Overheat detection circuit, household electrical appliance and plug overheating detection method

Abstract

The embodiment of the invention discloses an overheating detection circuit, a household appliance and a plug overheating detection method. The overheating detection circuit comprises a load, a power supply circuit, a thermal circuit breaker, a protection resistor, a detection circuit and a controller. The power supply circuit comprises a zero line and a live line which are used for supplying power to a load. The thermal circuit breaker is connected in series with a zero line or a live line; the protective resistor is connected in parallel with the thermal circuit breaker; the input end of the detection circuit is connected with the output end of a zero line or a live line connected in series with the thermal circuit breaker; the controller is connected with the output end of the detection circuit and the load, the controller is used for controlling the load to work during power-on so that the detection circuit can obtain a corresponding first detection signal, the controller judges whether the thermal circuit breaker is disconnected or not according to the first detection signal, and when the thermal circuit breaker is disconnected, the temperature of the plug is larger than or equal to the preset temperature; therefore, the probability of life and property loss of the user can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of household appliances, and in particular to an overheat detection circuit, a household appliance, and a method for detecting overheating of a plug. Background Art

[0002] In the relevant technical field, due to reasons such as socket electrical overload, socket aging, poor socket contact and humid environment, the plug may easily ignite when inserted into the socket, causing the temperature of the plug to rise. Long-term continued use may cause the metal part of the plug to ignite and burn, which may burn the plug and socket at the very least, or cause a fire at the worst, easily causing loss of life and property of the user. Summary of the invention

[0003] The embodiments of the present application provide an overheat detection circuit, a household appliance, and a method for detecting overheating of a plug, which are intended to detect the on / off state of a thermal circuit breaker through an overheat detection circuit. When the thermal circuit breaker is tripped, the temperature of the plug is greater than or equal to a preset temperature, and the load is controlled to stop working, thereby reducing the probability of loss of life and property of the user.

[0004] An embodiment of the present application provides an overheating detection circuit including a load, a power supply circuit, a thermal circuit breaker, a protective resistor, a detection circuit and a controller; the power supply circuit includes a neutral wire and a live wire, and the neutral wire and the live wire are used to supply power to the load; the thermal circuit breaker is connected in series with the neutral wire or the live wire; the protective resistor is connected in parallel with the thermal circuit breaker; the input end of the detection circuit is connected to the output end of the neutral wire or the live wire connected in series with the thermal circuit breaker; the controller is connected to the output end of the detection circuit and the load, and the controller is used to control the load to work when powered on, so that the detection circuit obtains a corresponding first detection signal, and the controller determines whether the thermal circuit breaker is open according to the first detection signal.

[0005] Based on the above embodiment, after the overheat detection circuit is powered on, the controller controls the load to work, and the controller obtains the first detection signal through the detection circuit. When the controller determines that the thermal circuit breaker is in the on state according to the first detection signal, it indicates that the temperature of the plug of the household appliance is less than the preset temperature, so that the controller can control the load to work normally. When the controller determines that the thermal circuit breaker is in the off state according to the first detection signal, the temperature of the plug is greater than or equal to the preset temperature, and the controller controls the load to stop working, so as to reduce the probability of damage to the household appliance, so that the household appliance can have a longer service life and reduce the probability of loss of life and property of the user.

[0006] In some of the embodiments, the detection circuit includes a voltage divider circuit, an input end of the voltage divider circuit is connected to an input end of the detection circuit, and an output end of the voltage divider circuit is connected to an output end of the detection circuit.

[0007] Based on the above embodiment, a voltage divider circuit is used to divide the voltage at the input end of the detection circuit to prevent a voltage signal greater than the rated voltage of the controller from entering the controller. This can reduce the probability of the controller failing, so that the controller can have a longer service life, and thus the detection circuit can have a longer service life.

[0008] In some embodiments, the load is an AC load, and the voltage divider circuit includes a first diode, a first resistor, a second resistor, a third resistor and a first capacitor, the positive electrode of the first diode is connected to the input end of the voltage divider circuit; the first end of the first resistor is connected to the negative electrode of the first diode; the first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the output end of the voltage divider circuit; the first end of the third resistor is connected to the second end of the second resistor, and the second end of the third resistor is grounded; the first capacitor is connected in parallel with the third resistor.

[0009] Based on the above embodiment, when the load is an AC load, the input end of the voltage divider circuit is connected to AC power, and the first diode is used to rectify the AC power into pulsed DC power. The pulsed DC power is divided by the first resistor, the second resistor and the third resistor. After the voltage division, the pulsed DC power can be filtered by the first capacitor to stabilize the signal input to the controller, thereby stabilizing the first detection signal obtained by the controller, which can improve the accuracy of the controller in judging whether the thermal circuit breaker is open.

[0010] In some of the embodiments, the detection circuit further includes a clamping circuit, an input end of the clamping circuit is connected to an output end of the voltage divider circuit, and an output end of the clamping circuit is used to connect to a power supply.

[0011] Based on the above embodiment, when the voltage at the output end of the voltage divider circuit is greater than or equal to the rated voltage of the clamping circuit, the clamping circuit is turned on to stabilize the voltage at the output end of the voltage divider circuit to the rated voltage, so as to reduce the probability of damage to the controller, thereby enabling the controller to have a longer service life, and enabling the overheat detection circuit to have a longer service life.

[0012] In some of the embodiments, the clamping circuit includes a second diode, an anode of the second diode is connected to the input terminal of the clamping circuit, and a cathode of the second diode is connected to the output terminal of the clamping circuit.

[0013] Based on the above embodiment, when the voltage at the output end of the voltage divider circuit is greater than or equal to the sum of the power supply voltage and the forward conduction voltage of the second diode, the positive and negative electrodes of the second diode are connected so that the voltage of the second diode is stabilized at the voltage value corresponding to the sum of the power supply voltage and the forward conduction voltage of the second diode, thereby reducing the probability of damage to the controller, and further allowing the controller to have a longer service life, so that the overheat detection circuit can have a longer service life.

[0014] In some embodiments, the detection circuit further includes a first current limiting circuit, an input end of the first current limiting circuit is connected to an output end of the voltage divider circuit, and an output end of the first current limiting circuit is connected to an output end of the detection circuit.

[0015] Based on the above embodiment, the first current limiting circuit is used to limit the current signal greater than the rated current of the controller from entering the controller, thereby reducing the probability of controller damage, so that the controller can have a longer service life, and further the overheating detection circuit can have a longer service life.

[0016] In some embodiments, the first current limiting circuit includes a fourth resistor, a first end of the fourth resistor is connected to an input end of the first current limiting circuit, and a second end of the fourth resistor is connected to an output end of the first current limiting circuit.

