Temperature measurement circuit and temperature measurement method

Abstract

The invention provides a temperature measurement circuit and a temperature measurement method, the temperature measurement circuit is composed of a constant voltage circuit, a resonance circuit, a driving circuit and a master control circuit, the constant voltage circuit provides a constant voltage power supply, during temperature measurement, the driving circuit is controlled to trigger the resonance circuit to switch to a resonance state, the resonance circuit generates an alternating current and a changing magnetic flux, and the alternating current and the changing magnetic flux are switched to the constant voltage power supply. The magnetic field acts on the heating body, when the heating body is at different temperatures, inductance of an inductance coil of the resonance circuit is different, generated electrical parameters are different, and the main control circuit determines the temperature of the heating body according to the electrical parameters, so that non-contact temperature measurement is realized, the temperature measurement circuit is simple in structure, the design cost is reduced, and the temperature measurement efficiency is improved by adopting a constant-voltage circuit to supply power. The electrical parameters are not influenced by the change of the power supply, and the accuracy of temperature measurement is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of temperature measurement, and in particular, relates to a temperature measurement circuit and a temperature measurement method. Background Art

[0002] Heating without burning low-temperature baking appliances are a new type of electronic aerosol generating device, which can generate aerosol in the atomizer into a matrix. It has the advantages of safety, convenience, health and environmental protection, and is therefore gaining more and more attention and favor. The heating technology of the atomization part usually adopts electromagnetic heating or resistance heating technology, and the temperature detection usually adopts temperature sensors such as thermocouples or thermal resistors.

[0003] Among them, the heating element uses a temperature sensor for contact temperature measurement, which has a complex structure and high cost. Summary of the invention

[0004] The purpose of the present application is to provide a temperature measurement circuit, aiming to solve the problem of complex structure and high cost of using temperature sensors to measure the temperature of traditional heating elements.

[0005] A first aspect of an embodiment of the present application provides a temperature measurement circuit, characterized in that it is used to measure the temperature of a heating element, the heating element being a heating element with magnetic temperature characteristics, and the temperature measurement circuit comprises:

[0006] A constant voltage circuit is used to connect to the power module, receive the power supply output by the power module, convert the power supply constant voltage into a constant voltage power supply and output it;

[0007] A resonant circuit, the resonant circuit comprising an inductor, and at least a portion of the inductor is arranged opposite to the heating element;

[0008] a driving circuit, wherein at least one of the driving circuit and the resonant circuit is connected to the constant voltage circuit, and the driving circuit is configured to be triggered by a first PWM modulation signal to drive the resonant circuit to switch to a resonant state;

[0009] A main control circuit is connected to the resonant circuit and the drive circuit respectively, and is used to output the first PWM modulation signal to the drive circuit, detect the electrical parameters of the resonant circuit in a resonant state, and determine the temperature of the heating element according to the electrical parameters.

[0010] Optionally, the heating element is further connected to a heating circuit, and the heating circuit is further connected to the power module;

[0011] The heating circuit is used for electric-thermal conversion to heat the heating element;

[0012] The heating element is a resistance heating component;

[0013] Alternatively, the heating element is a magnetic core, the heating circuit comprises a heating coil, and the heating coil and at least a portion of the inductance coil are spaced apart from the heating element.

[0014] Optionally, the temperature measurement circuit further includes:

[0015] A unidirectional conducting circuit, wherein the input end of the unidirectional conducting circuit is used to be connected to the power supply module, the output end of the unidirectional conducting circuit is connected to at least one of the driving circuit and the resonant circuit, and the unidirectional conducting circuit is turned on when the voltage at the output end is less than the voltage at the input end;

[0016] a first switch circuit, wherein an input end of the first switch circuit is connected to a power supply output end of the constant voltage circuit, an output end of the first switch circuit is connected to an output end of the unidirectional conduction circuit, and the first switch circuit is turned on by a first switch signal and turned off by a second switch signal;

[0017] The main control circuit is also connected to the control end of the first switch circuit, and the main control circuit is used for:

[0018] Output the first switch signal and the second switch signal according to a preset timing sequence;

[0019] When outputting the first switch signal, synchronously outputting the first PWM modulation signal to the drive circuit;

[0020] When the second switch signal is output, a second PWM modulation signal is synchronously output to the drive circuit to trigger the resonant circuit to generate an alternating current to heat the heating element;

[0021] Wherein, the voltage of the constant voltage power supply is greater than the voltage of the power supply power supply.

[0022] Optionally, the unidirectional conducting circuit includes a diode;

[0023] The anode of the diode is the input end of the unidirectional conducting circuit, and the cathode of the diode is the output end of the unidirectional conducting circuit.

[0024] Optionally, the temperature measurement circuit further includes:

[0025] a second switch circuit, wherein an input end of the second switch circuit is used to be connected to the power module, and an output end of the second switch circuit is connected to at least one of the drive circuit and the resonant circuit;

[0026] a first switch circuit, wherein an input end of the first switch circuit is connected to a power supply output end of the constant voltage circuit, and an output end of the first switch circuit is connected to an output end of the second switch circuit;

[0027] The main control circuit is also connected to the control end of the first switch circuit and the control end of the second switch circuit, and the main control circuit is used to:

[0028] Outputting a first switching signal to the first switching circuit and the second switching circuit to control the first switching circuit to be turned on while the second switching circuit is turned off, and synchronously outputting the first PWM modulation signal to the driving circuit;

[0029] Alternatively, a second switching signal is output to the first switching circuit and the second switching circuit to control the second switching circuit to be turned on while the first switching circuit is turned off, and a second PWM modulation signal is synchronously output to the driving circuit to trigger the resonant circuit to generate an alternating current to heat the heating element.

[0030] Optionally, the duty cycle, duration and period of the first PWM modulation signal are constant or vary according to a preset rule.

