Filter circuit, control circuit and circuit board of household appliance and household appliance

Abstract

The invention discloses a filter circuit, a control circuit and a circuit board of a household electrical appliance and the household electrical appliance, the filter circuit comprises a power supply access module, a filter module, a discharge module and a detection module, the power supply access module comprises a live wire input end and a zero line input end; the filtering module comprises a first X capacitor of which two ends are respectively connected to a live wire input end and a zero line input end; the discharge module comprises a first resistor and a discharge control unit, the live wire input end, the first resistor, the discharge control unit and the null line input end are connected in sequence, and the discharge control unit is configured as follows: when the power supply access module accesses an alternating current power supply, the discharge control unit is disconnected; when the alternating current power supply accessed by the power supply access module is disconnected, the discharge control unit is conducted; the detection module is connected with the live line input end and the zero line input end and is used for outputting a first level signal or outputting a second level signal according to the voltage at the two ends of the first X capacitor. The circuit loss of the household appliance can be reduced, and the safety and reliability of the circuit are improved.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a filter circuit, a control circuit, a circuit board and a household appliance. Background Art

[0002] At present, air conditioners and other household appliances generally use X capacitors to suppress electromagnetic interference from AC power, implement EMI filtering, and eliminate spark circuits, thereby ensuring that household appliances meet EMC requirements; in addition, a resistor connected in parallel with the X capacitor is also set to discharge the X capacitor. This also results in the resistor connected in parallel with the X capacitor being in a working state when the AC power supply is supplied to the household appliance, which continues to heat up and causes large circuit losses in the household appliance; after the AC power supply is cut off, the resistor connected in parallel with the X capacitor discharges slowly, causing the circuit board of the household appliance to be charged for a certain period of time, and the safety and reliability of the circuit are insufficient. Summary of the invention

[0003] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a filter circuit, a control circuit, a circuit board and a household appliance for a household appliance, which can reduce the circuit loss of the household appliance and improve the safety and reliability of the circuit.

[0004] In a first aspect, an embodiment of the present invention provides a filter circuit for a household appliance, including a power access module, a filter module, a discharge module and a detection module, wherein:

[0005] The power access module includes a live wire input terminal and a neutral wire input terminal;

[0006] The filtering module comprises a first X capacitor having two ends connected to the live line input end and the neutral line input end respectively;

[0007] The discharge module includes a first resistor and a discharge control unit, wherein the live input terminal, the first resistor, the discharge control unit, and the neutral input terminal are connected in sequence, and the discharge control unit is configured such that: when the power access module is connected to an AC power source, the discharge control unit is disconnected; when the AC power source connected to the power access module is disconnected, the discharge control unit is turned on;

[0008] The detection module is connected to the live line input terminal and the neutral line input terminal respectively, and is used to output a first level signal or a second level signal according to the voltage across the first X capacitor.

[0009] The filter circuit of the household appliance provided by the embodiment of the present invention has at least the following beneficial effects: the first X capacitor in the filter module is connected between the live input terminal and the neutral input terminal to suppress the electromagnetic interference of the AC power supply and realize EMI filtering; by setting a discharge module in parallel with the first X capacitor, the discharge module includes a first resistor and a discharge control unit connected in series, and the discharge control unit is disconnected when the power access module is connected to the AC power supply, so that when the AC power supply supplies power to the household appliance, the first X capacitor is in a charging state but the first resistor is not in a working state, and the first resistor does not generate heat, thereby reducing the heating and loss of the circuit; the discharge control unit is also turned on when the AC power supply connected to the power access module is disconnected, so that the first X capacitor can be quickly discharged through the first resistor at the moment when the AC power supply is disconnected, thereby improving the safety of the circuit; in addition, a detection module connected between the live input terminal and the neutral input terminal is also provided, which can detect whether the input of the AC power supply is disconnected on the one hand, and can output a first level signal or a second level signal according to the voltage across the first X capacitor on the other hand, so that after detecting that the input of the AC power supply is disconnected, it can be judged whether the discharge module can work normally based on the level signal output by the detection module, and it can be detected whether the discharge control unit fails, thereby improving the reliability of the circuit.

