Speaker modules, heating control circuits and outdoor fixed audio equipment

Abstract

The present invention discloses a heating control circuit, a speaker module and an outdoor fixed audio device, wherein the speaker module includes a metal mesh cloth, and the heating control circuit includes: a humidity detection circuit, the humidity detection circuit is used to detect the humidity of the metal mesh cloth and output a corresponding humidity detection signal; a main controller is electrically connected to the humidity detection circuit and the metal mesh cloth respectively, and the main controller is used to provide PWM electric energy to the metal mesh cloth when the humidity of the metal mesh cloth reaches a first preset humidity, so as to control the metal mesh cloth to convert electric energy into heat energy. The present invention solves the problem that the water stains left on the metal mesh cloth hinder the sound of the speaker, and the speaker fails.

Description

Technical Field

[0001] This invention relates to the field of loudspeaker technology, and in particular to a loudspeaker module, a heating control circuit, and an outdoor fixed audio device. Background Art

[0002] When speaker modules are used in outdoor fixed audio equipment, water stains are easily left on the speaker mesh in rainy or humid environments. This can hinder the speaker's sound production, especially severely suppressing high frequencies, resulting in low volume or noise. Water stains can even remain on the speaker diaphragm, damaging the diaphragm adhesive over time and causing the speaker to fail. Currently, the common solution is to add a waterproof housing or cover. However, this increases the design complexity of the speaker module's housing and also affects the speaker's sound output. Furthermore, once water gets into the waterproof housing or cover, it cannot actively drain the water. Summary of the Invention

[0003] The main objective of this invention is to provide a speaker module, a heating control circuit, and an outdoor fixed audio device, aiming to solve the problem that water stains remaining on the metal mesh fabric can obstruct the speaker's sound output and cause the speaker to malfunction.

[0004] To achieve the above objectives, the present invention proposes a heating control circuit, characterized in that it is applied in a speaker module, the speaker module comprising a metal mesh, and the heating control circuit comprising:

[0005] A humidity detection circuit is provided, which is used to detect the humidity of the metal mesh fabric and output a corresponding humidity detection signal.

[0006] The main controller is electrically connected to the humidity detection circuit and the metal mesh fabric respectively. When the humidity of the metal mesh fabric is detected to reach a first preset humidity, the main controller provides PWM power to the metal mesh fabric to control the metal mesh fabric to convert electrical energy into heat energy.

[0007] Optionally, the heating control circuit further includes:

[0008] A low-pass filter is connected in series between the main controller and the metal grid; the low-pass filter is used to filter out the high-frequency components in the PWM power to increase the AC power to the metal grid.

[0009] Optionally, the heating control circuit further includes:

[0010] A current-limiting resistor is connected in series between the main controller and the metal grid. The current-limiting resistor is used to limit the current output by the main controller.

[0011] Optionally, the heating control circuit further includes:

[0012] A first temperature detection circuit is used to detect the temperature of the metal mesh fabric and output a corresponding mesh fabric temperature detection signal.

[0013] The main controller is also connected to the first temperature detection circuit, and the main controller is also used to provide power to the metal mesh fabric or stop providing power to the metal mesh fabric according to the temperature detection signal of the mesh fabric when providing power to the metal mesh fabric.

[0014] Optionally, the speaker module further includes:

[0015] The second temperature detection circuit is used to detect the ambient temperature and output the ambient temperature detection signal;

[0016] The main controller is also connected to the second temperature detection circuit. The main controller is also used to provide power to the metal mesh fabric when, based on the mesh fabric temperature detection signal and the ambient temperature detection signal, the difference between the temperature of the metal mesh fabric and the ambient temperature is greater than a first preset difference.

[0017] When the temperature difference between the metal mesh and the ambient temperature is determined to be less than a first preset difference based on the mesh temperature detection signal and the ambient temperature detection signal, the supply of electrical energy to the metal mesh is stopped.

[0018] Optionally, the first temperature detection circuit includes a first thermistor and a first pull-up resistor. The thermistor is disposed close to the metal mesh. The output terminal of the second thermistor is interconnected with the first pull-up resistor and the first feedback terminal of the main controller. The second terminal of the first pull-up resistor is connected to a first DC power supply.

[0019] And / or, the second temperature detection circuit includes a second thermistor and a second pull-up resistor. The thermistor is disposed on the housing of the speaker assembly. The output terminal of the second thermistor is interconnected with the second pull-up resistor and the second feedback terminal of the main controller. The second terminal of the second pull-up resistor is connected to the first DC power supply.

[0020] Optionally, the heating control circuit further includes:

[0021] A power processing circuit, comprising a first power transmission terminal and a second power transmission terminal, wherein the first power transmission terminal is used to connect to an AC power source, the second power transmission terminal is used to connect to an energy storage device, and the output terminal of the power processing circuit is connected to the main controller.

[0022] The power processing circuit is used to disconnect the electrical connection with the energy storage device when it detects that an AC power voltage is connected to the first power transmission terminal, and to connect the electrical connection with the energy storage device when it detects that no AC power voltage is connected to the first power transmission terminal.

[0023] Optionally, the humidity detection circuit includes a humidity-sensitive resistor and a third pull-up resistor. The humidity-sensitive resistor is disposed close to the metal mesh. The output terminal of the humidity-sensitive resistor is interconnected with the third pull-up resistor and the feedback terminal of the main controller. The second terminal of the third pull-up resistor is connected to a DC power supply.

[0024] The present invention also proposes a speaker module, the speaker module comprising:

[0025] Speaker assembly;

[0026] The housing has a speaker housing cavity and a sound outlet communicating with the speaker housing cavity, and the speaker assembly is fixed inside the speaker housing cavity;

[0027] A metal mesh covering the sound outlet; and a heating control circuit as described above;

[0028] The heating control circuit is electrically connected to the metal mesh.

[0029] Optionally, the speaker module further includes:

[0030] An insulating layer is applied to both sides of the metal mesh fabric.

[0031] Optionally, the housing has a speaker housing cavity, the lower end of which, near the sound outlet, is inclined toward the speaker assembly;

[0032] And / or, the upper end of the speaker housing cavity near the sound outlet is inclined away from the speaker assembly.

[0033] The present invention also proposes an outdoor fixed audio device, including the heating control circuit described above;

[0034] And / or, including speaker modules as described above.

