Over-current and over-voltage protection circuit and household electrical appliance

Abstract

The invention belongs to the technical field of household appliances, and particularly relates to an overcurrent and overvoltage protection circuit and a household appliance, the overcurrent and overvoltage protection circuit comprises a controller, an overvoltage protection module and an overcurrent protection module, the overvoltage protection module comprises a first comparator, and the first comparator comprises a positive input end, a negative input end and an output end; the positive input end of the first comparator inputs a threshold voltage signal, the negative input end of the first comparator inputs a to-be-detected voltage signal, and the overvoltage protection module is used for comparing the to-be-detected voltage signal with the threshold voltage signal and outputting a first comparison signal; the over-current protection module comprises an input end and an output end, the over-current protection module is connected with the output end of the first comparator, the output end of the over-current protection module is connected with the input end of the controller, and the over-current protection module is used for outputting a protection signal executed by the tested circuit to the controller according to the sampling current in the tested circuit and the first comparison signal. According to the scheme, the input / output interface (I / O) of the controller can be saved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of household appliances, and particularly relates to an overcurrent and overvoltage protection circuit and a household appliance. BACKGROUND

[0002] The overcurrent and overvoltage protection function is an important function in circuit design, which can protect key devices, prevent device damage, and even smoke and fire in the case of circuit failure, abnormal software control, abnormal input power supply, and interference.

[0003] Generally, the variable frequency motor load circuit needs to detect whether the bus voltage is overvoltage and whether the bus voltage is overcurrent. The motor needs to be turned off in time when the overvoltage or overcurrent signal appears.

[0004] At present, the existing overvoltage protection and overcurrent protection usually deliver two separate protection fault signals to the controller, which needs to occupy two input and output interfaces of the controller, and too many interfaces are occupied. SUMMARY

[0005] The application aims to provide an overcurrent and overvoltage protection circuit and a household appliance, so that the overcurrent and overvoltage protection circuit occupies the same input and output interface of the controller.

[0006] The application provides an overcurrent and overvoltage protection circuit in the first aspect, which comprises:

[0007] a controller;

[0008] an overvoltage protection module, the overvoltage protection module comprising a first comparator, the first comparator comprising a positive input end, a negative input end and an output end, the positive input end of the first comparator inputting a threshold voltage signal, the negative input end of the first comparator inputting a to-be-detected voltage signal, the overvoltage protection module being configured to compare the to-be-detected voltage signal with the threshold voltage signal and output a first comparison signal;

[0009] an overcurrent protection module, the overcurrent protection module comprising an input end and an output end, the overcurrent protection module being connected with the output end of the first comparator, the output end of the overcurrent protection module being connected with an input end of the controller, and the overcurrent protection module being configured to output a protection signal executed by a to-be-detected circuit to the controller according to a sampling current in the to-be-detected circuit and the first comparison signal.

[0010] In an exemplary embodiment of the application, the controller can output the protection signal executed by the to-be-detected circuit when the overcurrent protection module outputs a low-level signal.

[0011] In an exemplary embodiment of the application, the overcurrent protection module comprises:

[0012] a first resistor, a first end of the first resistor being connected to a first node with an output end of the first comparator;

[0013] a second resistor, a first end of the second resistor being connected to a second end of the first resistor with the second node, a second end of the second resistor being connected to a first end of a sampling resistor, the sampling resistor being connected in series in a circuit to be measured, a current in the sampling resistor flowing from the first end of the sampling resistor to a second end of the sampling resistor;

[0014] a third resistor, a first end of the third resistor being connected to the first node;

[0015] a fourth resistor, a first end of the fourth resistor being connected to a second end of the third resistor with a third node, a second end of the fourth resistor being connected to the second end of the sampling resistor;

[0016] a second comparator, a positive input end of the second comparator being connected to the second node, a negative input end of the second comparator being connected to the third node, an output end of the second comparator being connected to an input end of the controller.

