Refrigerator and overvoltage protection circuit

Abstract

The invention provides a refrigerator and an overvoltage protection circuit, belongs to the technical field of electronic circuits, and aims to solve the technical problem of how to carry out wrong voltage input prevention protection on the refrigerator. The overvoltage protection circuit of the refrigerator comprises a thermistor, a piezoresistor and an overvoltage protection module, the first end of the thermistor, the first end of the overvoltage protection module and the first end of the load are used for connecting the first end of a target power supply, the second end of the thermistor is connected with the first end of the piezoresistor, and the second end of the piezoresistor, the second end of the overvoltage protection module and the second end of the load are used for connecting the second end of the target power supply; when the output voltage of the target power supply enables the piezoresistor to break down and work, the voltage at the two ends of the thermistor is increased; when the voltage at the two ends of the thermistor is increased to the target voltage, the target power supply is short-circuited and stops supplying power to the load. The refrigerator is protected against error voltage input, and the use safety of the refrigerator is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of electronic circuits, and in particular to a refrigerator and an overvoltage protection circuit. Background Art

[0002] The refrigerator can be connected to the mains and use the mains as the power source for the refrigerator to perform cooling work. However, the grid voltage (that is, the voltage of the mains) varies in different regions. For example, the grid voltage in some regions is 220V AC, while the grid voltage in some regions is 110V AC.

[0003] If the grid voltage connected to the refrigerator does not match the voltage required for the refrigerator to work, the refrigerator will not work properly. For example, if the refrigerator requires a 110V power supply, if the refrigerator is connected to a 220V mains supply, the main control board or the entire machine will be damaged. In addition, during the production process of the refrigerator, the refrigerator needs to undergo a variety of tests. If the power supply is used incorrectly to test the refrigerator, the main control board or the entire machine will also be damaged. Therefore, it is crucial to protect the refrigerator power supply from incorrect voltage input. Summary of the invention

[0004] The embodiments of the present application provide a refrigerator and an overvoltage protection circuit, which can solve the technical problem of how to protect the refrigerator against erroneous voltage input.

[0005] In a first aspect, an embodiment of the present application provides a refrigerator, comprising:

[0006] A load, wherein the load is an electrical component of the refrigerator;

[0007] An overvoltage protection circuit, the overvoltage protection circuit comprising: a voltage response module, and an overvoltage protection module; the voltage response module comprises: a thermistor and a varistor;

[0008] The first end of the thermistor, the first end of the overvoltage protection module, and the first end of the load are used to connect to the first end of the target power supply, the second end of the thermistor is connected to the first end of the varistor, and the second end of the varistor, the second end of the overvoltage protection module, and the second end of the load are used to connect to the second end of the target power supply;

[0009] When the output voltage of the target power supply causes the varistor to break down and work, the voltage across the thermistor increases;

[0010] When the voltage across the thermistor increases to a target voltage, the overvoltage protection module short-circuits the first end of the target power source and the second end of the target power source;

[0011] When the first end of the target power source and the second end of the target power source are short-circuited, the target power source stops supplying power to the load.

[0012] In the refrigerator of this embodiment, when the output voltage of the target power supply connected to the refrigerator is too large, the varistor can break down and work, thereby increasing the voltage across the thermistor. When the voltage of the thermistor increases to the target voltage, the first end of the target power supply and the second end of the target power supply are short-circuited, so as to stop supplying power to the load of the refrigerator. The varistor can be used to sense whether the target power supply connected to the refrigerator is over-voltage, and the target power supply can be controlled to be short-circuited by the thermistor, so as to stop supplying power to the load when the voltage of the target power supply connected to the refrigerator is over-voltage, that is, to stop supplying power to the load in the case of overvoltage, thereby avoiding damage to the load due to overvoltage of the target power supply, and improving the safety of the refrigerator.

[0013] In some embodiments of the present application, the target power source is an AC mains power source, the first end of the target power source is a live wire connection end of the mains power source, the second end of the target power source is a neutral wire connection end of the mains power source, and the overvoltage protection module includes: a first switch unit;

[0014] The first end of the first switch unit constitutes the first end of the overvoltage protection module, the second end of the first switch unit constitutes the second end of the overvoltage protection module, and the third end of the first switch unit is connected to the second end of the thermistor;

[0015] The first switch unit is used for conducting the live wire connection end and the neutral wire connection end to short-circuit the live wire connection end and the neutral wire connection end when the voltage across the thermistor increases to the target voltage during the positive half cycle of the AC mains.

[0016] In the refrigerator of this embodiment, the first switch unit can turn on the live wire connection terminal and the neutral wire connection terminal of the target power supply when the voltage across the thermistor increases to the target voltage, thereby short-circuiting the target power supply. Therefore, the AC power cannot supply power to the load of the refrigerator, that is, when the voltage of the AC power connected to the refrigerator is over-voltage, the power supply to the load is stopped, thereby avoiding damage to the load due to overvoltage of the AC power connected to the refrigerator, that is, connecting to the wrong voltage, thereby improving the safety of the use of the refrigerator.

[0017] In some embodiments of the present application, the first switch unit includes: a first NPN transistor, a first PNP transistor, a first current limiting resistor, and a first pull-up resistor;

[0018] The first end of the first NPN transistor is connected to the live wire connection end through the first current limiting resistor, and the second end of the first NPN transistor is connected to the live wire connection end; the third end of the first NPN transistor is connected to the first end of the first PNP transistor;

[0019] The second end of the first PNP transistor is connected to the second end of the thermistor through the first pull-up resistor; the third end of the first PNP transistor is connected to the neutral line connection end;

[0020] In the positive half cycle of the AC mains, when the voltage across the thermistor increases to the target voltage, the first NPN transistor and the first PNP transistor are turned on, so that the live wire connection end and the neutral wire connection end are turned on.