[0035] The heating control circuit of this invention detects the humidity of the metal mesh fabric using a humidity detection circuit and outputs a corresponding humidity detection signal to the main controller. The main controller compares the received humidity detection signal with a preset humidity threshold (first preset humidity). When the humidity of the metal mesh fabric reaches the first preset humidity, PWM power is supplied to the metal mesh fabric to control it to convert electrical energy into heat energy. This heat drives the metal mesh fabric to work, drying any water stains on it. This invention solves the problem of water stains remaining on the metal mesh fabric hindering speaker sound production, especially causing severe high-frequency suppression, resulting in low volume or noise. Furthermore, water stains remaining on the speaker diaphragm can damage the diaphragm adhesive over time, leading to speaker failure. Attached Figure Description

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0037] Figure 1 This is a functional module diagram of an embodiment of the heating control circuit of the present invention;

[0038] Figure 2 This is a schematic diagram of the circuit structure of an embodiment of the heating control circuit of the present invention;

[0039] Figure 3 This is a schematic diagram of the structure of an embodiment of the heating control circuit of the present invention applied to a speaker module;

[0040] Figure 4 This is a schematic diagram of the structure of a speaker module according to an embodiment of the present invention.

[0041] Description of Figure Numbers:

[0042] label name label name 100 Speaker components 20 Main controller 200 case 30 Low-pass filter 210 upper shell 40 First temperature detection circuit 220 Lower housing 50 Second temperature detection circuit 300 Metal mesh R2 Current limiting resistor 10 Humidity detection circuit

[0043] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0046] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0047] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0048] This invention proposes a heating control circuit for use in a speaker module, the speaker module comprising a metal mesh.

[0049] This speaker module is suitable for use in outdoor fixed audio equipment, such as cameras, outdoor speakers, smart doorbells, etc. With the increasing development of outdoor fixed audio equipment, people have higher and higher requirements for the sound quality of speaker modules. Speaker modules typically add a high-mesh mesh to the speaker outlet. Because the mesh openings are small and the spacing between the holes is also small, when the speaker module is used in outdoor fixed audio equipment, water stains can easily remain on the mesh in rainy or humid environments. This can hinder speaker sound production, especially severely suppressing high frequencies, resulting in low volume or noise; even water stains left on the speaker diaphragm can damage the diaphragm adhesive over time, leading to speaker failure.

[0050] Reference Figures 1 to 4 To address the aforementioned problems, in one embodiment of the present invention, the heating control circuit 400 includes:

[0051] Humidity detection circuit 10 is used to detect the humidity of the metal mesh fabric 300 and output a corresponding humidity detection signal. The humidity detection circuit 10 includes a humidity-sensitive resistor R4 and a third pull-up resistor R11. The humidity-sensitive resistor R4 is disposed close to the metal mesh fabric 300. The output terminal of the humidity-sensitive resistor R4 is interconnected with the third pull-up resistor R11 and the feedback terminal of the main controller 20. The second terminal of the third pull-up resistor R11 is connected to a DC power supply.

[0052] The main controller 20 is electrically connected to the humidity detection circuit 10 and the metal mesh fabric 300 respectively. The main controller 20 is used to provide PWM power to the metal mesh fabric 300 when the humidity of the metal mesh fabric 300 reaches a first preset humidity, so as to control the metal mesh fabric 300 to convert electrical energy into heat energy.

[0053] In this embodiment, the humidity detection device can be a humidity sensor, a heating control switch, or other device used to detect humidity. When the switch 400 is implemented using a humidity sensor, the humidity sensor detects the humidity of the metal mesh fabric and outputs a humidity detection signal, which is also a heating / stop heating trigger signal. The humidity sensor can be placed close to the thermally conductive and acoustically transparent mesh fabric 300, or it can be placed on the housing 100 of the speaker module, for example, on the inner and / or outer side walls of the housing 100. The humidity sensor can be implemented using a MEMS chip. The switch 400 can also be implemented using a humidity-sensitive resistor. When the switch 400 is implemented using a humidity-sensitive resistor, a pull-up resistor can also be provided. The pull-up resistor is connected to the output terminal of the humidity-sensitive resistor, and the other end of the humidity-sensitive resistor is connected to a DC power supply. The humidity-sensitive resistor and the pull-up resistor form a series voltage divider circuit. During operation, the humidity signal is converted into an electrical signal (impedance or capacitance, etc.) and then output to the electronic control component 500. The main controller 20 can determine whether to provide power to the metal mesh fabric 300 and whether to stop providing power based on the humidity detection signal. The main controller 20 compares the humidity detection signal with a preset first humidity level. When the humidity of the metal mesh fabric 300 is greater than or equal to the first preset humidity level, it supplies electrical energy to the metal mesh fabric 300 to drive it, causing the metal mesh fabric 300 to convert electrical energy into heat energy, thereby drying the water stains on the metal mesh fabric 300. The first preset humidity level can be set according to the environment, geographical location, daytime temperature changes, and nighttime temperature changes of the speaker module application. For example, in environments with abundant rainfall and prolonged damp and cold conditions, the first preset humidity level can be set lower; in environments with less rainfall and higher temperatures, the first preset humidity level can be set higher. The preset temperature threshold can also be adjusted according to the season. For example, in summer and autumn, when rainfall is less and temperatures are higher, the first preset humidity level can be set higher; in spring and winter, when rainfall is more and temperatures are lower, the first preset humidity level can be set lower. Furthermore, the settings can differ between daytime and nighttime, between higher and lower latitudes, and between higher and lower altitudes. The preset temperature threshold in this embodiment can also be adjusted according to the user's actual application environment to adapt to different environments and set different preset temperature thresholds. In some embodiments, the first preset humidity can also be set such that the heat generated by the speaker assembly 100 is insufficient to heat and dry the water stains on the metal mesh 300. That is, the heat generated by the speaker assembly 100 can dry some of the water stains, but it cannot guarantee that the metal mesh 300 will remain dry in a short period of time.In this embodiment, the main controller 20 can also be triggered by a heating control switch. This heating control switch can be a manual control switch or a humidity controller. When the manual control switch is triggered by the user, it outputs a heating trigger signal or a stop heating trigger signal. The humidity controller can output corresponding heating / stop heating trigger signals according to different humidity levels.

