Overcurrent protection circuit and household electrical appliance

Abstract

The invention belongs to the technical field of household appliances, and particularly relates to an overcurrent protection circuit and a household appliance. The input end of the resistance network module is connected with the output end of the controller, and the controller is used for adjusting the voltage value output by the resistance network module; the positive input end of the first comparator is connected with the output end of the resistance network module, and the negative input end of the first comparator is connected with the output end of the first comparator; the input end of the over-current protection module is connected with the output end of the first comparator, and the over-current protection module is used for outputting an over-current indication signal according to the sampling current in the detected circuit and the voltage output by the output end of the first comparator. According to the scheme, the current protection threshold value in the overcurrent protection module can be regulated and controlled, and better overcurrent protection operation can be carried out on the load circuit.

Description

TECHNICAL FIELD

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

[0002] The overcurrent 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] The overcurrent protection has two types of hardware overcurrent protection and software overcurrent protection, and the hardware overcurrent protection has the advantages of fast response and high sensitivity.

[0004] However, the hardware overcurrent protection has the problem that the overcurrent protection threshold cannot be adjusted. SUMMARY

[0005] The application aims to provide an overcurrent protection circuit and a household appliance, which can adjust the overcurrent protection threshold.

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

[0007] a controller;

[0008] a resistance network module, an input end of the resistance network module being connected with an output end of the controller, and the controller being configured to adjust a voltage value output by the resistance network module;

[0009] a first comparator, a positive input end of the first comparator being connected with an output end of the resistance network module, and a negative input end of the first comparator being connected with an output end of the first comparator;

[0010] an overcurrent protection module, an input end of the overcurrent protection module being connected with an output end of the first comparator, and the overcurrent protection module being configured to output an overcurrent indication signal according to a sampling current in a measured circuit and a voltage output by the output end of the first comparator.

[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 with the output end of the first comparator to a first node;

[0013] a second resistor, a first end of the second resistor being connected with a second end of the first resistor to a second node, and a second end of the second resistor being connected with a first end of a sampling resistor, the sampling resistor being connected in series in the measured circuit, and a current in the sampling resistor flowing from the second end of the sampling resistor to the first 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 and a third node, and a second end of the fourth resistor being connected to a 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, and 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, the second comparator is provided with a current threshold I limit for determining whether the sampling current is overcurrent. limit The current threshold I

[0018] wherein Vout is a voltage outputted by the output end of the first comparator, R1 is a resistance value of the first resistor, R2 is a resistance value of the second resistor, R3 is a resistance value of the second resistor, R4 is a resistance value of the second resistor, and R5 is a resistance value of the second resistor.

[0019] In an exemplary embodiment of the present application, the resistance network module comprises a plurality of control resistors arranged in parallel.

[0020] One end of the plurality of control resistors arranged in parallel serves as an input end of the resistance network module, and the other end of the plurality of control resistors arranged in parallel serves as an output end of the resistance network module.

[0021] In an exemplary embodiment of the present application, the plurality of control resistors arranged in parallel have the same resistance value.

[0022] In an exemplary embodiment of the present application, a voltage inputted by the positive input end of the first comparator corresponds to a number of high levels outputted by the control resistors in the resistance network module;

[0023] The voltage inputted by the positive input end of the first comparator and the number of high levels outputted by the control resistors satisfy the following formula:

[0024] wherein Vin is a voltage inputted by the positive input end of the first comparator, VCC is a voltage value of high level outputted by the control resistors to the control resistors, M is the number of high levels outputted by the control resistors in the resistance network module, and N is the number of control resistors in the resistance network module.

[0025] In an example embodiment of the present application, the resistance network module comprises:

[0026] an adjusting switch, comprising a control end, a first end and a second end, the control end of the adjusting switch being connected to the output end of the controller, the first end of the adjusting switch inputting a high-level signal;

[0027] an adjusting circuit, comprising a capacitor and a fifth resistor, a first end of the capacitor, a first end of the fifth resistor, a second end of the adjusting switch and a positive input end of the first comparator being connected to a fourth node, a second end of the capacitor and a second end of the fifth resistor being grounded.

