An air flow inductive sensor switch circuit

Abstract

The utility model relates to airflow control field, specifically disclose a kind of airflow response type sensor switch circuit, its circuit includes power filter module, airflow conversion module, control module, execution instruction module;The power filter module is composed of power supply B1, capacitor C1 and voltage stabilizing chip U2, the airflow conversion module is composed of airflow sensor AS, partial pressure resistance R1, partial pressure resistance R2, variable resistance RV, the control module is composed of operational amplifier U1 and resistance R4, the input of operational amplifier U1 is connected airflow conversion module output;The execution instruction module is composed of MOS tube Q1, light emitting diode D1 and load L.This application utilizes the resistance characteristic of RT with temperature variation, dynamically fine-tunes voltage stabilizing chip ground potential, effectively compensates the output voltage slight deviation of voltage stabilizing chip due to environmental temperature fluctuation, while limiting ground current protection chip under extreme temperature.

Description

Technical Field

[0001] This utility model relates to the field of airflow control, specifically to an airflow sensing sensor switching circuit. Background Technology

[0002] In various fields of automation control and sensing, airflow-sensing switching circuits are widely used because they enable non-contact signal triggering. For example, in scenarios such as e-cigarettes, ventilation systems, and security equipment, automatic switching control of loads is achieved by detecting changes in airflow. Existing airflow-sensing switching circuits typically consist of sensors, signal conversion, control, and execution modules. However, they still have several limitations in practical applications: Firstly, the circuit's operational stability is easily affected by ambient temperature. The output voltage of traditional voltage regulator circuits will fluctuate slightly with temperature changes, causing the signal detection reference to drift, thus affecting the sensitivity and accuracy of airflow sensing. Especially in high or low temperature environments, this temperature drift may cause false triggering or trigger delays. Secondly, most circuits have a fixed airflow detection threshold, making it impossible to flexibly adjust the sensitivity according to different usage scenarios or user needs. For example, in e-cigarette applications, different users have different inhalation intensities, making it difficult for a fixed threshold to adapt to diverse usage requirements. Furthermore, existing circuits lack effective isolation between the control and execution modules. Large current variations in the execution module can easily interfere with the stability of the control signal, leading to unreliable switching actions. Simultaneously, some circuits use relays and other components for load control, resulting in high power consumption and large size, making it difficult to meet the design requirements of miniaturized, low-power devices. Therefore, developing a flow-sensing sensor switch circuit with temperature adaptive compensation capabilities, adjustable sensitivity, stable operation, and compatibility with small devices has become a key requirement for improving the performance of equipment in related fields. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an airflow sensing sensor switching circuit to solve the problems mentioned in the background art.

[0004] This utility model provides an airflow sensing sensor switch circuit, including a power filtering module, an airflow conversion module, a control module, and an execution indication module;

[0005] The power filtering module consists of a power supply B1, a capacitor C1, and a voltage regulator chip U2. The positive terminal of the power supply B1 is electrically connected to one end of the capacitor C1 and the input terminal of the voltage regulator chip U2, respectively. The other end of the capacitor C1 is grounded, and the ground terminal of the voltage regulator chip U2 is grounded through a thermistor RT.

[0006] The airflow conversion module consists of an airflow sensor AS, voltage divider resistors R1 and R2, and a variable resistor RV. The airflow sensor AS includes an air inlet end and an electrical end. One end of the electrical end of the airflow sensor AS is electrically connected to the positive terminal of the power supply B1, and the other end of the airflow sensor AS is grounded after passing through switch K. The output end of the voltage regulator chip U2 is electrically connected to one end of the voltage divider resistors R1 and R2, respectively. The other ends of the voltage divider resistors R1 and R2, and the sliding end of the variable resistor RV are all connected to the control module.

[0007] The control module consists of an operational amplifier U1 and a resistor R4. The input of the operational amplifier U1 is connected to the output of the airflow conversion module.

[0008] The execution indication module consists of a MOSFET Q1, a light-emitting diode D1, and a load L. The drain of the MOSFET Q1 is electrically connected to the load L, and the load L is electrically connected to the negative terminal of the power supply B1.

[0009] Furthermore, one end of the thermistor RT is electrically connected to the ground terminal of the voltage regulator chip U2, and the other end of the thermistor RT is grounded.