[0017] Based on the above embodiment, the fourth resistor is used to limit the current signal greater than the rated current of the controller from entering the controller, so that the controller can have a longer service life, and further the overheat detection circuit can have a longer service life.

[0018] In some embodiments, the detection circuit further includes a filter circuit, an input end of the filter circuit is connected to an output end of the first current limiting circuit, and an output end of the filter circuit is grounded.

[0019] Based on the above embodiment, a filter circuit is used to filter out the high-frequency interference signal output from the output end of the first current limiting circuit to reduce the influence of the high-frequency interference signal on the first detection signal, thereby improving the accuracy of the controller in obtaining the first detection signal, thereby improving the accuracy of the controller in determining whether the thermal circuit breaker is open.

[0020] In some embodiments, the filter circuit includes a second capacitor, a first plate of the second capacitor is connected to the input end of the filter circuit, and a second plate of the second capacitor is connected to the output end of the filter circuit.

[0021] Based on the above embodiment, the second capacitor is used to filter out the high-frequency interference signal output from the output end of the first current limiting circuit to reduce the influence of the high-frequency interference signal on the first detection signal, thereby improving the accuracy of the controller in obtaining the first detection signal, so as to improve the accuracy of the controller in judging whether the thermal circuit breaker is open.

[0022] In some of the embodiments, the load is a DC load, and the power supply circuit further includes an AC-to-DC converter, the input end of the AC-to-DC converter is connected to the output end of the live wire and the output end of the neutral wire, and the output end of the AC-to-DC converter is connected to the load and the input end of the voltage divider circuit.

[0023] Based on the above embodiment, an AC-to-DC converter is used to convert the AC power output by the neutral line and the live line into DC power, so that the DC load can be powered by DC power. At this time, the input end of the detection circuit can be connected to the output end of the AC-to-DC converter, so that the first detection signal can be obtained through the output end of the AC-to-DC converter, and the on-off state of the thermal circuit breaker can also be determined by the first detection signal.

[0024] In some embodiments, the voltage divider circuit includes a fifth resistor and a sixth resistor, the first end of the fifth resistor is connected to the input end of the voltage divider circuit, and the second end of the fifth resistor is connected to the output end of the voltage divider circuit; the first end of the sixth resistor is connected to the second end of the fifth resistor, and the second end of the sixth resistor is grounded.

[0025] Based on the above embodiment, the fifth resistor and the sixth resistor are used to divide the DC voltage output by the AC-to-DC converter, which can prevent voltage signals exceeding the rated voltage of the controller from entering the controller, thereby reducing the probability of damage to the controller, thereby allowing the controller to have a longer service life, and further allowing the overheating detection circuit to have a longer service life.

[0026] In some embodiments, the detection circuit further includes a second current limiting circuit, an input end of the second current limiting circuit is connected to an output end of the voltage divider circuit, and an output end of the second current limiting circuit is connected to an output end of the detection circuit.

[0027] Based on the above embodiment, the second current limiting circuit is used to limit the current signal greater than the rated current of the controller from entering the controller, thereby reducing the probability of controller damage, so that the controller can have a longer service life, and further the overheating detection circuit can have a longer service life.

[0028] In some embodiments, the second current limiting circuit includes a seventh resistor, a first end of the seventh resistor is connected to an input end of the second current limiting circuit, and a second end of the seventh resistor is connected to an output end of the second current limiting circuit.

[0029] Based on the above embodiment, the seventh resistor is used to limit the current signal greater than the rated current of the controller from entering the controller, so that the controller can have a longer service life, and further the overheating detection circuit can have a longer service life.

[0030] In some of the embodiments, the power supply circuit further includes an AC-to-DC converter, an input end of the AC-to-DC converter is connected to an output end of the live wire and an output end of the neutral wire; and an output end of the AC-to-DC converter is connected to a power receiving end of the controller.

[0031] Based on the above embodiments, the controller can be powered by the output end of the AC-to-DC converter.

[0032] In some of the embodiments, the power supply circuit also includes an AC-to-DC converter and a DC-to-DC converter, the input end of the AC-to-DC converter is connected to the output end of the live wire and the output end of the neutral wire; the input end of the DC-to-DC converter is connected to the output end of the AC-to-DC converter, and the output end of the DC-to-DC converter is connected to the power receiving end of the controller.

[0033] Based on the above embodiments, the controller can be powered by the output end of the DC-to-DC converter.

[0034] In some of the embodiments, the overheat detection circuit further includes a prompt device, which is connected to the controller and is used to issue a prompt message.

[0035] Based on the above embodiment, when the controller determines that the thermal circuit breaker is in the disconnected state through the first detection signal, the controller can control the prompt device to issue a prompt message, and the prompt message includes at least one of display information, sound information and light information. The prompt device includes at least one of a display screen, a speaker and an indicator light.

[0036] An embodiment of the present application also provides a household appliance, including an overheat detection circuit and a plug, wherein the plug has two pins, the two pins are respectively connected to the input end of the live wire and the input end of the neutral wire, and a thermal circuit breaker and a protective resistor are both arranged in the plug.

[0037] Based on the above embodiment, when the plug of the household appliance ignites, the temperature of the plug will increase, so that the temperature of the thermal circuit breaker will increase. When the temperature of the thermal circuit breaker is greater than or equal to the preset temperature, the thermal circuit breaker will be disconnected, so that the protection resistor is connected to the circuit, so that a voltage drop is generated between the first end and the second end of the protection resistor, thereby reducing the power supply voltage of the controller, so that the controller is powered off, and the load is in a standby state. At this time, since the load is in the standby state, the voltage at the output end of the power supply circuit will increase, so that the controller can be powered, and the controller controls the load to run. When the controller obtains the first detection signal through the detection circuit to determine that the thermal circuit breaker is in the disconnected state, it means that the temperature of the plug is greater than or equal to the preset temperature.

[0038] When the temperature of the plug is lower than a preset temperature, the thermal circuit breaker is turned on to short-circuit the protective resistor, so that the neutral wire and the live wire can normally supply power to the load.

[0039] In some of the embodiments, the household appliance includes a heater, the load includes an AC load and / or a DC load, the AC load includes an AC fan and / or an AC heating element, and the DC load includes a DC fan and / or a DC heating element.

[0040] The present application also provides a method for detecting overheating of a plug, which is applicable to household appliances. The method comprises:

[0041] When the household appliance is powered on, the load is controlled to run for a first preset time;

[0042] Acquire a first detection signal when the load is running through a detection circuit;

[0043] If the first detection signal is less than the first threshold signal, it is determined that the thermal circuit breaker is in an overheated circuit breaker state; if the first detection signal is equal to the first threshold signal, it is determined that the thermal circuit breaker is in a conducting state.