[0031] Optionally, the resonant circuit includes an inductor and a resonant capacitor;

[0032] The inductor is connected in series or in parallel with the resonant capacitor.

[0033] Optionally, the driving circuit includes a first power switch tube;

[0034] The control end of the first power switch tube is connected to the main control circuit, the first end of the first power switch tube is connected to at least one of the constant voltage circuit and the resonant circuit, and the second end of the first power switch tube is grounded;

[0035] Alternatively, the driving circuit includes a second power switch tube and a third power switch tube, the control end of the second power switch tube and the control end of the third power switch tube are respectively connected to the main control circuit, the first end of the second power switch tube is connected to the power output end of the constant voltage circuit, the second end of the second power switch tube and the first end of the third power switch tube are connected in common and connected to the resonant circuit, and the second end of the third power switch tube is grounded.

[0036] Optionally, the constant voltage circuit includes a voltage stabilizing chip, a first capacitor and a second capacitor;

[0037] The input end of the voltage stabilizing chip and the first end of the first capacitor are connected together to form the input end of the constant voltage circuit, the output end of the voltage stabilizing chip and the second end of the second capacitor are connected together to form the output end of the constant voltage circuit, and the second end of the first capacitor and the second end of the second capacitor are grounded.

[0038] A second aspect of an embodiment of the present application provides a temperature measurement method for measuring the temperature of a heating element, wherein the heating element is a heating element having a magnetic temperature characteristic. The temperature measurement method comprises the following steps performed by a main control circuit in the temperature measurement circuit as described above:

[0039] Outputting a first PWM modulation signal to the driving circuit, so that the driving circuit is triggered by the first PWM modulation signal to drive the resonant circuit to switch to a resonant state;

[0040] The electrical parameters of the resonant circuit in the resonant state are detected and the temperature of the heating element is determined according to the electrical parameters.

[0041] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the above-mentioned temperature measurement circuit is composed of a constant voltage circuit, a resonant circuit, a drive circuit and a main control circuit. The constant voltage circuit provides a constant voltage power supply. When measuring temperature, the drive circuit is controlled to trigger the resonant circuit to switch to a resonant state. The resonant circuit generates an alternating current and a changing magnetic flux. The magnetic field acts on the heating element. When the heating element is at different temperatures, the inductance of the inductor coil of the resonant circuit is different, and the generated electrical parameters are different. The main control circuit determines the temperature of the heating element according to the size of the electrical parameters, thereby realizing contactless temperature measurement. The temperature measurement circuit has a simple structure, which reduces the design cost. In addition, by adopting a constant voltage circuit for power supply, the electrical parameters are not affected by changes in the power supply, thereby improving the accuracy of temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0043] Figure 1 A schematic diagram of the structure of the temperature measurement circuit provided in Example 1 of the present application;

[0044] Figure 2 A schematic diagram of the structure of the temperature measurement circuit provided in the second embodiment of the present application;

[0045] Figure 3 A first circuit diagram of a temperature measurement circuit provided in Example 1 of the present application;

[0046] Figure 4 A second circuit diagram of the temperature measurement circuit provided in Example 1 of the present application;

[0047] Figure 5 A schematic diagram of the structure of the temperature measurement circuit provided in the third embodiment of the present application;

[0048] Figure 6 A circuit diagram of a temperature measurement circuit provided in Embodiment 3 of the present application;

[0049] Figure 7 A schematic diagram of the structure of the temperature measurement circuit provided in the fourth embodiment of the present application;

[0050] Figure 8 A circuit diagram of a temperature measurement circuit provided in Embodiment 4 of the present application;

[0051] Fig. 9 This is a flow chart of the temperature measurement method provided in Example 5 of the present application. DETAILED DESCRIPTION

[0052] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0054] Embodiment 1

[0055] A first aspect of an embodiment of the present application proposes a temperature measurement circuit 100 for measuring the temperature of a heating element 1. The heating element 1 is a heating element 1 with magneto-thermal properties, that is, a metal or alloy with a specific Curie temperature point. Below the specific Curie temperature point (for example, 420°C), its magnetic induction value decreases with increasing temperature, and is almost linearly related. The material of the heating element 1 can be selected according to the needs. The corresponding type of metal or alloy, for example, iron-nickel-chromium alloy can be selected.

[0056] Among them, the heating element 1 is heated according to the received current signal or alternating magnetic field. For example, when the heating element 1 is a resistive heating component, the resistive heating component generates heat by passing direct current. The resistive heating component is set close to the atomizer or embedded in the atomizer, and heats the atomizing medium in the atomizer to generate an aerosol.

[0057] Alternatively, the heating element 1 may adopt a magnetic core structure, and the heating element 1 is wound with a corresponding heating coil L2. The heating coil L2 is passed with an alternating current, and the heating element 1 is inductively heated to atomize and heat the atomizer. The structure and heating method of the heating element 1 can be set according to the structure and type of the low-temperature baking appliance.

[0058] In order to realize the temperature detection of the heating element 1 and the feedback adjustment of the atomizer temperature, and at the same time simplify the temperature measurement structure, in this embodiment, the temperature measurement circuit 100 includes a constant voltage circuit 110, a resonant circuit 130, a driving circuit 120 and a main control circuit 140.

[0059] Among them, the constant voltage circuit 110 is used to connect with the power supply module 10, that is, when performing temperature measurement, the power input end of the constant voltage circuit 110 is connected to the power output end of the power supply module 10. The power supply module 10 can be a battery component and / or a power conversion circuit and other structures. For example, a rechargeable battery component can be selected. The power supply module 10 can be arranged in the temperature measurement circuit 100, or be arranged independently from the temperature measurement circuit 100, and can also be arranged outside the aerosol generating device. The specific setting method is not limited.