[0054] The main controller 20 can be implemented using amplifier U1 and driver 520, or it can be implemented using a microprocessor such as a microcontroller or DSP. When using amplifier U1, the positive input terminal of amplifier U1 can be connected to a reference voltage to characterize the first preset humidity, and the negative input terminal of amplifier U1 is connected to the output terminal of humidity detection circuit 10. When the detected humidity of the metal mesh fabric 300 is greater than the first preset humidity, amplifier U1 outputs a high-level control signal to driver 520 to drive the output of PWM power and control the metal mesh fabric 300 to heat up. When the detected humidity of the metal mesh fabric 300 is less than the first preset humidity, amplifier U1 outputs a low-level control signal to driver 520 to drive the stop output of PWM power, thereby controlling the metal mesh fabric 300 to stop heating. Amplifier U1 can be implemented using a negative feedback proportional amplifier circuit, with Vin as the input voltage, Vo as the output voltage, and the amplification factor A = Vo / Vin = -Rf / Rin.

[0055] When using a microprocessor, those skilled in the art can integrate hardware circuits and software programs, such as analysis, calculation, and comparison software programs, as well as hardware drivers 520, into the microprocessor to control the heating of the metal mesh fabric 300. That is, the microprocessor can integrate functions to analyze and compare the humidity of the metal mesh fabric 300 with a first preset humidity level, and then control the heating / stopping of the metal mesh fabric 300 based on the comparison result. For example, if the main controller 20 determines that the humidity of the metal mesh fabric 300 is less than the first preset humidity based on the humidity detection signal, it outputs a low level "0" to turn off the driver 520. At this time, there is no PWM power output, and the metal mesh fabric 300 does not heat. If the main controller 20 determines that the humidity of the metal mesh fabric 300 is greater than the first preset humidity based on the humidity detection signal, it outputs a high level "1" to turn on the driver 520 and provide PWM power to the metal mesh fabric 300 for heating.

[0056] The main controller 20 integrates a control area, ADC1 interface, ADC2 interface, and PWM output interface. The control area is connected to the power management chip 61 through the I2C interface and the enable interface. The PWM output interface is connected to the metal grid 300. The ADC1 interface and ADC2 interface are used to connect to the humidity detection circuit 10 and the first temperature detection circuit 40, respectively.

[0057] In another embodiment, when controlling the metal mesh fabric 300 to heat up, the main controller 20 can also calculate the heating current and heating duration required by the metal mesh fabric 300 based on the operating status and operating time of the speaker assembly 100. That is, during the process of controlling the heating of the metal mesh fabric 300, the power of the metal mesh fabric 300 can be adjusted in real time according to the operating status of the speaker module, thereby achieving rapid heating of the metal mesh fabric 300 while reducing the power consumption caused by heating the metal mesh fabric 300, thus achieving energy saving and emission reduction.

[0058] The heating control circuit 400 of this invention detects the humidity of the metal mesh fabric 300 by setting a humidity detection circuit 10, and outputs a corresponding humidity detection signal to the main controller 20. The main controller 20 compares the received humidity detection signal with a preset humidity threshold (first preset humidity). When the humidity of the metal mesh fabric 300 reaches the first preset humidity, it provides PWM power to the metal mesh fabric 300 to control it to convert electrical energy into heat energy. This heat drives the metal mesh fabric 300 to work, drying the water stains on it. This invention solves the problem that residual water stains on the metal mesh fabric 300 hinder speaker sound production, especially causing severe high-frequency suppression, resulting in low volume or noise. Furthermore, residual water stains on the speaker diaphragm can damage the diaphragm adhesive over time, leading to speaker failure.

[0059] Reference Figures 1 to 4 In one embodiment, the main controller 20 is further configured to stop supplying electrical energy to the metal mesh fabric when the humidity of the metal mesh fabric is greater than or equal to a first preset humidity and less than or equal to a second preset humidity; wherein the first preset humidity is greater than the second preset humidity.

[0060] In this embodiment, the second preset humidity can be set according to the environment of the metal mesh 300 energy storage system. Specifically, it can be set according to the season, geographical location, daytime temperature changes, nighttime temperature changes, etc. For example, the second preset humidity can be set differently in winter and summer, different during the day and night, different at higher and lower latitudes, and different at higher and lower altitudes. It is understood that the metal mesh 300 consumes electrical energy when working. In practical applications, in order to reduce the electrical energy consumption of the metal mesh 300, achieve energy conservation and emission reduction, and reduce the power consumption of the speaker module itself, the second preset humidity can be set so that the heat generated by the speaker assembly 100 can dry the remaining water stains on the metal mesh 300, or the remaining water stains on the metal mesh 300 can evaporate naturally and not penetrate into the speaker module housing 200. To prevent water stains from failing to evaporate in time and seeping into the speaker assembly 100, thus affecting its normal operation, the second preset humidity can be a level that ensures the sound quality of the speaker assembly 100 is not affected by water stains during operation. Alternatively, the second preset humidity can be a level that ensures that even if water stains continuously accumulate on the metal mesh 300 during the operation of the speaker assembly 100, the amount of water will not seep into the speaker assembly 100. The specific setting can be made according to actual needs. The main controller 20 monitors the humidity of the metal mesh 300 in real time. During the heating process of the metal mesh 300, when the water stains on the metal mesh 300 decrease due to the drying effect of the metal mesh 300, and the humidity of the metal mesh 300 drops from higher than or equal to the first preset humidity to lower than or equal to the second preset humidity, the supply of electrical energy to the metal mesh 300 can be stopped, thus stopping the heating of the metal mesh 300.

[0061] Reference Figures 1 to 4 It should be noted that when the humidity of the metal mesh fabric is between the first preset humidity and the second preset humidity, the electronic control component 500 controls the dynamic heating of the metal mesh fabric:

[0062] It should be noted that the decrease in humidity of the metal mesh fabric may be non-linear, and the humidity control of the metal mesh fabric has a certain lag. For example, when providing electrical energy to the metal mesh fabric, if the metal mesh fabric is only stopped when its current humidity drops to less than or equal to a second preset humidity, the temperature of the metal mesh fabric will not drop sharply, and residual heat will remain, causing the temperature of the metal mesh fabric to continue to rise. Similarly, after heating stops, when water stains accumulate on the metal mesh fabric due to the influence of ambient humidity, if the metal mesh fabric is only started when its humidity rises to greater than or equal to a first preset humidity, the temperature of the metal mesh fabric will not rise sharply. The metal mesh fabric needs a certain amount of time to preheat before the water stains can be dried, so the humidity of the metal mesh fabric will continue to rise, resulting in an actual humidity of the metal mesh fabric that is higher than the first preset humidity.