[0044] In some embodiments, before the step of controlling the load to run for the first preset time, the method further includes:

[0045] Control household appliances to standby and keep them on for a second preset time.

[0046] In some embodiments, after the step of determining that the thermal circuit breaker is in an overheating circuit breaker state, the step further includes:

[0047] The load is controlled to stop working, and the prompt device is controlled to send out a first prompt message.

[0048] In some embodiments, the first threshold signal is a normal operating voltage of the load when the thermal circuit breaker is turned on; or,

[0049] The first threshold signal is a first preset voltage.

[0050] In some embodiments, before the step of controlling the load to run for the first preset time, the method further includes:

[0051] Acquire a second detection signal when the load is in standby mode through a detection circuit;

[0052] If the second detection signal is greater than the second threshold signal, the step of controlling the load to run for a first preset time is executed; if the second detection signal is less than or equal to the second threshold signal, the prompt device is controlled to issue a second prompt message;

[0053] The second threshold signal is smaller than the first threshold signal.

[0054] Based on the overheat detection circuit of the present application, after the overheat detection circuit is powered on, the controller controls the load to work, and the controller obtains a first detection signal through the detection circuit. When the controller determines that the thermal circuit breaker is in the on state according to the first detection signal, it indicates that the temperature of the plug of the household appliance is less than the preset temperature, so that the controller can control the load to work normally. When the controller determines that the thermal circuit breaker is in the off state according to the first detection signal, it indicates that the temperature of the plug is greater than or equal to the preset temperature, and the controller controls the load to stop working, so as to reduce the probability of damage to the household appliance, so that the household appliance can have a longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, 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 those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0056] Figure 1 This is a schematic diagram of the structure of a household appliance in one embodiment of the present application;

[0057] Figure 2 This is a schematic diagram of a framework structure in which a plug is connected to an overheat detection circuit in one embodiment of the present application;

[0058] Figure 3 This is a schematic diagram of the framework structure of a detection circuit, a controller and a prompt device in one embodiment of the present application;

[0059] Figure 4 A circuit diagram of a detection circuit in one embodiment of the present application;

[0060] Figure 5 This is a schematic diagram of a framework structure in which a plug is connected to an overheat detection circuit in another embodiment of the present application;

[0061] Figure 6 This is a schematic diagram of the framework structure of a detection circuit, a controller and a prompt device in another embodiment of the present application;

[0062] Figure 7 A circuit diagram of a detection circuit in another embodiment of the present application;

[0063] Figure 8 This is a schematic diagram of a framework structure in which a plug is connected to an overheat detection circuit in another embodiment of the present application;

[0064] Fig. 9 This is a flow chart of a method for detecting overheating of a plug in an embodiment of the present application;

[0065] Fig.10 This is a flow chart of a method for detecting plug overheating in another embodiment of the present application;

[0066] Fig.11 This is a flow chart of a method for detecting plug overheating in another embodiment of the present application;

[0067] Fig.12 This is a flow chart of a method for detecting plug overheating in another embodiment of the present application.

[0068] Explanation of the accompanying drawings: 1. household appliance; 11. body; 12. plug; 121. pin; 2. overheat detection circuit; 21. load; 22. power supply circuit; 221. neutral line; 222. live line; 223. AC to DC converter; 224. DC to DC converter; 23. thermal circuit breaker; 24. protection resistor; 25. detection circuit; 251. voltage divider circuit; 252. clamping circuit; 253. first current limiting circuit; 254. filtering circuit; 255. second current limiting circuit; 26. controller; 27. prompt device; D1. first diode; D2. second diode; R1. first resistor; R2. second resistor; R3. third resistor; R4. fourth resistor; R5. fifth resistor; R6. sixth resistor; R7. seventh resistor; C1. first capacitor; C2. second capacitor. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of 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.

[0070] Please refer to Figure 1 In a first aspect, an embodiment of the present application provides a household appliance 1 , which includes a body 11 and a plug 12 connected to the body 11 .

[0071] When the plug 12 is connected to the socket, the plug 12 can be connected to the mains power to supply power to the body 11 through the mains power, so that the household appliance 1 can work.

[0072] However, in the related art, due to reasons such as electrical overload of the socket, aging of the socket, poor contact of the socket, and humid environment, the plug 12 may easily ignite when inserted into the socket, causing the temperature of the plug 12 to rise. Continuous use for a long time may cause the metal part of the plug 12 to ignite and burn, which may burn the plug 12 socket at the least and cause a fire at the worst, which may easily cause loss of life and property of the user.

[0073] Based on the above problem, the household appliance 1 also includes an overheating detection circuit 2, which detects whether the temperature of the plug 12 exceeds the preset temperature. When the temperature of the plug 12 exceeds the preset temperature, the load 21 is controlled to stop working to reduce the probability of damage to the household appliance 1, so that the household appliance 1 can have a longer service life.

[0074] Please refer to Figure 1 and Figure 2Specifically, the plug 12 has two pins 121, and the overheat detection circuit 2 may include a load 21, a power supply circuit 22, a thermal circuit breaker 23, a protective resistor 24, a detection circuit 25, and a controller 26; the power supply circuit 22 includes a neutral line 221 and a live line 222, which are respectively connected to the two pins 121 and are used to supply power to the load 21; the thermal circuit breaker 23 is connected in series with the neutral line 221; the protective resistor 24 is connected in parallel with the thermal circuit breaker 23; the input end of the detection circuit 25 is connected to the output end of the neutral line 221 connected in series with the thermal circuit breaker 23; and the controller 26 is connected to the output end of the detection circuit 25 and the load 21. It can be understood that the thermal circuit breaker 23 can also be connected in series with the live line 222, and in this case, the input end of the detection circuit 25 is connected to the output end of the live line 222 connected in series with the thermal circuit breaker 23.

[0075] In the embodiment of the present application, after the overheat detection circuit 2 is powered on, the controller 26 controls the load 21 to work, and the controller 26 obtains the first detection signal through the detection circuit 25. When the controller 26 determines that the thermal circuit breaker 23 is in the on state according to the first detection signal, it indicates that the temperature of the plug 12 of the household appliance 1 is less than the preset temperature, so that the controller 26 can control the load 21 to work normally. When the controller 26 determines that the thermal circuit breaker 23 is in the off state through the first detection signal, it indicates that the temperature of the plug 12 is greater than or equal to the preset temperature, and the controller 26 controls the load 21 to stop working, so as to reduce the probability of damage to the household appliance 1, so that the household appliance 1 can have a longer service life.

