CN118077980A

CN118077980A - Signal processing method, signal processing circuit, piezoelectric sensing system and electronic cigarette

Info

Publication number: CN118077980A
Application number: CN202410161041.2A
Authority: CN
Inventors: 王志轩; 包远鑫; 杨佳锋; 王佳鑫; 陈磊
Original assignee: Wuxi Micronano Core Electronic Technology Co ltd
Current assignee: Wuxi Micronano Core Electronic Technology Co ltd
Priority date: 2024-02-04
Filing date: 2024-02-04
Publication date: 2024-05-28

Abstract

The application relates to a signal processing method, a signal processing circuit, a piezoelectric sensing system and an electronic cigarette, wherein the output voltage of a piezoelectric sensor is subjected to differential transformation to obtain a first differential voltage; comparing the first differential voltage with a threshold voltage; the absolute value of the threshold voltage is larger than the absolute value obtained by performing differential transformation on the temperature drift voltage of the piezoelectric sensor under the condition of no pressure; in the case that the absolute value of the first differential voltage is not less than the absolute value of the threshold voltage, it is determined that the piezoelectric sensor has a pressure event. According to the application, the temperature drift influence of the piezoelectric sensor can be eliminated, and the false triggering of the pressure event is avoided.

Description

Signal processing method, signal processing circuit, piezoelectric sensing system and electronic cigarette

Technical Field

The application relates to the field of piezoelectric sensor signal processing, in particular to a signal processing method, a signal processing circuit, a piezoelectric sensing system and an electronic cigarette.

Background

A piezoelectric sensor, which is a sensor that converts mechanical pressure into an electrical signal, uses the characteristics of a piezoelectric material, and when an external force is applied to the surface thereof, the internal charge distribution changes, thereby generating a voltage. The piezoelectric sensor converts a physical quantity into an electrical signal, and the processing of the electrical signal requires a chip. Therefore, in practical applications, the piezoelectric sensor and the signal processing circuit are usually combined with each other, so as to enhance the function and measurement accuracy of the sensor, and better meet the requirements of different industries.

Fig. 1 is a state change schematic diagram of a related art piezoelectric sensor. Wherein, fig. 1a represents a state change process of the piezoelectric sensor when being stressed. Piezoelectric sensors are typically parallel plate-like capacitor structures with uniform positive and negative charges in the medium. Under the condition of no external force, the whole body presents electric neutrality, and when the sensor is stressed, the geometric centers of positive and negative charges are dislocated, so that induced charges are presented on the two polar plates. The greater the force, the greater the degree of misalignment of the geometric centers of the positive and negative charges, and the greater the amount of charge on the plate. If the sensor is subjected to pressure in the opposite direction, charges are generated as well, but the charge sign corresponding to each polar plate is changed according to the direction of the force. The piezoelectric sensor outputs voltage when the internal charge of the piezoelectric sensor changes, and the signal processing circuit judges whether a pressure event occurs according to the output voltage. Fig. 1b represents the state change process when the piezoelectric sensor is affected by temperature drift. When the temperature of the piezoelectric sensor increases due to an increase in the ambient temperature, the piezoelectric sensor also generates induced charges, which causes a baseline voltage of the piezoelectric sensor (an output voltage of the piezoelectric sensor when the piezoelectric sensor is not under force) to rise, possibly causing the signal processing circuit to erroneously determine that a pressure event has occurred.

Aiming at the problem that the piezoelectric sensor is influenced by temperature drift to trigger a pressure event by mistake in the related art, no effective solution is proposed at present.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a signal processing method, a signal processing circuit, a piezoelectric sensing system, and an electronic cigarette that can eliminate the influence of temperature drift of a piezoelectric sensor.