[0028] In an example embodiment of the present application, the controller outputs a low-level voltage of 0 volt to the control resistance.

[0029] In an example embodiment of the present application, the controller is configured to input a pulse width modulation signal to the control end of the adjusting switch, so as to adjust the voltage value input to the adjusting circuit.

[0030] The second aspect of the present application provides a household appliance, comprising:

[0031] a rectifier module, connected to an alternating current power supply, for converting alternating current provided by the alternating current power supply into direct current;

[0032] a switching device, a first end of the switching device being connected to a first output end of the rectifier module through an inductive device, a second end of the switching device being connected to a second output end of the rectifier module through a sampling resistor;

[0033] a load circuit, a first end of the load circuit being connected to the first end of the switching device, a second end of the load circuit being connected to the second end of the switching device; and

[0034] The overcurrent protection circuit according to any one of the above, a first end of an overcurrent protection module in the overcurrent protection circuit being connected to a first end of the sampling resistor, a second end of the overcurrent protection module being connected to a second end of the sampling resistor, the controller being configured to perform overcurrent protection operation on the load circuit according to an overcurrent indication signal output by the overcurrent protection module.

[0035] The overcurrent protection circuit and the household appliance provided by the present application have the following beneficial effects:

[0036] The overcurrent protection circuit of the application includes a controller, a resistance network module, a first comparator and an overcurrent protection module. The controller can adjust the voltage value output by the resistance network module, and the voltage value output by the resistance network module can input voltage to the first comparator. Since the negative input end of the first comparator is connected to the output end of the first comparator, the voltage at the positive input end of the first comparator is the same as that at the output end of the first comparator. The overcurrent protection module is used to output an overcurrent indication signal according to the sampling current in the measured circuit and the voltage output by the output end of the first comparator. The overcurrent indication signal can be sent to the input end of the controller, and the controller can control the load circuit according to the overcurrent indication signal to perform overcurrent protection on the load circuit. Since the overcurrent threshold in the overcurrent protection module is related to the voltage output by the output end of the first comparator, that is, the current threshold changes according to the voltage output by the output end of the first comparator, and the voltage at the output end of the first comparator is related to the output voltage of the resistance network module, which is controlled by the controller. Therefore, the current threshold in the overcurrent protection module can be changed according to the voltage output by the resistance network module controlled by the controller, so that the overcurrent protection module can output different overcurrent indication signals. That is, the voltage input to the overcurrent protection module can be changed by the controller, and the protection threshold in the overcurrent protection module can be changed, the current protection threshold is adjustable, and the load circuit can be better protected against overcurrent.

[0037] 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.

[0038] 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 application. BRIEF DESCRIPTION OF DRAWINGS

[0039] The drawings incorporated into the specification and forming a part thereof illustrate embodiments in accordance with the present application and, together with the description, serve to explain the principles of the application. It is clear that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained from these drawings without creative labor for those skilled in the art.

[0040] Figure 1 A circuit structure schematic diagram of the resistance network module using multiple control resistors in the overcurrent protection circuit provided by the embodiment of the application is shown;

[0041] Figure 2 A circuit structure schematic diagram of the resistance network module using an adjustment switch and an adjustment circuit in the overcurrent protection circuit provided by the embodiment of the application is shown;

[0042] Figure 3A circuit structure schematic diagram of a circuit provided by the embodiment of the application is shown, which connects an overcurrent protection circuit, a rectifier module, a switching device, a sampling resistor and a load circuit.