[0017] In an exemplary embodiment of the present application, a voltage at an end of the sampling resistor connected with the fourth resistor is V R5+ ;

[0018] a voltage at an end of the sampling resistor connected with the second resistor is V R5- ;

[0019] a voltage at an end of the first resistor and the second resistor is V C+ ;

[0020] a voltage at an end of the third resistor and the fourth resistor is V C- ;

[0021] wherein, when the second comparator outputs a high level signal, a voltage in the overcurrent module satisfies the following formula: V R5- + V C+ > V R5+ + V C- ;

[0022] when the second comparator outputs a low level signal, a voltage in the overcurrent module satisfies the following formula: V R5- + V C+ ≤ V R5+ + V C- .

[0023] In an exemplary embodiment of the present application, a current flowing through the sampling resistor is IR5 a current value I flowing through the sampling resistor R5 satisfies the following formula:

[0024] wherein I R5 is a current value flowing through the sampling resistor, V R5+ is a voltage at one end of the sampling resistor connected with the fourth resistor, V R5- is a voltage at one end of the sampling resistor connected with the second resistor, and R5 is a resistance value of the sampling resistor.

[0025] In an exemplary embodiment of the present application, when the signal outputted by the output end of the second comparator is a high level signal, the current value I R5 satisfies the following formula:

[0026] wherein I R5 is a current value flowing through the sampling resistor, V C+ is a positive bias voltage of the second comparator obtained by voltage division of the first resistor and the second resistor, V C- is a negative bias voltage of the second comparator obtained by voltage division of the third resistor and the fourth resistor, and R5 is a resistance value of the sampling resistor.

[0027] When the signal outputted by the output end of the first comparator is a low level signal, the current value of the sampling resistor satisfies the following formula:

[0028] wherein I R5 is a current value flowing through the sampling resistor, V C+ is a positive bias voltage of the second comparator obtained by voltage division of the first resistor and the second resistor, V C- is a negative bias voltage of the second comparator obtained by voltage division of the third resistor and the fourth resistor, and R5 is a resistance value of the sampling resistor.

[0029] In an exemplary embodiment of the present application, when the overvoltage protection module outputs a low level signal, the current threshold value of the overcurrent protection module is zero.

[0030] In an exemplary embodiment of the present application, when the overvoltage protection module outputs a high level signal, the current threshold value of the overcurrent protection module corresponds to the resistance values of the first resistor, the second resistor, the third resistor and the fourth resistor.

[0031] In an exemplary embodiment of the present application, the overvoltage protection module further comprises:

[0032] A fifth resistor, a first end of the fifth resistor inputs the level signal, and a second end of the fifth resistor is connected to the positive input end of the first comparator at a fourth node;

[0033] A sixth resistor, a first end of the sixth resistor is connected to the fourth node, and a second end of the sixth resistor is grounded.

[0034] The second aspect of the present application provides a household appliance, the household appliance comprising:

[0035] A rectifier module connected to an alternating current power supply, for converting alternating current provided by the alternating current power supply into direct current;

[0036] A switching device, a first end of the switching device is connected to a first output end of the rectifier module through an inductive device, and a second end of the switching device is connected to a second output end of the rectifier module through a sampling resistor;

[0037] A load circuit, the load circuit comprising a capacitor, a first end of the capacitor is connected to the first end of the switching device and a first end of the inductive device, and a second end of the capacitor is connected to the first end of the switching device and a first end of the sampling resistor; and

[0038] The overcurrent and overvoltage protection circuit according to any one of the preceding aspects, a first end of an overcurrent protection module in the overcurrent and overvoltage protection circuit is connected to the first end of the sampling resistor, and a second end of the overcurrent protection module is connected to the second end of the sampling resistor; a first end of an overvoltage protection module is connected to the first end of the capacitor, and a second end of the overvoltage protection module is connected to the second end of the capacitor; and the controller is configured to perform overcurrent and overvoltage protection operations on the load circuit according to a protection signal output by the overcurrent protection module and executed on the measured circuit.