In a first aspect, the present application provides a signal processing method, including:

Performing differential transformation on the output voltage of the piezoelectric sensor to obtain a first differential voltage;

Comparing the first differential voltage with a threshold voltage; the absolute value of the threshold voltage is larger than the absolute value obtained by performing differential transformation on the temperature drift voltage of the piezoelectric sensor under the condition of no pressure;

And in the case that the absolute value of the first differential voltage is not smaller than the absolute value of the threshold voltage, determining that the piezoelectric sensor has a pressure event.

In some embodiments, the absolute value of the threshold voltage is smaller than the absolute value of a second differential voltage, and the second differential voltage is a maximum differential voltage or a minimum differential voltage obtained by performing differential transformation on the output voltage when the piezoelectric sensor generates a pressure event.

In some of these embodiments, the threshold voltage comprises a first threshold voltage that is greater than zero and less than the maximum differential voltage.

In some of these embodiments, determining that the piezoelectric sensor has a pressure event comprises:

and determining that the piezoelectric sensor is in a pressed state under the condition that the first differential voltage is larger than zero and not smaller than the first threshold voltage.

In some of these embodiments, the threshold voltage comprises a second threshold voltage that is less than zero and greater than the minimum differential voltage.

And under the condition that the first differential voltage is smaller than zero and not larger than the second threshold voltage, judging that the piezoelectric sensor is in a force-withdrawing state.

In some of these embodiments, the threshold voltage comprises a first threshold voltage that is greater than zero and less than the maximum differential voltage and a second threshold voltage that is less than zero and greater than the minimum differential voltage; determining that a pressure event occurred with the piezoelectric sensor comprises:

comparing the first differential voltage with the first threshold voltage;

Comparing the first differential voltage with the second threshold voltage in response to a comparison result that the first differential voltage is not less than the first threshold voltage;

and in response to a comparison result that the first differential voltage is not greater than the second threshold voltage, determining that a pressure event occurs to the piezoelectric sensor.

In a second aspect, the present application provides a signal processing circuit comprising: the system comprises a differential module and a control module, wherein the differential module is connected with the control module; wherein,

The differential module is used for carrying out differential transformation on the output voltage of the piezoelectric sensor to obtain a first differential voltage;

The control module for performing the signal processing method of any one of claims 1 to 7.

In some of these embodiments, the differentiating module comprises: the first amplifying unit, the capacitor and the resistor; the capacitor is connected to the input end of the first amplifying unit, and the resistor is connected between the input end and the output end of the first amplifying unit.

In some of these embodiments, the control module comprises: the device comprises a comparison unit and a logic unit, wherein the comparison unit is connected with the logic unit; wherein,

The comparison unit is used for comparing the first differential voltage with a threshold voltage to obtain a comparison result;

and the logic unit is used for outputting a judging result according to the comparison result, wherein the judging result comprises whether a pressure event occurs or not.

In some of these embodiments, the comparing unit comprises: the input ends of the first comparator and the second comparator are respectively connected with the output end of the differential module, and the output ends of the first comparator and the second comparator are respectively connected with the input end of the logic unit;

Wherein,

The first comparator is configured to compare the first differential voltage with a first threshold voltage;

The second comparator is configured to compare the first differential voltage with a second threshold voltage.

In some of these embodiments, further comprising: and the second amplifying unit is connected with the differentiating module and is used for amplifying the output voltage of the piezoelectric sensor and/or the first differentiating voltage.

In a third aspect, the present application provides a piezoelectric sensing system comprising: a piezoelectric sensor and the signal processing circuit of the second aspect, the piezoelectric sensor being connected to the signal processing circuit.

In a fourth aspect, the present application provides an electronic cigarette, comprising: the main body is provided with a piezoelectric sensor and the signal processing circuit of the second aspect, and the piezoelectric sensor is connected with the signal processing circuit.