[0043] Legend of reference signs:

[0044] 100, overcurrent protection circuit; 110, controller; 120, resistor network module; 121, control resistor; 122, adjusting switch; 123, adjusting circuit; 1230, capacitor; 1231, fifth resistor; 124, fourth node; 130, first comparator; 140, overcurrent protection module; 141, first resistor; 142, second resistor; 143, third resistor; 144, fourth resistor; 145, second comparator; 146, first node; 147, second node; 148, third node;

[0045] 200, sampling resistor; 300, rectifier module; 400, switching device; 500, load circuit;

[0046] Vin, voltage of the positive input end of the first comparator; Vout, voltage of the output end of the first comparator; V 输出 , voltage of the output end of the resistor network module; I, sampling current; I limit , threshold current; VCC, high level; M, number of control resistors outputting high level in the resistor network module; N, number of control resistors in the resistor network module. DETAILED DESCRIPTION

[0047] 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.

[0048] 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 implicitly indicating 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 specifically limited.

[0049] In this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0050] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0051] Figure 1 The diagram shows a circuit structure diagram of the resistor network module using multiple control resistors in the overcurrent protection circuit provided in the embodiment of this application; Figure 2 The diagram shows a schematic of the circuit structure of the resistor network module in the overcurrent protection circuit provided in this embodiment of the application, which uses an adjusting switch and an adjusting circuit. Figure 3 This paper shows a schematic diagram of the circuit structure of the overcurrent protection circuit, rectifier module, switching device, sampling resistor and load circuit connection provided in the embodiment of this application.

[0052] Please see Figure 3 As shown, the load circuit 500 of the variable frequency motor requires an overcurrent protection circuit 100 to prevent damage to the load circuit 500 when the current is too high. Existing overcurrent protection usually adopts two types: hardware overcurrent protection and software overcurrent protection. Among them, the protection threshold of the hardware overcurrent protection circuit 100 is determined by hardware and cannot be adjusted, so the protection is relatively simple and uncontrollable.

[0053] Therefore, please see Figure 1 or Figure 2 As shown, this application embodiment provides an overcurrent protection circuit 100, which can adjust the overcurrent protection threshold and the current threshold is controllable.

[0054] Please see Figure 1 or Figure 2As shown, the overcurrent protection circuit 100 includes a controller 110, which has multiple input / output interfaces (I / O). Different protection thresholds are set by adjusting the output states of the I / O interfaces (I / O) through software. The controller 110 can adjust itself or perform protection actions based on the overcurrent indication signal output by the overcurrent protection module 140 described below.

[0055] Please see Figure 1 or Figure 2 As shown, the overcurrent protection circuit 100 also includes a resistor network module 120. The input terminal of the resistor network module 120 is connected to the output terminal of the controller 110. The controller 110 is used to adjust the voltage value output by the resistor network module 120. The controller 110 can output a protection action based on the overcurrent indication signal output by the overcurrent protection module 140 or by its own adjustment, thereby protecting the load circuit 500.

[0056] Please see Figure 1 or Figure 2 As shown, the overcurrent protection circuit 100 also includes a first comparator 130. The positive input terminal of the first comparator 130 is connected to the output terminal of the resistor network module 120, and the negative input terminal of the first comparator 130 is connected to its output terminal. The first comparator 130 provides a low-impedance voltage source to ensure that the voltage Vin at the positive input terminal of the first comparator 130 is equal to the voltage Vout at its output terminal. Because of this, the voltage Vin at the positive input terminal of the first comparator 130 is connected to the output terminal of the resistor network module 120. In other words, the voltage Vout at the output terminal of the first comparator 130 is equal to the voltage Vout at the output terminal of the resistor network module 120. 输出 Equal to the voltage V at the output of resistor network module 120 输出 Related to controller 110, controller 110 can determine the voltage V at the output terminal of resistor network module 120. 输出 .