[0010] Furthermore, one end of the variable resistor RV is electrically connected to the positive terminal of the power supply B1 via a resistor R3, and the other end of the variable resistor RV is grounded.

[0011] Furthermore, the output terminal of the voltage regulator chip U2, one end of the voltage divider resistor R1, and one end of the voltage divider resistor R2 are all connected to the inverting input terminal of the operational amplifier U1.

[0012] Furthermore, the negative input terminal of operational amplifier U1 is electrically connected to the other end of voltage divider resistor R1, the other end of voltage divider resistor R2, and one end of the thermistor RT, respectively, and the non-inverting input terminal of operational amplifier U1 is electrically connected to the sliding end of variable resistor RV.

[0013] Furthermore, the positive terminal of operational amplifier U1 is electrically connected to the positive terminal of power supply B1, the negative terminal of operational amplifier U1 is grounded, the output terminal of operational amplifier U1 is electrically connected to resistor R4, and the output terminal of operational amplifier U1 is connected to the execution indication module via resistor R4.

[0014] Furthermore, the gate of the MOS transistor Q1 and the positive terminal of the light-emitting diode D1 are connected to the output terminal of the operational amplifier U1 through the resistor R4, the negative terminal of the light-emitting diode D1 is grounded, and the source of the MOS transistor Q1 is grounded.

[0015] The beneficial effects of this utility model are:

[0016] First, the thermistor RT in the power supply filter module is connected in series with the ground terminal of the voltage regulator chip U2. By utilizing the resistance characteristics of RT that change with temperature, the potential of the ground terminal of the voltage regulator chip is dynamically and finely adjusted, which effectively compensates for the slight deviation of the output voltage of the voltage regulator chip caused by the fluctuation of ambient temperature. At the same time, it limits the ground current to protect the chip under extreme temperatures, which significantly improves the working stability of the circuit in the temperature change environment and solves the problem of temperature drift affecting the detection accuracy in the existing technology.

[0017] Secondly, the airflow conversion module indirectly affects the ground terminal potential of the voltage regulator chip through the resistance change of the airflow sensor AS. Combined with the reference voltage branch formed by the voltage divider resistors R1 and R2 and the reference voltage adjustment branch of the variable resistor RV, the airflow signal is accurately converted into an electrical signal. The setting of the variable resistor RV allows for flexible adjustment of the airflow detection threshold, adapting to the sensitivity requirements of different scenarios and overcoming the applicability limitations caused by the fixed threshold in the existing technology.

[0018] The control module uses an operational amplifier as a voltage comparator, which can quickly respond to voltage changes at the inverting and non-inverting input terminals. Combined with the current limiting and isolation function of resistor R4, it ensures stable output of the control signal, avoids interference from current changes in the execution module on the comparison accuracy, and improves the reliability of the circuit operation.

[0019] The execution indication module achieves efficient switching control of high-current loads through MOSFET Q1, and is equipped with LED D1 to provide real-time feedback on the working status. Compared with the existing technology that uses relays and other solutions, it has the advantages of lower power consumption and smaller size, and is more suitable for small portable devices such as electronic cigarettes.

[0020] In addition, the overall circuit adopts low-power component selection and design, with extremely low current in standby mode, which significantly extends the service life of battery-powered devices. At the same time, the modules are simple in structure and highly efficient in collaboration, forming a complete closed loop from airflow detection to load control. It realizes the integrated functions of airflow triggering, signal conversion, precise control and status indication, meeting the application requirements of miniaturized, low-power and high-sensitivity devices. Attached Figure Description

[0021] Figure 1 This is a circuit diagram of a switch circuit for an airflow sensing sensor according to the present invention. Detailed Implementation

[0022] This utility model provides a switch circuit for an airflow-sensing sensor, such as... Figure 1As shown, it includes a power filtering module, an airflow conversion module, a control module, and an execution indication module. The power filtering module consists of a power supply B1, a capacitor C1, and a voltage regulator chip U2. The positive terminal of the power supply B1 is electrically connected to one end of the capacitor C1 and the input terminal of the voltage regulator chip U2, respectively. The other end of the capacitor C1 is grounded. The ground terminal of the voltage regulator chip U2 is grounded through a thermistor RT. One end of the thermistor RT is electrically connected to the ground terminal of the voltage regulator chip U2, and the other end of the thermistor RT is grounded.