[0076] Exemplarily, the preset temperature may be 75°C, 80°C, 90°C, ... In the embodiment of the present application, there is no limitation on the specific value of the preset temperature, and a suitable preset temperature value may be selected according to usage requirements.

[0077] Please refer to Figure 1 and Figure 2 In one embodiment, in order to facilitate the thermal circuit breaker 23 to break the circuit when the temperature of the plug 12 is greater than or equal to the preset temperature, the thermal circuit breaker 23 is arranged in the plug 12. And the protection resistor 24 can also be arranged in the plug 12, so that the length of the wire between the protection resistor 24 and the thermal circuit breaker 23 can be shortened to improve the stability of the parallel connection of the protection resistor 24 and the thermal circuit breaker 23. And because the length of the wire between the protection resistor 24 and the thermal circuit breaker 23 is short, the use of wires can be reduced to reduce the cost of the overheating detection circuit 2, and then the overall cost of the household appliance 1 can be reduced. It can be understood that the load 21 is arranged in the body 11. Exemplarily, the thermal circuit breaker 23 can be a bimetallic thermal circuit breaker 23. In other embodiments, the thermal circuit breaker 23 can also be in other forms. In the embodiment of the present application, the specific form of the thermal circuit breaker 23 is not limited.

[0078] Furthermore, the overheat detection circuit 2 may also include a heat-conducting element (not shown in the figure), which connects the two pins 121 and the thermal circuit breaker 23, so that the heat transfer from the pins 121 to the thermal circuit breaker 23 can be improved by using the heat-conducting element, and the thermal reaction speed of the thermal circuit breaker 23 can be improved to provide reliable protection for the use of the household appliance 1. Exemplarily, the heat-conducting element may be an insulating thermally conductive ceramic. In other embodiments, the heat-conducting element may also be in other forms. In the embodiments of the present application, the specific form of the heat-conducting element is not limited.

[0079] Please refer to Figure 1 and Figure 2 In the embodiment of the present application, when the plug 12 of the household appliance 1 ignites, the temperature of the plug 12 will increase, so that the temperature of the thermal circuit breaker 23 will increase. When the temperature of the thermal circuit breaker 23 is greater than or equal to the preset temperature, the thermal circuit breaker 23 is disconnected, so that the protection resistor 24 is connected to the circuit, so that a voltage drop is generated between the first end and the second end of the protection resistor 24, thereby reducing the power supply voltage of the controller 26, so that the controller 26 is powered off, and the load 21 is in a standby state. At this time, since the load 21 is in the standby state, the voltage between the output end of the neutral line 221 and the output end of the live line 222 will increase to supply power to the controller 26. The controller 26 controls the operation of the load 21. When the controller 26 obtains the first detection signal through the detection circuit 25 to determine that the thermal circuit breaker 23 is in the disconnected state, it indicates that the temperature of the plug 12 of the household appliance 1 is greater than or equal to the preset temperature. When the temperature of the plug 12 is lower than a preset temperature, the thermal circuit breaker 23 is turned on to short-circuit the protective resistor 24 , so that the voltage between the neutral line 221 and the live line 222 can supply power to the controller 26 and the load 21 normally.

[0080] It can be understood that the household appliance 1 may include at least one of a heater, an electric fan, an electric rice cooker, an air conditioner, a refrigerator, and a clothes processing device.

[0081] In the embodiment of the present application, the household appliance 1 is explained by taking a heater as an example.

[0082] Specifically, the heater includes a housing and a load 21 disposed in the housing, wherein the load 21 includes at least one of an AC load and a DC load. The AC load may include at least one of an AC fan and an AC heating element. The DC load may include at least one of a DC fan and a DC heating element.

[0083] The shell may have an air inlet and an air outlet, and an air duct is arranged inside the shell, the air duct connects the air inlet and the air outlet, the heating element and the fan are arranged in the air duct, and the fan is arranged closer to the air inlet than the heating element, and the heating element is arranged closer to the air outlet than the fan.

[0084] When the fan is running, air can be sucked into the air duct from the air inlet and blown out from the air outlet through the air duct. If the heating element is in a heating state, the air in the air duct can be heated and then blown out through the air outlet, thereby providing heating to the user.

[0085] It is understood that the material of the shell can be at least one of metal and plastic. In the embodiment of the present application, there is no specific limitation on the material of the shell. It is understood that the shape of the shell can be at least one of a cylinder or a disc. In the embodiment of the present application, there is no specific limitation on the shape of the shell.

[0086] Please refer to Figure 2 and Figure 3 In one embodiment, the detection circuit 25 includes a voltage divider circuit 251, the input end of the voltage divider circuit 251 is connected to the input end of the detection circuit 25, and the output end of the voltage divider circuit 251 is connected to the output end of the detection circuit 25. The voltage divider circuit 251 is used to divide the voltage at the input end of the detection circuit 25 to prevent a voltage signal greater than the rated voltage of the controller 26 from entering the controller 26, which can reduce the probability of the controller 26, so that the controller 26 can have a longer service life, and thus the detection circuit 25 can have a longer service life.

[0087] Please refer to Figure 2-4 In one embodiment, the load 21 may be an AC load, and the voltage divider circuit 251 may include a first diode D1, a first resistor R1, a second resistor R2, a third resistor R3 and a first capacitor C1. The positive electrode of the first diode D1 is connected to the input end of the voltage divider circuit 251; the first end of the first resistor R1 is connected to the negative electrode of the first diode D1; the first end of the second resistor R2 is connected to the second end of the first resistor R1, and the second end of the second resistor R2 is connected to the output end of the voltage divider circuit 251; the first end of the third resistor R3 is connected to the second end of the second resistor R2, and the second end of the third resistor R3 is grounded; the first capacitor C1 is connected in parallel with the third resistor R3.

[0088] When the load 21 is an AC load, the input end of the voltage divider circuit 251 is connected to AC power, and the first diode D1 is used to rectify the AC power into pulsed DC power. The pulsed DC power is divided by the first resistor R1, the second resistor R2, and the third resistor R3. After the voltage division, the pulsed DC power can be filtered by the first capacitor C1 to stabilize the signal input to the controller 26, thereby stabilizing the first detection signal obtained by the controller 26, and improving the accuracy of the controller 26 in judging whether the thermal circuit breaker 23 is open. It can be understood that in other embodiments, the voltage divider circuit 251 can also be in other forms. In the embodiment of the present application, the specific form of the voltage divider circuit 251 is not limited.