[0060] The constant voltage circuit 110 receives the power supply output by the power module 10, and converts the power supply into a constant voltage power supply, thereby providing a working power supply or a reference source for the back-end driving circuit 120 and other circuit modules. The main control circuit 140 can also be powered by the constant voltage circuit 110, or by other external constant current modules. The specific power source of the main control circuit 140 is not limited.

[0061] The resonant circuit 130 is an LC resonant circuit, including an inductor L1 , and at least a portion of the inductor L1 is disposed opposite to the heating element 1 . The inductor L1 can be directly wound on the heating element 1 , or disposed at a preset distance from the heating element 1 .

[0062] At least one of the driving circuit 120 and the resonant circuit 130 is connected to the constant voltage circuit 110, and the constant voltage power output by the constant voltage circuit 110 is output to at least one of the driving circuit 120 and the resonant circuit 130. The resonant circuit 130 is connected to the driving circuit 120, and the driving circuit 120 is used to be triggered by the first PWM modulation signal PWM1 to drive the resonant circuit 130 to switch to a resonant state.

[0063] The main control circuit 140 is connected to the resonant circuit 130 and the driving circuit 120 respectively. The main control circuit 140 is used to output a first PWM modulation signal PWM1 to the driving circuit 120, detect electrical parameters of the resonant circuit 130 in a resonant state, and determine the temperature of the heating element 1 according to the electrical parameters.

[0064] In this embodiment, the temperature of the heating element 1 is measured by electromagnetic induction. When the temperature of the heating element 1 changes, since it has obvious magnetic-temperature characteristics under specific temperature conditions (between 150°C and 420°C), it will affect the apparent resistance and inductance of the inductor L1, thereby causing the electrical parameters of the resonant circuit 130 to change. The electrical parameters may be one or more of the electrical parameters such as the oscillation period of the voltage or current of the resonant circuit 130, the peak voltage, etc.

[0065] When the temperature of the heating element 1 increases, the parameters such as the magnetic permeability of the heating element 1 change, the inductance of the inductor L1 decreases, and the oscillation period of the voltage or current of the resonant circuit 130 decreases. When the temperature of the heating element 1 decreases, the magnetic induction value of the magnetic field of the heating element 1 increases, and the inductance of the inductor L1 increases, thereby causing the oscillation period of the voltage or current of the resonant circuit 130 to increase.

[0066] The heating element 1 performs resistance heating according to the received current signal or performs induction heating by induction when it is induced by the alternating magnetic field. When measuring the temperature, the main control circuit 140 outputs the first PWM modulation signal PWM1 to the drive circuit 120. The drive circuit 120 drives the resonant circuit 130 to switch to the resonant state. When the resonant circuit 130 switches to the resonant state, the inductor L1 and the corresponding resonant capacitor Cc inside the resonant circuit 130 are charged and discharged to generate an alternating current, thereby generating a changing magnetic flux. The changing magnetic flux acts on the heating element 1. When the heating element 1 is at different temperatures, the parameters such as the magnetic permeability are not the same. Correspondingly, the magnetic induction intensity inside the inductor L1 is different, and the overall inductance of the inductor L1 is different, which in turn causes changes in corresponding electrical parameters such as the oscillation period or peak voltage of the voltage or current of the resonant circuit 130. According to the magnetic field effect between the inductor L1 and the heating element 1, the temperature and change trend of the heating element 1 can be determined by detecting the size of the electrical parameters of the resonant circuit 130 and their changes, thereby realizing contactless temperature measurement. The circuit structure is simple, and no complex signal processing circuits and software calibration algorithms are required, which is conducive to reducing the cost of the temperature measurement circuit 100 and miniaturization of the device.

[0067] Furthermore, in order to more conveniently obtain the current temperature of the heating element 1, a calibration test is performed before temperature measurement. By changing the temperature of the heating element 1, the main control circuit 140 records the temperature and electrical parameters under the control of the first PWM modulation signal PWM1, and calibrates the temperature and electrical parameters. By establishing a curve fitting algorithm or a table lookup method, wireless temperature measurement of the heating element 1 based on electromagnetic induction can be achieved. At the same time, closed-loop constant temperature control of the heating element 1 can also be achieved based on the temperature measurement results.

[0068] The constant voltage circuit 110 is used to isolate the power module 10 from the resonant circuit 130, so that the resonant circuit 130 receives a constant voltage, thereby preventing the changing power supply from causing changes in the electrical parameters of the resonant circuit 130, thereby improving the detection accuracy.

[0069] Among them, the heating method of the heating element 1 can be resistive heating or electromagnetic heating. When electromagnetic heating is used, the heating coil L2 is connected to the heating circuit 200. Since the working current of the LC power circuit is large in electromagnetic induction heating, the constant voltage circuit 110 cannot be used directly for power supply. Therefore, the heating circuit 200 is connected to the power module 10 and is powered by the power module 10.

[0070] Among them, the duty cycle and period of the first PWM modulation signal PWM1 can be adjusted accordingly according to needs. In order to improve the temperature measurement accuracy, optionally, the duty cycle, duration and period of the first PWM modulation signal PWM1 are constant or change according to preset rules. By setting the first PWM modulation signal PWM1 that changes with a fixed or preset rule, a fixed or regularly changing energy is provided to the resonant circuit 130, and each time the temperature is measured, the voltage and duty cycle at both ends of the inductor L1 are the same, thereby reducing the influence of other factors and improving the temperature measurement accuracy. Among them, the preset rule change can be that within a unit time, for example, 10ms, the duty cycle increases or decreases according to a gradient.

[0071] The resonant circuit 130 adopts an LC resonant circuit, such as Figure 3 or Figure 4 As shown, optionally, the resonant circuit 130 includes an inductor L1 and a resonant capacitor Cc, and the inductor L1 and the resonant capacitor Cc are connected in series or in parallel. When the driving circuit 120 receives the first PWM modulation signal PWM1, it drives the inductor L1 and the resonant capacitor Cc to charge and discharge, and generates an alternating current and a changing magnetic flux. The magnetic field acts on the heating element 1. When the heating element 1 is at different temperatures, the inductance of the inductor L1 of the resonant circuit 130 is different, and the generated electrical parameters are different. The main control circuit 140 thereby determines the temperature of the heating element 1 according to the changed electrical parameters.