[0023] The power supply filtering module is the core of the entire circuit for energy supply and stability assurance. It consists of power supply B1, capacitor C1, voltage regulator chip U2, and thermistor RT. Its working logic is as follows:

[0024] The power supply is fundamental; power supply B1 provides initial electrical energy to the entire circuit, and the voltage output from its positive terminal is the energy source for the operation of each module in the circuit.

[0025] Voltage ripple filtering is achieved by connecting one end of capacitor C1 to the positive terminal of power supply B1 and the other end to ground. Utilizing the capacitor's characteristic of "blocking DC and passing AC," it filters AC ripple in the output voltage of power supply B1. When the output voltage of power supply B1 fluctuates, capacitor C1 absorbs these fluctuations through charging and discharging, making the voltage input to the voltage regulator chip U2 more stable and preventing ripple from interfering with signal detection in subsequent modules.

[0026] The voltage regulator chip U2 has a stable output voltage. Its input terminal is connected to the power supply B1 voltage after being filtered by capacitor C1. Its core function is to convert the unstable input voltage into a fixed stable voltage, providing a stable operating voltage for the voltage divider circuit in the airflow conversion module and ensuring the accuracy of airflow signal conversion.

[0027] For temperature compensation and protection, the ground terminal of the voltage regulator chip U2 is not directly grounded, but rather connected in series with a thermistor RT before grounding. The resistance value of the thermistor RT changes significantly with temperature. When the ambient temperature changes, the change in the resistance of the thermistor RT finely adjusts the potential of the ground terminal of the voltage regulator chip U2, indirectly compensating for the slight deviation in the output voltage of the voltage regulator chip U2 caused by temperature changes. At the same time, it can limit the grounding current under extreme temperatures, protecting the voltage regulator chip U2 from damage and further improving the stability of the circuit under fluctuating temperature environments.

[0028] The airflow conversion module consists of an airflow sensor AS, voltage divider resistors R1 and R2, and a variable resistor RV. The airflow sensor AS includes an inlet end and an electrical end. One end of the electrical end of the airflow sensor AS is electrically connected to the positive terminal of the power supply B1, and the other end of the airflow sensor AS is grounded after passing through switch K. The output terminal of the voltage regulator chip U2 is electrically connected to one end of the voltage divider resistors R1 and R2, respectively. The other ends of the voltage divider resistors R1 and R2, and the sliding end of the variable resistor RV are all connected to the control module. One end of the variable resistor RV is electrically connected to the positive terminal of the power supply B1 after passing through a resistor R3, and the other end of the variable resistor RV is grounded.

[0029] The airflow conversion module is the core component for converting airflow signals into electrical signals. It consists of an airflow sensor AS, voltage divider resistors R1 and R2, a variable resistor RV, a switch K, and a resistor R3. Its operating logic is as follows:

[0030] The airflow sensor AS senses signals and has an inlet end and an electrical end. The inlet end only serves as an airflow channel and has no electrical connection. The electrical characteristics (such as resistance) of the electrical end change with the intensity / presence of airflow at the inlet end. For example, the resistance of the airflow sensor AS decreases when there is airflow and increases when there is no airflow. One end of the electrical end of the airflow sensor AS is connected to the positive terminal of the power supply B1, and the other end is grounded through switch K. Switch K is used to control whether the airflow sensor AS is connected to the circuit. When closed, the airflow sensor AS is working; when open, the airflow sensor AS does not participate in signal conversion.

[0031] The reference voltage and voltage divider circuit connects the output of voltage regulator chip U2 to one end of both voltage divider resistors R1 and R2. The other ends of R1 and R2 are connected to the inverting input of operational amplifier U1 in the control module, forming a voltage divider branch. The voltage in this branch is determined by the resistance ratio of voltage divider resistors R1 and R2 and the stable voltage output of voltage regulator chip U2, serving as a "signal voltage" reference reflecting changes in airflow.