[0021] The refrigerator of this embodiment, through the above-mentioned first NPN transistor and the first PNP transistor, can turn on the first NPN transistor when the voltage across the thermistor increases to the target voltage, thereby turning on the first PNP transistor, so that the target power supply is short-circuited, laying the foundation for stopping the power supply to the load when the target power supply is over-voltage. The first current limiting resistor and the first pull-up resistor ensure the safety of the operation of the first NPN transistor and the first PNP transistor in the first switch unit, thereby improving the safety of the refrigerator using the overvoltage protection circuit.

[0022] In some embodiments of the present application, the first switch unit further includes: a first pull-down resistor and a second current limiting resistor;

[0023] The first end of the first pull-down resistor is connected to the second end of the first NPN transistor; the second end of the first pull-down resistor is connected to the first end of the second current limiting resistor and the second end of the thermistor; the second end of the second current limiting resistor is connected to the third end of the first NPN transistor.

[0024] The refrigerator of this embodiment realizes the protection of the first NPN transistor and the first PNP transistor and other components in the first switch unit through the above-mentioned first pull-down resistor and the second current-limiting resistor, thereby improving the safety of overvoltage protection based on the first switch unit.

[0025] In some embodiments of the present application, the overvoltage protection module further includes: a second switch unit;

[0026] The first end of the second switch unit is connected to the live wire connection end, the second end of the second switch unit is connected to the first end of the thermistor, the third end of the second switch unit is connected to the second end of the thermistor, and the fourth end of the second switch unit is connected to the neutral wire connection end;

[0027] The second switch unit is used to conduct the live wire connection end and the neutral wire connection end to short-circuit the live wire connection end and the neutral wire connection end when the voltage across the thermistor increases to the target voltage during the negative half cycle of the AC mains.

[0028] The refrigerator of this embodiment can connect the live wire connection terminal and the neutral wire connection terminal of the target power supply through the second switch unit when the voltage across the thermistor increases to the target voltage during the negative half cycle of the AC mains, i.e., when the output voltage of the target power supply is overvoltage, so that the target power supply is short-circuited, thereby stopping power supply to the load. Therefore, the overvoltage protection of the load during the negative half cycle of the AC mains is achieved through the second switch unit.

[0029] In some embodiments of the present application, the second switch unit includes: a second NPN transistor, a second PNP transistor, a second pull-up resistor, and a second pull-down resistor;

[0030] The first end of the second PNP transistor is connected to the live wire connection end, the second end of the second PNP transistor is connected to the first end of the second pull-up resistor; the second end of the second pull-up resistor is connected to the first end of the second pull-down resistor and the first end of the thermistor; the third end of the second PNP transistor is connected to the first end of the second NPN transistor;

[0031] The second end of the second pull-down resistor and the second end of the second NPN transistor are connected to the second end of the thermistor, and the third end of the second NPN transistor is connected to the neutral line connection end;

[0032] In the negative half cycle of the AC mains, when the voltage across the thermistor increases to the target voltage, the second NPN transistor and the second PNP transistor are turned on, so that the live wire connection end and the neutral wire connection end are turned on.

[0033] The refrigerator of this embodiment, through the second NPN transistor and the second PNP transistor, can turn on the first NPN transistor when the voltage across the thermistor increases to the target voltage, thereby turning on the first PNP transistor, so that the target power supply is short-circuited, laying the foundation for stopping the load from being supplied with power in the negative half cycle of the AC mains when the target power supply is over-voltage. The second pull-up resistor and the second pull-down resistor ensure the safety of the operation of the second NPN transistor and the second PNP transistor in the second switch unit, thereby improving the safety of the refrigerator using the overvoltage protection circuit.

[0034] In some embodiments of the present application, the second switch unit further includes: a third current limiting resistor and a fourth current limiting resistor;

[0035] The third end of the second NPN transistor is connected to the neutral line connection end through the third current limiting resistor; the first end of the fourth current limiting resistor is connected to the third end of the second PNP transistor, and the second end of the fourth current limiting resistor is connected to the first end of the thermistor.

[0036] The refrigerator of this embodiment realizes the protection of components such as the second NPN transistor and the second PNP transistor in the second switch unit through the above-mentioned third current limiting resistor and the fourth current limiting resistor, thereby improving the safety of overvoltage protection based on the second switch unit in the negative half cycle of the AC mains.

[0037] In some embodiments of the present application, the overvoltage protection circuit further includes:

[0038] a prompt module, wherein a first end of the prompt module is connected to a first end of the target power source, and a second end of the prompt module is connected to a second end of the target power source;

[0039] The prompt module is used to output a prompt message when the output voltage of the target power supply fails to cause the varistor to break down and work; the prompt message is used to indicate that the output voltage of the target power supply does not exceed the voltage required for the refrigerator to work.

[0040] The refrigerator of this embodiment can output a prompt message to remind the user that the output voltage of the target power supply is normal through the prompt module when the output voltage of the target power supply is not over-voltage, so that the user can continue to use the target power supply to power the refrigerator, thereby improving the user experience.

[0041] In some embodiments of the present application, the prompt module includes: an indicator light and a fifth current limiting resistor;

[0042] The first end of the indicator light is connected to the first end of the target power supply through the fifth current limiting resistor, and the second end of the indicator light is connected to the second end of the target power supply;

[0043] The indicator light is used to light up when the output voltage of the target power supply fails to cause the varistor to break down and work, so as to output the prompt information.