[0039] The overcurrent and overvoltage protection circuit and the household appliance provided in the present application have at least the following beneficial effects:

[0040] The application scheme comprises an overcurrent and overvoltage protection circuit, which comprises a controller, an overvoltage protection module and an overcurrent protection module. The overvoltage protection module comprises a first comparator, a threshold voltage signal is input to the positive input end of the first comparator, and a to-be-measured voltage signal is input to the negative input end of the first comparator. The to-be-measured voltage signal is compared with the threshold voltage signal to obtain a first comparison signal, and the first comparison signal is input to the overcurrent protection module. The overcurrent protection module is used for outputting a protection signal executed by the to-be-measured circuit according to the current adopted in the to-be-measured circuit and the first comparison signal, and inputting the protection signal executed by the to-be-measured circuit to the controller. The controller controls the overcurrent and overvoltage protection of the load circuit according to the protection signal executed by the to-be-measured circuit. The first comparison signal is output to the input end of the overcurrent protection circuit. When an overvoltage fault occurs, the overcurrent protection circuit outputs the protection signal executed by the to-be-measured circuit to the controller to perform overvoltage protection on the to-be-measured circuit. When an overcurrent fault occurs, the overcurrent protection circuit outputs the protection signal executed by the to-be-measured circuit to the controller. The overvoltage protection and the overcurrent protection are combined, and the overcurrent and overvoltage protection only occupies one input and output interface (I / O) of the controller, thereby saving the input and output interface (I / O) of the controller.

[0041] Other features and advantages of the present application will become apparent from the following detailed description, or will be learned by practice of the present application.

[0042] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the present application. BRIEF DESCRIPTION OF DRAWINGS

[0043] The drawings incorporated into the specification and forming a part thereof illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0044] Figure 1 A circuit structure schematic diagram of an overcurrent and overvoltage protection circuit provided by an embodiment of the present application is shown;

[0045] Figure 2 A structure schematic diagram of connection of a rectifier module, a switching device, a load circuit, a sampling resistor and an overcurrent and overvoltage protection circuit provided by an embodiment of the present application is shown.

[0046] Explanation of reference signs:

[0047] 100, overcurrent overvoltage protection circuit; 110, controller; 120, overvoltage protection module; 121, first comparator; 122, fifth resistor; 123, sixth resistor; 124, fourth node; 130, overcurrent protection module; 131, first resistor; 132, second resistor; 133, third resistor; 134, fourth resistor; 135, second comparator; 136, first node; 137, second node; 138, third node;

[0048] 200, sampling resistor; 300, rectifier module; 400, switching device; 500, load circuit; 510, capacitor;

[0049] V1, first comparison signal; V R5+ , voltage at one end of the sampling resistor and the fourth resistor; V R5- , voltage at one end of the sampling resistor and the second resistor; V C+ , positive bias voltage of the second comparator obtained by voltage division of the first resistor and the second resistor; V C- , negative bias voltage of the second comparator obtained by voltage division of the third resistor and the fourth resistor; I R5 , sampling resistor current value; R5, sampling resistor resistance value. DETAILED DESCRIPTION

[0050] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example implementations to those skilled in the art.

[0051] In the present application, the terms "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0052] In the present application, unless otherwise explicitly specified and limited, the terms "assembly", "connection" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0053] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the application can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.

[0054] The load circuit 500 of the variable frequency motor needs the overcurrent and overvoltage protection circuit 100 to avoid damage to the load circuit 500 when the current and voltage are too large. The existing overcurrent and overvoltage protection is usually a single independent protection circuit, which occupies two input and output interfaces (I / O) of the controller 110 respectively, and too many input and output interfaces (I / O) of the controller 110 are occupied.

[0055] Therefore, the embodiment of the application provides an overcurrent and overvoltage protection circuit 100, which only occupies one input and output interface (I / O) of the controller 110, and can realize double protection of overcurrent and overvoltage of the load circuit 500, thereby saving the input and output interface (I / O) of the controller 110.