[0010] According to the filter circuit provided by some embodiments of the present invention, the discharge module further includes a second resistor connected between the discharge control unit and the neutral line input terminal.

[0011] According to the filter circuit provided by some embodiments of the present invention, the discharge control unit is implemented by an X-capacitor discharge control chip.

[0012] According to the filter circuit provided by some embodiments of the present invention, the discharge control unit includes a power detection unit connected to the power access module and a switch unit connected between the first resistor and the neutral line input terminal, and the output terminal of the power detection unit is connected to the switch unit.

[0013] According to the filtering circuit provided by some embodiments of the present invention, the detection module includes a third resistor, a fourth resistor, a fifth resistor and an optocoupler, the live wire input end, the third resistor, the fourth resistor and the neutral wire input end are connected in sequence, the two ends of the fourth resistor are also respectively connected to the two ends of the light emitter of the optocoupler, one end of the light receiver of the optocoupler is connected to a DC power supply, and the other end is connected to the fifth resistor, and the other end of the fifth resistor serves as the output end of the detection module.

[0014] According to the filter circuit provided by some embodiments of the present invention, the detection module further includes a sixth resistor connected in parallel with the fourth resistor.

[0015] According to the filter circuit provided by some embodiments of the present invention, the detection module further includes a third capacitor connected between the other end of the fifth resistor and the ground.

[0016] According to the filter circuit provided by some embodiments of the present invention, the filter module further includes a common-mode inductor and a second X capacitor, two input ends of the common-mode inductor are respectively connected to two ends of the first X capacitor, and two output ends of the common-mode inductor are respectively connected to two ends of the second X capacitor.

[0017] In a second aspect, an embodiment of the present invention provides a control circuit for a household appliance, comprising a control module and a filter circuit as described in the embodiment of the first aspect above, wherein the input end of the control module is connected to the output end of the detection module to obtain a level signal output by the detection module and to determine whether the discharge control unit is faulty.

[0018] According to the control circuit provided by some embodiments of the present invention, the determining whether the discharge control unit is faulty includes:

[0019] When no switching from the first level signal to the second level signal is detected within the first preset time period, or no switching from the second level signal to the first level signal is detected, starting timing;

[0020] When the timing duration reaches a second preset duration, obtaining the level signal output by the detection module at the current moment;

[0021] When the level signal currently output by the detection module is a first level signal, a fault signal is issued, and the fault signal indicates that a fault occurs in the discharge control unit.

[0022] In a third aspect, an embodiment of the present invention provides a circuit board, comprising the filter circuit as described in the embodiment of the first aspect above or the control circuit as described in the embodiment of the second aspect above.

[0023] In a fourth aspect, an embodiment of the present invention provides a household appliance, comprising the filter circuit as described in the embodiment of the first aspect, the control circuit as described in the embodiment of the second aspect, or the circuit board as described in the embodiment of the third aspect.

[0024] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0027] Figure 1 is a circuit schematic diagram of a filter circuit for a household appliance provided by an embodiment of the present invention;

[0028] Figure 2 is a circuit schematic diagram of a filter circuit for a household appliance provided by another embodiment of the present invention;

[0029] Figure 3 is a circuit schematic diagram of a control circuit of a household appliance provided by an embodiment of the present invention;

[0030] Figure 4 is a flow chart of a method executed by a control module of a control circuit of a household appliance provided by an embodiment of the present invention;

[0031] Figure 5 It is a structural schematic diagram of the operation control device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0033] In the description of the embodiments of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, "above", "below", "within", etc. are understood to include the number itself, "at least one" means one or more, "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. If there is a description of "first", "second", etc., it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0034] It should be noted that the terms such as setting, installing, and connecting in the embodiments of the present invention should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the embodiments of the present invention in combination with the specific content of the technical solution. For example, the term "connection" can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected or indirectly connected through an intermediate medium.