[0044] In some embodiments of the present application, the refrigerator can output prompt information to the user that the output voltage of the target power supply is normal by lighting up an indicator light, so that the user can know that the output voltage of the target power supply is normal, thereby improving the user experience and reducing the complexity of the overvoltage protection circuit in outputting prompt information.

[0045] In a second aspect, the present application provides an overvoltage protection circuit, the overvoltage protection circuit comprising:

[0046] Voltage response module, and,overvoltage protection module;

[0047] The voltage response module includes: a thermistor and a varistor;

[0048] The first end of the thermistor and the first end of the overvoltage protection module are used to connect to the first end of the target power supply, the second end of the thermistor is connected to the first end of the varistor, and the second end of the varistor and the second end of the overvoltage protection module are used to connect to the second end of the target power supply; the first end of the overvoltage protection module is also connected to the first end of the load; the second end of the overvoltage protection module is also connected to the second end of the load;

[0049] When the output voltage of the target power supply causes the varistor to break down and work, the voltage across the thermistor increases;

[0050] When the voltage across the thermistor increases to a target voltage, the overvoltage protection module short-circuits the first end of the target power source and the second end of the target power source;

[0051] When the first end of the target power source and the second end of the target power source are short-circuited, the target power source stops supplying power to the load.

[0052] The refrigerator and overvoltage protection circuit provided by the present application can break down and work when the output voltage of the target power supply is too large, thereby increasing the voltage across the thermistor. When the voltage of the thermistor increases to the target voltage, the first end of the target power supply and the second end of the target power supply are short-circuited to stop supplying power to the load. The above-mentioned varistor can sense whether the target power supply is overvoltage, and the above-mentioned thermistor can control the short circuit of the target power supply to stop supplying power to the load when the voltage of the target power supply is overvoltage, that is, stop supplying power to the load in the case of overvoltage, avoid damage to the load due to overvoltage of the target power supply, and improve the safety of the use of electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the implementation methods in the embodiments of the present application or the related technologies, the following is a brief introduction to the drawings required for use in the embodiments or the related technology descriptions. Obviously, the drawings described below are some embodiments of the present application, and a person skilled in the art can also obtain other drawings based on these drawings.

[0054] Figure 1 This is a schematic diagram of the structure of a refrigerator according to an embodiment of the present application;

[0055] Figure 2 A schematic diagram of the structure of an overvoltage protection circuit 12 provided in the present application;

[0056] Figure 3 A schematic diagram of the structure of an overvoltage protection module 22 provided in this application;

[0057] Figure 4 A schematic diagram of the structure of a first switch unit 31 provided in the present application;

[0058] Figure 5 A schematic diagram of the structure of another first switch unit 31 provided in the present application;

[0059] Figure 6 A schematic diagram of the structure of another overvoltage protection module 22 provided in the present application;

[0060] Figure 7 A schematic diagram of the structure of a second switch unit 61 provided in the present application;

[0061] Figure 8 A structural schematic diagram of another overvoltage protection circuit 12 provided in the present application;

[0062] Fig. 9 A structural schematic diagram of another overvoltage protection circuit 12 provided in the present application;

[0063] Fig.10 Schematic diagram of the positive half-cycle and negative half-cycle of alternating current provided for this application. DETAILED DESCRIPTION

[0064] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0065] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and common meanings.

[0066] In addition, the terms "include" and "have" and any variations thereof are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to those components explicitly listed but may include other components not explicitly listed or inherent to such products or devices.

[0067] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0068] The terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third" may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0069] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0070] A refrigerator can be connected to the mains and use the mains as the power source for refrigeration. However, the grid voltage (that is, the voltage of the mains) varies in different regions. For example, the grid voltage in some regions is 220V AC, while the grid voltage in some regions is 110V AC. If the grid voltage connected to the refrigerator does not match the voltage required for the refrigerator to work, the refrigerator will not work properly. For example, if the power source required for the refrigerator to work is 110V, if the refrigerator is connected to the 220V mains, the main control board or the entire refrigerator will be damaged.

[0071] In addition, various related tests are also required during the production process of the refrigerator. There are usually multiple different power sources in the laboratory, such as alternating current (AC) 110V, AC220V, etc. If the wrong power supply is used, the main control board or the entire machine is at risk of damage.

[0072] Therefore, it is crucial to protect the refrigerator power supply against incorrect voltage input.

[0073] At present, the existing methods of preventing wrong voltage input protection mainly include adaptive switching, using electronic circuits and sensors and other components to automatically detect the input voltage and switch the power supply voltage according to the preset logic. However, this method requires the introduction of software control, which increases the software development requirements and debugging difficulty, leading to the complexity of refrigerator development and operation.

[0074] Considering the above problems existing in the existing refrigerators, the present application proposes an overvoltage protection circuit for overvoltage protection of the refrigerator load. The circuit can sense whether the output voltage of the target power supply connected to the refrigerator exceeds the voltage required for the operation of the refrigerator through a varistor, and control the target power supply through a thermistor to stop supplying power to the refrigerator load when the output voltage exceeds the voltage required for the operation of the refrigerator, thereby improving the safety of the refrigerator connected to the target power supply.

[0075] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0076] Figure 1 This is a schematic diagram of the structure of a refrigerator provided in this application. Figure 1 As shown, the refrigerator may include: a load 11 and an overvoltage protection circuit 12 .

[0077] The load 11 may be an electrical component of the refrigerator.

[0078] Exemplarily, the load 11 may be any electrical component of the refrigerator, which is not limited in the present application. For example, the load 11 may be a component such as a main control board of the refrigerator.

[0079] Figure 2 Schematic diagram of the structure of an overvoltage protection circuit 12 provided in this application. Figure 2 As shown, the overvoltage protection circuit 12 may include: a voltage response module 21 and an overvoltage protection module 22. The voltage response module 21 may include: a thermistor 23 and a varistor 24, for example.