[0063] In order to prevent the humidity of the metal mesh fabric 300 from continuously decreasing or continuously increasing, the main controller 20 in this embodiment is further configured to adjust the power value of the electrical energy supplied to the metal mesh fabric 300 according to the detected humidity of the metal mesh fabric 300 when the humidity of the metal mesh fabric 300 is between the first preset humidity and the second preset humidity.

[0064] Specifically, when the humidity of the metal mesh fabric 300 is between a first preset humidity and a second preset humidity, the power value of the metal mesh fabric 300 can be adjusted from high to low. That is, when approaching the first preset humidity, a larger current is used to control the heating of the metal mesh fabric 300, thereby increasing the power of the metal mesh fabric 300 and enabling the humidity of the metal mesh fabric 300 to quickly reach a better temperature suitable for charging. When approaching the second preset humidity, a smaller power value can be used to control the heating of the metal mesh fabric 300, thereby reducing the power of the metal mesh fabric 300 and allowing the battery to reach the second preset humidity slowly. Of course, in other embodiments, the heating of the metal mesh fabric 300 can also be controlled intermittently. For example, when the humidity of the metal mesh fabric 300 is between the first preset humidity and the second preset humidity, the metal mesh fabric 300 can be heated for a certain period of time and then stopped for a certain period of time, and this process can be repeated. The heating time and the time to stop heating can be adjusted in real time according to the humidity of the metal mesh fabric 300 to ensure that the water stains on the metal mesh fabric 300 are dried, while reducing the power consumption of the speaker module.

[0065] In one embodiment, a humidity-sensitive resistor R4 is placed at the bottom of the metal mesh 300 to pick up humidity and convert it into an electrical signal (impedance or capacitance, etc.). This signal is then divided by a third pull-up resistor R11 and transmitted to the ADC1 path of the main controller 20 to monitor the humidity of the mesh in real time. The main controller 20 compares the picked-up humidity with a preset threshold. In practical applications, the first preset humidity can be determined by testing the impact of different residual water amounts on acoustic performance to find a critical value, which is the threshold. If the humidity is less than the threshold, the main chip shuts off the PWM path; if it is greater than the threshold, it outputs "1" to turn on the PWM to heat the metal mesh 300. The heating control circuit 400 can also be connected to a terminal device wirelessly, which can then send a message to the user that the speaker assembly 100 needs to stop working, ensuring electrical safety while enabling human-computer interaction. For example, a warning message such as "There is moisture, it is evaporating" can be displayed on the user's terminal interface.

[0066] Reference Figures 1 to 4 In one embodiment, the heating control circuit 400 further includes:

[0067] A low-pass filter 30 is connected in series between the main controller 20 and the metal grid; the low-pass filter 30 is used to filter out the high-frequency components in the PWM power to increase the AC power to the metal grid 300.

[0068] In this embodiment, the low-pass filter 30 can be implemented using a capacitor and a resistor. The resistor is connected in series between the main controller 20 and the metal grid. One end of the capacitor is interconnected with the resistor and the metal grid, and the other end of the capacitor is grounded. The low-pass filter 30 formed by the resistor R1 and the capacitor C1 can filter out the high-frequency components in the PWM power and strip out the low-frequency AC power to drive the heating of the metal grid. The frequency of the high-frequency power can be selected as a sine wave of 50 to 100 Hz.

[0069] Reference Figures 1 to 4 In one embodiment, the heating control circuit 400 further includes:

[0070] A current-limiting resistor R2 is connected in series between the main controller 20 and the metal grid. The current-limiting resistor R2 is used to limit the current output by the main controller 20.

[0071] Understandably, because the impedance of the metal mesh is relatively low (e.g., 0.1 ohms), using direct current, even at a low voltage like 0.1V, would generate a 1000mA current, placing a significant burden on the entire circuit system. Therefore, a 100-fold current-limiting resistor R2 can be connected in series between the metal mesh 300 and the driver 520 to limit the current. Alternatively, alternating current can be used to drive the heating of the metal mesh 300; to eliminate the introduction of high-frequency sources, a 50–100Hz sine wave can be selected.

[0072] Reference Figures 1 to 4 In one embodiment, the heating control circuit 400 further includes:

[0073] A first temperature detection circuit 40 is used to detect the temperature of the metal mesh fabric 300 and output a corresponding mesh fabric temperature detection signal. The first temperature detection circuit 40 includes a first thermistor Rt1 and a first pull-up resistor R41. The first thermistor Rt1 is disposed close to the metal mesh fabric 300. The output terminal of the first thermistor Rt1 is interconnected with the first pull-up resistor R41 and the first feedback terminal of the main controller 20. The second terminal of the first pull-up resistor R41 is connected to the first DC power supply VDD.

[0074] The main controller 20 is also connected to the first temperature detection circuit 40. The main controller 20 is also used to provide power to the metal mesh fabric 300 or stop providing power to the metal mesh fabric 300 according to the temperature detection signal of the mesh fabric when providing power to the metal mesh fabric 300.

[0075] When the temperature detection signal of the metal mesh fabric 300 is determined to be less than the first preset temperature threshold, the power supply to the metal mesh fabric 300 is maintained.

[0076] When the temperature detection signal of the metal mesh fabric 300 is determined to be greater than the first preset temperature threshold, the supply of electrical energy to the metal mesh fabric 300 is stopped.