[0035] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] At present, air conditioners and other household appliances generally use X capacitors to suppress electromagnetic interference from AC power, implement EMI filtering, and eliminate spark circuits, thereby ensuring that household appliances meet EMC requirements; in addition, a resistor connected in parallel with the X capacitor is also set to discharge the X capacitor. This also results in the resistor connected in parallel with the X capacitor being in a working state when the AC power supply is supplied to the household appliance, which continues to heat up and causes large circuit losses in the household appliance; after the AC power supply is cut off, the resistor connected in parallel with the X capacitor discharges slowly, causing the circuit board of the household appliance to be charged for a certain period of time, and the safety and reliability of the circuit are insufficient.

[0037] Based on this, an embodiment of the present invention provides a filter circuit, a control circuit, a circuit board and a household appliance for a household appliance, which can reduce the circuit loss of the household appliance and improve the safety and reliability of the circuit.

[0038] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0039] Figure 1 FIG. 1 is a circuit diagram of a filter circuit for a household appliance provided by an embodiment of the present invention. Figure 1 The first aspect of the present invention provides a filter circuit for a household appliance, comprising a power access module 100, a filter module 200, a discharge module 300 and a detection module 400, wherein:

[0040] The power access module 100 includes a live input terminal L and a neutral input terminal N. It is understandable that the power access module 100 can obtain city power through the live input terminal L and the neutral input terminal N, for example, obtain 220V AC power.

[0041] The filter module 200 includes a first X capacitor C1, and two ends of the first X capacitor C1 are respectively connected to the live input terminal L and the neutral input terminal N. It can be understood that the first X capacitor C1 in the filter module 200 is connected between the live input terminal L and the neutral input terminal N to suppress electromagnetic interference of the AC power supply and achieve EMI filtering.

[0042] The discharge module 300 includes a first resistor R1 and a discharge control unit 310. The live input terminal L, the first resistor R1, the discharge control unit 310, and the neutral input terminal N are connected in sequence. The discharge control unit 310 is configured as follows: when the power access module 100 is connected to the AC power supply, the discharge control unit 310 is disconnected; when the AC power supply connected to the power access module 100 is disconnected, the discharge control unit 310 is turned on. It can be understood that by setting the discharge module 300 in parallel with the first X capacitor C1, the discharge module 300 includes the first resistor R1 and the discharge control unit 310 connected in series, and the discharge control unit 310 is disconnected when the power access module 100 is connected to the AC power supply, so that when the AC power supply is supplied to the household appliance, the first X capacitor C1 is in a charging state but the first resistor R1 is not in a working state, and the first resistor R1 does not generate heat, thereby reducing the heating and loss of the circuit; the discharge control unit 310 is also turned on when the AC power supply connected to the power access module 100 is disconnected, so that the first X capacitor C1 can be quickly discharged through the first resistor R1 at the moment when the AC power supply is disconnected, thereby improving the safety of the circuit.

[0043] The detection module 400 is connected to the live input terminal L and the neutral input terminal N, respectively, and is used to output a first level signal or a second level signal according to the voltage across the first X capacitor C1. It can be understood that the detection module 400 connected between the live input terminal L and the neutral input terminal N can detect whether the input of the AC power supply is disconnected on the one hand, and can output a first level signal or a second level signal according to the voltage across the first X capacitor C1 on the other hand, so that after detecting that the input of the AC power supply is disconnected, it can be judged whether the discharge module 300 can work normally based on the level signal output by the detection module 400, and it can detect whether the discharge control unit 310 fails, thereby improving the reliability of the circuit.

[0044] Reference Figure 1 In the filter circuit provided in some embodiments of the present invention, the discharge module 300 further includes a second resistor R2 connected between the discharge control unit 310 and the zero line input terminal N.

[0045] It can be understood that the first resistor R1 is located between the live wire input terminal L and the discharge control unit 310, so that the live wire input terminal L is not directly connected to the discharge control unit 310, avoiding the high voltage electricity in the positive half cycle of the AC power supply directly connected to the discharge control unit 310, which can help protect the discharge control unit 310 and prevent the discharge control unit 310 from being damaged; similarly, the second resistor R2 is set between the discharge control unit 310 and the neutral wire input terminal N, so that the neutral wire input terminal N is not directly connected to the discharge control unit 310, avoiding the high voltage electricity in the negative half cycle of the AC power supply directly connected to the discharge control unit 310, which can help protect the discharge control unit 310 and prevent the discharge control unit 310 from being damaged.