According to the signal processing method, the signal processing circuit, the piezoelectric sensing system and the electronic cigarette, the slope of the output voltage caused by pressure intensity is larger, the differentiated value is larger, the slope of the output voltage caused by temperature drift is smaller, and the differentiated value is smaller, so that the differential conversion of the output voltage of the piezoelectric sensor can be performed, the threshold voltage is set to distinguish the differential value of the output voltage caused by pressure intensity from the differential value of the temperature drift voltage, the temperature drift effect is eliminated, and the false triggering of the pressure event is avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1a is a schematic diagram of a state change of a piezoelectric sensor according to the related art when the piezoelectric sensor is stressed;

FIG. 1b is a schematic diagram showing a state change of a piezoelectric sensor in the related art when temperature drift occurs;

FIG. 2 is a schematic diagram of an equivalent circuit of a piezoelectric sensor;

FIG. 3 is a schematic diagram of a response curve of a piezoelectric sensor;

FIG. 4 is a flow diagram of a method of signal processing in one embodiment;

FIG. 5 is a schematic diagram of a response curve before and after differential transformation of the output voltage of the piezoelectric sensor in one embodiment;

FIG. 6 is an architecture diagram of signal processing circuitry in one embodiment;

FIG. 7 is a schematic diagram of the architecture of a signal processing circuit in one embodiment;

fig. 8 is a schematic diagram of a signal processing circuit in another embodiment.

Reference numerals illustrate: 1. a signal processing circuit; 11. a differentiating module; 111. a first amplifying unit; r, resistance; C. a capacitor; 12. a control module; 121. a comparison unit; 1211. a first comparator; 1212. a second comparator; 122. a logic unit; 13. a first pin; 14. a second pin; 15. a third pin; 16. a second amplifying unit; 161. a first amplifier; 162. a second amplifier; 17. a voltage generation module; q, a charge source; cp, capacitance; rp, resistance; MEMS, piezoelectric sensor; voltage output pins of the Vout and piezoelectric sensors; vref, reference voltage input pin of the piezoelectric sensor.

Detailed Description

In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Embodiments of the application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the application. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

It is understood that "at least one" means one or more and "a plurality" means two or more. "at least part of an element" means part or all of the element.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

Fig. 2 is a schematic diagram of an equivalent circuit of a piezoelectric sensor. As shown in fig. 2, where MEMS represents a piezoelectric sensor, which may be equivalently referred to as a charge source q, a capacitor Cp, and a resistor Rp are connected in parallel with each other, vout represents an output voltage of the piezoelectric sensor, and Vref represents a reference voltage of the piezoelectric sensor. When the plate is pressed, the charge source q generates a charge and stores the charge in the capacitor Cp, forming a voltage difference of Vout-vref=q/Cp, however, due to the resistor Rp, the charge on the capacitor Cp slowly leaks through Rp, resulting in a decrease in the charge amount on the capacitor Cp, and thus the value of Vout-Vref decreases until vout=vref, where the charge is 0.

Fig. 3 is a schematic diagram of a response curve of a piezoelectric sensor. As shown in fig. 3, in the front section of the curve, when pressure is applied to the piezoelectric sensor, electric charges are generated on the polar plate to form a voltage; as the force increases, the amount of charge increases and the output voltage Vout increases; when the force just changes from increasing to maintaining, the output voltage Vout peaks, and then, the output voltage Vout slowly decreases due to the aforementioned charge leakage; if a "force-withdrawal process" occurs before the charge is completely leaked, the internal charge of the piezoelectric sensor will be of opposite sign, counteracting the charge generated during the "force-withdrawal process" and appearing as a falling edge and bouncing overshoot on the output voltage.

In the middle section of the curve, when the temperature rises, the piezoelectric sensor generates extra charges, the output voltage Vout also drifts towards the increasing direction, so that the baseline voltage rises, namely, the temperature drift voltage is generated, if the piezoelectric sensor receives external pressure in the heating process, the output voltage increment caused by the pressure is superposed on the temperature drift voltage, and misjudgment is easily caused when a subsequent signal processing circuit processes signals. The main situation that causes the piezoelectric sensor to warm up is the rise in its ambient temperature, most commonly the heating of the power device or the charging of the device. It should be noted that the additional charge generation rate of the piezoelectric sensor due to temperature rise is much slower than that of the piezoelectric sensor when it is subjected to pressure, in other words, the rising and falling edges of the output voltage of the piezoelectric sensor caused by force application and force withdrawal are much steeper than the rising slope of the output voltage caused by temperature rise.