[0089] Please refer to Figure 2-4In one embodiment, the detection circuit 25 also includes a clamping circuit 252, the input end of the clamping circuit 252 is connected to the output end of the voltage divider circuit 251, and the output end of the clamping circuit 252 is used to connect to a power supply. When the voltage at the output end of the voltage divider circuit 251 is greater than or equal to the rated voltage of the clamping circuit 252, the clamping circuit 252 is turned on to stabilize the voltage at the output end of the voltage divider circuit 251 at the rated voltage, so as to reduce the probability of damage to the controller 26, thereby allowing the controller 26 to have a longer service life, so that the overheat detection circuit 2 can have a longer service life.

[0090] Specifically, the clamp circuit 252 may include a second diode D2, the anode of the second diode D2 is connected to the input end of the clamp circuit 252, and the cathode of the second diode D2 is connected to the output end of the clamp circuit 252. When the voltage at the output end of the voltage divider circuit 251 is greater than or equal to the sum of the power supply voltage and the forward conduction voltage of the second diode D2, the anode and cathode of the second diode D2 are connected, so that the voltage of the second diode D2 is stabilized at the voltage value corresponding to the sum of the power supply voltage and the forward conduction voltage of the second diode D2, thereby reducing the probability of damage to the controller 26, and further allowing the controller 26 to have a longer service life, so that the overheat detection circuit 2 can have a longer service life. It can be understood that in other embodiments, the clamp circuit 252 can also be in other forms. In the embodiment of the present application, the specific form of the clamp circuit 252 is not limited.

[0091] It is understandable that the voltage applied to the cathode of the second diode D2 can be provided by an independent power supply, or by converting AC power into DC power through a DC-to-DC converter and providing it to the cathode of the second diode D2. In the embodiment of the present application, there is no limitation on the method of providing the voltage to the cathode of the second diode D2.

[0092] Please refer to Figure 2-4 In one embodiment, the detection circuit 25 further includes a first current limiting circuit 253, the input end of the first current limiting circuit 253 is connected to the output end of the voltage divider circuit 251, and the output end of the first current limiting circuit 253 is connected to the output end of the detection circuit 25. The first current limiting circuit 253 is used to limit the current signal greater than the rated current of the controller 26 from entering the controller 26, thereby reducing the probability of damage to the controller 26, so that the controller 26 can have a longer service life, and thus the overheat detection circuit 2 can have a longer service life.

[0093] Please refer to Figure 2-4Specifically, the first current limiting circuit 253 may include a fourth resistor R4, a first end of the fourth resistor R4 is connected to the input end of the first current limiting circuit 253, and a second end of the fourth resistor R4 is connected to the output end of the first current limiting circuit 253. The fourth resistor R4 is used to limit the current signal greater than the rated current of the controller 26 from entering the controller 26, so that the controller 26 can have a longer service life, and thus the overheat detection circuit 2 can have a longer service life. It can be understood that in other embodiments, the first current limiting circuit 253 can also be in other forms. In the embodiment of the present application, the specific form of the first current limiting circuit 253 is not limited.

[0094] Please refer to Figure 2-4 In one embodiment, the detection circuit 25 further includes a filter circuit 254, the input end of the filter circuit 254 is connected to the output end of the first current limiting circuit 253, and the output end of the filter circuit 254 is grounded. The filter circuit 254 is used to filter out the high-frequency interference signal output by the output end of the first current limiting circuit 253, so as to reduce the influence of the high-frequency interference signal on the first detection signal, thereby improving the accuracy of the controller 26 in acquiring the first detection signal, so as to improve the accuracy of the controller 26 in judging whether the thermal circuit breaker 23 is disconnected.

[0095] Please refer to Figure 2-4 Specifically, the filter circuit 254 may include a second capacitor C2, a first plate of the second capacitor C2 is connected to the input end of the filter circuit 254, and a second plate of the second capacitor C2 is connected to the output end of the filter circuit 254. The second capacitor C2 is used to filter out the high-frequency interference signal output by the output end of the first current limiting circuit 253 to reduce the influence of the high-frequency interference signal on the first detection signal, thereby improving the accuracy of the controller 26 in obtaining the first detection signal, so as to improve the accuracy of the controller 26 in judging whether the thermal circuit breaker 23 is open. It can be understood that in other embodiments, the filter circuit 254 can also be in other forms. In the embodiment of the present application, the specific form of the filter circuit 254 is not limited.

[0096] Please refer to Figure 5-7In another embodiment, the load 21 may also be a DC load, and the power supply circuit 22 further includes an AC-to-DC converter 223, the input end of the AC-to-DC converter 223 is connected to the output end of the live wire 222 and the output end of the neutral wire 221, and the output end of the AC-to-DC converter 223 is connected to the load 21 and the input end of the voltage divider circuit 251. The AC-to-DC converter 223 is used to convert the AC power outputted from the neutral wire 221 and the live wire 222 into DC power, so that the DC power can be used to power the DC load. At this time, the input end of the detection circuit 25 can be connected to the output end of the AC-to-DC converter 223, so that the first detection signal can be obtained through the output end of the AC-to-DC converter 223, and the on-off state of the thermal circuit breaker 23 can also be determined through the first detection signal.

[0097] Please refer to Figure 5-7 Specifically, the voltage divider circuit 251 may include a fifth resistor R5 and a sixth resistor R6, wherein the first end of the fifth resistor R5 is connected to the input end of the voltage divider circuit 251, and the second end of the fifth resistor R5 is connected to the output end of the voltage divider circuit 251; the first end of the sixth resistor R6 is connected to the second end of the fifth resistor R5, and the second end of the sixth resistor R6 is grounded. By using the fifth resistor R5 and the sixth resistor R6 to divide the DC voltage output by the AC-DC converter, a voltage signal exceeding the rated voltage of the controller 26 can be prevented from entering the controller 26, so as to reduce the probability of damage to the controller 26, thereby enabling the controller 26 to have a longer service life, and further enabling the overheat detection circuit 2 to have a longer service life. It is understandable that in other embodiments, the voltage divider circuit 251 may also be in other forms. In the embodiment of the present application, there is no limitation on the specific form of the voltage divider circuit 251.

[0098] Please refer to Figure 5-7 In one embodiment, the detection circuit 25 further includes a second current limiting circuit 255, the input end of the second current limiting circuit 255 is connected to the output end of the voltage divider circuit 251, and the output end of the second current limiting circuit 255 is connected to the output end of the detection circuit 25. The second current limiting circuit 255 is used to limit the current signal greater than the rated current of the controller 26 from entering the controller 26, thereby reducing the probability of damage to the controller 26, so that the controller 26 can have a longer service life, and thus the overheat detection circuit 2 can have a longer service life.

