Communication circuit of indoor unit and air conditioner

Abstract

The embodiment of the application discloses a communication circuit of an indoor unit and an air conditioner. The communication circuit of the indoor unit comprises a first communication module and a first control module. The first communication module comprises a voltage reduction resistor unit and a first communication unit. The voltage reduction resistor unit is connected with a power supply and the first communication unit respectively. The voltage reduction resistor unit is used for reducing the first voltage provided by the power supply to obtain the second voltage to supply power for the first communication unit. The first control module is connected with the voltage reduction resistor unit. The first control module is used for outputting the level signal corresponding to the power supply type of the power supply according to the power supply type of the power supply. The level signal is used for controlling the first communication module to adjust the resistance value of the voltage reduction resistor unit. The resistance value of the voltage reduction resistor unit is matched with the power supply type of the power supply, thereby avoiding causing the damage of the first communication unit. Meanwhile, it is ensured that the first communication unit can be driven to work, thereby improving the communication reliability of the communication circuit of the indoor unit.

Description

Technical Field

[0001] This application relates to the field of air conditioner technology, specifically to a communication circuit for an indoor unit and an air conditioner. Background Technology

[0002] With the increasing trend of intelligent and modular development of air conditioners, air conditioners are usually composed of an indoor unit and an outdoor unit. The indoor and outdoor units need to communicate with each other through communication lines to achieve various functions (such as temperature regulation, operation status feedback, etc.).

[0003] However, during the use of air conditioners, there may be situations where the indoor and outdoor units cannot communicate, resulting in poor communication reliability. Utility Model Content

[0004] This application discloses a communication circuit for an indoor unit and an air conditioner, which can improve the communication reliability of the communication circuit of the indoor unit.

[0005] This application discloses a communication circuit for an indoor unit, applied to the indoor unit of an air conditioner. The communication circuit of the indoor unit includes:

[0006] The first communication module is connected to the communication circuit of the outdoor unit of the air conditioner. The first communication module is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit.

[0007] A first control module is connected to the first communication module, and the first control module is used to control the first communication module to be in a receiving state or a sending state.

[0008] The first communication module includes:

[0009] The first communication unit is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit.

[0010] A step-down resistor unit is connected to the power supply and the first communication unit respectively. The step-down resistor unit is used to step down the first voltage provided by the power supply to obtain a second voltage, which is used to power the first communication unit.

[0011] The first control module is further configured to output a level signal corresponding to the power type according to the power type of the power supply, and the level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit.

[0012] In this embodiment, the communication circuit of the indoor unit includes a first communication module and a first control module. The first communication module is connected to the communication circuit of the outdoor unit of the air conditioner. The first communication module is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit. The first control module is used to control the first communication module to be in a receiving state or a sending state. The first communication module includes a step-down resistor unit and a first communication unit. The step-down resistor unit is connected to the power supply and the first communication unit respectively. The step-down resistor unit is used to step down the first voltage provided by the power supply to obtain a second voltage to power the first communication unit. The first control module is also used to output a power level signal corresponding to the power type of the power supply. This power level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit so that the resistance value of the step-down resistor unit matches the power type of the power supply. This avoids the second voltage after stepping down by the step-down resistor unit being too high or too low when different power types are connected due to the fixed resistance value of the step-down resistor unit. This prevents damage to the first communication unit due to excessive voltage. At the same time, it ensures that the operating voltage required for the first communication unit can be provided to drive the first communication unit to work, thereby ensuring the communication reliability of the indoor unit's communication circuit.

[0013] In some embodiments, the first communication module includes a first resistor and a selection unit, wherein the first resistor is connected to the power supply, the selection unit and the first communication unit respectively, and the selection unit is also connected to the first control module;

[0014] The selection unit includes a second resistor connected to the first resistor; the step-down resistor unit consists of the first resistor, or is composed of the first resistor and the second resistor.

[0015] The selection unit is configured to, based on the level signal, allow the current supplied by the power supply to pass through or not pass through the second resistor.

[0016] When the current supplied by the power source passes through the second resistor, the resistance value of the step-down resistor unit is determined based on the resistance values ​​of the first resistor and the second resistor.

[0017] When the current supplied by the power source does not pass through the second resistor, the resistance value of the step-down resistor unit is equal to the resistance value of the first resistor.