[0057] Please see Figure 1 or Figure 2 As shown, the overcurrent protection circuit 100 also includes an overcurrent protection module 140. The overcurrent protection module 140 can collect the sampled current I in the circuit under test. The input terminal of the overcurrent protection module 140 is connected to the output terminal of the first comparator 130. The overcurrent protection module 140 is used to output an overcurrent indication signal based on the sampled current in the circuit under test and the voltage Vout output by the first comparator 130. The overcurrent protection module 140 can also calculate the threshold current I based on the voltage Vout at the output terminal of the first comparator 130. limit The sampled current I and the threshold current I limitThe comparison is performed to obtain a comparison signal, and the controller 110 outputs different signals based on this comparison signal. If the comparison signal is an overcurrent indication signal, the controller 110 will perform overcurrent protection operation on the load circuit 500 to prevent damage to the load circuit 500. If the comparison signal is a normal signal, the controller 110 will not perform overcurrent protection operation on the load circuit 500.

[0058] The controller 110 can control the voltage V output by the resistor network module 120. 输出 This, in turn, regulates the voltage Vout at the output of the first comparator 130 and the voltage input to the overcurrent protection module 140. Based on the regulated voltage, a threshold current is obtained again. That is, based on the voltage Vout output by the resistor network module 120. 输出 To obtain different threshold currents, so that the threshold current is adjustable and can adapt to different load circuits 500.

[0059] In other words, this overcurrent protection circuit 100 includes a controller 110, a resistor network module 120, a first comparator 130, and an overcurrent protection module 140. The controller 110, resistor network module 120, first comparator 130, and overcurrent protection module 140 can transmit an overcurrent indication signal to the controller 110. The controller 110 then provides overcurrent protection to the load circuit 500 based on this overcurrent indication signal, ensuring the integrity of the load circuit 500. Furthermore, the controller 110 can control the output voltage V at the output terminal of the resistor network module 120. 输出 The output voltage Vout of the first comparator 130 is controlled, and the overcurrent protection module 140 determines the threshold current I in the overcurrent protection module 140 based on this output voltage Vout. limit Therefore, the threshold current I of this overcurrent protection module 140 can be controlled by the controller 110 and the resistor network module 120. limit This makes the threshold current I limit It is controllable and can adapt to different load circuits.

[0060] Please see below. Figure 1 or Figure 2 As shown, this overcurrent protection module 140 includes a first resistor 141. The first end of the first resistor 141 is connected to the output end of the first comparator 130 at the first node 146, that is, the first resistor 141 is connected to the output end of the first comparator 130.

[0061] Please see Figure 1 or Figure 2As shown, the overcurrent protection module 140 includes a second resistor 142. The first end of the second resistor 142 is connected to the second end of the first resistor 141 at the second node 147. The second end of the second resistor 142 is connected to the first end of the sampling resistor 200. The sampling resistor 200 is connected in series in the circuit under test. The current in the sampling resistor 200 flows from the second end of the sampling resistor 200 to the first end of the sampling resistor 200.

[0062] Please see Figure 1 or Figure 2 As shown, the overcurrent protection module 140 includes a third resistor 143. The first end of the third resistor 143 is connected to the first node 146. That is, the first resistor 141, the output of the first comparator 130 and the third resistor 143 converge at the first node 146. The voltage of the output of the first comparator 130 is output to the first resistor 141 and the third resistor 143 respectively.

[0063] Please see Figure 1 or Figure 2 As shown, the overcurrent protection module 140 includes a fourth resistor 144. The first end of the fourth resistor 144 is connected to the second end of the third resistor 143 at the third node 148, and the second end of the fourth resistor 144 is connected to the second end of the sampling resistor 200.

[0064] Please see Figure 1 or Figure 1 As shown, the overcurrent protection module 140 includes a second comparator 145. The positive input terminal of the second comparator 145 is connected to the second node 147, that is, the positive input terminal of the second comparator 145, the second end of the first resistor 141, and the first end of the second resistor 142 are connected to the second node 147. The negative input terminal of the second comparator 145 is connected to the third node 148, and the negative input terminal of the second comparator 145, the second end of the third resistor 143, and the first end of the fourth resistor 144 are connected to the third node 148. The output terminal of the second comparator 145 is connected to the input terminal of the controller 110. That is, the second comparator 145 can input an overcurrent indication signal to the controller 110 according to the sampled current and the voltage Vout output by the first comparator 130, thereby providing overcurrent protection for the load circuit 500.