In the latter section of the curve, when the temperature rises to a certain value and remains unchanged, the temperature drift of the voltage slowly falls back due to the charge leakage principle. This means that the temperature drift of the piezoelectric sensor output voltage is independent of the absolute value of the temperature and is only dependent on the rate of temperature change.

Based on the above analysis, in one embodiment, referring to fig. 4, a signal processing method is provided, which includes the following steps:

Step S401, performing differential transformation on the output voltage of the piezoelectric sensor to obtain a first differential voltage;

Step S402, comparing the first differential voltage with a threshold voltage; the absolute value of the threshold voltage is larger than the absolute value obtained by performing differential transformation on the temperature drift voltage of the piezoelectric sensor under the condition of no pressure;

In step S403, in the case where the absolute value of the first differential voltage is not smaller than the absolute value of the threshold voltage, it is determined that the piezoelectric sensor has a pressure event.

As can be seen from the temperature drift characteristics of the piezoelectric sensor, the temperature drift of the output voltage of the piezoelectric sensor is independent of the absolute magnitude of temperature and is only related to the rate of change of temperature, and the slope of the temperature drift voltage is far smaller than that of the output voltage caused by pressure. According to the signal processing method provided by the embodiment, as the slope of the output voltage caused by pressure is larger, the differentiated value is larger, the slope of the output voltage caused by temperature drift is smaller, and the differentiated value is smaller, the output voltage of the piezoelectric sensor can be subjected to differential transformation, the threshold voltage is set to distinguish the differential value of the output voltage caused by pressure from the differential value of the temperature drift voltage, the temperature drift effect is eliminated, and the false triggering of the pressure event is avoided.

The design of the threshold voltage and the method of determining the pressure event will be further described below.

In one embodiment, the absolute value of the threshold voltage is less than the absolute value of a second differential voltage, which is the maximum differential voltage or the minimum differential voltage obtained by differential transforming the output voltage when a pressure event occurs to the piezoelectric sensor.

For ease of understanding, fig. 5 shows response curves before and after differential transformation of the output voltage of the piezoelectric sensor. As shown in fig. 5, when a pressure event occurs in the piezoelectric sensor, the output voltage is subjected to differential conversion, and then the maximum differential voltage Vmax can be obtained in the rising edge phase of the output voltage, and the minimum differential voltage Vmin can be obtained in the falling edge phase of the output voltage. V1 represents a differential voltage at the rising edge of the output voltage, 0 < V1 < Vmax. V2 represents a differential voltage at the falling edge phase of the output voltage, vmin < V2 < 0.

Optionally, the threshold voltage includes a first threshold voltage, and the first threshold voltage is V1. And under the condition that the first differential voltage is larger than zero and not smaller than the first threshold voltage, determining that the piezoelectric sensor is in a pressing state. In this embodiment, a threshold voltage V1 is set to detect the forward differential signal, i.e., the process of applying pressure to the piezoelectric sensor.

Optionally, the threshold voltage includes a second threshold voltage, the second threshold voltage being V2. And under the condition that the first differential voltage is smaller than zero and not larger than the second threshold voltage, determining that the piezoelectric sensor is in a force-removing state. In this embodiment, a threshold voltage V2 is set to detect a negative differential signal, i.e., to detect the process of removing pressure from the piezoelectric sensor.