[0077] In this embodiment, the first temperature detection circuit 40 can be implemented using a temperature sensor or a thermistor. Specifically, the temperature sensor can be implemented using a MEMS chip. When the first temperature detection circuit 40 is implemented using a thermistor, a pull-up resistor can also be provided. The pull-up resistor is connected to the output terminal of the thermistor, and the other end of the thermistor is connected to a DC power supply. The thermistor and the pull-up resistor form a series voltage divider circuit. During operation, the temperature signal is converted into an electrical signal and output to the main controller 20. The thermistor can be implemented using a negative temperature coefficient thermistor or a positive temperature coefficient thermistor. When a positive temperature coefficient thermistor is used, the main controller 20 can determine whether to supply power to the metal mesh 300 and whether to stop supplying power based on the temperature detection signal. Specifically, the main controller 20 can compare the received temperature detection signal with a preset temperature threshold. When the temperature of the metal mesh 300 reaches the preset temperature threshold, it stops supplying power to the metal mesh 300 to drive it, causing the metal mesh 300 to convert electrical energy into heat energy, thereby drying the water stains on the metal mesh 300. When the temperature of the metal mesh 300 is lower than the preset temperature threshold, it continues to supply power to the metal mesh 300, and the metal mesh 300 stops heating. The preset temperature threshold can be set to 45℃, which is stable and will not cause burns even if touched. Through simulation of heating and heat dissipation (thermal radiation and convection), it is known that a current of approximately 12-26mA is needed to reach thermal equilibrium, at which point the moisture on the metal mesh 300 will continuously evaporate. Specifically, a thermistor Rf can be attached to the metal mesh 300; the higher the temperature, the lower the resistance value. The thermal element picks up the temperature on the metal mesh 300 and transmits it to the main controller 20. Once the temperature exceeds a preset value of 45°C, the resistance value is reduced. At this point, the PWM duty cycle can be reduced, lowering the effective power of the output energy. It can even stop supplying power to the metal mesh 300, thereby controlling the metal mesh 300 to stop heating and prevent damage from overheating or excessive heat radiation that could damage the speaker diaphragm. This invention uses a first temperature detection circuit 40 to detect temperature and a humidity detection circuit 10 to detect humidity, forming a closed-loop control system. This accelerates the evaporation of moisture from the mesh while ensuring safe heating of the mesh.

[0078] Reference Figures 1 to 4 In one embodiment, the speaker module further includes:

[0079] The second temperature detection circuit 50 is disposed on the housing 200 and away from the metal mesh 300. The second temperature detection circuit 50 is used to detect the ambient temperature and output an ambient temperature detection signal. The second temperature detection circuit 50 includes a second thermistor and a second pull-up resistor. The thermistor Rt2 is disposed on the housing 200 of the speaker assembly 100. The output terminal of the second thermistor Rt2 is interconnected with the second pull-up resistor and the second feedback terminal of the main controller 20. The second terminal of the second pull-up resistor is connected to the first DC power supply VDD.

[0080] The main controller 20 is also connected to the second temperature detection circuit 50. The main controller 20 is also used to provide power to the metal mesh fabric 300 when the temperature difference between the metal mesh fabric 300 and the ambient temperature is greater than a first preset difference, while providing power to the metal mesh fabric 300.

[0081] When the temperature difference between the metal mesh fabric 300 and the ambient temperature is determined to be less than a first preset difference based on the mesh fabric temperature detection signal and the ambient temperature detection signal, the supply of electrical energy to the metal mesh fabric 300 is stopped.

[0082] In this embodiment, the second temperature detection circuit 50 can be implemented using a temperature sensor or a thermistor. Specifically, the temperature sensor can be implemented using a MEMS chip. When the second temperature detection circuit 50 is implemented using a thermistor, a pull-up resistor can also be provided. The pull-up resistor is connected to the output terminal of the thermistor, and the other end of the thermistor is connected to a DC power supply. The thermistor and the pull-up resistor form a series voltage divider circuit. During operation, the temperature signal is converted into an electrical signal and output to the main controller 20. The thermistor can be implemented using a negative temperature coefficient thermistor or a positive temperature coefficient thermistor. When a positive temperature coefficient thermistor is used, the second temperature detection circuit 50 is used to detect the ambient temperature outside the speaker module housing 200. The main controller 20 can determine whether to provide power to the metal mesh 300 and whether to stop providing power based on the temperature detection signal. Specifically, when the temperature difference between the metal mesh fabric 300 and the ambient temperature is greater than a first preset difference, based on the mesh fabric temperature detection signal and the ambient temperature detection signal, electrical energy is supplied to the metal mesh fabric 300; when the temperature difference between the metal mesh fabric 300 and the ambient temperature is less than the first preset difference, the supply of electrical energy to the metal mesh fabric 300 is stopped.

[0083] In this embodiment, the difference between the detected ambient temperature and the mesh fabric temperature is calculated, and then the difference is used to determine whether to supply power to the metal mesh fabric 300 and whether to stop supplying power. When the mesh fabric temperature is higher than the ambient temperature and the difference between the two is greater than a first preset difference, it can be determined that the current environment of the speaker module is relatively humid and cold. At this time, the metal mesh fabric 300 can be controlled to heat up. When the mesh fabric temperature is higher than the ambient temperature, but the difference between the two is less than the first preset difference, it can be determined that the current ambient temperature of the speaker module is relatively high. At this time, the metal mesh fabric 300 can be controlled to stop heating up.

[0084] Reference Figures 1 to 4 In one embodiment, the main controller 20 is also electrically connected to the speaker assembly 100, and the main controller 20 is also configured to stop supplying power to the speaker assembly 100 when it detects that the humidity of the metal mesh fabric 300 reaches a third preset humidity; wherein the third preset humidity is greater than the first preset humidity.

[0085] It is understandable that during typhoons, heavy rains, or prolonged periods of overcast and rainy weather, the metal mesh 300 may not be able to prevent rainwater from seeping into the speaker module. To avoid water seepage inside the speaker module housing 200 and leakage or short circuits when the speaker assembly 100 continues to operate, this embodiment can stop supplying power to the speaker assembly 100 when the humidity of the metal mesh 300 reaches a third preset humidity level. At the same time, it can also send a message to the user via a terminal device connected to the speaker module wirelessly, indicating that the speaker assembly 100 needs to stop working, thus ensuring electrical safety while enabling human-computer interaction.

[0086] Reference Figures 1 to 4 In one embodiment, the main controller 20 is also electrically connected to the speaker assembly 100, and the main controller 20 is also configured to provide power to the speaker assembly 100 when the humidity of the metal mesh fabric 300 is detected to be less than or equal to the first preset humidity.