[0072] The driving circuit 120 may adopt a switch structure with controlled on / off. In order to achieve high frequency on / off to generate an alternating magnetic field, in an optional embodiment, Figure 4 As shown, the driving circuit 120 includes a first power switch tube Q1, a control end of the first power switch tube Q1 is connected to the main control circuit 140, a first end of the first power switch tube Q1 is connected to at least one of the constant voltage circuit 110 and the resonant circuit 130, and a second end of the first power switch tube Q1 is grounded.

[0073] The first power switch tube Q1 can be connected between the constant voltage circuit 110 and the resonant circuit 130, or connected to the back end of the resonant circuit 130. The main control circuit 140 controls the on and off of the first power switch tube Q1 by outputting a first PWM modulation signal PWM1 with a fixed duration, duty cycle and period, thereby controlling the charging and discharging of the inductor coil L1 and the resonant capacitor Cc.

[0074] Or, in another alternative embodiment, if Figure 3 As shown, the driving circuit 120 includes a second power switch tube Q4 and a third power switch tube Q5, the control end of the second power switch tube Q4 and the control end of the third power switch tube Q5 are respectively connected to the main control circuit 140, the first end of the second power switch tube Q4 is connected to the power output end of the constant voltage circuit 110, the second end of the second power switch tube Q4 and the first end of the third power switch tube Q5 are commonly connected and connected to the resonant circuit 130, and the second end of the third power switch tube Q5 is grounded.

[0075] The main control circuit 140 controls the second power switch tube Q4 and the third power switch tube Q5 to be alternately turned on by outputting the first PWM modulation signal PWM1 with a fixed duration, duty cycle and period, thereby controlling the charging and discharging of the inductor coil L1 and the resonant capacitors Cc1 and Cc2. The alternating current and the alternating magnetic field generated by the resonant circuit 130 are related to the conduction frequency and control time of the two power switch tubes.

[0076] The constant voltage circuit 110 may adopt a corresponding circuit structure such as a low voltage difference linear power supply, a boost power supply, etc., optionally, as Figure 3 and Figure 4 As shown, the constant voltage circuit 110 includes a voltage stabilizing chip U1, a first capacitor C1 and a second capacitor C2;

[0077] The input end of the voltage stabilizing chip U1 and the first end of the first capacitor C1 are connected together to form the input end of the constant voltage circuit 110, the output end of the voltage stabilizing chip U1 and the second end of the second capacitor C2 are connected together to form the output end of the constant voltage circuit 110, and the second end of the first capacitor C1 and the second end of the second capacitor C2 are grounded.

[0078] The voltage stabilizing chip U1 can perform step-up and step-down conversion on the power supply according to demand, and the first capacitor C1 and the second capacitor C2 are used to implement input filtering and output filtering to reduce noise input and output.

[0079] The main control circuit 140 can adopt corresponding electrical parameter sampling circuits and controller structures. The electrical parameter sampling circuit may include an amplification circuit, a comparison circuit, and a zero-crossing detection circuit. By collecting the electrical parameters of the resonant circuit 130 and outputting the electrical parameter sampling signal to the controller, the controller determines the real-time temperature of the heating element 1 based on the mapping relationship between the temperature and the electrical parameters.

[0080] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the above-mentioned temperature measurement circuit 100 is composed of a constant voltage circuit 110, a resonant circuit 130, a drive circuit 120 and a main control circuit 140. The constant voltage circuit 110 provides a constant voltage power supply. When measuring temperature, the drive circuit 120 is controlled to trigger the resonant circuit 130 to switch to a resonant state. The resonant circuit 130 generates an alternating current and a changing magnetic flux. The magnetic field acts on the heating element 1. When the heating element 1 is at different temperatures, the inductance of the inductor L1 of the resonant circuit 130 is different, and the generated electrical parameters are different. The main control circuit 140 determines the temperature of the heating element 1 according to the size of the electrical parameters, thereby realizing contactless temperature measurement. The temperature measurement circuit 100 has a simple structure, reduces design costs, and is powered by the constant voltage circuit 110. The electrical parameters are not affected by changes in the power supply, thereby improving the accuracy of temperature measurement.

[0081] Embodiment 2

[0082] Based on the first embodiment, refinement and optimization are performed. Optionally, as Figure 2 As shown, the heating element 1 is also connected to the heating circuit 200, and the heating circuit 200 is also connected to the power module 10;

[0083] The heating circuit 200 is used for electric-thermal conversion to heat the heating element 1;

[0084] The heating element 1 is a resistance heating component;

[0085] Alternatively, the heating element 1 is a magnetic core, and the heating circuit 200 includes a heating coil L2 , and the heating coil L2 and at least a portion of the inductance coil L1 are spaced apart from the heating element 1 .

[0086] In this embodiment, the heating and temperature measurement of the heating element 1 adopt two independent circuit structures, and the inductor coil L1 is independent of the heating coil L2 or the heating circuit 200.

[0087] In the heating mode, the power module 10 provides power supply to the heating circuit 200. When a resistive heating component is used, the heating circuit 200 is connected to the heating element 1 through a connecting line. The heating circuit 200 outputs direct current to the heating element 1. The heating element 1 generates heat by passing direct current. The heating element 1 is set close to the atomizer or embedded in the atomizer, and heats the atomization matrix in the atomizer to generate an aerosol.

[0088] The heating circuit 200 may adopt a power conversion circuit structure, and output direct current of different magnitudes according to the received temperature adjustment signal, thereby changing the temperature of the heating element 1 and the heating temperature of the atomizer.