[0080] The first end of the thermistor 23 and the first end of the overvoltage protection module 22 can be used to connect to the first end of the target power supply. The second end of the thermistor 23 can be connected to the first end of the varistor 24. The second end of the varistor 24 and the second end of the overvoltage protection module 22 can be used to connect to the second end of the target power supply.

[0081] The first end of the overvoltage protection module 22 is also connected to the first end of the load 11 , and the second end of the overvoltage protection module 22 is also connected to the second end of the load 11 .

[0082] Optionally, the overvoltage protection module 22 can be applied to the refrigerator described in any embodiment of the present application. Taking the overvoltage protection module 22 applied to the refrigerator as an example, the load 11 connected between the first end and the second end of the overvoltage protection module 22 can be the electrical component of the refrigerator mentioned above.

[0083] Alternatively, the overvoltage protection module 22 can also be applied to any electrical device other than a refrigerator, such as a smart TV, an air conditioner, a washing machine, a dishwasher, etc. Taking the application of the overvoltage protection module 22 to any electrical device as an example, the load 11 connected between the first end and the second end of the overvoltage protection module 22 can be any electrical component in the above-mentioned electrical device.

[0084] The following uses the overpressure protection module 22 applied to the refrigerator described in any embodiment of the present application as an example to exemplify the structure of the overpressure protection module 22.

[0085] Optionally, the thermistor 23 may be a positive temperature coefficient (PTC) thermistor. When the temperature of the thermistor 23 exceeds a certain temperature (Curie temperature), the resistance value of the thermistor 23 may increase as the temperature increases.

[0086] Optionally, the varistor 24 may be, for example, any existing resistor device having nonlinear volt-ampere characteristics. It should be understood that the present application does not limit the type of the varistor 24. For example, the resistor material of the varistor 24 may be a semiconductor. In some embodiments, the varistor 24 may be a zinc oxide (ZnO) varistor 24.

[0087] In some embodiments, when the voltage applied to the varistor 24 is lower than the breakdown threshold of the varistor 24, the current flowing through the varistor 24 is extremely small. Therefore, the varistor 24 is equivalent to a resistor with infinite resistance. At this time, it can also be said that the varistor 24 is not broken down. When the voltage applied to the varistor 24 exceeds the breakdown threshold of the varistor 24, the current flowing through the varistor 24 surges. Therefore, the varistor 24 is equivalent to a resistor with infinite resistance. At this time, it can also be said that the varistor 24 is broken down (or the varistor 24 is working in breakdown).

[0088] Optionally, the target power source may be any power source capable of providing AC power, such as a mains or an uninterruptible power supply (UPS), etc. The voltage of the AC power involved here may be, for example, 220V, 110V, etc., which is not limited.

[0089] When the output voltage of the target power source causes the varistor 24 to break down, the voltage across the thermistor 23 increases.

[0090] The output voltage of the target power supply may be, for example, the output voltage of the mains (or the grid voltage). Alternatively, the output voltage of the target power supply may be the output voltage of the UPS. In some embodiments, the output voltage of the target power supply may be, for example, alternating current.

[0091] When the voltage across the thermistor 23 increases to a target voltage, the overvoltage protection module 22 may short-circuit the first end of the target power source and the second end of the target power source.

[0092] The output voltage of the target power source causes the varistor 24 to break down, indicating that the output voltage of the target power source is too large, causing the varistor 24 to break down. For example, taking the load 11 as a main control board of a refrigerator as an example, assuming that the input voltage of the main control board is AC110V, if the current input voltage (i.e., the output voltage of the target power source) is AC220V, the varistor 24 breaks down, and the voltage on the target power source forms a loop through the thermistor 23 and the varistor 24. Taking the thermistor 23 as a positive temperature coefficient thermistor as an example, as the temperature of the thermistor 23 increases, the resistance value at both ends of the thermistor 23 increases, thereby increasing the voltage at both ends of the thermistor 23.

[0093] Exemplarily, the overvoltage protection module 22 may include a switch device, which may be turned on when the voltage across the thermistor 23 increases to a target voltage, thereby short-circuiting the first end of the target power supply and the second end of the target power supply.

[0094] When the first end of the target power source and the second end of the target power source are short-circuited, the target power source stops supplying power to the load 11 .

[0095] The output voltage of the target power supply causes the above-mentioned varistor 24 to break down, indicating that the output voltage of the target power supply is too large, and then the target power supply stops supplying power to the above-mentioned load 11, thereby stopping supplying power to the load 11 when the output voltage of the target power supply is too large, thereby avoiding damage to the load 11 caused by the output voltage of the target power supply being too large.

[0096] In this embodiment, when the output voltage of the target power supply connected to the refrigerator is too large, the varistor 24 can break down and work, thereby increasing the voltage across the thermistor 23. When the voltage of the thermistor 23 increases to the target voltage, the first end of the target power supply and the second end of the target power supply are short-circuited, so as to stop supplying power to the load 11 of the refrigerator. The varistor 24 can sense whether the target power supply connected to the refrigerator is over-voltage, and the thermistor 23 can control the target power supply to be short-circuited, so as to stop supplying power to the load 11 when the voltage of the target power supply connected to the refrigerator is over-voltage, that is, to stop supplying power to the load 11 in the over-voltage situation, thereby avoiding damage to the load 11 due to over-voltage of the target power supply, and improving the safety of the refrigerator.

[0097] The structure of the overvoltage protection module 22 is described in detail below:

[0098] Taking the target power source as AC mains as an example, as a possible implementation, the first end of the target power source may be a live wire connection end of the mains, and the second end of the target power source may be a neutral wire connection end of the mains.