[0056] The overcurrent and overvoltage protection circuit 100 comprises a controller 110, the controller 110 comprises a plurality of input and output interfaces (I / O), and the controller 110 can adjust itself or perform a protection action according to a protection signal output by the overcurrent protection module 130.

[0057] The overcurrent and overvoltage protection circuit 100 further comprises an overvoltage protection module 120, the overvoltage protection module 120 comprises a first comparator 121, the first comparator 121 comprises a positive input end, a negative input end and an output end, the threshold voltage signal is input to the positive input end of the first comparator 121, the voltage to be measured is input to the negative input end of the first comparator 121, and the overvoltage protection module 120 is used for comparing the voltage to be measured with the threshold voltage signal and outputting a first comparison signal. When the voltage to be measured exceeds the threshold voltage signal, the first comparison signal output by the first comparator 121 is a low voltage; otherwise, when the voltage to be measured is less than or equal to the threshold voltage signal, the first comparison signal output by the first comparator 121 is a high voltage.

[0058] The overcurrent overvoltage protection circuit 100 further comprises an overcurrent protection module 130, the overcurrent protection module 130 comprises an input end and an output end, the overcurrent protection module 130 is connected with the output end of the first comparator 121, and the overcurrent protection module 130 is used for receiving the first comparison signal output by the first comparator 121; the output end of the overcurrent protection module 130 is connected with the input end of the controller 110, and the overcurrent protection module 130 is used for outputting the protection signal executed by the measured circuit to the controller 110 according to the sampling current in the measured circuit and the first comparison signal output by the first comparator 121.

[0059] The overcurrent overvoltage protection circuit 100 comprises the controller 110, the overvoltage protection module 120 and the overcurrent protection module 130, the overcurrent protection module 130 outputs the protection signal executed by the measured circuit to the controller 110 according to the obtained sampling current and the first comparison signal output by the overvoltage protection module 120, and the controller 110 makes the overcurrent and / or overvoltage protection signal to protect the load circuit 500. That is, the overvoltage protection module 120 can output the overvoltage fault signal to the overcurrent protection module 130, the overvoltage fault output is triggered when the overvoltage fault occurs, and the overcurrent fault signal is also triggered when the overcurrent fault occurs, so that the overcurrent overvoltage fault is combined, and the input and output interfaces (I / O) of control are saved.

[0060] The controller 110 is configured to output the protection signal executed by the measured circuit when the overcurrent protection module 130 outputs a low-level signal. That is, when the overcurrent protection module 130 outputs a low-level signal to the controller 110, the controller 110 will execute the protection signal executed by the measured circuit to protect the load circuit 500 from overcurrent and / or overvoltage.

[0061] The overcurrent protection module 130 comprises a first resistor 131, a first end of the first resistor 131 is connected with the output end of the first comparator 121 at a first node 136.

[0062] The overcurrent protection module 130 comprises a second resistor 132, a first end of the second resistor 132 is connected with a second end of the first resistor 131 at a second node 137, and a second end of the second resistor 132 is connected with a first end of a sampling resistor 200, the sampling resistor 200 is connected in series in the measured circuit, and the current in the sampling resistor 200 flows from the first end of the sampling resistor 200 to the second end of the sampling resistor 200.

[0063] The overcurrent protection module 130 comprises a third resistor 133, a first end of the third resistor 133 is connected with the first node 136. That is, the first resistor 131, the output end of the first comparator 121 and the third resistor 133 converge at the first node 136, and the voltage of the output end of the first comparator 121 is output to the first resistor 131 and the third resistor 133 respectively.

[0064] The over-current protection module 130 comprises a fourth resistor 134, a first end of the fourth resistor 134 is connected to the second end of the third resistor 133 at a third node 138, and a second end of the fourth resistor 134 is connected to the second end of the sampling resistor 200.