[0089] Furthermore, in order to simplify the structure of the aerosol generating device, the main control circuit 140 is also connected to the heating circuit 200. The main control circuit 140 compares the set temperature of the heating element 1 and the detected actual temperature of the heating element 1, and outputs a corresponding temperature control signal to the heating circuit 200, so that the heating circuit 200 outputs a corresponding amount of direct current to the heating element 1, controls the temperature of the heating element 1 within the set temperature threshold, and realizes feedback constant temperature regulation.

[0090] When electromagnetic heating is adopted, the heating circuit 200 includes another LC resonant circuit, and the resonant circuit 130 includes a heating coil L2, and the heating coil L2 and at least a part of the inductance coil L1 are arranged relative to the heating element 1, wherein the heating coil L2 and the inductance coil can be wound around the heating element 1, or arranged relative to the heating element in a contactless manner. After receiving the power supply, the other LC resonant circuit generates an alternating current and an alternating magnetic field, the heating element 1 is inductively heated, and the atomization matrix in the atomizer is heated, thereby generating an aerosol.

[0091] Furthermore, in order to simplify the structure of the aerosol generating device, the main control circuit 140 is also connected to the heating circuit 200. The main control circuit 140 compares the set temperature of the heating element 1 and the detected actual temperature of the heating element 1, and outputs a temperature control signal to the heating circuit 200 accordingly, so that the heating circuit 200 outputs an alternating current and an alternating magnetic field of corresponding magnitude to the heating element 1, thereby controlling the temperature of the heating element 1 within the set temperature threshold and realizing feedback constant temperature regulation.

[0092] When measuring temperature, the constant voltage circuit 110 outputs a constant voltage power supply to at least one of the driving circuit 120 and the resonant circuit 130. After receiving the first PWM modulation signal PWM1, the driving circuit 120 drives the resonant circuit 130 to switch to the resonant state. The resonant circuit 130 generates an alternating current and a changing magnetic flux. The magnetic field acts on the heating element. When the heating element 1 is at different temperatures, the inductance of the inductor L1 of the resonant circuit 130 is different, and the generated electrical parameters are different. The main control circuit 140 determines the temperature of the heating element 1 according to the size of the electrical parameters, thereby realizing contactless temperature measurement.

[0093] By independently arranging the heating circuit 200 and the temperature measurement circuit 100, the heating mode and the temperature measurement mode can be performed synchronously or in different time periods without interfering with each other, thereby reducing the temperature measurement requirements.

[0094] Embodiment 3

[0095] Based on the refinement and optimization of the first embodiment, in order to simplify the structure of the aerosol generating device, the inductor coil L1 is reused as the heating coil L2, such as Figure 5 As shown, optionally, the temperature measurement circuit 100 further includes:

[0096] A unidirectional conducting circuit 150, wherein the input end of the unidirectional conducting circuit 150 is used to be connected to the power module 10, and the output end of the unidirectional conducting circuit 150 is connected to at least one of the driving circuit 120 and the resonant circuit 130. The unidirectional conducting circuit 150 is turned on when the voltage at its output end is less than the voltage at its input end;

[0097] A first switch circuit 160, wherein an input end of the first switch circuit 160 is connected to a power supply output end of the constant voltage circuit 110, an output end of the first switch circuit 160 is connected to an output end of the unidirectional conduction circuit 150, and the first switch circuit 160 is turned on by a first switch signal and turned off by a second switch signal;

[0098] The main control circuit 140 is also connected to the control end of the first switch circuit 160. The main control circuit 140 is used for:

[0099] Outputting a first switching signal and a second switching signal according to a preset timing sequence;

[0100] When outputting the first switch signal, synchronously outputting the first PWM modulation signal PWM1 to the driving circuit 120;

[0101] When the second switch signal is output, the second PWM modulation signal PWM2 is synchronously output to the driving circuit 120 to trigger the resonant circuit 130 to generate an alternating current to heat the heating element 1;

[0102] The voltage V2 of the constant voltage power supply is greater than the voltage V1 of the power supply.

[0103] In this embodiment, the inductor coil L1 is reused as the heating coil L2, and the heating mode adopts electromagnetic heating.

[0104] During heating, the main control circuit 140 outputs a second switching signal to the first switching circuit 160, and the first switching circuit 160 is controlled to be turned off. At this time, there is no power flow between the constant voltage circuit 110 and the drive circuit 120, and it switches to the heating mode. The power module 10 outputs the power supply to the drive circuit 120 through the unidirectional conduction circuit 150. After the drive circuit 120 receives the second PWM modulation signal PWM2 output by the main control circuit 140, it drives the inductor L1 and the resonant capacitor Cc of the resonant circuit 130 to charge and discharge, and generates an alternating current corresponding to the second PWM modulation signal PWM2, and generates a corresponding alternating magnetic field. The heating element 1 is inductively heated, and the atomization matrix in the atomizer is heated, thereby generating an aerosol.

[0105] And, in the temperature measurement mode, the main control circuit 140 outputs a first switch signal to the first switch circuit 160, and the first switch circuit 160 is controlled to be turned on. At this time, the constant voltage circuit 110 outputs a constant voltage power supply to at least one of the drive circuit 120 and the resonant circuit 130 and the output end of the unidirectional conduction circuit 150. At this time, since the voltage V2 of the constant voltage power supply is greater than the voltage V1 of the power supply, the unidirectional conduction circuit 150 is turned off. At this time, the constant voltage circuit 110, the drive circuit 120, the resonant circuit 130 and the main control circuit 140 are combined. The temperature measurement circuit 100 is formed, and the main control circuit 140 outputs the first PWM modulation signal PWM1 with a fixed duty cycle, duration and period to the driving circuit 120, and drives the resonant circuit 130 to switch to a resonant state. The resonant circuit 130 generates an alternating current and a changing magnetic flux, and the magnetic field acts on the heating element 1. When the heating element 1 is at different temperatures, the inductance of the inductor L1 of the resonant circuit 130 is different, and the generated electrical parameters are different. The main control circuit 140 determines the temperature of the heating element 1 according to the size of the electrical parameters, thereby realizing contactless temperature measurement.