[0046] Reference Figure 3 In the filter circuit provided in some embodiments of the present invention, the discharge control unit 310 is implemented by using an X-capacitor discharge control chip U1.

[0047] It can be understood that the X-capacitor discharge control chip U1, i.e., an integrated chip with an automatic discharge control function, can disconnect the connection between the first resistor R1 and the neutral input terminal N when the input of the AC power supply is detected, so that the current branch formed by the live input terminal L, the first resistor R1, the discharge control unit 310, and the neutral input terminal N is not conductive; and can connect the connection between the first resistor R1 and the neutral input terminal N when the input of the AC power supply is detected to be disconnected, forming a discharge branch with one end of the first X-capacitor C1 connected to the live input terminal L, the first resistor R1, the discharge control unit 310, and the first X-capacitor C1 connected to the neutral input terminal N. It should be noted that there are currently many types of integrated chips that can realize the above-mentioned automatic discharge control function, so the embodiment of the present invention does not limit the type and model of the X-capacitor discharge control chip U1.

[0048] Figure 2 FIG. 1 is a circuit diagram of a filter circuit for a household appliance provided by another embodiment of the present invention. Figure 2 In the filter circuit provided in some embodiments of the present invention, the discharge control unit 310 includes a power detection unit 311 connected to the power access module 100 and a switch unit 312 connected between the first resistor R1 and the neutral line input terminal N, and the output end of the power detection unit 311 is connected to the switch unit 312.

[0049] It is understandable that compared to Figure 3 The discharge control unit 310 shown is an embodiment implemented by using the X-capacitor discharge control chip U1; this embodiment provides another implementation of the discharge control unit 310, the discharge control unit 310 is composed of a power detection unit 311 and a switch unit 312, the power detection unit 311 is respectively connected to the live input terminal L and the neutral input terminal N, so as to detect whether the AC power supply is input, and whether the AC power supply input is disconnected. Among them, the power detection unit 311 can be implemented in a variety of ways, for example, it can be implemented by using a series resistor voltage division method; the switch unit 312 can be implemented by using an intermediate relay or a switch device such as a thyristor, a bipolar transistor, or a field effect transistor.

[0050] Figure 3 is a circuit schematic diagram of a control circuit of a household appliance provided by an embodiment of the present invention, wherein the control circuit of the household appliance includes a filter circuit provided by some embodiments of the present invention. Figure 3In the filtering circuit provided in some embodiments of the present invention, the detection module 400 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5 and an optocoupler 410, the live wire input terminal L, the third resistor R3, the fourth resistor R4, and the neutral wire input terminal N are connected in sequence, and the two ends of the fourth resistor R4 are also respectively connected to the two ends of the light emitter of the optocoupler 410, one end of the light receiver of the optocoupler 410 is connected to a DC power supply +5V, and the other end is connected to the fifth resistor R5, and the other end of the fifth resistor R5 serves as the output end of the detection module 400.

[0051] It can be understood that the third resistor R3 and the fourth resistor R4 are connected in series between the live wire input terminal L and the neutral wire input terminal N, so as to divide the voltage between the live wire input terminal L and the neutral wire input terminal N, and then input it to the light emitter of the optocoupler 410. After the light emitter of the optocoupler 410 emits light, the emitted light is received by the light receiver of the optocoupler 410, so that the DC power supply +5V is output through the fifth resistor R5, that is, the output end of the detection module 400 can output a high-level signal.

[0052] Reference Figure 3 In the filter circuit provided in some embodiments of the present invention, the detection module 400 further includes a sixth resistor R6 connected in parallel with the fourth resistor R4.

[0053] In this embodiment, a sixth resistor R6 is provided in parallel at both ends of the fourth resistor R4 as an input resistor of the light emitter of the optocoupler 410 , which can protect the light emitter of the optocoupler 410 and prevent the light emitter of the optocoupler 410 from being easily damaged.