[0065] The over-current protection module 130 comprises a second comparator 135, a positive input end of the second comparator 135 is connected to the second node 137, i.e. the positive input end of the second comparator 135, the second end of the first resistor 131 and the first end of the second resistor 132 are connected to the second node 137; a negative input end of the second comparator 135 is connected to the third node 138, i.e. the negative input end of the second comparator 135, the second end of the third resistor 133 and the first end of the fourth resistor 134 are connected to the third node 138; an output end of the second comparator 135 is connected to an input end of the controller 110, i.e. the over-voltage protection module 120 is connected to an input / output interface (I / O) of the controller 110 through the over-current protection module 130, which saves the interface of the controller 110 occupied by the over-voltage protection module 120, so that the over-voltage protection module 120 and the over-current protection module 130 only occupy one input / output interface (I / O) of the controller 110, and the over-current and over-voltage faults are combined.

[0066] When the second comparison signal outputs a low-level signal in the over-current protection module 130, the controller 110 triggers a protection action; otherwise, when the second comparison signal outputs a high-level signal, the controller 110 does not trigger a protection action. That is, the input / output interface (I / O) of the controller 110 is saved, but the over-current and over-voltage protection actions of the controller 110 are not affected, which can effectively ensure the protection of the load circuit 500.

[0067] When the second comparator 135 outputs a high-level signal, the voltage in the over-current module satisfies the following formula: V R5- +V C+ >V R5+ +V C- ; when the second comparator 135 outputs a low-level signal, the voltage in the over-current module satisfies the following formula: V R5- +V C+ ≤V R5+ +V C- . Wherein, the voltage at one end of the sampling resistor 200 and the fourth resistor 134 is V R5+ ; the voltage at one end of the sampling resistor 200 and the second resistor 132 is V R5- ; the positive bias voltage of the second comparator 135 obtained by voltage division of the first resistor 131 and the second resistor 132 is V C+ ; and the negative bias voltage of the second comparator 135 obtained by voltage division of the third resistor 133 and the fourth resistor 134 is V C- .

[0068] The overcurrent protection module 130 is used to collect the current value I of the sampling resistor 200. R5 and the collected current value I R5 The current value is compared with the preset current value, and the comparison signal is input to the controller 110. The controller 110 decides whether to perform the protection action based on the comparison signal.

[0069] The current flowing through the sampling resistor 200 is I. R5 The current value I flowing through the sampling resistor 200 R5 Satisfy the following formula:

[0070] Among them, I R5 V represents the current flowing through the sampling resistor 200Ω. R5+ V is the voltage at one end where the sampling resistor 200 is connected to the fourth resistor 134. R5- R5 is the voltage across the connection between sampling resistor 200 and second resistor 132, and R5 is the resistance value of sampling resistor 200.

[0071] When the output signal of the second comparator 135 is a high-level signal, the current value I of the sampling resistor 200 is... R5 Satisfy the following formula:

[0072] Among them, I R5 V represents the current flowing through the sampling resistor 200Ω. C+ The forward bias voltage of the second comparator 135 is obtained by dividing the voltage between the first resistor 131 and the second resistor 132. C- The negative bias voltage of the second comparator 135 is obtained by dividing the voltage of the third resistor 133 and the fourth resistor 134, and R5 is the resistance value of the sampling resistor 200.

[0073] When the output signal of the first comparator 121 is a low-level signal, the current value of the sampling resistor 200 satisfies the following formula:

[0074] Among them, I R5 V represents the current flowing through the sampling resistor 200Ω. C+ The forward bias voltage of the second comparator 135 is obtained by dividing the voltage between the first resistor 131 and the second resistor 132. C- The negative bias voltage of the second comparator 135 is obtained by dividing the voltage of the third resistor 133 and the fourth resistor 134, and R5 is the resistance value of the sampling resistor 200.