[0065] It should be noted that the current threshold I in the overcurrent protection module 140 limit The value is determined by the first resistor 141, the second resistor 142, the third resistor 143, the fourth resistor 144, and the output voltage Vout at the output terminal of the first comparator 130.

[0066] The second comparator 145 is provided with a current threshold I for determining whether the sampled current is overcurrent. limit Current threshold I limit Satisfy the following formula:

[0067] Wherein, Vout is the voltage outputted by the output end of the first comparator 130, R1 is the resistance value of the first resistor 141, R2 is the resistance value of the second resistor 142, R3 is the resistance value of the second resistor 142, R4 is the resistance value of the second resistor 142, and R5 is the resistance value of the second resistor 142.

[0068] It can be understood that the voltage Vout outputted by the output end of the first comparator 130 is determined according to the voltage of the positive input end of the first comparator 130, and the voltage of the positive input end of the first comparator 130 is determined by the output voltage V 输出 of the resistance network module 120. 输出 The output voltage V limit of the resistance network module 120 is controlled by the controller 110. That is, when the current value of the threshold current I 输出 needs to be regulated, the controller 110 only needs to regulate the output voltage V limit of the resistance network module 120 to regulate the threshold current I 输出 in the overcurrent protection module 140.

[0069] In addition, the resistance values of the first resistor 141, the second resistor 142, the third resistor 143 and the fourth resistor 144 can be the same or different, which can be designed according to different embodiments.

[0070] In order to realize that the resistance network module 120 outputs different voltages under the action of the controller 110.

[0071] In an optional embodiment of the present application, as shown in Figure 2 , the resistance network module 120 includes a plurality of control resistors 121 arranged in parallel. One end of the plurality of control resistors 121 connected in parallel serves as the input end of the resistance network module 120, and the other end of the plurality of control resistors 121 connected in parallel serves as the output end of the resistance network module 120, that is, the input end of the plurality of control resistors 121 is connected to the output end of the controller 110 (the input / output interface (I / O) of the controller 110), and the output end of the plurality of control resistors 121 is connected to the positive input end of the first comparator 130. The controller 110 can regulate the voltage V 输出 outputted by the output end of the resistance network module 120 according to the plurality of control resistors 121 arranged in parallel.

[0072] It is worth mentioning that the input / output interface (I / O) of the controller 110 has two states, high level and low level. Among them, the high level is VCC volts, and the low level is 0 volts.

[0073] In addition, as shown in Figure 2As shown, the resistance values of the plurality of control resistors 121 arranged in parallel can be the same or different; when the resistance values of the control resistors 121 are the same, the current flowing through each control resistor 121 is equal. The voltage inputted by the positive input terminal of the first comparator 130 corresponds to the number of control resistors 121 outputting high level in the resistance network module 120.

[0074] The voltage inputted by the positive input terminal of the first comparator 130 and the number of control resistors 121 outputting high level satisfy the following formula:

[0075] Wherein, Vin is the voltage inputted by the positive input terminal of the first comparator 130, VCC is the voltage value of the high level outputted by the controller 110 to the control resistors 121, M is the number of control resistors 121 outputting high level in the resistance network module 120, and N is the number of control resistors 121 in the resistance network module 120. That is, the more high levels outputted by the resistance network module 120, the greater the voltage Vin inputted by the positive input terminal of the first comparator 130, and the greater the value of the threshold current I limit .

[0076] The relationship between the output voltage V 输出 of the resistance network module and the number of control resistors outputting high level is shown in the following figure:

[0077]

[0078] In another alternative embodiment of the present application, please refer to Figure 2 As shown, the resistance network module 120 includes an adjusting switch 122, the adjusting switch 122 includes a control terminal, a first terminal and a second terminal, the control terminal of the adjusting switch 122 is connected with the output terminal of the controller 110, the first terminal of the adjusting switch 122 inputs a high level signal, and the high level signal can be VCC volts.