[0106] Among them, the heating mode and the heating mode are carried out in a time-sharing manner. After obtaining the temperature of the heating element 1, the main control circuit 140 adjusts the duty cycle of the second PWM modulation signal PWM2 according to the set temperature of the heating element 1 and the actual temperature of the heating element 1 in the heating mode, thereby changing the alternating current size and the alternating magnetic field size in the heating mode, thereby adjusting the heating temperature of the heating element 1 and the heating temperature of the atomizer.

[0107] The first switch circuit 160 may be a switch device with controlled on / off, such as a transistor, a MOS tube, a relay, etc. Figure 6 As shown, the first switch circuit 160 includes a first PMOS tube Q2, the source of the first PMOS tube Q2 constitutes the input end of the first switch circuit 160, the drain of the first PMOS tube Q2 constitutes the output end of the first switch circuit 160, the gate of the first PMOS tube Q2 constitutes the control end of the first switch circuit 160, the first switch signal is a low level signal, and the second switch signal is a high level signal.

[0108] The unidirectional conduction circuit 150 can adopt a voltage comparison circuit, a diode D1 and the like. In order to simplify the circuit structure, as shown in FIG. Figure 6 As shown, optionally, the unidirectional conducting circuit 150 includes a diode D1;

[0109] The anode of the diode D1 is the input terminal of the unidirectional conducting circuit 150 , and the cathode of the diode D1 is the output terminal of the unidirectional conducting circuit 150 .

[0110] In this embodiment, in the temperature measurement mode, the voltage V2 of the constant voltage power supply output by the voltage stabilizing chip U1 is greater than the voltage V1 of the power supply. At this time, the cathode voltage of the diode D1 is greater than the anode voltage of the diode D1, and the diode D1 is reversely cut off. The temperature measurement circuit 100 is composed of a constant voltage circuit 110, a drive circuit 120, a resonant circuit 130 and a main control circuit 140. The main control circuit 140 determines the temperature of the heating element 1 according to the size of the electrical parameters, thereby realizing non-contact temperature measurement.

[0111] Embodiment 4

[0112] Based on the refinement and optimization of the first embodiment, in order to simplify the structure of the aerosol generating device, the inductor coil L1 is reused as the heating coil L2. In another optional embodiment, as shown in FIG. Figure 7 As shown, the temperature measurement circuit 100 also includes:

[0113] A second switch circuit 170, wherein an input end of the second switch circuit 170 is used to be connected to the power module 10, and an output end of the second switch circuit 170 is connected to at least one of the drive circuit 120 and the resonant circuit 130;

[0114] A first switch circuit 160, wherein an input end of the first switch circuit 160 is connected to a power supply output end of the constant voltage circuit 110, and an output end of the first switch circuit 160 is connected to an output end of the second switch circuit 170;

[0115] The main control circuit 140 is also connected to the control end of the first switch circuit 160 and the control end of the second switch circuit 170. The main control circuit 140 is used for:

[0116] Outputting a first switch signal to the first switch circuit 160 and the second switch circuit 170 to control the second switch circuit 170 to be turned off when the first switch circuit 160 is turned on, and synchronously outputting a first PWM modulation signal PWM1 to the driving circuit 120;

[0117] Alternatively, a second switching signal is output to the first switching circuit 160 and the second switching circuit 170 to control the first switching circuit 160 to be turned off when the second switching circuit 170 is turned on, and a second PWM modulation signal PWM2 is synchronously output to the driving circuit 120 to trigger the resonant circuit 130 to generate an alternating current to heat the heating element 1.

[0118] In this embodiment, the inductor coil L1 is reused as the heating coil L2, and the heating mode adopts electromagnetic heating.

[0119] During heating, the main control circuit 140 outputs a second switch signal to the first switch circuit 160 and the second switch circuit 170, the first switch circuit 160 is controlled to be turned off, and the second switch circuit 170 is controlled to be turned on. At this time, there is no power flow between the constant voltage circuit 110 and the drive circuit 120, and the power is supplied by the power module 10. The power module 10 outputs the power supply to the drive circuit 120 through the second switch circuit 170. The drive circuit 120 is triggered after receiving the second PWM modulation signal PWM2 output by the main control circuit 140, and drives the inductor L1 and the resonant capacitor Cc of the resonant circuit 130 to charge and discharge, and generates an alternating current corresponding to the second PWM modulation signal PWM2 and a corresponding alternating magnetic field. The heating element 1 is inductively heated, and the atomization matrix in the atomizer is heated, thereby generating an aerosol.

[0120] And, in the temperature measurement mode, the main control circuit 140 outputs a first switch signal to the first switch circuit 160 and the second switch circuit 170, the first switch circuit 160 is controlled to be turned on, and the second switch circuit 170 is controlled to be turned off. At this time, the constant voltage circuit 110 outputs a constant voltage power supply to at least one of the drive circuit 120 and the resonant circuit 130 and the output end of the unidirectional conduction circuit 150. At this time, the constant voltage circuit 110, the drive circuit 120, the resonant circuit 130 and the main control circuit 140 form a temperature measurement circuit 100. The control circuit 140 outputs the first PWM modulation signal PWM1 with a fixed duty cycle, duration and period to the driving circuit 120. The driving circuit 120 drives the resonant circuit 130 to switch to a resonant state. The resonant circuit 130 generates an alternating current and a changing magnetic flux. The magnetic field acts on the heating element 1. When the heating element 1 is at different temperatures, the inductance of the inductor L1 of the resonant circuit 130 is different, and the generated electrical parameters are different. The main control circuit 140 determines the temperature of the heating element 1 according to the size of the electrical parameters, thereby realizing contactless temperature measurement.