[0075] It is understandable that the forward bias voltage V of the second comparator 135 is obtained by adjusting the voltage divider of the first resistor 131 and the second resistor 132. C+and the third resistor 133 and the fourth resistor 134 to obtain a negative bias voltage V C- to adjust the over-current protection threshold, the first resistor 131 and the second resistor 132 to obtain a positive bias voltage V C+ and the third resistor 133 and the fourth resistor 134 to obtain a negative bias voltage V C- The first comparison signal output by the over-voltage protection module 120 controls. When the first comparison signal of the first comparator 121 of the over-voltage protection module 120 is a low-level signal, the first resistor 131 and the second resistor 132 to obtain a positive bias voltage V C+ and the third resistor 133 and the fourth resistor 134 to obtain a negative bias voltage V C- are all 0 volts; when the first comparison signal of the first comparator 121 of the over-voltage protection module 120 is a high-level signal, the first resistor 131 and the second resistor 132 to obtain a positive bias voltage V C+ and the third resistor 133 and the fourth resistor 134 to obtain a negative bias voltage V C- Controlled by the first resistor 131, the second resistor 132, the third resistor 133 and the fourth resistor 134; that is, the threshold current in the over-current protection module 130 is controlled by the first resistor 131, the second resistor 132, the third resistor 133 and the fourth resistor 134.

[0076] Wherein, when the over-voltage protection module 120 outputs a low-level signal, the current threshold in the over-current protection module 130 is zero. That is, as long as there is any size of current flowing from the sampling resistor 200, the over-current protection module 130 will output a protection signal to the controller 110 executed by the measured circuit, so that the controller 110 performs protection action to protect the load circuit 500. And according to the above description, it can be known that when the voltage signal to be measured is higher than the threshold voltage, the first comparator 121 outputs a low-level signal. That is, when the over-voltage protection module 120 is over-voltage, no matter how the current in the over-current protection module 130 is, the controller 110 will trigger the protection action to protect the load circuit 500 from over-voltage.

[0077] When the overvoltage protection module 120 outputs a high level signal, the current threshold of the overcurrent protection module 130 corresponds to the resistance values of the first resistor 131, the second resistor 132, the third resistor 133 and the fourth resistor 134. That is, the current threshold is controlled by the first resistor 131, the second resistor 132, the third resistor 133 and the fourth resistor 134. When the sampling current on the sampling resistor 200 exceeds the current threshold, the second comparator 135 in the overcurrent protection module 130 will output a protection signal executed by the measured circuit to the controller 110, and the controller 110 triggers a protection action to protect the load circuit 500.

[0078] That is, when the overvoltage protection module 120 is overvoltage, no matter the state of the sampling current in the overcurrent protection module 130, the protection signal executed by the measured circuit will be output to the controller 110, and the controller 110 executes a protection action to the load circuit 500 according to the protection signal executed by the measured circuit. When the overvoltage protection module 120 is not overvoltage, and the sampling current in the overcurrent protection module 130 exceeds the threshold current, the protection signal executed by the measured circuit will be output to the controller 110, and the controller 110 executes a protection action to the load circuit 500 according to the protection signal executed by the measured circuit. Only when the overvoltage protection module 120 is not overvoltage, and the overcurrent protection module 130 is not overcurrent, the second comparator 135 will not output the protection signal executed by the measured circuit to the controller 110, and the controller 110 will not trigger a protection action.

[0079] That is, the scheme can realize overvoltage protection and overcurrent protection when the overvoltage protection module 120 and the overcurrent protection module 130 are connected to only one input and output interface (I / O) of the controller 110.

[0080] The overvoltage protection module 120 further comprises a fifth resistor 122, a first end of the fifth resistor 122 inputs the level signal, and a second end of the fifth resistor 122 is connected to the positive input end of the first comparator 121 at the fourth node 124.

[0081] The overvoltage protection module 120 further comprises a sixth resistor 123, a first end of the sixth resistor 123 is connected to the fourth node 124, that is, the second end of the fifth resistor 122, the positive input end of the first comparator 121 and the first end of the sixth resistor 123 are connected to each other, and a second end of the sixth resistor 123 is grounded.

[0082] The overvoltage protection module 120 comprises the fifth resistor 122 and the sixth resistor 123, and a threshold voltage is obtained by voltage division through the fifth resistor 122 and the sixth resistor 123.