[0099] Figure 3 Schematic diagram of the structure of an overvoltage protection module 22 provided in this application. Figure 3 As shown, the above-mentioned overvoltage protection module 22 may include, for example: a first switch unit 31 .

[0100] The first end of the first switch unit 31 may constitute the first end of the overvoltage protection module 22. The second end of the first switch unit 31 may constitute the second end of the overvoltage protection module 22. The third end of the first switch unit 31 may be connected to the second end of the thermistor 23.

[0101] The first switch unit 31 can be used to conduct the live wire connection terminal and the neutral wire connection terminal of the above-mentioned target power supply to short-circuit the live wire connection terminal and the neutral wire connection terminal when the voltage across the thermistor 23 increases to the target voltage during the positive half cycle of the AC mains.

[0102] Through the above method, the first switch unit 31 can turn on the live wire connection terminal and the neutral wire connection terminal of the target power supply when the voltage across the thermistor 23 increases to the target voltage, thereby short-circuiting the target power supply. Therefore, the AC power cannot supply power to the load 11 of the refrigerator, that is, when the voltage of the AC power connected to the refrigerator is over-voltage, the power supply to the load 11 is stopped, thereby avoiding damage to the load 11 due to the overvoltage of the AC power connected to the refrigerator, that is, the connection to the wrong voltage, thereby improving the safety of the use of the refrigerator.

[0103] Figure 4 Schematic diagram of the structure of a first switch unit 31 provided in this application. Figure 4As shown, in some embodiments, the above-mentioned first switch unit 31 may, for example, include: a first NPN (i.e., the abbreviation of negative-positive-negative) type transistor 41, a first PNP (i.e., the abbreviation of positive-negative-positive) type transistor 42, a first current limiting resistor 43 and a first pull-up resistor 44.

[0104] The first end of the first NPN transistor 41 can be connected to the live wire connection end through the first current limiting resistor 43. The second end of the first NPN transistor 41 can be connected to the live wire connection end. The third end of the first NPN transistor 41 can be connected to the first end of the first PNP transistor 42.

[0105] The second end of the first PNP transistor 42 may be connected to the second end of the thermistor 23 via the first pull-up resistor 44. The third end of the first PNP transistor 42 may be connected to the neutral line connection end.

[0106] In the positive half cycle of the above-mentioned AC mains, when the voltage across the thermistor 23 increases to the target voltage, the first NPN transistor 41 and the first PNP transistor 42 can be turned on to achieve conduction between the live wire connection terminal and the neutral wire connection terminal, thereby short-circuiting the target power supply and stopping power supply to the load 11.

[0107] Exemplarily, the first end of the first NPN transistor 41 can be, for example, the collector of the first NPN transistor 41, the second end of the first NPN transistor 41 can be, for example, the base of the first NPN transistor 41, and the third end of the first NPN transistor 41 can be, for example, the emitter of the first NPN transistor 41.

[0108] Exemplarily, the first end of the first PNP type transistor 42 can be, for example, the emitter of the first PNP type transistor 42, the second end of the first PNP type transistor 42 can be, for example, the base of the first PNP type transistor 42, and the third end of the first PNP type transistor 42 can be, for example, the collector of the first PNP type transistor 42.

[0109] In some embodiments, the first pull-up resistor 44 can clamp the uncertain signal at a high level through a resistor. In some embodiments, the first pull-up resistor 44 can also be used for current limiting.

[0110] By means of the first NPN transistor 41 and the first PNP transistor 42, when the voltage across the thermistor 23 increases to the target voltage, the first NPN transistor 41 is turned on, thereby turning on the first PNP transistor 42, so that the target power supply is short-circuited, laying a foundation for stopping the power supply to the load 11 when the target power supply is over-voltage. By means of the first current limiting resistor 43 and the first pull-up resistor 44, the safety of the operation of the first NPN transistor 41 and the first PNP transistor 42 in the first switch unit 31 is guaranteed, thereby improving the safety of the refrigerator using the overvoltage protection circuit 12.

[0111] Optionally, in some embodiments, the first switch unit 31 may further include, for example: a first pull-down resistor 51 and a second current-limiting resistor 52 .

[0112] For example, Figure 5 FIG. 3 is a schematic diagram of the structure of another first switch unit 31 provided in the present application. Figure 5 As shown, in some embodiments, the first end of the first pull-down resistor 51 can be connected to the second end of the first NPN transistor 41. The second end of the first pull-down resistor 51 can be connected to the first end of the second current limiting resistor 52 and the second end of the thermistor 23. The second end of the second current limiting resistor 52 can be connected to the third end of the first NPN transistor 41.

[0113] It should be understood that the present application does not limit the resistance values ​​of the first pull-up resistor 44 , the first pull-down resistor 51 , the first current-limiting resistor 43 , and the second current-limiting resistor 52 .

[0114] The first pull-down resistor 51 and the second current-limiting resistor 52 are used to protect the first NPN transistor 41 and the first PNP transistor 42 in the first switch unit 31 , thereby improving the safety of overvoltage protection based on the first switch unit 31 .

[0115] Figure 6 This is a schematic diagram of the structure of another overvoltage protection module 22 provided in this application. Figure 6 As shown, in some embodiments, the overvoltage protection module 22 may further include: a second switch unit 61 .

[0116] The first end of the second switch unit 61 can be connected to the live wire connection end of the target power supply. The second end of the second switch unit 61 can be connected to the first end of the thermistor 23. The third end of the second switch unit 61 can be connected to the second end of the thermistor 23. The fourth end of the second switch unit 61 can be connected to the neutral wire connection end of the target power supply.