[0087] In this embodiment, to ensure electrical safety, during typhoons, heavy rains, or prolonged periods of overcast and rainy weather, the metal mesh 300 may not be able to prevent rainwater from seeping into the speaker module. To avoid leakage or short circuits when the speaker assembly 100 continues to operate with water seepage inside the speaker module housing 200, this embodiment can disconnect the power supply to the speaker assembly 100 when the humidity of the metal mesh 300 reaches a first preset humidity or a third preset humidity. Under the heating control of the main controller 20, the water stains on the metal mesh 300 will decrease, causing the humidity of the metal mesh 300 to drop. When the humidity is detected to be less than or equal to the first preset humidity, the power supply to the speaker assembly 100 is restored to ensure electrical safety, allowing the speaker assembly 100 to quickly resume normal operation in harsh environments.

[0088] Reference Figures 1 to 4 In one embodiment, the heating control circuit 400 further includes:

[0089] The power processing circuit 60 includes a first power transmission terminal and a second power transmission terminal. The first power transmission terminal of the power processing circuit 60 is used to connect to an AC power source, and the second power transmission terminal is used to connect to an energy storage device. The output terminal of the power processing circuit 60 is connected to the main controller 20.

[0090] The power processing circuit 60 is used to disconnect the electrical connection with the energy storage device when it detects that an AC power voltage is connected to the first power transmission terminal, and to connect the electrical connection with the energy storage device when it detects that no AC power voltage is connected to the first power transmission terminal.

[0091] In this embodiment, the power processing circuit 60 includes a power management chip 61 and a power switching switch 62. The power management chip 61 can be connected to an AC power source, such as mains power (commonly 220V), via an adapter. The adapter converts the AC power into DC voltage, such as 5V, 9V, or 12V, which is then converted by the power management chip 61 into system power supplies VSYS (system power) and VDD (I / O power supply) to power the main controller 20, etc. Simultaneously, when energy storage devices, such as batteries or electrolytic capacitors, are installed in the speaker module, the energy converted by the power management chip 61 can also charge the battery. The power switching switch 62 is connected in series between the power management chip 61 and the battery. If the power adapter disconnects from the mains power or there is a power outage, the power switching switch 62 closes to activate the battery to power the power management chip 61, thus providing power to the entire system. When the mains power is restored, the power switching switch 62 opens to allow the power adapter to connect to the mains power to power the power management chip 61, thus providing power to the entire system. The power management chip 61 integrates a control area, a charging area, an AC power input interface, and a DC / DC converter. The main controller 20 can control the power management chip 61 to achieve the above control through I2C and enable pins. The DC / DC converter in the power management chip 61 generates VSYS and VDD and outputs them. The charging area is connected to an energy storage device, such as a battery, through a power switch 62, and can output power to the battery or receive power output from the battery.

[0092] The present invention also proposes a speaker module.

[0093] Reference Figure 3 and Figure 4 The speaker module includes:

[0094] Speaker assembly 100;

[0095] The housing 200 is provided with a speaker housing cavity and a sound outlet communicating with the speaker housing cavity, and the speaker assembly 100 is fixed in the speaker housing cavity;

[0096] A metal mesh 300 covering the sound outlet; and a heating control circuit 400 as described above;

[0097] The heating control circuit 400 is electrically connected to the metal mesh 300.

[0098] In this embodiment, the shape and size of the housing 200 can be designed according to the size and frequency (high, mid, and low frequencies) of the speaker assembly 100. The housing 200 can be made of waterproof materials such as plastics (the plastics can be rigid plastics, such as ABS, POM, PS, PMMA, PC, PET, PBT, PPO, etc.). This is more conducive to improving the stability of the housing 200, thereby effectively improving the practicality, reliability, and durability of the housing 200. The speaker assembly 100 is an air-conducting speaker. The speaker assembly includes a vibration system and a magnetic circuit system. The vibration system includes a diaphragm and a voice coil that drives the diaphragm to vibrate. The voice coil is connected to the diaphragm. The magnetic circuit system includes a frame and a magnetic component mounted on the frame. The magnetic component can be a magnet, which can be a permanent magnet. The magnetic component can be made of natural magnetite or artificial magnet. When the speaker assembly is working, the magnetic component generates a magnetic field to drive the voice coil assembly to drive the diaphragm to vibrate, thereby converting the electrical signal into a sound signal and realizing the transmission of the sound signal. The basin frame is made of magnetic material, usually iron-based.

[0099] The speaker assembly 100 and the housing 200 are fixed together by screws, i.e., the connection method is threaded connection. The speaker assembly 100 has connection holes around its periphery, and the housing 200 has threaded holes corresponding to the periphery of the speaker assembly 100. The screws passing through the connection holes and threaded holes ensure a stable installation structure for the speaker assembly 100. When the speaker assembly 100 is installed inside the housing 200, the speaker cavity can be sealed. At this time, the front end of the speaker assembly 100 faces the outside of the housing 200, and the rear end faces the inside of the housing 200. The speaker assembly 100 and the metal mesh 300 form the front acoustic cavity of the speaker module, and the sealed space formed by the speaker assembly 100 and the housing 200 is the rear acoustic cavity of the speaker module.

[0100] The metal mesh 300 can prevent external objects from puncturing the diaphragm in the speaker assembly 100, and also provides a certain degree of waterproofing. The higher the mesh count of the metal mesh 300, the stronger its waterproofing effect. The metal mesh 300 can also be used for dust prevention, sound tuning, etc. The metal mesh 300 can be made of stainless steel, aluminum, aluminum alloy, copper, copper alloy, iron, iron alloy, silver, and silver alloy, etc. Of course, in other embodiments, other metal materials or their alloys can also be used, which is not limited here.

[0101] It should be noted that loudspeakers generate heat during operation. Due to the small size and complex internal structure of loudspeaker modules, heat dissipation is often a problem. The high temperatures generated during loudspeaker operation can affect components such as the diaphragm and magnetic circuit system, causing changes in diaphragm elasticity and demagnetization of the magnetic circuit system, which seriously affects the sound performance of the loudspeaker.

[0102] Therefore, this invention utilizes the fact that the sound waves generated by the speaker assembly 100 are mainly emitted from the front acoustic cavity. The vibration of the diaphragm and the transmission of sound waves cause airflow in the front acoustic cavity, creating airflow between the front acoustic cavity and the external space. The heat generated by the speaker assembly 100 during operation can be transferred to the metal mesh 300 located in the front acoustic cavity through radiation from the diaphragm. Thus, through thermal radiation and the effect of airflow, the heat dissipation rate of the speaker assembly 100 can be improved, and heat can be conducted to the external space more efficiently. Furthermore, the thermal conductivity of the metal mesh 300 can save the use of other heat dissipation devices, reducing the size of the heat dissipation devices. Alternatively, when other heat dissipation devices (e.g., other heat dissipation devices can be installed in the rear acoustic cavity of the speaker assembly 100) are simultaneously used to dissipate heat from the speaker assembly 100, the number of heat dissipation points of the speaker assembly 100 can be increased, further improving the heat dissipation rate of the speaker assembly 100.