[0083] The embodiment of the application further provides a household appliance, which can be an air conditioner, a refrigerator, a washing machine, a television and the like.

[0084] The household appliance comprises a rectifier module 300 connected to an alternating current power supply, for converting alternating current provided by the alternating current power supply into direct current.

[0085] The household appliance further comprises a switching device 400, a first end of the switching device 400 being connected to a first output end of the rectifier module 300 through an inductive device, and a second end of the switching device 400 being connected to a second output end of the rectifier module 300 through a sampling resistor 200.

[0086] The household appliance further comprises a load circuit 500, the load circuit 500 comprising a capacitor 510, a first end of the capacitor 510 being connected to a first end of the switching device 400 and a first end of the inductive device, and a second end of the capacitor 510 being connected to a first end of the switching device 400 and a first end of the sampling resistor 200.

[0087] The household appliance further comprises the overcurrent and overvoltage protection circuit 100 as described above, the overcurrent and overvoltage protection circuit 100 occupying less input and output interfaces (I / O) of the controller 110, thereby saving the input and output interfaces (I / O) of the controller 110. A first end of the overcurrent protection module 130 in the overcurrent and overvoltage protection circuit 100 is connected to a first end of the sampling resistor 200, and a second end of the overcurrent protection module 130 is connected to a second end of the sampling resistor 200; a first end of the overvoltage protection module 120 is connected to a first end of the capacitor 510, and a second end of the overvoltage protection module 120 is connected to a second end of the capacitor 510; the controller 110 is configured to perform overcurrent and overvoltage protection operations on the load circuit 500 according to a protection signal output by the overcurrent protection module 130.

[0088] In this way, the controller 110 can trigger a protection action when receiving a low-level signal output by the second comparator 135 in the overcurrent protection module 130, so as to perform overcurrent and overvoltage protection operations on the load circuit 500, thereby ensuring safe operation conditions of the load circuit 500.

[0089] In the description of the present specification, the description referring to the terms "some embodiments", "exemplarily", and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0090] Although the embodiments of the present application have been shown and described above, it is to be understood that the above embodiments are merely exemplary, and are not to be understood as limiting the present application, and any changes, modifications, replacements and variations of the above embodiments made by those skilled in the art within the scope of the present application should be included in the scope of the present application.

Claims

1. An overcurrent overvoltage protection circuit, characterized by The over-current and over-voltage protection circuit comprises: a controller; an over-voltage protection module, which comprises a first comparator having a positive input end, a negative input end and an output end, wherein the positive input end of the first comparator inputs a threshold voltage signal, the negative input end of the first comparator inputs a voltage signal to be measured, and the over-voltage protection module is configured to compare the voltage signal to be measured with the threshold voltage signal and output a first comparison signal; an over-current protection module, which comprises an input end and an output end, wherein the output end of the over-current protection module is connected to the output end of the first comparator, and the input end of the controller is connected to the output end of the over-current protection module, and the over-current protection module is configured to output a protection signal executed by a measured circuit to the controller according to a sampling current in the measured circuit and the first comparison signal.

2. The overcurrent overvoltage protection circuit of claim 1, wherein, The controller is capable of outputting the protection signal executed by the measured circuit when the over-current protection module outputs a low-level signal.

3. The overcurrent and overvoltage protection circuit of claim 1, wherein, The over-current protection module comprises: a first resistor, a first end of which is connected to a first node at the output end of the first comparator; a second resistor, a first end of which is connected to a second end of the first resistor at the second node, and a second end of which is connected to a first end of a sampling resistor, wherein the sampling resistor is connected in series in the measured circuit, and a current in the sampling resistor flows from the first end of the sampling resistor to a second end of the sampling resistor; a third resistor, a first end of which is connected to the first node; a fourth resistor, a first end of which is connected to a second end of the third resistor at a third node, and a second end of which is connected to the second end of the sampling resistor; a second comparator, a positive input end of which is connected to the second node, a negative input end of which is connected to the third node, and an output end of which is connected to the input end of the controller.