[0121] Among them, the heating mode and the heating mode are carried out in a time-sharing manner. After obtaining the temperature of the heating element 1, the main control circuit 140 adjusts the duty cycle of the second PWM modulation signal PWM2 according to the set temperature of the heating element 1 and the actual temperature of the heating element 1 in the heating mode, thereby changing the alternating current size and the alternating magnetic field size in the heating mode, thereby adjusting the heating temperature of the heating element 1 and the heating temperature of the atomizer.

[0122] The first switch circuit 160 and the second switch circuit 170 may be switch devices with controlled on / off, such as transistors, MOS tubes, relays, etc. Figure 8As shown, the first switch circuit 160 includes a first PMOS tube Q2, the source of the first PMOS tube Q2 constitutes the input end of the first switch circuit 160, the drain of the first PMOS tube Q2 constitutes the output end of the first switch circuit 160, and the gate of the first PMOS tube Q2 constitutes the control end of the first switch circuit 160.

[0123] The second switch circuit 170 uses a second PMOS transistor Q3, the source of the second PMOS transistor Q3 constitutes the input end of the second switch circuit 170, the drain of the second PMOS transistor Q3 constitutes the output end of the second switch circuit 170, and the gate of the second PMOS transistor Q3 constitutes the control end of the second switch circuit 170.

[0124] In the heating mode, the switch signal received by the first switch circuit 160 is a high level signal, and the switch signal received by the second switch circuit 170 is a low level signal.

[0125] And in the temperature measurement mode, the switch signal received by the first switch circuit 160 is a low level signal, and the switch signal received by the second switch circuit 170 is a high level signal.

[0126] Embodiment 5

[0127] The second aspect of the embodiment of the present application proposes a temperature measurement method for measuring the temperature of a heating element 1, wherein the heating element 1 is a heating element 1 with magneto-thermal properties, that is, a metal or alloy with a specific Curie temperature point. Below the specific Curie temperature point (for example, 420°C), its magnetic induction value decreases with increasing temperature, and is almost linearly related. The material of the heating element 1 can be selected according to the needs. The corresponding type of metal or alloy, for example, iron-nickel-chromium alloy can be selected.

[0128] Among them, the heating element 1 is heated according to the received current signal or alternating magnetic field. For example, when the heating element 1 is a resistive heating component, the resistive heating component generates heat by passing direct current. The resistive heating component is set close to the atomizer or embedded in the atomizer, and heats the atomization matrix in the atomizer to generate an aerosol.

[0129] Alternatively, the heating element 1 may adopt a magnetic core structure, and the heating element 1 is wound with a corresponding heating coil L2. The heating coil L2 is passed with an alternating current, and the heating element 1 is inductively heated to atomize and heat the atomizer. The structure and heating method of the heating element 1 can be set according to the structure and type of the low-temperature baking appliance.

[0130] like Fig. 9 As shown, the temperature measurement method includes the following steps performed by the main control circuit 140 in the temperature measurement circuit 100:

[0131] Step S10 , outputting the first PWM modulation signal PWM1 to the driving circuit 120 , so that the driving circuit 120 is triggered by the first PWM modulation signal PWM1 to drive the resonant circuit 130 to switch to a resonant state.

[0132] Step S20 , detecting electrical parameters of the resonant circuit 130 in the resonant state and determining the temperature of the heating element 1 according to the electrical parameters.

[0133] The heating element 1 performs resistance heating according to the received current signal or performs induction heating when it is induced by the alternating magnetic field. When measuring the temperature, the main control circuit 140 outputs the first PWM modulation signal PWM1 to the driving circuit 120, and the driving circuit 120 drives the resonant circuit 130 to switch to the resonant state. When switching to the resonant state, the inductor L1 and the corresponding resonant capacitor Cc inside the resonant circuit 130 are charged and discharged to generate an alternating current, thereby generating a changing magnetic flux. The magnetic field acts on the heating element 1. When the heating element 1 is at different temperatures, the inductance of the inductor L1 of the resonant circuit 130 is different, and the electrical parameters such as the oscillation period or peak voltage of the voltage or current of the resonant circuit 130 are different. According to the magnetic field effect between the inductor L1 and the heating element 1, the temperature size and change trend of the heating element 1 can be determined by detecting the size and change of the electrical parameters of the resonant circuit 130, thereby realizing contactless temperature measurement. The circuit structure is simple, and no complex signal processing circuit and software calibration algorithm are required, which is conducive to reducing the cost of the temperature measurement circuit 100 and miniaturization of the device.

[0134] Among them, in order to more conveniently obtain the current temperature of the heating element 1, a calibration test is performed before temperature measurement. By changing the temperature of the heating element 1, the main control circuit 140 records the temperature and electrical parameters under the control of the first PWM modulation signal PWM1, and calibrates the temperature and electrical parameters. By establishing a curve fitting algorithm or a table lookup method, wireless temperature measurement of the heating element 1 based on electromagnetic induction can be achieved. At the same time, closed-loop constant temperature control of the heating element 1 can also be achieved according to the temperature measurement results.

[0135] The constant voltage circuit 110 is used to isolate the power module 10 from the resonant circuit 130, so that the resonant circuit 130 and / or the driving circuit 120 receive a constant voltage, thereby preventing the changing power supply from causing changes in the electrical parameters of the resonant circuit 130, thereby improving the detection accuracy.

[0136] The duty cycle and period of the first PWM modulation signal PWM1 can be adjusted accordingly as required. Optionally, the duty cycle, duration and period of the first PWM modulation signal PWM1 are constant or vary according to preset rules. By setting the first PWM modulation signal PWM1 to be fixed or vary according to preset rules, fixed or regularly varying energy is provided to the resonant circuit 130, and each time the temperature is measured, the voltage and duty cycle at both ends of the inductor L1 are the same, thereby reducing the influence of other factors and improving the temperature measurement accuracy.