[0103] When the heat generated by the speaker assembly 100 radiates onto the metal mesh 300, the temperature of the metal mesh 300 will be higher than the ambient temperature. If there are water stains remaining on the metal mesh 300, the heat generated by the speaker assembly 100 can accelerate the evaporation of the water stains on the metal mesh 300, allowing the water stains on the metal mesh 300 and between the metal mesh 300 and the diaphragm to evaporate quickly, ensuring that the metal mesh 300 and the speaker assembly 100 maintain a dry environment.

[0104] The metal mesh 300 of this invention is made of a material with high thermal conductivity. Reusing the metal mesh 300 can improve the heat dissipation rate of the speaker assembly 100. It can also increase the evaporation rate of water residue remaining on the metal mesh 300. Water residue can hinder speaker sound production, especially severely suppressing high frequencies, resulting in low volume or noise; furthermore, water residue on the speaker diaphragm can damage the diaphragm adhesive over time, leading to speaker failure.

[0105] The speaker module of the present invention comprises a speaker assembly 100, a housing 200, and a metal mesh 300. The housing 200 has a speaker housing cavity and a sound outlet communicating with the speaker housing cavity, thereby fixing the speaker assembly 100 within the speaker housing cavity; and the metal mesh 300 covers the sound outlet. The metal mesh 300 is made of a material with high thermal conductivity. Reusing the metal mesh 300 improves the heat dissipation rate of the speaker assembly 100 and also increases the evaporation rate of water stains remaining on the metal mesh 300. The present invention also includes a heating control circuit 400 that compares a received humidity detection signal with a preset humidity threshold (a first preset humidity). When the humidity of the metal mesh 300 reaches the first preset humidity, electrical energy is supplied to the metal mesh 300 to drive it to work, causing the metal mesh 300 to convert electrical energy into heat energy, thereby drying the water stains on the metal mesh 300. This invention solves the problem that residual water stains on the metal mesh fabric 300 hinder the speaker's sound production, especially severely suppressing high frequencies, resulting in low volume or noise, and even the residual water stains on the speaker diaphragm can damage the diaphragm adhesive over time, leading to speaker failure.

[0106] Reference Figure 3 and Figure 4 In one embodiment, the speaker module further includes:

[0107] An insulating layer (not shown in the figure) covers both sides of the metal mesh 300.

[0108] In this embodiment, the insulating layer can cover both sides of the metal mesh 300, or it can be set only on the side of the metal mesh 300 away from (away from) the speaker assembly 100. The insulating layer can be made of materials with certain waterproof properties, such as water-based paint, to prevent the metal mesh 300 from oxidizing and being corroded.

[0109] To further improve the heat dissipation capacity of the speaker module, the metal mesh 300 can be provided with a thermally conductive extension. This extension can contact the speaker assembly 100, allowing heat from the speaker assembly 100 to be conducted to the metal mesh 300 through the extension. The thermally conductive extension of the metal mesh 300 can also contact components of the speaker assembly 100 that generate significant heat or have high thermal conductivity, thereby increasing the rate of heat transfer. The speaker assembly 100 includes a magnetic circuit system, which is a component in the speaker that generates a significant amount of heat and is typically made of metal, possessing strong thermal conductivity. The thermally conductive extension of the metal mesh 300 can contact the bottom surface of the magnetic circuit system through the housing 200.

[0110] In some embodiments, a buffer layer may be provided between the metal mesh 300 and the speaker assembly 100. The buffer layer may be foam, which is used to seal the speaker assembly 100 and also to buffer the sound wave pressure generated by the speaker assembly 100 on the metal mesh 300.

[0111] Reference Figures 1 to 4 In one embodiment, the upper end 210 of the speaker housing cavity near the sound outlet is inclined away from the speaker assembly 100.

[0112] In this embodiment, the end of the upper part 210 of the speaker housing cavity is inclined at a certain angle to the horizontal plane to form a rainproof structure, so that the rain that drifts into the speaker module flows to the speaker module along the rainproof structure, which can reduce the accumulation of water stains on the heat-conducting and sound-permeable mesh.

[0113] In this embodiment, the housing 200 includes an upper end 210 and a lower end 220 of a speaker housing cavity. The upper end 210 forms a speaker housing cavity, and the sound outlet is formed at one end edge of both the upper end 210 and the lower end 220. Setting the housing 200 as a split structure facilitates its manufacturing. Both the upper end 210 and the lower end 220 of the speaker housing cavity can be made of plastic, and they can be connected by snap-fit ​​connections, or by snap-fit ​​connections or threaded connections. This structure also facilitates the assembly of the speaker 100. During assembly, the speaker assembly 100 can be installed in the speaker housing cavity, and then the heat-conducting and sound-permeable mesh can be encapsulated on the sound outlet, improving assembly efficiency. The lower end 220 of the speaker housing is inclined at a certain angle to the horizontal plane, forming a water-guiding structure. When water stains on the heat-conducting and sound-permeable mesh 300 flow into the lower end 220 of the speaker housing under the action of gravity, the water flow is accelerated through the inclined surface of the lower end 220 of the speaker housing, which can prevent water stains from accumulating in the lower end 220 of the speaker housing or even penetrating into the housing 200.

[0114] Reference Figure 3 and Figure 4 In one embodiment, the metal mesh 300 and the housing 200 are fixedly connected by screws / buckles;

[0115] Alternatively, the metal mesh 300 may also have a riveting part, and be riveted and fixed to the housing 200 by the riveting part;

[0116] Alternatively, the metal mesh 300 is bonded to the housing 200.