[0117] The second switch unit 61 can be used to provide overvoltage protection for the load 11 during the negative half cycle of the AC mains.

[0118] For example, the second switch unit 61 can be used to conduct the live wire connection terminal and the neutral wire connection terminal of the target power supply to short-circuit the live wire connection terminal and the neutral wire connection terminal when the voltage across the thermistor 23 increases to the target voltage during the negative half cycle of the AC mains.

[0119] It should be understood that the present application does not limit the transmission mode of the positive half cycle and the negative half cycle of the AC mains.

[0120] Through the above method, in the negative half cycle of the AC mains, when the voltage across the thermistor 23 increases to the target voltage, that is, when the output voltage of the target power source is overvoltage, the live wire connection end and the neutral wire connection end of the target power source are turned on through the second switch unit 61, that is, the target power source is short-circuited, thereby stopping power supply to the load 11. Therefore, through the above second switch unit 61, overvoltage protection of the load 11 is achieved in the negative half cycle of the AC mains.

[0121] The structure of the second switch unit 61 is exemplarily described below:

[0122] Figure 7 Schematic diagram of the structure of a second switch unit 61 provided in this application. Figure 7 As shown, optionally, the second switch unit 61 may include, for example: a second NPN transistor 71 , a second PNP transistor 72 , a second pull-up resistor 73 and a second pull-down resistor 74 .

[0123] The first end of the second PNP transistor 72 can be connected to the live wire connection end, and the second end of the second PNP transistor 72 can be connected to the first end of the second pull-up resistor 73. The second end of the second pull-up resistor 73 can be connected to the first end of the second pull-down resistor 74 and the first end of the thermistor 23. The third end of the second PNP transistor 72 can be connected to the first end of the second NPN transistor 71.

[0124] The second end of the second pull-down resistor 74 and the second end of the second NPN transistor 71 may be connected to the second end of the thermistor 23. The third end of the second NPN transistor 71 may be connected to the neutral line connection end.

[0125] Exemplarily, the first end of the second PNP transistor 72 can be, for example, the collector of the second PNP transistor 72 , the second end of the second PNP transistor 72 can be, for example, the base of the second PNP transistor 72 , and the third end of the second PNP transistor 72 can be, for example, the emitter of the second PNP transistor 72 .

[0126] Exemplarily, the first end of the second NPN transistor 71 can be, for example, the emitter of the second NPN transistor 71, the second end of the second NPN transistor 71 can be, for example, the base of the second NPN transistor 71, and the third end of the second NPN transistor 71 can be, for example, the collector of the second NPN transistor 71.

[0127] In some embodiments, the second pull-up resistor 73 can clamp the uncertain signal at a high level through a resistor, and in some embodiments, the second pull-up resistor 73 can also be used for current limiting. The second pull-down resistor 74 can clamp the uncertain signal at a low level through a resistor, and in some embodiments, the second pull-down resistor 74 can also be used for current limiting.

[0128] In the negative half cycle of the AC mains, when the voltage across the thermistor 23 increases to the target voltage, the second NPN transistor 71 and the second PNP transistor 72 can be turned on, so that the live wire connection end and the neutral wire connection end of the target power supply are connected. When the live wire connection end and the neutral wire connection end of the target power supply are connected, the live wire connection end and the neutral wire connection end of the target power supply are short-circuited, and the target power supply cannot supply power to the load 11.

[0129] By means of the second NPN transistor 71 and the second PNP transistor 72, when the voltage across the thermistor 23 increases to the target voltage, the first NPN transistor 41 is turned on, thereby turning on the first PNP transistor 42, so that the target power supply is short-circuited, which lays the foundation for stopping the power supply to the load 11 in the negative half cycle of the AC mains when the target power supply is over-voltage. The second pull-up resistor 73 and the second pull-down resistor 74 ensure the safety of the operation of the second NPN transistor 71 and the second PNP transistor 72 in the second switch unit 61, thereby improving the safety of the refrigerator using the overvoltage protection circuit 12.

[0130] Optionally, in some embodiments, the second switch unit 61 may further include, for example: a third current limiting resistor and a fourth current limiting resistor.

[0131] The third end of the second NPN transistor 71 can be connected to the zero line connection end through the third current limiting resistor. The first end of the fourth current limiting resistor can be connected to the third end of the second PNP transistor 72. The second end of the fourth current limiting resistor can be connected to the first end of the thermistor 23.

[0132] It should be understood that the present application does not limit the resistance values ​​of the second pull-up resistor 73 , the second pull-down resistor 74 , the third current-limiting resistor, and the fourth current-limiting resistor.

[0133] Through the above-mentioned third current limiting resistor and fourth current limiting resistor, protection of components such as the second NPN transistor 71 and the second PNP transistor 72 in the second switch unit 61 is achieved, thereby improving the safety of overvoltage protection based on the second switch unit 61 in the negative half cycle of the AC mains.

[0134] As a possible implementation manner, the overvoltage protection circuit 12 may further include, for example: a prompt module.

[0135] The first end of the prompt module may be connected to the first end of the target power supply, for example. The second end of the prompt module may be connected to the second end of the target power supply, for example.

[0136] The prompt module can be used to output prompt information when the output voltage of the target power source fails to cause the varistor 24 to break down and operate, that is, when the output voltage of the target power source is not over-voltage.

[0137] The prompt information can be used to indicate that the output voltage of the target power supply does not exceed the voltage required for the refrigerator to work, that is, the output voltage of the target power supply is normal.

[0138] Through the prompt module, when the output voltage of the target power supply is not over-voltage, prompt information for prompting the user that the output voltage of the target power supply is normal can be output, so that the user can continue to use the target power supply to power the refrigerator, thereby improving the user experience.