[0032] With reference voltage adjustment, the variable resistor RV forms an independent voltage divider branch. One end of the variable resistor RV is connected to the positive terminal of power supply B1 via resistor R3, and the other end is grounded. Its sliding contact is connected to the non-inverting input terminal of operational amplifier U1. Resistor R3 is a current-limiting resistor to prevent short circuits and damage to the power supply when the variable resistor RV slides. By adjusting the position of the sliding contact of the variable resistor RV, the voltage output to the non-inverting input terminal of operational amplifier U1 can be changed. This voltage is used to set the threshold for airflow detection, such as the criteria for judging "airflow present" and "airflow absent".

[0033] The conversion of airflow signal to electrical signal: When airflow passes through the air inlet of airflow sensor AS, the electrical characteristics (resistance) of airflow sensor AS change, which will indirectly affect the node voltage connected to the inverting input of operational amplifier U1, that is, the connection point of voltage divider resistors R1 and R2.

[0034] For example, when there is airflow, the resistance of the airflow sensor AS decreases, leading to an increase in the current in the branch containing the airflow sensor AS. This indirectly causes a slight change in the potential of the ground terminal of the voltage regulator chip U2 (via the thermistor RT), which in turn changes the voltage after voltage division by the voltage divider resistors R1 and R2, i.e., the voltage at the inverting input terminal of the operational amplifier U1. When there is no airflow, the resistance of the airflow sensor AS recovers, and the voltage after voltage division by the voltage divider resistors R1 and R2 returns to its initial value. At the same time, the thermistor RT adjusts the potential of the ground terminal of the voltage regulator chip U2 according to the ambient temperature to compensate for the effect of temperature on the voltage division by the voltage divider resistors R1 and R2, ensuring that the airflow signal conversion is not affected by temperature. Ultimately, the presence or absence / strength of airflow is converted into a voltage change at the inverting input terminal of the operational amplifier U1.

[0035] The control module consists of an operational amplifier U1 and a resistor R4. The inverting input of the operational amplifier U1 is connected to the output of the airflow conversion module. Specifically, the negative input of the operational amplifier U1 is electrically connected to the other end of the voltage divider resistor R1, the other end of the voltage divider resistor R2, and one end of the thermistor RT. The non-inverting input of the operational amplifier U1 is electrically connected to the sliding end of the variable resistor RV. The positive terminal of the operational amplifier U1 is electrically connected to the positive terminal of the power supply B1. The negative terminal of the operational amplifier U1 is grounded. The output of the operational amplifier U1 is electrically connected to the resistor R4. The output of the operational amplifier U1 is connected to the execution indication module via the resistor R4. The output of the voltage regulator chip U2, one end of the voltage divider resistor R1, and one end of the voltage divider resistor R2 are all connected to the inverting input of the operational amplifier U1.

[0036] The control module is the decision-making core of the circuit, consisting of operational amplifier U1 and resistor R4. Its function is to compare the airflow signal voltage with the reference voltage and output a control signal. The working logic is as follows:

[0037] The operational amplifier (OPA) is powered and functions as follows: The positive terminal of OPA U1 is connected to the positive terminal of power supply B1, and the negative terminal is directly grounded to ensure that OPA U1 operates under a stable power supply. OPA U1 is used as a voltage comparator; its core function is to compare the voltages at its two input terminals. The inverting input terminal is connected to the signal voltage from the airflow conversion module, reflecting the airflow conditions. The non-inverting input terminal is connected to the reference voltage set by the variable resistor RV, used for threshold detection.

[0038] Voltage comparison and signal output: When there is no airflow or the airflow intensity is below the threshold, the voltage at the inverting input terminal (signal voltage) of operational amplifier U1 is higher than the voltage at the non-inverting input terminal (reference voltage). According to the characteristics of operational amplifier, the output terminal of operational amplifier U1 is at a low potential at this time.

[0039] When there is airflow or the airflow intensity exceeds a threshold, the change in the airflow sensor AS causes the voltage at the reverse input terminal to decrease, falling below the reference voltage at the non-inverting input terminal. At this time, the output terminal of the operational amplifier U1 switches to a high potential. This change in output potential is the control signal converted from the airflow signal.