[0018] In this embodiment, the first communication module includes a first resistor and a selection unit. The selection unit includes a second resistor. The selection unit selectively allows the current supplied by the power supply to pass through or not pass through the second resistor, so that the resistance value of the step-down resistor unit is equal to the resistance value of the first resistor, or determined by the resistance values ​​of the first resistor and the second resistor. In other words, the resistance value of the step-down resistor unit can be the resistance value of the first resistor, or deviate from the resistance value of the first resistor. The first communication module can provide step-down resistor units with at least two resistance values, and the circuit structure is simple, which can reduce the cost and area of ​​the first communication module.

[0019] In some embodiments, the selection unit is connected in parallel with the first resistor, and the selection unit is connected to the power supply and the first communication unit respectively. The selection unit further includes a first switch, which is connected in series with the second resistor.

[0020] When the first switch is closed, the current supplied by the power source passes through the second resistor;

[0021] When the first switch is in the open state, the current supplied by the power source does not pass through the second resistor.

[0022] In this embodiment, when the first switch is closed, the current supplied by the power supply passes through the second resistor, and the resistance of the step-down resistor unit is the resistance value corresponding to the parallel resistance formed by the first resistor and the second resistor connected in parallel. When the first switch is open, the current supplied by the power supply does not pass through the second resistor, and the resistance of the step-down resistor unit is the resistance value of the first resistor. By adjusting the open and closed state of the first switch (open state and closed state), the parallel connection of the second resistor and the first resistor can be dynamically adjusted, thereby adjusting the resistance value of the step-down resistor unit, ensuring the reliability of the resistance value adjustment, and at the same time, the adjustment method is simple.

[0023] In some embodiments, the first switch includes a first optocoupler;

[0024] The collector of the transistor in the first optocoupler is connected to the second resistor, the emitter of the first optocoupler is connected to the first communication unit and the first resistor, the anode of the diode in the first optocoupler is connected to the first voltage input terminal, and the cathode of the diode in the first optocoupler is connected to the first control module.

[0025] In this embodiment, the first switch includes a first optocoupler, which can isolate the power supply (high voltage side) from the first control module, ensuring the safety and reliability of the first control module and improving the safety and reliability of the communication circuit of the indoor unit.

[0026] In some embodiments, the selection unit further includes a second switch, the second resistor is connected in series with the first resistor, and the second resistor is connected to the power supply or the first communication unit, and the second switch is connected in parallel with the second resistor;

[0027] When the second switch is in the off state, the current supplied by the power source passes through the second resistor;

[0028] When the second switch is closed, the second resistor is short-circuited, and the current supplied by the power source does not pass through the second resistor.

[0029] In this embodiment, when the second switch is in the open state, the current supplied by the power supply passes through the second resistor, and the resistance of the step-down resistor unit is the resistance value corresponding to the series resistance formed by the first resistor and the second resistor connected in series. When the second switch is in the closed state, the current supplied by the power supply does not pass through the second resistor, and the resistance of the step-down resistor unit is the resistance value of the first resistor. By adjusting the open and closed state of the second switch (open state and closed state), the series connection between the second resistor and the first resistor can be dynamically adjusted, thereby adjusting the resistance value of the step-down resistor unit, ensuring the reliability of the resistance value adjustment, and at the same time, the adjustment method is simple.

[0030] In some embodiments, the first voltage is an AC voltage, and the communication circuit of the indoor unit further includes a zero-crossing detection circuit;

[0031] The zero-crossing detection circuit is connected to the power supply. The zero-crossing detection circuit is used to output a zero-crossing signal based on the first voltage. The zero-crossing signal is used to characterize the zero-point information of the first voltage.

[0032] The first control module is also connected to the zero-crossing detection circuit, and the first control module is used to determine the power supply type corresponding to the power supply based on the zero-crossing signal.

[0033] Different power types correspond to different zero-crossing signals output by the zero-crossing detection circuit. In this embodiment, the communication circuit of the indoor unit is also equipped with a zero-crossing detection circuit. The zero-crossing detection circuit is connected to the power supply and the first control module respectively. The first control module is also used to obtain the zero-crossing signal output by the zero-crossing detection circuit based on the first voltage provided by the power supply, and determine the power type corresponding to the power supply according to the zero-crossing signal, so as to ensure the accuracy of the obtained power type, thereby ensuring the accuracy of adjusting the resistance value of the step-down resistor unit.

[0034] In some embodiments, the communication circuit of the indoor unit further includes a voltage detection unit, and the first control module further includes a comparator;

[0035] The voltage detection unit is connected to the power supply and is used to detect the first voltage to obtain a voltage detection signal.

[0036] The comparator has a first input terminal connected to the voltage detection unit, a second input terminal for inputting a target voltage, and an output terminal connected to the first communication module. The comparator is used to compare the voltage detection signal with the target voltage and output a level signal.