[0139] In some embodiments, the prompt module may include an indicator light, that is, the refrigerator may indicate whether the output voltage of the target power supply is over-voltage by the indicator light.

[0140] For example, the prompt module may include: an indicator light and a fifth current limiting resistor.

[0141] The first end of the indicator light may be connected to the first end of the target power source via a fifth current limiting resistor, and the second end of the indicator light may be connected to the second end of the target power source.

[0142] The indicator light can be used to light up when the output voltage of the target power supply fails to cause the varistor 24 to break down, that is, when the output voltage of the target power supply is not over-voltage, the above prompt information is output.

[0143] Through the above method, the refrigerator can output a prompt message to the user that the output voltage of the target power supply is normal by lighting up the indicator light, so that the user can know that the output voltage of the target power supply is normal, which improves the user experience and reduces the complexity of the overvoltage protection circuit 12 in outputting the prompt information.

[0144] For example, Figure 8FIG. 1 is a structural diagram of another overvoltage protection circuit 12 provided in the present application. Figure 8 As shown, the overvoltage protection circuit 12 may include, for example: an indication circuit, a transistor control circuit and a protection circuit. The indication circuit is the aforementioned prompt module. The transistor control circuit may refer to the aforementioned overvoltage protection module 22. The protection circuit may refer to the aforementioned voltage response module 21. L represents the live wire connection end of the mains, and N represents the neutral wire connection end of the mains.

[0145] Fig. 9 FIG. 1 is a structural diagram of another overvoltage protection circuit 12 provided in the present application. Fig. 9 As shown, the indicating circuit may include a resistor R7 (the fifth current resistor mentioned above) and an indicator light LED1.

[0146] The transistor control circuit includes: transistor P2 (the above-mentioned second PNP transistor 72), transistor N2 (the above-mentioned second NPN transistor 71), transistor N1 (the above-mentioned first NPN transistor 41), transistor P1 (the above-mentioned first PNP transistor 42), resistor R11 (second pull-up resistor 73), resistor R4 (second pull-down resistor 74), resistor R10 (fourth current limiting resistor), resistor R3 (third current limiting resistor), resistor R2 (first current limiting resistor 43), resistor R1 (first pull-down resistor 51), resistor R8 (second current limiting resistor 52), and resistor R9 (first pull-up resistor 44).

[0147] The protection circuit includes: a thermistor 23PTC1 and a varistor 24RV1.

[0148] Based on Fig. 9 The overvoltage protection circuit 12 shown, Fig.10 Schematic diagram of the positive half-cycle and negative half-cycle of alternating current provided in this application. The direction of the solid arrow is the direction of the positive half-cycle of alternating current, and the direction of the dotted arrow is the direction of the negative half-cycle of alternating current.

[0149] Taking the positive half cycle of alternating current as an example, the voltage at point L is greater than the voltage at point N, and the voltage path is a solid line.

[0150] 1. When the input voltage is correct, such as the input voltage of the refrigerator main control board is designed to be AC110V, and the current input voltage is also AC110V, RV1 (for example, the body diameter is 14mm, and the working voltage is 270V effective value) does not work. Then the voltage across PTC1 is 0, so that both transistors N1 and N2 cannot meet the emitter junction conduction voltage and do not work.

[0151] At this time, R7 and LED1 between L and N form a circuit, and the indicator light lights up, indicating that the current power supply voltage is correct.

[0152] 2. When the input voltage is wrong, such as the input voltage of the main control board is designed to be AC110V, and the current input voltage is AC220V. At this time, RV1 breaks down and the voltage on L flows back to N (neutral connection end) through PTC and RV1 to form a loop. Taking thermistor 23PTC1 as an example, which is a positive temperature coefficient thermistor, as the temperature of the body increases, the resistance at both ends increases, and then the voltage at both ends of PTC increases. When the voltage at both ends of R1, that is, the voltage between point C and point D, is greater than 0.7V (emitter junction voltage), the voltage at both ends of transistors N1 and P1 is 0, causing L and N to short-circuit. At this time, the external power supply device trips, and the main control board cannot be powered on and is protected. At this time, there is a short circuit between L and N, there is no voltage, R7 and LED1 cannot form a loop, and the indicator light is off, indicating that the power supply voltage is wrong.

[0153] In the negative half cycle of the alternating current, the voltage at point L is less than the voltage at point N, and the voltage path is a dotted line. The working mode of the overvoltage protection can refer to the positive half cycle mentioned above as an example, which will not be repeated here.

[0154] In this embodiment, by combining the varistor 24 and the PTC resistor, the voltage of the refrigerator main control board is protected from wrong power supply by controlling the conduction of the transistor, so as to avoid the problem of damage to the components of the main control board due to the wrong voltage, that is, the voltage of the power supply is over-voltage in the case of operation error, thereby improving the safety and service life of the refrigerator. In addition, the overvoltage protection circuit 12 provided by the present application only needs to add a few electronic components, and the number of components used is small, thereby reducing the difficulty of debugging the refrigerator hard circuit, reducing the complexity of the refrigerator structure, and no software participation is required, reducing the complexity of code maintenance and main control board design.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0156] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A refrigerator, characterized in that: include: A load, wherein the load is an electrical component of the refrigerator; An overvoltage protection circuit, the overvoltage protection circuit comprising: a voltage response module, and an overvoltage protection module; the voltage response module comprises: a thermistor and a varistor; The first end of the thermistor, the first end of the overvoltage protection module, and the first end of the load are used to connect to the first end of the target power supply, the second end of the thermistor is connected to the first end of the varistor, and the second end of the varistor, the second end of the overvoltage protection module, and the second end of the load are used to connect to the second end of the target power supply; When the output voltage of the target power supply causes the varistor to break down and work, the voltage across the thermistor increases; When the voltage across the thermistor increases to a target voltage, the overvoltage protection module short-circuits the first end of the target power source and the second end of the target power source; When the first end of the target power source and the second end of the target power source are short-circuited, the target power source stops supplying power to the load.