[0054] Reference Figure 3 In the filter circuit provided in some embodiments of the present invention, the detection module 400 further includes a third capacitor C3 connected between the other end of the fifth resistor R5 and the ground. In addition, it can be seen that the detection module 400 further includes a seventh resistor R7, one end of the seventh resistor R7 is connected to the connection point between the fifth resistor R5 and the light receiver of the optical coupler 410, and the other end of the seventh resistor R7 is grounded.

[0055] In this embodiment, the third capacitor C3 and the fifth resistor R5 can form an RC filter circuit, so as to filter the signal output by the optical coupler 410 and eliminate the interference signal therein.

[0056] Reference Figures 1 to 3 In the filter circuit provided in some embodiments of the present invention, the filter module 200 further includes a common-mode inductor L1 and a second X-capacitor C2, wherein two input ends of the common-mode inductor L1 are respectively connected to two ends of the first X-capacitor C1, and two output ends of the common-mode inductor L1 are respectively connected to two ends of the second X-capacitor C2.

[0057] It should be noted that the π-type filter is composed of the first X capacitor C1, the common-mode inductor L1 and the second X capacitor C2. The first X capacitor C1 and the second X capacitor C2 are mainly used to suppress differential mode interference, and the common-mode inductor L1 is mainly used to suppress common mode interference. In addition, the π-type filter can also suppress the interference of the AC power supply AC, such as the mains, on the subsequent circuit, and can also suppress the interference of the subsequent circuit on the AC power supply AC, such as the mains.

[0058] In addition, refer to Figure 3 The second aspect of the present invention provides a control circuit of a household appliance, including a control module 500 and a filter circuit as described in the first aspect of the present invention. That is, the control circuit of the household appliance includes a power access module 100, a filter module 200, a discharge module 300, a detection module 400 and a control module 500. The input end of the control module 500 is connected to the output end of the detection module 400 to obtain a level signal output by the detection module 400, and to determine whether the discharge control unit 310 is faulty.

[0059] It can be understood that, in the present embodiment, the detection module 400 can detect whether the input of the AC power supply is disconnected on the one hand, and can output the first level signal or the second level signal according to the voltage across the first X capacitor C1 on the other hand, so that after detecting that the input of the AC power supply is disconnected, it can be determined whether the discharge module 300 can work normally based on the level signal output by the detection module 400, and it can be detected whether the discharge control unit 310 fails, thereby improving the reliability of the circuit.

[0060] Reference Figure 4 In the control circuit provided in some embodiments of the present invention, the method for determining whether the discharge control unit 310 is faulty in the control module 500 includes but is not limited to steps S410 to S430:

[0061] Step S410: when no switching from the first level signal to the second level signal is detected within the first preset time period, or no switching from the second level signal to the first level signal is detected, start timing;

[0062] Step S420: when the timing duration reaches the second preset duration, obtaining the level signal output by the detection module 400 at the current moment;

[0063] Step S430: When the level signal currently output by the detection module 400 is a first level signal, a fault signal is issued, and the fault signal indicates that a fault occurs in the discharge control unit 310 .