Optionally, the threshold voltages include a first threshold voltage and a second threshold voltage, the first threshold voltage taking V1 and the second threshold voltage taking V2. Comparing the first differential voltage with a first threshold voltage V1; comparing the first differential voltage with the second threshold voltage V2 in response to the comparison result that the first differential voltage is not less than the first threshold voltage V1; and in response to the comparison result that the first differential voltage is not greater than the second threshold voltage V2, determining that the piezoelectric sensor has a pressure event. In this embodiment, two threshold voltages V1 and V2, V1 are set for detecting a positive differential signal, i.e., detecting a process of applying a pressure to the piezoelectric sensor, and V2 is set for detecting a negative differential signal, i.e., detecting a process of removing a pressure to the piezoelectric sensor. By detecting the force applying and withdrawing processes respectively, the pressure event encountered by the piezoelectric sensor can be judged, and compared with the process of detecting the force applying and withdrawing independently, the detection result is more accurate.

Based on the same inventive concept, in one embodiment, a signal processing circuit is provided for implementing the signal processing method of the above embodiment. Fig. 6 is a schematic diagram of a signal processing circuit of the present embodiment, and as shown in fig. 6, the signal processing circuit 1 includes: the system comprises a differential module 11 and a control module 12, wherein the differential module 11 is connected with the control module 12; the differentiating module 11 is configured to perform differential transformation on an output voltage of the piezoelectric sensor to obtain a first differential voltage; a control module 12 for executing the signal processing method of the above embodiment.

In this embodiment, the differentiating module 11 performs differential transformation on the output voltage of the piezoelectric sensor to obtain a first differential voltage. The control module 12 determines whether a pressure event has occurred by comparing the absolute value of the first differential voltage and the threshold voltage during execution of the signal processing method. The slope of the output voltage caused by pressure is larger, the value after differentiation is larger, and the slope of the output voltage caused by temperature drift is smaller, so that the output voltage caused by pressure and the temperature drift voltage can be distinguished by setting the threshold voltage, the temperature drift influence is eliminated, and the false triggering of the pressure event is avoided. Reference may be made to the above-described embodiments for the principle and effect of the signal processing method, and the description thereof will not be repeated here.

In one embodiment, fig. 7 shows a schematic diagram of a signal processing circuit. As shown in fig. 7, the differentiating module 11 includes a first amplifying unit 111, a capacitor C, and a resistor R; the control module 12 includes a comparison unit 121 and a logic unit 122. The capacitor C is connected to the input end of the first amplifying unit 111, and the resistor R is connected between the input end and the output end of the first amplifying unit 111; the comparison unit 121 is connected to the logic unit 122. Wherein, the comparing unit 121 is configured to compare the first differential voltage with a threshold voltage to obtain a comparison result; the logic unit 122 is configured to output a determination result according to the comparison result, where the determination result includes whether a pressure event occurs.

The first amplifying unit 111 may be implemented as a buffer amplifier, a single-ended amplifier, a differential amplifier, or a programmable gain amplifier. Logic 122 may be implemented using any one or more combinations of flip-flops, and gates, not gates, or gates.

With continued reference to fig. 7, the signal processing circuit further includes a first pin 13, a second pin 14, and a third pin 15. The first pin 13 is used for being connected with a voltage output pin (Vout end) of the piezoelectric sensor, the second pin 14 is used for being connected with a reference voltage input pin (Vref end) of the piezoelectric sensor, the third pin 15 is used as a signal output end of the whole signal processing circuit, and the meaning represented by an output signal is determined by application requirements.

Alternatively, the signal processing circuit 1 may also be provided with a second amplifying unit 16. The second amplifying unit 16 is connected to the differentiating module 11 for amplifying the output voltage of the piezoelectric sensor and/or the first differentiated voltage. The second amplifying unit 16 is shown to be provided at the input of the differentiating module 11, and in other embodiments, the second amplifying unit 16 may be provided at the input and the output of the differentiating module 11, respectively. The second amplifying unit 16 may be implemented with a buffer amplifier, a single-ended amplifier, a differential amplifier, or a programmable gain amplifier.