[0137] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0138] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A temperature measurement circuit, characterized in that: Used to measure the temperature of a heating element, the heating element is a heating element with magnetic temperature characteristics, and the temperature measurement circuit includes: A constant voltage circuit is used to connect to the power module, receive the power supply output by the power module, convert the power supply constant voltage into a constant voltage power supply and output it; A resonant circuit, the resonant circuit comprising an inductor, and at least a portion of the inductor is arranged opposite to the heating element; a driving circuit, wherein at least one of the driving circuit and the resonant circuit is connected to the constant voltage circuit, and the driving circuit is configured to be triggered by a first PWM modulation signal to drive the resonant circuit to switch to a resonant state; A main control circuit is connected to the resonant circuit and the drive circuit respectively, and is used to output the first PWM modulation signal to the drive circuit, detect the electrical parameters of the resonant circuit in a resonant state, and determine the temperature of the heating element according to the electrical parameters.

2. The temperature measuring circuit according to claim 1, characterized in that: The heating element is also connected to a heating circuit, and the heating circuit is also connected to the power module; The heating circuit is used for electric-thermal conversion to heat the heating element; The heating element is a resistance heating component; Alternatively, the heating element is a magnetic core, the heating circuit comprises a heating coil, and the heating coil and at least a portion of the inductance coil are spaced apart from the heating element.

3. The temperature measuring circuit according to claim 1, characterized in that: The temperature measurement circuit also includes: A unidirectional conducting circuit, wherein the input end of the unidirectional conducting circuit is used to be connected to the power supply module, the output end of the unidirectional conducting circuit is connected to at least one of the driving circuit and the resonant circuit, and the unidirectional conducting circuit is turned on when the voltage at its output end is less than the voltage at its input end; a first switch circuit, wherein an input end of the first switch circuit is connected to a power supply output end of the constant voltage circuit, an output end of the first switch circuit is connected to an output end of the unidirectional conduction circuit, and the first switch circuit is turned on by a first switch signal and turned off by a second switch signal; The main control circuit is also connected to the control end of the first switch circuit, and the main control circuit is used for: Output the first switch signal and the second switch signal according to a preset timing sequence; When outputting the first switch signal, synchronously outputting the first PWM modulation signal to the drive circuit; When the second switch signal is output, a second PWM modulation signal is synchronously output to the drive circuit to trigger the resonant circuit to generate an alternating current to heat the heating element; Wherein, the voltage of the constant voltage power supply is greater than the voltage of the power supply power supply.

4. The temperature measuring circuit according to claim 3, characterized in that: The unidirectional conducting circuit comprises a diode; The anode of the diode is the input end of the unidirectional conducting circuit, and the cathode of the diode is the output end of the unidirectional conducting circuit.

5. The temperature measuring circuit according to claim 1, characterized in that: The temperature measurement circuit also includes: a second switch circuit, wherein an input end of the second switch circuit is used to be connected to the power module, and an output end of the second switch circuit is connected to at least one of the drive circuit and the resonant circuit; a first switch circuit, wherein an input end of the first switch circuit is connected to a power supply output end of the constant voltage circuit, and an output end of the first switch circuit is connected to an output end of the second switch circuit; The main control circuit is also connected to the control end of the first switch circuit and the control end of the second switch circuit, and the main control circuit is used to: Outputting a first switching signal to the first switching circuit and the second switching circuit to control the first switching circuit to be turned on while the second switching circuit is turned off, and synchronously outputting the first PWM modulation signal to the driving circuit; Alternatively, a second switching signal is output to the first switching circuit and the second switching circuit to control the second switching circuit to be turned on while the first switching circuit is turned off, and a second PWM modulation signal is synchronously output to the driving circuit to trigger the resonant circuit to generate an alternating current to heat the heating element.

6. The temperature measuring circuit according to claim 3 or 5, characterized in that: The duty cycle, duration and period of the first PWM modulation signal are constant or vary according to a preset rule.

7. The temperature measuring circuit according to claim 1, characterized in that: The resonant circuit comprises an inductor and a resonant capacitor; The inductor is connected in series or in parallel with the resonant capacitor.

8. The temperature measuring circuit according to claim 7, characterized in that: The driving circuit includes a first power switch tube; The control end of the first power switch tube is connected to the main control circuit, the first end of the first power switch tube is connected to at least one of the constant voltage circuit and the resonant circuit, and the second end of the first power switch tube is grounded; Alternatively, the driving circuit includes a second power switch tube and a third power switch tube, the control end of the second power switch tube and the control end of the third power switch tube are respectively connected to the main control circuit, the first end of the second power switch tube is connected to the power output end of the constant voltage circuit, the second end of the second power switch tube and the first end of the third power switch tube are connected in common and connected to the resonant circuit, and the second end of the third power switch tube is grounded.

9. The temperature measuring circuit according to claim 1, characterized in that: The constant voltage circuit includes a voltage stabilizing chip, a first capacitor and a second capacitor; The input end of the voltage stabilizing chip and the first end of the first capacitor are connected together to form the input end of the constant voltage circuit, the output end of the voltage stabilizing chip and the second end of the second capacitor are connected together to form the output end of the constant voltage circuit, and the second end of the first capacitor and the second end of the second capacitor are grounded.

10. A temperature measurement method, characterized in that: Used to measure the temperature of a heating element, the heating element being a heating element with magnetic temperature characteristics, the temperature measurement method comprising the following steps performed by the main control circuit in the temperature measurement circuit according to any one of claims 1 to 9: Outputting a first PWM modulation signal to the driving circuit, so that the driving circuit is triggered by the first PWM modulation signal to drive the resonant circuit to switch to a resonant state; The electrical parameters of the resonant circuit in the resonant state are detected and the temperature of the heating element is determined according to the electrical parameters.

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