[0040] For signal transmission and isolation, the output of operational amplifier U1 is connected to the execution indicator module via resistor R4. The function of resistor R4 is to limit current, preventing excessive current from damaging operational amplifier U1 when the output of operational amplifier U1 is directly connected to a load (such as the gate of MOSFET Q1 or LED D1). It also serves as signal isolation, ensuring that current changes in the execution module do not affect the comparison result of operational amplifier U1.

[0041] The execution indication module consists of a MOSFET Q1, a light-emitting diode D1, and a load L. The gate of the MOSFET Q1 and the anode of the light-emitting diode D1 are connected to the output terminal of the operational amplifier U1 via a resistor R4. The cathode of the light-emitting diode D1 is grounded, the source of the MOSFET Q1 is grounded, the drain of the MOSFET Q1 is electrically connected to the load L, the source of the MOSFET Q1 is grounded, and the load L is electrically connected to the cathode of the power supply B1.

[0042] The execution indicator module is the "action and feedback terminal" of the circuit, consisting of MOSFET Q1, LED D1, and load L. Its function is to convert the electrical signal from the control module into a visible indication (LED D1 on / off) and the action (work / stop) of load L. The working logic is as follows:

[0043] Signal reception and splitting: The signal (high / low potential) output by the control module is split into two paths after passing through resistor R4: one path connects to the gate of MOSFET Q1, and the other path connects to the positive terminal of LED D1. Resistor R4 simultaneously limits the current flowing into the gate of MOSFET Q1 and LED D1, protecting the components.

[0044] The LED has an indicator function. When the operational amplifier U1 outputs a high potential, current flows through resistor R4 to the positive terminal of LED D1, and the negative terminal of LED D1 is grounded, forming a loop. LED D1 then conducts and emits light (indicating "airflow detected").

[0045] When the operational amplifier U1 outputs a low potential, there is no positive voltage across the LED D1, so it does not conduct and is turned off (indicating "no airflow detected").

[0046] The switching and load control of the MOSFET: MOSFET Q1 is an N-channel enhancement-mode MOSFET. Its gate (G) is connected to resistor R4, its source (S) is grounded, and its drain (D) is connected to the load L. The other end of the load L is connected to the negative terminal of power supply B1 (a prerequisite for forming a loop). When the operational amplifier U1 outputs a high potential, the gate (G) receives a positive voltage, and MOSFET Q1 conducts (the resistance between the drain and source is extremely small). The load L forms a closed loop with ground through MOSFET Q1, and the current supplied by power supply B1 flows through the load L, causing the load L to start working. When the operational amplifier U1 outputs a low potential, there is no positive voltage on the gate (G), MOSFET Q1 is cut off (the resistance between the drain and source is high), the loop of the load L is broken, and it stops working.

[0047] In one specific embodiment, the airflow-sensing sensor switch circuit of this application is applied to an electronic cigarette. Addressing the electronic cigarette's requirement of "heating triggered by inhalation and stopping operation upon stopping inhalation," the circuit structure is based on the characteristics of an electronic cigarette powered by a 3.7V lithium battery, with an operating current of 1-3A and a standby current <100μA. The component parameters are selected as shown in Table 1 below:

[0048] Table 1 Selection of Parameters for Electronic Components in Electronic Cigarettes

[0049]

[0050] The working principle of the circuit in this application in the electronic cigarette scenario is as follows:

[0051] In standby mode, i.e., when there is no intake airflow, lithium battery B1 outputs its operating voltage. Capacitor C1 filters voltage fluctuations through charging and discharging, and voltage regulator chip U2 outputs a stable voltage. Thermistor RT maintains a stable resistance value at room temperature, stabilizing the potential of the ground terminal of voltage regulator chip U2 at near 0V, ensuring the reliability of the voltage divider circuit reference. When there is no intake airflow, the microphone (airflow sensor AS) resistor is in a high-resistance state, the current in the branch containing airflow sensor AS is extremely small, and the potential of the ground terminal of voltage regulator chip U2 does not change significantly. After voltage divider resistors R1 and R2 divide the stable voltage output by voltage regulator chip U2, the inverting input terminal of operational amplifier U1 obtains a higher voltage. The variable resistor RV is adjusted to the reference voltage (trigger threshold) of the non-inverting input terminal. At this time, the voltage of the inverting input terminal is higher than the reference voltage. Since the voltage of the inverting input terminal of operational amplifier U1 is higher than the reference voltage of the non-inverting input terminal, operational amplifier U1 outputs a low potential. There is no forward voltage across the LED D1, so it is in the off state; there is no driving voltage at the gate of the MOSFET Q1, so it is in the cut-off state; no current flows through the heating wire (load L), and the overall power consumption of the circuit is extremely low.