Alternatively, the signal processing circuit 1 may also be provided with a voltage generation module 17. The voltage generating module 17 is connected to the second pin 14 and is responsible for providing a dc bias to the piezoelectric sensor. The voltage generating module 17 can be selected and removed according to the application requirement, and at this time, the Vref terminal of the piezoelectric sensor can be grounded according to the application requirement.

In one embodiment, fig. 8 shows a schematic diagram of another signal processing circuit. As shown in fig. 8, the second amplifying unit 16 includes a first amplifier 161 and a second amplifier 162 on the basis of fig. 7, and the comparing unit 121 includes a first comparator 1211 and a second comparator 1212. The first amplifier 161, the differentiating module 11 and the second amplifier 162 are sequentially connected, input ends of the first comparator 1211 and the second comparator 1212 are respectively connected with an output end of the second amplifier 162, and output ends of the first comparator 1211 and the second comparator 1212 are respectively connected with an input end of the logic unit 122. Wherein the first amplifier 161 is for amplifying an output voltage of the piezoelectric sensor; the second amplifier 162 is configured to amplify the first differential voltage output from the differential module 11; the first comparator 1211 is for comparing the first differential voltage with a first threshold voltage; the second comparator 1212 is used to compare the first differential voltage to a second threshold voltage.

In this embodiment, the voltage generating module 17 provides a dc voltage bias for the piezoelectric sensor, and the first amplifier 161 serves as a pre-amplifier to pre-amplify the small signal output by the piezoelectric sensor; the differentiating module 11 performs differential transformation on the amplified signal and outputs a first differential voltage; since the amplitude of the differentiated signal is reduced compared with the amplitude of the signal before differentiation, the second amplifier 162 is introduced in the embodiment, and the differentiated signal is amplified again; the threshold voltages of the first comparator 1211 and the second comparator 1212 are V1 and V2, respectively, V1 being used to detect a positive differential signal, i.e., to detect a process of applying a pressure to the piezoelectric sensor, and V2 being used to detect a negative differential signal, i.e., to detect a process of removing a pressure from the piezoelectric sensor; the logic unit 122 comprehensively derives the final output result of the signal processing circuit according to the output results of the two comparators.

In addition, the signal processing circuit 1 provided in any of the embodiments can be integrated into a chip, fully considers the hardware area cost and the power consumption cost, suppresses the temperature drift with the least cost, avoids the use of complex circuits such as an ADC, a DAC and the like, and also avoids the complex logic circuit design. It will be appreciated that the above-described signal processing circuit 1 may take other forms as well, without being limited to the form already mentioned in the above-described embodiment, as long as it can achieve the temperature drift suppression function.

In one embodiment, a piezoelectric sensing system is provided that includes a piezoelectric sensor and the signal processing circuitry of any of the embodiments described above, the piezoelectric sensor being coupled to the signal processing circuitry. The piezoelectric sensor converts the physical quantity into an electrical signal, and the processing of the electrical signal can be accomplished by a signal processing circuit. The signal processing circuit can periodically reset the piezoelectric sensor to inhibit the baseline voltage from rising, and avoid false triggering of the pressure event, so that the reliability of the piezoelectric sensing system is improved. The piezoelectric sensing system can be widely applied to various fields, including but not limited to: industrial automation, piezoelectric sensors can be used to measure the execution dynamics of the robot terminal actuators to ensure that they operate accurately; the medical equipment, the piezoelectric sensor can be used for measuring physiological parameters such as blood pressure, respiratory rate, heartbeat rate and the like; the piezoelectric sensor can be used for measuring the weight and pressure distribution of the vehicle in the automobile industry, providing data support for the design of the vehicle and monitoring the systems such as an air bag, a brake and the like; air quality detection, piezoelectric sensors can be used to measure pressure and humidity in the air, thereby helping to detect harmful gases in the air; the piezoelectric sensor can be used for monitoring the structural safety and stability of a building and measuring the vibration conditions of structures such as bridges, tunnels and the like; consumer electronics, such as electronic cigarettes, piezoelectric sensors may be used to detect a smoking or blowing action, triggering a function switch of the electronic cigarette.