[0064] It is understandable that, in this embodiment, the first level signal can be a high level signal, and the second level signal can be a low level signal. In one cycle of the AC power supply, the output level signal of the detection module 400 will switch from the first level signal to the second level signal, or from the second level signal to the first level signal, that is, the detection module 400 can detect the zero-crossing signal of the AC power supply. Therefore, when the switching from the first level signal to the second level signal is not detected within the first preset time period, or the switching from the second level signal to the first level signal is not detected, it indicates that the input of the AC power supply is disconnected; at this time, the discharge control unit 310 in the discharge module 300 is turned on, forming a discharge branch from one end of the first X capacitor C1 connected to the live input terminal L, the first resistor R1, the discharge control unit 310, the second resistor R2, and one end of the first X capacitor C1 connected to the neutral input terminal N, so that the first X capacitor C1 can be quickly discharged through the first resistor R1 and the second resistor R2 at the moment when the AC power supply is disconnected, wherein the discharge time of the first X capacitor C1 is relatively short; in addition, before the first X capacitor C1 is discharged, since a certain amount of electricity is stored in the first X capacitor C1, the optical coupler 410 will be turned on, and the detection module 400 outputs a high level signal; after the first X capacitor C1 is discharged, the optical coupler 410 is no longer turned on, and the detection module 400 outputs a low level signal. Therefore, the timing starts when the input of the AC power source is disconnected. When the timing duration reaches the second preset duration and the level signal output by the detection module 400 at the current moment is still at a high level, it means that the first X capacitor C1 cannot be discharged normally, that is, the discharge control unit 310 is not turned on after the input of the AC power source is disconnected. Therefore, it can be determined that the discharge control unit 310 has a fault. The control module 500 sends a fault signal to remind the user to perform maintenance and repair, thereby improving the safety of the circuit.

[0065] In addition, a third aspect of the present invention provides a circuit board, including the filter circuit of the first aspect or the control circuit of the second aspect.

[0066] According to the circuit board provided by the embodiment of the present invention, the first X capacitor in the filtering module of the circuit board is connected between the live input terminal and the neutral input terminal to suppress the electromagnetic interference of the AC power supply and realize EMI filtering; by setting a discharge module in parallel with the first X capacitor, the discharge module includes a first resistor and a discharge control unit connected in series, and the discharge control unit is disconnected when the power access module is connected to the AC power supply, so that when the AC power supply supplies power to the household appliance, the first X capacitor is in a charging state but the first resistor is not in a working state, and the first resistor does not generate heat, thereby reducing the heating and loss of the circuit; the discharge control unit is also turned on when the AC power supply connected to the power access module is disconnected, so that the first X capacitor can be quickly discharged through the first resistor at the moment when the AC power supply is disconnected, thereby improving the safety of the circuit; in addition, a detection module connected between the live input terminal and the neutral input terminal is also provided, which can detect whether the input of the AC power supply is disconnected on the one hand, and can output a first level signal or a second level signal according to the voltage across the first X capacitor on the other hand, so that after detecting that the input of the AC power supply is disconnected, it can be judged whether the discharge module can work normally based on the level signal output by the detection module, and it can be detected whether the discharge control unit fails, thereby improving the reliability of the circuit.

[0067] In addition, a fourth aspect of the present invention provides a household appliance, comprising the filter circuit of the first aspect, the control circuit of the second aspect, or the circuit board of the third aspect.

[0068] According to the household appliance provided by the embodiment of the present invention, the first X capacitor in the filtering module of the household appliance is connected between the live input terminal and the neutral input terminal to suppress the electromagnetic interference of the AC power supply and realize EMI filtering; by setting a discharge module in parallel with the first X capacitor, the discharge module includes a first resistor and a discharge control unit connected in series, and the discharge control unit is disconnected when the power access module is connected to the AC power supply, so that when the AC power supply supplies power to the household appliance, the first X capacitor is in a charging state but the first resistor is not in a working state, and the first resistor does not generate heat, thereby reducing the heating and loss of the circuit; the discharge control unit is also turned on when the AC power supply connected to the power access module is disconnected, so that the first X capacitor can be quickly discharged through the first resistor at the moment when the AC power supply is disconnected, thereby improving the safety of the circuit; in addition, a detection module connected between the live input terminal and the neutral input terminal is also provided, which can detect whether the input of the AC power supply is disconnected on the one hand, and can output a first level signal or a second level signal according to the voltage across the first X capacitor on the other hand, so that after detecting that the input of the AC power supply is disconnected, it can be judged whether the discharge module can work normally based on the level signal output by the detection module, and it can be detected whether the discharge control unit fails, thereby improving the reliability of the circuit.

[0069] It can be understood that the household appliances referred to in this embodiment may be air conditioners, electric water heaters, refrigerators, washing machines, induction cookers, range hoods, etc., or other household appliances not specifically listed.