[0052] When the user inhales, the airflow passes through the inlet of the microphone (airflow sensor AS). The resistance of the airflow sensor AS drops significantly from a high-resistance state, increasing the current in its branch. The current flows through the airflow sensor AS, the thermistor RT, and ground, causing a voltage drop across the thermistor RT. This raises the potential at the ground terminal of the voltage regulator chip U2. At this time, the reference ground potential of the voltage divider resistors R1 and R2 increases, causing the voltage at the inverting input of operational amplifier U1 to decrease and fall below the reference voltage at the non-inverting input. Because the voltage at the inverting input of operational amplifier U1 is lower than the reference voltage at the non-inverting input, operational amplifier U1 outputs a high potential. This high potential output from operational amplifier U1, after current limiting by resistor R4, drives LED D1 to illuminate, indicating the operating status. The other path is applied to the gate of MOSFET Q1, causing Q1 to switch from a cutoff state to a conducting state. This creates a closed circuit between the heating wire (load L) and the lithium battery B1, allowing current to flow through the heating wire (load L) and generate heat, thus atomizing the e-liquid.

[0053] After the user stops inhaling, the microphone (airflow sensor AS) resistor returns from a low resistance state to a high resistance state, the current in its branch decreases to a minimum, the voltage drop across the thermistor RT disappears, and the voltage at the ground terminal of the voltage regulator chip U2 returns to near 0V. After the voltage divider resistors R1 and R2 divide the voltage, the voltage at the inverting input terminal of operational amplifier U1 rises back to a level higher than the reference voltage at the non-inverting input terminal. The output terminal of operational amplifier U1 returns from a high potential to a low potential, the LED D1 turns off, the MOSFET Q1 switches from the on state to the off state, the heating wire (load L) is de-energized and stops working, and the circuit returns to standby mode.

[0054] When the electronic cigarette is working, the heating wire (load L) heats up, causing the ambient temperature to rise. The resistance of the NTC thermistor RT decreases as the temperature rises. The decrease in the resistance of the thermistor RT reduces its voltage division ratio in the circuit, which offsets the slight drop in the output voltage of the voltage regulator chip U2 caused by the temperature rise. This ensures that the voltage at the inverting input of the operational amplifier U1 after voltage division by voltage divider resistors R1 and R2 is stable, and avoids interference from temperature changes on the inhalation sensitivity.

[0055] The circuit of this application is applied to electronic cigarettes, realizing the core functions of "inhalation trigger, real-time indication, and shutdown when inhalation stops". It has the characteristics of low power consumption, high sensitivity and temperature self-adaptation, and is suitable for the miniaturization and portability of electronic cigarettes.

[0056] In summary, the technical effects of this application can be seen, including the following aspects:

[0057] First, the thermistor RT in the power supply filter module is connected in series with the ground terminal of the voltage regulator chip U2. By utilizing the resistance characteristics of RT that change with temperature, the potential of the ground terminal of the voltage regulator chip is dynamically and finely adjusted, which effectively compensates for the slight deviation of the output voltage of the voltage regulator chip caused by the fluctuation of ambient temperature. At the same time, it limits the ground current to protect the chip under extreme temperatures, which significantly improves the working stability of the circuit in the temperature change environment and solves the problem of temperature drift affecting the detection accuracy in the existing technology.

[0058] Secondly, the airflow conversion module indirectly affects the ground terminal potential of the voltage regulator chip through the resistance change of the airflow sensor AS. Combined with the reference voltage branch formed by the voltage divider resistors R1 and R2 and the reference voltage adjustment branch of the variable resistor RV, the airflow signal is accurately converted into an electrical signal. The setting of the variable resistor RV allows for flexible adjustment of the airflow detection threshold, adapting to the sensitivity requirements of different scenarios and overcoming the applicability limitations caused by the fixed threshold in the existing technology.