[0099] Please refer to Figure 5-7Specifically, the second current limiting circuit 255 may include a seventh resistor R7, a first end of the seventh resistor R7 is connected to the input end of the second current limiting circuit 255, and a second end of the seventh resistor R7 is connected to the output end of the second current limiting circuit 255. The seventh resistor R7 is used to limit the current signal greater than the rated current of the controller 26 from entering the controller 26, so that the controller 26 can have a longer service life, and thus the overheat detection circuit 2 can have a longer service life. It can be understood that in other embodiments, the second current limiting circuit 255 can also be in other forms. In the embodiment of the present application, the specific form of the second current limiting circuit 255 is not limited.

[0100] Please refer to Figure 5 In one embodiment, the output end of the AC-to-DC converter 223 may be connected to the power receiving end of the controller 26 , so that the controller 26 may be powered by the output end of the AC-to-DC converter 223 .

[0101] Please refer to Figure 8 In other embodiments, the power supply circuit 22 may further include a DC-to-DC converter 224, the input end of the DC-to-DC converter 224 is connected to the output end of the AC-to-DC converter 223, and the output end of the DC-to-DC converter 224 is connected to the power receiving end of the controller 26, so that the controller 26 can be powered by the output end of the DC-to-DC converter 224. In the embodiment of the present application, there is no restriction on the power supply method of the controller 26.

[0102] It is understandable that when the voltage required by the load 21 does not match the output voltage of the AC-DC converter 223, the output voltage of the AC-DC converter 223 can be changed by one or more DC-DC converters 224 until it matches the voltage required by the load 21, so the detection circuit 25 can also be connected to the output end of any DC-DC converter 224, and the first detection signal can also be obtained, and the on-off state of the thermal circuit breaker 23 can be determined by the first detection signal. In the embodiment of the present application, this will not be described in detail.

[0103] Please refer to Figure 3 and Figure 6In one embodiment, the overheat detection circuit 2 also includes a prompt device 27, which is connected to the controller 26 and is used to issue a prompt message. When the controller 26 determines that the thermal circuit breaker 23 is in a circuit-breaking state through the first detection signal, the controller 26 can control the prompt device 27 to issue a prompt message to remind the user that the plug 12 needs to be separated from the socket, or the plug 12 needs to be replaced. Exemplarily, the prompt message includes at least one of display information, sound information, and light information. In other embodiments, the prompt message can also be in other forms. In the embodiments of the present application, the specific form of the prompt message is not limited. The prompt device 27 includes at least one of a display screen, a speaker, and an indicator light. In other embodiments, the prompt device 27 can also be in other forms. In the embodiments of the present application, the specific form of the prompt device 27 is not limited.

[0104] Please refer to Figure 1 , Figure 2 and Fig. 9 In a second aspect, the embodiment of the present application further provides a method for detecting overheating of a plug 12, which is applicable to a household appliance 1, and the detection method comprises:

[0105] Step S10: The household appliance 1 is powered on.

[0106] In the embodiment of the present application, when the plug 12 is connected to the socket, the mains power can supply power to the plug 12 through the socket, so that the household appliance 1 is powered on.

[0107] Step S20, controlling the load 21 to run for a first preset time period.

[0108] In the embodiment of the present application, after the household appliance 1 is powered on, the controller 26 controls the load 21 to run for a first preset time so that the current and voltage of the overheat detection circuit 2 are in a stable state, thereby improving the accuracy of the first detection signal obtained by the controller 26 through the detection circuit 25, and further improving the accuracy of judging whether the thermal circuit breaker 23 is disconnected according to the first detection signal. Exemplarily, the first preset time can be greater than or equal to 0.5s and less than or equal to 5s. Specifically, the first preset time can be 1s, 2s, 3s, 4s, or 5s. In the embodiment of the present application, there is no specific limitation on the duration of the first preset time.

[0109] Step S30 : obtaining a first detection signal when the load 21 is running through the detection circuit 25 .

[0110] In the embodiment of the present application, the controller 26 can obtain a first detection signal when the load 21 is running through the detection circuit 25, so that the controller 26 can obtain the on / off state of the thermal circuit breaker 23 through the first detection signal.

[0111] Step S40: If the first detection signal is less than the first threshold signal, it is determined that the thermal circuit breaker 23 is in an overheating circuit breaker state.

[0112] Since when the load 21 is not running, no matter the thermal circuit breaker 23 is in the on or off state, the difference between the detection signal obtained by the controller 26 and the first threshold signal is small, which makes it difficult for the controller 26 to judge the on and off state of the thermal circuit breaker 23. In the embodiment of the present application, when the thermal circuit breaker 23 is on, the controller 26 can obtain the first detection signal when the load 21 is running through the detection circuit 25. If the thermal circuit breaker 23 is off, when the load 21 is in the running state, there will be a large difference between the first detection signal and the first threshold signal, so that the controller 26 can easily distinguish the first detection signal from the first threshold signal. When the load 21 is in the standby state, the first detection signal obtained by the controller 23 is the same as the first threshold signal, which can improve the accuracy of judging the on and off state of the thermal circuit breaker 23. Therefore, when the first detection signal is less than the first threshold signal, the controller 26 can determine that the thermal circuit breaker 23 is in the overheating circuit breaker state, which means that the temperature of the plug 12 is greater than or equal to the preset temperature.

[0113] It is understandable that the first threshold signal may be a voltage at which the load 21 works normally, obtained by the controller 26 through the detection circuit 25. In other embodiments, the first threshold signal may also be a first preset voltage. In the embodiment of the present application, the specific form of the first threshold signal is not limited.

[0114] Step S50: If the first detection signal is equal to the first threshold signal, it is determined that the thermal circuit breaker 23 is in the on state.

[0115] In the embodiment of the present application, if the first detection signal is equal to the first threshold signal, the controller 26 determines that the thermal circuit breaker 23 is in the on state, which means that the temperature of the plug 12 is lower than the preset temperature. At this time, the controller 26 can control the load 21 to continue working.

[0116] Please refer to Figure 1 , Figure 2 and Fig.10 In one embodiment, before step S20, the detection method further includes:

[0117] Step S11, controlling the household appliance 1 to be in standby mode and maintaining the standby mode for a second preset time period.

[0118] In the embodiment of the present application, when the thermal circuit breaker 23 is turned on and the first threshold signal is the voltage of the load 21 that is normally working, which is obtained by the controller 26 through the detection circuit 25, after the user connects the plug 12 to the socket, the household appliance 1 is in a standby state, and the controller 26 controls the standby state to maintain a second preset time length, so that the current and voltage in the overheat detection circuit 2 are stable, thereby improving the accuracy of the controller 26 in obtaining the first threshold signal, thereby improving the accuracy of the controller 26 in judging the on-off state of the thermal circuit breaker 23. Exemplarily, the second preset time length may be greater than or equal to 0.5s and less than or equal to 5s. Specifically, the second preset time length may be 1s, 2s, 3s, 4s, or 5s. In the embodiment of the present application, there is no specific limitation on the duration of the second preset time length.