[0117] In this embodiment, the metal mesh 300 can be bonded to the housing 210 via the adhesive layer 103 and the buffer layer. The metal mesh 300 can also be fixedly connected to the speaker assembly 100 via the buffer layer 101 and the adhesive layer 102. During speaker module assembly, after setting the buffer layer and adhesive layer between the metal mesh 300 and the housing 200, the thermally conductive and acoustically transparent mesh is fixed to the housing 200 via the adhesive layer, allowing the metal mesh 300 to directly contact the buffer layer and be fixed to the housing 200 by pressing. After setting the buffer layer 101 and adhesive layer 102 between the metal mesh 300 and the speaker assembly 100, the speaker assembly 100 can be fixed to the housing 200 using screws, clips, etc. The buffer layer can be implemented using foam. Foam 101 retains a certain amount of compression to prevent noise caused by vibrations generated during the operation of the speaker assembly 100 colliding with the housing 200. The metal mesh 300 is adhered to the foam (not shown in the figure) and the housing 200 using double-sided adhesive 103. Because the foam 101 is compressed, the metal mesh 300 is also compressed, ensuring a secure assembly. Adhesive layers 102 and 103 are typically made of waterproof materials and have a width greater than 2mm, thus ensuring overall waterproofing.

[0118] The present invention also proposes an outdoor fixed audio device, including the heating control circuit 400 as described above;

[0119] And / or, including speaker modules as described above.

[0120] The detailed structure of the speaker module and heating control circuit 400 can be referred to the above embodiments, and will not be repeated here. It can be understood that since the above speaker module and heating control circuit 400 are used in the outdoor fixed audio equipment of the present invention, the embodiments of the outdoor fixed audio equipment of the present invention include all the technical solutions of all the embodiments of the above speaker module and heating control circuit 400, and the technical effects achieved are exactly the same, and will not be repeated here.

[0121] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A heating control circuit, characterized in that: Applied in a speaker module, the speaker module includes a sound outlet and a metal mesh, the metal mesh covers the sound outlet, and the heating control circuit includes: A humidity detection circuit, the humidity detection circuit is used to detect the humidity of the metal mesh and output a corresponding humidity detection signal; A main controller is electrically connected to the humidity detection circuit and the metal mesh cloth respectively, and is used to provide PWM power to the metal mesh cloth when detecting that the humidity of the metal mesh cloth reaches a first preset humidity, so as to control the metal mesh cloth to convert the electrical energy into heat energy, so as to dry the water stains on the metal mesh cloth; The heating control circuit also includes: A first temperature detection circuit, the temperature detection circuit is used to detect the temperature of the metal mesh and output a corresponding mesh temperature detection signal; The main controller is also connected to the first temperature detection circuit. The main controller is also used to provide power to the metal mesh cloth / stop providing power to the metal mesh cloth according to the mesh cloth temperature detection signal when providing power to the metal mesh cloth.

2. The heating control circuit according to claim 1, characterized in that: The heating control circuit also includes: A low-pass filter is arranged in series between the main controller and the metal mesh; the low-pass filter is used to filter out high-frequency components in the PWM electric energy to increase AC electric energy to the metal mesh.

3. The heating control circuit according to claim 1, characterized in that: The heating control circuit also includes: A current limiting resistor is connected in series between the main controller and the metal mesh cloth, and is used to limit the current output by the main controller.

4. The heating control circuit according to claim 1, characterized in that: The speaker module also includes: The second temperature detection circuit is used to detect the ambient temperature and output an ambient temperature detection signal; The main controller is also connected to the second temperature detection circuit, and is further used to provide electric energy to the metal mesh when it is determined according to the mesh temperature detection signal and the ambient temperature detection signal that the difference between the temperature of the metal mesh and the ambient temperature is greater than a first preset difference. When it is determined according to the mesh temperature detection signal and the ambient temperature detection signal that the difference between the temperature of the metal mesh and the ambient temperature is less than a first preset difference, supplying electric energy to the metal mesh is stopped.

5. The heating control circuit according to claim 4, characterized in that: The first temperature detection circuit includes a first thermistor and a first pull-up resistor, the second temperature detection circuit includes a second thermistor and a second pull-up resistor, the first thermistor is arranged close to the metal mesh, the output end of the second thermistor is interconnected with the first pull-up resistor and the first feedback end of the main controller, and the second end of the first pull-up resistor is connected to a first DC power supply; And / or, the second thermistor is arranged on the shell of the speaker module, the output end of the second thermistor is interconnected with the second pull-up resistor and the second feedback end of the main controller, and the second end of the second pull-up resistor is connected to the first DC power supply.

6. The heating control circuit according to any one of claims 1 to 5, characterized in that: The heating control circuit also includes: A power processing circuit, the power processing circuit comprising a first power transmission end and a second power transmission end, the first power transmission end of the power processing circuit is used to access an AC power supply, the second power transmission end is used to access an energy storage device, and the output end of the power processing circuit is connected to the main controller; The power processing circuit is used to disconnect the electrical connection with the energy storage device when it is detected that the AC power supply voltage is connected to the first power transmission end, and to connect the electrical connection with the energy storage device when it is detected that the AC power supply voltage is not connected to the first power transmission end.

7. The heating control circuit according to any one of claims 1 to 5, characterized in that: The humidity detection circuit includes a humidity-sensitive resistor and a third pull-up resistor. The humidity-sensitive resistor is arranged close to the metal mesh cloth. The output end of the humidity-sensitive resistor is interconnected with the third pull-up resistor and the feedback end of the main controller. The second end of the third pull-up resistor is connected to a DC power supply.

8. A speaker module, characterized in that: The speaker module comprises: Speaker assembly; A housing, wherein the housing is provided with a speaker accommodating cavity and a sound outlet communicated with the speaker accommodating cavity, and the speaker assembly is fixed in the speaker accommodating cavity; A metal mesh cloth, the metal mesh cloth covering the sound outlet; And, the heating control circuit as described in any one of claims 1 to 7; the heating control circuit is electrically connected to the metal mesh cloth.

9. The speaker module according to claim 8, characterized in that: The speaker module also includes: The insulating layer is coated on both side surfaces of the metal mesh cloth.

10. The speaker module according to claim 8, wherein: The housing has a speaker accommodating cavity, and the end of the lower end of the speaker accommodating cavity close to the sound outlet is inclined toward the speaker assembly; And / or, an end portion of the upper end of the speaker accommodating cavity close to the sound outlet is inclined away from the speaker assembly.

11. An outdoor fixed audio device, characterized in that: It comprises a heating control circuit as described in any one of claims 1 to 7; and / or it comprises a speaker module as described in any one of claims 8 to 10.

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