4. The over-current and over-voltage protection circuit according to claim 3, wherein The voltage at one end of the fourth resistance connected with the sampling resistance is V R5+ ; The voltage at one end of the sampling resistor connected with the second resistor is V R5- ; The first resistor and the second resistor divide the voltage to obtain a forward bias voltage of the second comparator as V C+ ; The third resistor and the fourth resistor are divided to obtain a negative bias voltage V C- for the second comparator Wherein, when the second comparator outputs a high level signal, the voltage in the overcurrent module satisfies the following formula: V R5- +V C+ >V R5+ +V C- ; When the second comparator outputs a low level signal, the voltage in the overcurrent module satisfies the following formula: V R5- +V C+ ≤V R5+ +V C- .

5. The overcurrent overvoltage protection circuit of claim 4, wherein, The current value flowing through the sampling resistor is I R5 The current value flowing through the sampling resistor I R5 satisfies the following formula: wherein I R5 is a current value flowing through the sampling resistor, V R5+ is a voltage at one end of the sampling resistor connected with the fourth resistor, V R5- is a voltage at one end of the sampling resistor connected with the second resistor, R5 is a resistance value of the sampling resistor.

6. The over-current and over-voltage protection circuit according to claim 5, wherein The signal outputted by the output end of the second comparator is a high level signal when the current value I of the sampling resistor R5 satisfies the following formula: wherein I R5 is a current value flowing through the sampling resistor, V C+ is a positive bias voltage of the second comparator obtained by voltage division of the first resistor and the second resistor, V C- is a negative bias voltage of the second comparator obtained by voltage division of the third resistor and the fourth resistor, R5 is a resistance value of the sampling resistor; when the output end of the first comparator outputs a low-level signal, the current value of the sampling resistor satisfies the following formula: wherein I R5 is a current value flowing through the sampling resistor, V C+ is a positive bias voltage of the second comparator obtained by voltage division of the first resistor and the second resistor, V C- is a negative bias voltage of the second comparator obtained by voltage division of the third resistor and the fourth resistor, R5 is a resistance value of the sampling resistor.

7. The overcurrent overvoltage protection circuit according to any one of claims 4 to 6, characterized in that, when the over-voltage protection module outputs a low-level signal, the current threshold value of the over-current protection module is zero.

8. The overcurrent overvoltage protection circuit of claim 7, wherein, when the over-voltage protection module outputs a high-level signal, the current threshold value of the over-current protection module corresponds to the resistance values of the first resistor, the second resistor, the third resistor and the fourth resistor.

9. The overcurrent and overvoltage protection circuit of claim 1, wherein, The over-voltage protection module further comprises: a fifth resistor, a first end of which inputs a level signal, and a second end of which is connected to the positive input end of the first comparator at a fourth node; a sixth resistor, a first end of which is connected to the fourth node, and a second end of which is grounded.

10. A domestic appliance characterized in that, The household appliance comprises: a rectifier module connected to an alternating current power supply and configured to convert alternating current provided by the alternating current power supply into direct current; a switch device, a first end of the switch device is connected with the first output end of the rectifier module through an inductive device, and a second end of the switch device is connected with the second output end of the rectifier module through a sampling resistor; a load circuit, the load circuit comprises a capacitor, a first end of the capacitor is connected with the first end of the switch device and the first end of the inductive device, and a second end of the capacitor is connected with the first end of the switch device and the first end of the sampling resistor; and The overcurrent and overvoltage protection circuit according to any one of claims 1 to 9, a first end of an overcurrent protection module in the overcurrent and overvoltage protection circuit is connected with the first end of the sampling resistor, and a second end of the overcurrent protection module is connected with the second end of the sampling resistor; a first end of an overvoltage protection module is connected with the first end of the capacitor, and a second end of the overvoltage protection module is connected with the second end of the capacitor; and the controller is configured to perform overcurrent and overvoltage protection operations on the load circuit according to a protection signal output by the overcurrent protection module and executed on the measured circuit.

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