[0119] Please refer to Figure 1 , Figure 2 and Fig.11 In one embodiment, after step S40, the detection method further includes:

[0120] Step S41, control the load 21 to stop working, and control the prompt device 27 to send out a first prompt message.

[0121] In an embodiment of the present application, when the first detection voltage obtained by the controller 26 through the detection circuit 25 is less than the first threshold signal, the thermal circuit breaker 23 is in an open circuit state, and the controller 26 can determine that the thermal circuit breaker 23 is in an overheated open circuit state. At this time, the controller 26 controls the load 21 to stop working, and controls the prompt device 27 to send a first prompt message to remind the user that the plug 12 needs to be separated from the socket, or the plug 12 needs to be replaced.

[0122] Please refer to Figure 1 , Figure 2 and Fig.12 In one embodiment, before step S20, the detection method further includes:

[0123] Step S12: Acquire a second detection signal when the load 21 is in standby mode through the detection circuit 25.

[0124] In the embodiment of the present application, the controller 26 obtains the second detection signal when the load 21 is in standby mode through the detection circuit 25 .

[0125] Step S13: If the second detection signal is greater than or equal to the second threshold signal, execute step S20.

[0126] In the embodiment of the present application, when the second detection signal obtained by the controller 26 through the detection circuit 25 is greater than or equal to the second threshold signal, the controller 26 determines that the voltage value of the mains is within the normal range, and then the controller 26 can control the load 21 to work to detect the on-off state of the thermal circuit breaker 23. It is also convenient to use the mains within the normal range to power the load 21, so as to drive the load 21 to work, thereby reducing the probability of damage to the load 21, so that the load 21 can have a longer service life, and then the household appliance 1 can have a longer service life. Among them, the second threshold signal is greater than the first threshold signal.

[0127] Step S14: If the second detection signal is less than the second threshold signal, the prompt device 27 is controlled to issue a second prompt message.

[0128] In an embodiment of the present application, when the second detection signal obtained by the controller 26 through the detection circuit 25 is less than the second threshold signal, the controller 26 determines that the voltage value of the AC power is lower than the normal range, and the controller 26 can control the prompt device 27 to issue a second prompt message to prompt the user that the AC power is undervoltage.

[0129] In the embodiment of the present application, when the load 21 of the heater includes a heating element and an AC fan, the heater is connected to the socket through the plug 12 so that after the heater is powered on, the controller 26 controls the heating element and the AC fan to be in a standby state, and the controller 26 obtains the second detection signal of the heating element and the AC fan in standby state through the detection circuit 25; if the second detection signal is greater than or equal to the second threshold signal, the controller 26 determines that the voltage value of the mains is within the normal range, and the controller 26 can control the heating element and the AC fan to work normally. If the second detection signal is less than the second threshold signal, the controller 26 determines that the voltage value of the mains is lower than the normal range, and the controller 26 can control the prompt device 27 to send a second prompt message to prompt the user that the mains is undervoltage.

[0130] After the controller 26 determines that the voltage value of the mains is within the normal range, the controller 26 controls the heating element and the AC fan to remain in the standby state for a second preset time period, so that the current and voltage in the overheat detection circuit 2 are stable; after the second preset time period, the controller 26 controls the AC fan to run for a first preset time period, so that the current and voltage of the overheat detection circuit 2 are in a stable state. After the AC fan runs for the first preset time period, the controller 26 can obtain a first detection signal when the AC fan is running through the detection circuit 25;

[0131] If the first detection signal is equal to the first threshold signal, the controller 26 determines that the thermal circuit breaker 23 is in the on state, which means that the temperature of the plug 12 is lower than the preset temperature. At this time, the controller 26 can control the AC fan to continue working;

[0132] If the first detection signal is less than the first threshold signal, the controller 26 determines that the thermal circuit breaker 23 is in an overheating circuit breaker state, and the controller 26 controls the prompt device 27 to issue a first prompt message to prompt the user to separate the plug 12 from the socket, or to replace the plug 12. And because the thermal circuit breaker 23 is in an overheating circuit breaker state, the protective resistor 24 will be connected to the circuit, which can reduce the voltage between the output end of the live wire 222 and the output end of the neutral wire 221; until it is lower than the rated voltage of the AC-DC converter 223, resulting in the output end of the AC-DC converter 223 being unable to output the power receiving voltage required by the controller 26 to the controller 26, so that the controller 26 is powered off, thereby causing the heating element and the AC fan to lose the control signal, so that the heating element and the AC fan are in a standby state. Thereby, the voltage between the output end of the live wire 222 and the output end of the neutral wire 221 can be increased until the rated voltage of the AC-to-DC converter 223 is met. At this time, the output end of the AC-to-DC converter 223 can normally supply power to the controller 26, and the controller 26 restarts and controls the heating element and the AC fan to remain in standby mode.

[0133] In the embodiment of the present application, when the load 21 of the heater includes a heating element and a DC fan, the heater is connected to the socket through the plug 12 so that after the heater is powered on, the controller 26 controls the heating element and the DC fan to remain in a standby state for a second preset time period, so that the current and voltage in the overheat detection circuit 2 are stable; after the second preset time period, the controller 26 controls the DC fan to run for a first preset time period, so that the current and voltage of the overheat detection circuit 2 are in a stable state, and after the DC fan runs for the first preset time period, the controller 26 can obtain a first detection signal when the DC fan is running through the detection circuit 25;

[0134] If the first detection signal is equal to the first threshold signal, the controller 26 determines that the thermal circuit breaker 23 is in the on state, which means that the temperature of the plug 12 is lower than the preset temperature. At this time, the controller 26 can control the DC fan to continue working;

[0135] If the first detection signal is less than the first threshold signal, the controller 26 determines that the thermal circuit breaker 23 is in an overheating circuit breaker state, and the controller 26 controls the prompt device 27 to send a first prompt message to prompt the user to separate the plug 12 from the socket, or to replace the plug 12. And because the thermal circuit breaker 23 is in an overheating circuit breaker state, the protective resistor 24 will be connected to the circuit, which can reduce the voltage between the output end of the live wire 222 and the output end of the neutral wire 221 until it is lower than the rated voltage of the AC-DC converter 223, resulting in the output end of the AC-DC converter 223 being unable to output the power receiving voltage required by the controller 26 to the controller 26, so that the controller 26 is powered off, thereby causing the heating element and the DC fan to lose the control signal, so that the heating element and the DC fan are in a standby state. Thereby, the voltage between the output end of the live wire 222 and the output end of the neutral wire 221 can be increased until the rated voltage of the AC-to-DC converter 223 is met. At this time, the output end of the AC-to-DC converter 223 can normally supply power to the controller 26, and the controller 26 restarts and controls the heating element and the DC fan to remain in standby mode.