[0079] In another alternative embodiment of the present application, please refer to Figure 3 As shown, the resistance network module 120 further includes an adjusting circuit 123, the adjusting circuit 123 includes a capacitor 1230 and a fifth resistor 1231, the first terminal of the capacitor 1230, the first terminal of the fifth resistor 1231, the second terminal of the adjusting switch 122 and the positive input terminal of the first comparator 130 are connected to a fourth node 124, and the second terminal of the capacitor 1230 and the second terminal of the fifth resistor 1231 are grounded. By the opening and closing of the control terminal of the adjusting switch 122, the signal delivered to the adjusting circuit 123 can be opened.

[0080] In another alternative embodiment of the present application, please refer to Figure 3As shown, the resistance network module 120 comprises a regulating switch 122 and a regulating circuit 123, and the controller 110 is configured to input a pulse width modulation signal to a control end of the regulating switch 122, and the regulating switch 122 is configured to transmit a signal from a first end to a second end, and then regulate a voltage value input to the regulating circuit 123.

[0081] It should be noted that the controller 110 is configured to adjust the I / O port to output the pulse width modulation signal, and then set different voltage values.

[0082] It should be noted that when the sampling current I exceeds the current threshold I limit in the overcurrent protection module 140, the overcurrent protection module 140 outputs a low-level signal to the controller 110, and the controller 110 is configured to perform an overcurrent protection operation on the load circuit 500 according to the overcurrent indication signal. Conversely, when the sampling current is less than or equal to the current threshold in the overcurrent protection module 140, the overcurrent protection module 140 outputs a high-level signal to the controller 110, and the controller 110 does not perform an overcurrent protection operation on the load circuit 500, and continuously monitors the overcurrent protection of the load circuit 500.

[0083] The embodiments of the present application also provide a household appliance, which can be an air conditioner, a refrigerator, a washing machine, a television, etc.

[0084] As shown in Figure 3 , the household appliance comprises a rectifier module 300 connected to an alternating current power supply, configured to convert alternating current provided by the alternating current power supply into direct current.

[0085] As shown in Figure 1 , 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] As shown in Figure 2 , the household appliance further comprises a load circuit 500, a first end of the load circuit 500 being connected to the first end of the switching device 400, and a second end of the load circuit 500 being connected to the second end of the switching device 400, and the load circuit 500 is provided with a variable frequency motor.

[0087] As shown in Figure 3 , ​ and ​As shown, the household appliance further comprises the overcurrent protection circuit 100 as described above, a first end of the overcurrent protection module 140 in the overcurrent protection circuit 100 is connected with a first end of the sampling resistor 200, a second end of the overcurrent protection module 140 is connected with a second end of the sampling resistor 200, the overcurrent protection module 140 is used for collecting the current value on the sampling resistor 200 and comparing it with the overcurrent threshold value, and the controller 110 makes overcurrent protection operation according to the overcurrent indication signal; that is, the controller 110 is used for executing overcurrent protection operation on the load circuit 500 according to the overcurrent indication signal output by the overcurrent protection module 140, so as to protect the load circuit 500, and further to better protect the household appliance.

[0088] 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 is not necessarily directed 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, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0089] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application, therefore any changes or modifications made according to the claims and the specification of the present application shall be within the scope of the present application.

Claims

1. An overcurrent protection circuit, characterized by, The overcurrent protection circuit comprises: a controller; a resistance network module, an input end of the resistance network module being connected with an output end of the controller, the controller being configured to adjust a voltage value output by the resistance network module; a first comparator, a positive input end of the first comparator being connected with an output end of the resistance network module, and a negative input end of the first comparator being connected with an output end of the first comparator; an overcurrent protection module, an input end of the overcurrent protection module being connected with an output end of the first comparator, the overcurrent protection module being configured to output an overcurrent indication signal according to a sampling current in a measured circuit and a voltage output by the output end of the first comparator.