In one embodiment, an electronic cigarette is provided that includes a body configured with a piezoelectric sensor, the body further configured with the signal processing circuit described above, or integrated with a chip including the signal processing circuit described above, or configured with the piezoelectric sensing system described above. Optionally, the main body further comprises a PCB motherboard, and the piezoelectric sensor is disposed on the PCB motherboard.

The influence of temperature drift is mainly reflected when the temperature rate changes greatly. Since the volume of an electronic cigarette is generally small, the capacity of its battery is also generally limited. When the electronic cigarette is charged, the charging can be completed within about 3 minutes. Under the charging scene, the PCB main board heats and conducts heat to the piezoelectric sensor, so that the temperature rise of about 3min can reach 30-40 ℃. The temperature drift effect is particularly obvious at such a large rate of temperature change, and therefore, the probability of the electronic cigarette being misfiring/activation/ignition is also high.

Compared with other schemes for solving the problem by improving external conditions (such as improving heat dissipation performance), the electronic cigarette provided by the embodiment can effectively inhibit temperature drift in the scene by arranging the signal processing circuit, and avoid false triggering pressure event, thereby reducing the probability of false triggering/false activating/false igniting of the electronic cigarette, and has better effect and cost control.

In the description of the present specification, reference to the term "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.

Claims

1. A signal processing method, comprising:

2. The signal processing method according to claim 1, wherein the absolute value of the threshold voltage is smaller than the absolute value of a second differential voltage, which is a maximum differential voltage or a minimum differential voltage obtained by differential transforming the output voltage when the piezoelectric sensor generates a pressure event.

3. The signal processing method of claim 2, wherein the threshold voltage comprises a first threshold voltage, the first threshold voltage being greater than zero and less than the maximum differential voltage.

4. A signal processing method according to claim 3, wherein determining that a pressure event has occurred in the piezoelectric sensor comprises:

5. The signal processing method of claim 2, wherein the threshold voltage comprises a second threshold voltage, the second threshold voltage being less than zero and greater than the minimum differential voltage.

6. The signal processing method of claim 5, wherein determining that a pressure event has occurred with the piezoelectric sensor comprises:

7. The signal processing method of claim 2, wherein the threshold voltages comprise a first threshold voltage greater than zero and less than the maximum differential voltage and a second threshold voltage less than zero and greater than the minimum differential voltage; determining that a pressure event occurred with the piezoelectric sensor comprises:

comparing the first differential voltage with the first threshold voltage;

8. A signal processing circuit, comprising: the system comprises a differential module and a control module, wherein the differential module is connected with the control module; wherein,

9. The signal processing circuit of claim 8, wherein the differentiating module comprises: the first amplifying unit, the capacitor and the resistor; the capacitor is connected to the input end of the first amplifying unit, and the resistor is connected between the input end and the output end of the first amplifying unit.

10. The signal processing circuit of claim 8, wherein the control module comprises: the device comprises a comparison unit and a logic unit, wherein the comparison unit is connected with the logic unit; wherein,

11. The signal processing circuit of claim 10, wherein the comparison unit comprises: the input ends of the first comparator and the second comparator are respectively connected with the output end of the differential module, and the output ends of the first comparator and the second comparator are respectively connected with the input end of the logic unit; wherein,

12. The signal processing circuit of claim 8, further comprising: and the second amplifying unit is connected with the differentiating module and is used for amplifying the output voltage of the piezoelectric sensor and/or the first differentiating voltage.

13. A piezoelectric sensing system, comprising: a piezoelectric sensor and the signal processing circuit of any one of claims 8 to 12, the piezoelectric sensor being connected to the signal processing circuit.

14. An electronic cigarette, comprising: a main body on which a piezoelectric sensor and the signal processing circuit of any one of claims 8 to 12 are provided, the piezoelectric sensor being connected to the signal processing circuit.