[0136] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0137] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An overheat detection circuit, characterized in that: The overheat detection circuit comprises: load; A power supply circuit, comprising a neutral line and a live line, wherein the neutral line and the live line are used to supply power to the load; A thermal circuit breaker, connected in series to the neutral line or the live line; A protective resistor connected in parallel with the thermal circuit breaker; A detection circuit, the input end of which is connected to the output end of the neutral line or the live line connected in series with the thermal circuit breaker; A controller is connected to the output end of the detection circuit and the load. The controller is used to control the load to work when powered on so that the detection circuit can obtain a corresponding first detection signal. The controller determines whether the thermal circuit breaker is open according to the first detection signal.

2. The overheat detection circuit according to claim 1, characterized in that: The detection circuit comprises: The voltage divider circuit has an input end connected to the input end of the detection circuit and an output end connected to the output end of the detection circuit.

3. The overheat detection circuit according to claim 2, characterized in that: The load is an AC load, and the voltage divider circuit includes: A first diode, the anode of which is connected to the input end of the voltage divider circuit; a first resistor, a first end of which is connected to the cathode of the first diode; a second resistor, a first end of which is connected to the second end of the first resistor, and a second end of which is connected to the output end of the voltage divider circuit; a third resistor, a first end of which is connected to the second end of the second resistor, and a second end of which is grounded; The first capacitor is connected in parallel with the third resistor.

4. The overheat detection circuit according to claim 3, characterized in that: The detection circuit also includes: The clamp circuit has an input end connected to the output end of the voltage divider circuit, and an output end used to connect to a power supply.

5. The overheat detection circuit according to claim 4, characterized in that: The clamping circuit comprises: The second diode has an anode connected to the input end of the clamping circuit and a cathode connected to the output end of the clamping circuit.

6. The overheat detection circuit according to claim 3, characterized in that: The detection circuit also includes: The first current limiting circuit has an input end connected to the output end of the voltage divider circuit, and an output end connected to the output end of the detection circuit.

7. The overheat detection circuit according to claim 6, characterized in that: The first current limiting circuit comprises: A fourth resistor has a first end connected to the input end of the first current limiting circuit, and a second end connected to the output end of the first current limiting circuit.

8. The overheat detection circuit according to claim 6, characterized in that: The detection circuit also includes: The filter circuit has an input end connected to the output end of the first current limiting circuit and an output end grounded.

9. The overheat detection circuit according to claim 8, characterized in that: The filtering circuit comprises: The second capacitor has a first plate connected to the input end of the filter circuit and a second plate connected to the output end of the filter circuit.

10. The overheat detection circuit according to claim 2, characterized in that: The load is a DC load, and the power supply circuit further includes: The AC-to-DC converter has an input end connected to the output end of the live wire and the output end of the neutral wire, and an output end connected to the load and the input end of the voltage divider circuit.

11. The overheat detection circuit according to claim 10, characterized in that: The voltage divider circuit comprises: a fifth resistor, a first end of which is connected to the input end of the voltage divider circuit, and a second end of which is connected to the output end of the voltage divider circuit; A sixth resistor has a first end connected to the second end of the fifth resistor and a second end grounded.

12. The overheat detection circuit according to claim 10, characterized in that: The detection circuit also includes: The second current limiting circuit has an input end connected to the output end of the voltage divider circuit, and an output end connected to the output end of the detection circuit.

13. The overheat detection circuit according to claim 12, characterized in that: The second current limiting circuit comprises: A seventh resistor has a first end connected to the input end of the second current limiting circuit, and a second end connected to the output end of the second current limiting circuit.

14. The overheat detection circuit according to claim 1, characterized in that: The power supply circuit also includes: An AC-to-DC converter, the input end of which is connected to the output end of the live wire and the output end of the neutral wire; the output end of which is connected to the power receiving end of the controller; or, The power supply circuit further includes: an AC-to-DC converter, the input end of which is connected to the output end of the live wire and the output end of the neutral wire; A DC-to-DC converter has an input end connected to the output end of the AC-to-DC converter, and an output end connected to the power receiving end of the controller.

15. The overheat detection circuit according to any one of claims 1 to 14, characterized in that: Also includes: The prompt device is connected to the controller and is used for issuing prompt information.

16. A household appliance, characterized in that: include: An overheat detection circuit as claimed in any one of claims 1 to 15; The plug has two pins, which are respectively connected to the input end of the live wire and the input end of the neutral wire, and the thermal circuit breaker and the protective resistor are both arranged in the plug.

17. The household appliance according to claim 16, characterized in that: The household appliance includes a heater, the load includes an AC load and / or a DC load, the AC load includes an AC fan and / or an AC heating element, and the DC load includes a DC fan and / or a DC heating element.

18. A method for detecting plug overheating, characterized in that: Applicable to the household appliance according to any one of claims 16 to 17, the detection method comprises: Powering on the household appliance; Controlling the load to run for a first preset time period; Acquiring the first detection signal when the load is running through the detection circuit; If the first detection signal is less than a first threshold signal, it is determined that the thermal circuit breaker is in an overheating circuit breaker state; If the first detection signal is equal to the first threshold signal, it is determined that the thermal circuit breaker is in the on state.

19. The detection method according to claim 18, characterized in that: Before the step of controlling the load to run for a first preset time, the method further includes: The household appliance is controlled to be in standby mode and maintained for a second preset time period.

20. The method for detecting plug overheating according to claim 18, characterized in that: After the step of determining that the thermal circuit breaker is in an overheated circuit breaker state, the method further includes: The load is controlled to stop working, and the prompt device is controlled to send out a first prompt message.

21. The method for detecting plug overheating according to claim 18, characterized in that: The first threshold signal is the voltage at which the load operates normally when the thermal circuit breaker is turned on and obtained by the controller through the detection circuit; or The first threshold signal is a first preset voltage.

22. The method for detecting plug overheating according to claim 18, characterized in that: Before the step of controlling the load to run for a first preset time, the method further includes: Acquiring a second detection signal when the load is in standby mode through the detection circuit; If the second detection signal is greater than or equal to a second threshold signal, executing the step of controlling the load to run for a first preset time period; If the second detection signal is less than a second threshold signal, controlling the prompt device to issue a second prompt message; Wherein, the second threshold signal is greater than the first threshold signal.

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