminal.

3. The voltage acquisition circuit according to claim 1, characterized in that, The protection unit includes: a second resistor and a first diode; The second resistor is connected between the second end of the buffer unit and the ground terminal; The first end of the first diode is connected to the first end of the control module, and the second end of the first diode is connected to the second DC voltage source.

4. The voltage acquisition circuit according to claim 1, characterized in that, Also includes: The first filtering module, the second filtering module, and the third filtering module; The first filtering module is connected to the second end of the gas sensor, and the first filtering module is used to filter the signal input to the second end of the gas sensor. The second filtering module is connected between the third terminal of the buffer unit and the first DC voltage source, and the second filtering module is used to filter out the noise of the first DC voltage source; The first end of the third filtering module is connected to the second end of the buffer unit, and the second end of the third filtering module is connected to the first end of the protection unit. The third filtering module is used to filter the signal output by the buffer unit.

5. The voltage acquisition circuit according to claim 4, characterized in that, The first filtering module includes: The system comprises a first magnetic bead assembly, a second capacitor, and a third capacitor; a first terminal of the first magnetic bead assembly is connected to a third DC voltage source, and a second terminal of the first magnetic bead assembly is connected to a second terminal of the gas sensor; the second capacitor is connected between the second terminal of the first magnetic bead assembly and a ground terminal; and the third capacitor is connected in parallel with the second capacitor.

6. The voltage acquisition circuit according to claim 4, characterized in that, The second filtering module includes: A second ferrite bead assembly, a fourth capacitor, and a fifth capacitor; the first end of the second ferrite bead assembly is connected to the third end of the buffer unit, and the second end of the second ferrite bead assembly is connected to the first DC voltage source; the fourth capacitor is connected between the first end of the second ferrite bead assembly and the ground terminal; the fifth capacitor is connected between the second end of the second ferrite bead assembly and the ground terminal. The third filtering module includes: a third resistor and a sixth capacitor; The third resistor is connected between the second end of the buffer unit and the first end of the protection unit; the sixth capacitor is connected between the first end of the protection unit and the grounding end.

7. A gas sensor, characterized in that, The gas sensor is connected to the voltage acquisition circuit according to any one of claims 1-6 via a gas sensor interface.

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