2. The overcurrent protection circuit of claim 1, wherein, The overcurrent protection module comprises: a first resistor, a first end of the first resistor being connected with the output end of the first comparator to a first node; a second resistor, a first end of the second resistor being connected with a second end of the first resistor to a second node, and a second end of the second resistor being connected with a first end of a sampling resistor, the sampling resistor being connected in series in the measured circuit, and a current in the sampling resistor flowing from a second end of the sampling resistor to the first end of the sampling resistor; a third resistor, a first end of the third resistor being connected with the first node; a fourth resistor, a first end of the fourth resistor being connected with a second end of the third resistor to a third node, and a second end of the fourth resistor being connected with the second end of the sampling resistor; a second comparator, a positive input end of the second comparator being connected with the second node, a negative input end of the second comparator being connected with the third node, and an output end of the second comparator being connected with an input end of the controller.

3. The overcurrent protection circuit of claim 2, wherein, The second comparator is provided with a current threshold I for determining whether the sampling current is overcurrent limit The current threshold I limit satisfies the following formula: wherein Vout is the voltage outputted by the output end of the first comparator, R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, R3 is the resistance value of the second resistor, R4 is the resistance value of the second resistor, and R5 is the resistance value of the second resistor.

4. The overcurrent protection circuit of any one of claims 1 to 3, wherein, The resistance network module comprises a plurality of control resistors arranged in parallel; one end of the plurality of control resistors arranged in parallel serves as an input end of the resistance network module, and the other end of the plurality of control resistors arranged in parallel serves as an output end of the resistance network module.

5. The overcurrent protection circuit of claim 4, wherein, The plurality of control resistors arranged in parallel have the same resistance value.

6. The overcurrent protection circuit of claim 5, wherein, The voltage input by the positive input end of the first comparator corresponds to the number of control resistors outputting high levels in the resistance network module; The voltage input by the positive input end of the first comparator and the number of control resistors outputting high levels satisfy the following formula: Wherein, Vin is the voltage inputted by the first comparator positive input end, VCC is the voltage value outputted by the controller to the control resistance in high level, M is the number of control resistance outputted in high level in the resistance network module, and N is the number of control resistance in the resistance network module.

7. The overcurrent protection circuit of any one of claims 1 to 3, wherein, The resistance network module comprises: an adjusting switch, the adjusting switch comprising a control end, a first end and a second end, the control end of the adjusting switch being connected with an output end of the controller, and the first end of the adjusting switch inputting a high-level signal; an adjusting circuit, the adjusting circuit comprising a capacitor and a fifth resistor, a first end of the capacitor, a first end of the fifth resistor, a second end of the adjusting switch and a positive input end of the first comparator being connected to a fourth node, and a second end of the capacitor and a second end of the fifth resistor being grounded.

8. The overcurrent protection circuit of claim 6, wherein, The controller outputs a voltage of 0 volt to the control resistors outputting low levels.

9. The overcurrent protection circuit of claim 7, wherein, The controller is configured to input a pulse width modulation signal to the control end of the adjusting switch to adjust the voltage value input to the adjusting circuit.

10. A domestic appliance characterized in that, The household appliance comprises: a rectifier module connected to an alternating current power supply, for converting alternating current provided by the alternating current power supply into direct current; a switching device, a first end of the switching device being connected to a first output end of the rectifier module through an inductive device, a second end of the switching device being connected to a second output end of the rectifier module through a sampling resistor; a load circuit, a first end of the load circuit being connected to the first end of the switching device, a second end of the load circuit being connected to the second end of the switching device; and the overcurrent protection circuit according to any one of claims 1 to 9, a first end of an overcurrent protection module in the overcurrent protection circuit being connected to a first end of the sampling resistor, a second end of the overcurrent protection module being connected to a second end of the sampling resistor, the controller being configured to perform an overcurrent protection operation on the load circuit according to an overcurrent indication signal output by the overcurrent protection module.

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