2. The refrigerator according to claim 1, characterized in that: The target power source is an alternating current mains power source, the first end of the target power source is a live wire connection end of the mains power source, the second end of the target power source is a neutral wire connection end of the mains power source, and the overvoltage protection module includes: a first switch unit; The first end of the first switch unit constitutes the first end of the overvoltage protection module, the second end of the first switch unit constitutes the second end of the overvoltage protection module, and the third end of the first switch unit is connected to the second end of the thermistor; The first switch unit is used for conducting the live wire connection end and the neutral wire connection end to short-circuit the live wire connection end and the neutral wire connection end when the voltage across the thermistor increases to the target voltage during the positive half cycle of the AC mains.

3. The refrigerator according to claim 2, characterized in that: The first switch unit includes: a first NPN transistor, a first PNP transistor, a first current limiting resistor, and a first pull-up resistor; The first end of the first NPN transistor is connected to the live wire connection end through the first current limiting resistor, and the second end of the first NPN transistor is connected to the live wire connection end; the third end of the first NPN transistor is connected to the first end of the first PNP transistor; The second end of the first PNP transistor is connected to the second end of the thermistor through the first pull-up resistor; the third end of the first PNP transistor is connected to the neutral line connection end; In the positive half cycle of the AC mains, when the voltage across the thermistor increases to the target voltage, the first NPN transistor and the first PNP transistor are turned on, so that the live wire connection end and the neutral wire connection end are turned on.

4. The refrigerator according to claim 3, characterized in that: The first switch unit further includes: a first pull-down resistor and a second current limiting resistor; The first end of the first pull-down resistor is connected to the second end of the first NPN transistor; the second end of the first pull-down resistor is connected to the first end of the second current limiting resistor and the second end of the thermistor; the second end of the second current limiting resistor is connected to the third end of the first NPN transistor.

5. The refrigerator according to any one of claims 2 to 4, characterized in that: The overvoltage protection module further includes: a second switch unit; The first end of the second switch unit is connected to the live wire connection end, the second end of the second switch unit is connected to the first end of the thermistor, the third end of the second switch unit is connected to the second end of the thermistor, and the fourth end of the second switch unit is connected to the neutral wire connection end; The second switch unit is used to conduct the live wire connection end and the neutral wire connection end to short-circuit the live wire connection end and the neutral wire connection end when the voltage across the thermistor increases to the target voltage during the negative half cycle of the AC mains.

6. The refrigerator according to claim 5, characterized in that: The second switch unit includes: a second NPN transistor, a second PNP transistor, a second pull-up resistor, and a second pull-down resistor; The first end of the second PNP transistor is connected to the live wire connection end, the second end of the second PNP transistor is connected to the first end of the second pull-up resistor; the second end of the second pull-up resistor is connected to the first end of the second pull-down resistor and the first end of the thermistor; the third end of the second PNP transistor is connected to the first end of the second NPN transistor; The second end of the second pull-down resistor and the second end of the second NPN transistor are connected to the second end of the thermistor, and the third end of the second NPN transistor is connected to the neutral line connection end; In the negative half cycle of the AC mains, when the voltage across the thermistor increases to the target voltage, the second NPN transistor and the second PNP transistor are turned on, so that the live wire connection end and the neutral wire connection end are turned on.

7. The refrigerator according to claim 6, characterized in that: The second switch unit further includes: a third current limiting resistor and a fourth current limiting resistor; The third end of the second NPN transistor is connected to the neutral line connection end through the third current limiting resistor; the first end of the fourth current limiting resistor is connected to the third end of the second PNP transistor, and the second end of the fourth current limiting resistor is connected to the first end of the thermistor.

8. The refrigerator according to any one of claims 1 to 4, characterized in that: The overvoltage protection circuit further includes: a prompt module, wherein a first end of the prompt module is connected to a first end of the target power source, and a second end of the prompt module is connected to a second end of the target power source; The prompt module is used to output a prompt message when the output voltage of the target power supply fails to cause the varistor to break down and work; the prompt message is used to indicate that the output voltage of the target power supply does not exceed the voltage required for the refrigerator to work.

9. The refrigerator according to claim 8, characterized in that: The prompt module includes: an indicator light and a fifth current limiting resistor; The first end of the indicator light is connected to the first end of the target power supply through the fifth current limiting resistor, and the second end of the indicator light is connected to the second end of the target power supply; The indicator light is used to light up when the output voltage of the target power supply fails to cause the varistor to break down and work, so as to output the prompt information.

10. An overvoltage protection circuit, characterized in that: The overvoltage protection circuit comprises: Voltage response module, and,overvoltage protection module; The voltage response module includes: a thermistor and a varistor; The first end of the thermistor and the first end of the overvoltage protection module are used to connect to the first end of the target power supply, the second end of the thermistor is connected to the first end of the varistor, and the second end of the varistor and the second end of the overvoltage protection module are used to connect to the second end of the target power supply; the first end of the overvoltage protection module is also connected to the first end of the load; the second end of the overvoltage protection module is also connected to the second end of the load; When the output voltage of the target power supply causes the varistor to break down and work, the voltage across the thermistor increases; When the voltage across the thermistor increases to a target voltage, the overvoltage protection module short-circuits the first end of the target power source and the second end of the target power source; When the first end of the target power source and the second end of the target power source are short-circuited, the target power source stops supplying power to the load.

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