[0070] In addition, refer to Figure 5 The embodiment of the present invention further provides an operation control device 500, comprising a memory 510, a processor 520, and a computer program stored in the memory 510 and executable on the processor 520. The processor 520 executes the program to implement the method flow chart of determining whether the discharge control unit 310 is faulty as performed by the control circuit of the household appliance in the second embodiment of the above, for example, executing Figure 4 Method steps S410 to S430.

[0071] In addition, an embodiment of the present invention further provides a computer-readable storage medium, which stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the flowchart of the method for determining whether the discharge control unit 310 is faulty as executed by the control circuit of the household appliance in the second embodiment of the above, for example, executing Figure 4 Method steps S410 to S430.

[0072] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed methods above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium or a non-transitory medium and a communication medium or a temporary medium. As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk DVD or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0073] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A filter circuit for household appliances, characterized in that: include: A power access module, including a live wire input terminal and a neutral wire input terminal; The filtering module comprises a first X capacitor having two ends respectively connected to the live line input end and the neutral line input end; The discharge module comprises a first resistor and a discharge control unit, wherein the live line input terminal, the first resistor, the discharge control unit and the neutral line input terminal are connected in sequence, and the discharge control unit is configured as follows: when the power access module is connected to an AC power source, the discharge control unit is disconnected; when the AC power source connected to the power access module is disconnected, the discharge control unit is turned on; The detection module is connected to the live line input terminal and the neutral line input terminal respectively, and is used to output a first level signal or a second level signal according to the voltage across the first X capacitor.

2. The filter circuit according to claim 1, characterized in that: The discharge module further includes a second resistor connected between the discharge control unit and the neutral line input terminal.

3. The filter circuit according to claim 1, characterized in that: The discharge control unit is implemented by using an X-capacitor discharge control chip.

4. The filter circuit according to claim 1, characterized in that: The discharge control unit comprises a power detection unit connected to the power access module and a switch unit connected between the first resistor and the neutral line input terminal, and an output terminal of the power detection unit is connected to the switch unit.

5. The filter circuit according to claim 1, characterized in that: The detection module includes a third resistor, a fourth resistor, a fifth resistor and an optocoupler. The live wire input terminal, the third resistor, the fourth resistor and the neutral wire input terminal are connected in sequence. The two ends of the fourth resistor are also respectively connected to the two ends of the light emitter of the optocoupler. One end of the light receiver of the optocoupler is connected to a DC power supply, and the other end is connected to the fifth resistor. The other end of the fifth resistor serves as the output end of the detection module.

6. The filter circuit according to claim 5, characterized in that: The detection module further includes a sixth resistor connected in parallel with the fourth resistor.

7. The filter circuit according to claim 5, characterized in that: The detection module further includes a third capacitor connected between the other end of the fifth resistor and a ground end.

8. The filter circuit according to claim 1, characterized in that: The filtering module further includes a common mode inductor and a second X capacitor, wherein two input ends of the common mode inductor are respectively connected to two ends of the first X capacitor, and two output ends of the common mode inductor are respectively connected to two ends of the second X capacitor.

9. A control circuit for a household appliance, characterized in that: It comprises a control module and the filtering circuit according to any one of claims 1 to 8, wherein the input end of the control module is connected to the output end of the detection module to obtain the level signal output by the detection module and to determine whether the discharge control unit is faulty.

10. The control circuit according to claim 9, characterized in that: The determining whether the discharge control unit is faulty includes: When no switching from the first level signal to the second level signal is detected within the first preset time period, or no switching from the second level signal to the first level signal is detected, starting timing; When the timing duration reaches a second preset duration, obtaining the level signal output by the detection module at the current moment; When the level signal currently output by the detection module is a first level signal, a fault signal is issued, and the fault signal indicates that a fault occurs in the discharge control unit.

11. A circuit board, characterized in that: The filter circuit according to any one of claims 1 to 8 or the control circuit according to any one of claims 9 to 10.

12. A household appliance, characterized in that: The invention comprises the filter circuit according to any one of claims 1 to 8, the control circuit according to any one of claims 9 to 10, or the circuit board according to claim 11.

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