[0059] The control module uses an operational amplifier as a voltage comparator, which can quickly respond to voltage changes at the inverting and non-inverting input terminals. Combined with the current limiting and isolation function of resistor R4, it ensures stable output of the control signal, avoids interference from current changes in the execution module on the comparison accuracy, and improves the reliability of the circuit operation.

[0060] The execution indication module achieves efficient switching control of high-current loads through MOSFET Q1, and is equipped with LED D1 to provide real-time feedback on the working status. Compared with the existing technology that uses relays and other solutions, it has the advantages of lower power consumption and smaller size, and is more suitable for small portable devices such as electronic cigarettes.

[0061] In addition, the overall circuit adopts low-power component selection and design, with extremely low current in standby mode, which significantly extends the service life of battery-powered devices. At the same time, each module has a simple structure and works together efficiently, forming a complete closed loop from airflow detection to load control. It realizes the integrated function of "airflow triggering, signal conversion, precise control, and status indication", meeting the application requirements of miniaturized, low-power, and high-sensitivity devices.

[0062] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

[0063] The above are all preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A switch circuit for an airflow-sensing sensor, characterized in that, It includes a power filtering module, an airflow conversion module, a control module, and an execution indication module; The power filtering module consists of a power supply B1, a capacitor C1, and a voltage regulator chip U2. The positive terminal of the power supply B1 is electrically connected to one end of the capacitor C1 and the input terminal of the voltage regulator chip U2, respectively. The other end of the capacitor C1 is grounded, and the ground terminal of the voltage regulator chip U2 is grounded through a thermistor RT. The airflow conversion module consists of an airflow sensor AS, voltage divider resistors R1 and R2, and a variable resistor RV. The airflow sensor AS includes an air inlet end and an electrical end. One end of the electrical end of the airflow sensor AS is electrically connected to the positive terminal of the power supply B1, and the other end of the airflow sensor AS is grounded after passing through switch K. The output end of the voltage regulator chip U2 is electrically connected to one end of the voltage divider resistors R1 and R2, respectively. The other ends of the voltage divider resistors R1 and R2, and the sliding end of the variable resistor RV are all connected to the control module. The control module consists of an operational amplifier U1 and a resistor R4. The input of the operational amplifier U1 is connected to the output of the airflow conversion module. The execution indication module consists of a MOSFET Q1, a light-emitting diode D1, and a load L. The drain of the MOSFET Q1 is electrically connected to the load L, and the load L is electrically connected to the negative terminal of the power supply B1.

2. The airflow sensing sensor switching circuit according to claim 1, characterized in that, One end of the thermistor RT is electrically connected to the ground terminal of the voltage regulator chip U2, and the other end of the thermistor RT is grounded.

3. The airflow sensing sensor switching circuit according to claim 1, characterized in that, One end of the variable resistor RV is connected to the positive terminal of the power supply B1 via a resistor R3, and the other end of the variable resistor RV is grounded.

4. The airflow sensing sensor switching circuit according to claim 1, characterized in that, The output of the voltage regulator chip U2, one end of the voltage divider resistor R1, and one end of the voltage divider resistor R2 are all connected to the inverting input of the operational amplifier U1.

5. The airflow sensing sensor switching circuit according to claim 1, characterized in that, The negative input terminal of operational amplifier U1 is electrically connected to the other end of voltage divider resistor R1, the other end of voltage divider resistor R2, and one end of the thermistor RT, respectively. The non-inverting input terminal of operational amplifier U1 is electrically connected to the sliding end of variable resistor RV.

6. The airflow sensing sensor switching circuit according to claim 1, characterized in that, The positive terminal of operational amplifier U1 is electrically connected to the positive terminal of power supply B1, the negative terminal of operational amplifier U1 is grounded, the output terminal of operational amplifier U1 is electrically connected to resistor R4, and the output terminal of operational amplifier U1 is connected to the execution indication module through resistor R4.

7. The airflow sensing sensor switching circuit according to claim 1, characterized in that, The gate of the MOS transistor Q1 and the positive terminal of the LED D1 are connected to the output terminal of the operational amplifier U1 through the resistor R4. The negative terminal of the LED D1 is grounded, and the source of the MOS transistor Q1 is grounded.

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