[0037] In this embodiment, a voltage detection unit is set in the communication circuit of the indoor unit. The first control module includes a comparator. The voltage detection unit detects the first voltage provided by the power supply to obtain a voltage detection signal. The first input terminal of the comparator is connected to the voltage detection unit, and the second input terminal of the comparator is input with the target voltage. The comparator compares the voltage detection signal with the target voltage and outputs a level signal to adjust the resistance value of the step-down resistor unit. Since the voltage detection signal reflects the power supply type, the level signal obtained by comparing the voltage detection signal with the target voltage through the comparator adjusts the resistance value of the step-down resistor unit, ensuring that the adjusted resistance value of the step-down resistor unit is compatible with the power supply type.

[0038] In some embodiments, the power supply type includes a first power supply type and a second power supply type, wherein the peak voltage corresponding to the first voltage provided by the power supply of the first power supply type is less than the peak voltage corresponding to the first voltage provided by the power supply of the second power supply type, and the level signal includes a first level signal and a second level signal.

[0039] The first level signal corresponds to the first power supply type, and the first level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit to the first resistance value;

[0040] The second level signal corresponds to the second power supply type, and the second level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit to the second resistance value;

[0041] The first resistance value is less than the second resistance value.

[0042] In this embodiment, when the power supply type is the first power supply type, i.e., the peak voltage of the first voltage is relatively small, the first control module outputs a first level signal to make the resistance of the step-down resistor unit relatively small, so as to ensure that the first communication unit can be driven to work. When the power supply type is the second power supply type, i.e., the peak voltage of the first voltage is relatively large, the first control module outputs a second level signal to make the resistance of the step-down resistor unit relatively large, thereby reducing the power consumption of the first communication unit.

[0043] In some embodiments, the first communication module includes a Zener diode, which is connected to the step-down resistor unit and the first communication unit respectively, wherein the second voltage is greater than or equal to the breakdown voltage of the Zener diode.

[0044] In this embodiment, the second voltage being greater than or equal to the breakdown voltage of the Zener diode causes the power supply voltage of the first communication unit to be clamped at the breakdown voltage of the Zener diode, preventing the first communication unit from being damaged by excessive voltage, while ensuring the operational stability of the first communication unit.

[0045] This application discloses an air conditioner, including:

[0046] Outdoor unit;

[0047] The indoor unit includes the communication circuit of any of the indoor units disclosed in the embodiments of this application. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a structural diagram of an air conditioner provided in related technologies;

[0050] Figure 2 This is one of the structural schematic diagrams of the communication circuit of an indoor unit disclosed in an embodiment of this application;

[0051] Figure 3 This is a schematic diagram of the structure of a first communication unit disclosed in an embodiment of this application;

[0052] Figure 4 This is a schematic diagram of another first communication unit disclosed in an embodiment of this application;

[0053] Figure 5 This is a schematic diagram of the structure of a second communication module and a second control module disclosed in an embodiment of this application.

[0054] Figure 6a This is one of the structural schematic diagrams of a first communication module disclosed in an embodiment of this application;

[0055] Figure 6b This is a second schematic diagram of the structure of a first communication module disclosed in an embodiment of this application;

[0056] Figure 7This is the third schematic diagram of the structure of a first communication module disclosed in the embodiments of this application;

[0057] Figure 8 This illustration shows a structural schematic diagram of a selection unit provided in an embodiment of this application;

[0058] Figure 9 This is the fourth schematic diagram of the structure of a first communication module disclosed in the embodiments of this application;

[0059] Figure 10 This is a second schematic diagram of the communication circuit of an indoor unit disclosed in an embodiment of this application;

[0060] Figure 11 This is the third schematic diagram of the communication circuit structure of an indoor unit disclosed in the embodiments of this application;

[0061] Figure 12 This is a schematic diagram of the structure of a zero-crossing detection circuit disclosed in an embodiment of this application;

[0062] Figure 13 This is a schematic diagram of another zero-crossing detection circuit disclosed in an embodiment of this application;

[0063] Figure 14a This is a waveform diagram of a first voltage with a peak voltage of 230V and a frequency of 60Hz, as disclosed in an embodiment of this application.

[0064] Figure 14b This is a waveform diagram of a fifth voltage obtained after full-wave rectification of a first voltage with a peak voltage of 230V and a frequency of 60Hz, as disclosed in an embodiment of this application.

[0065] Figure 14c This is a waveform diagram of a zero-crossing signal corresponding to an AC voltage with a peak voltage of 230V and a frequency of 60Hz, as disclosed in an embodiment of this application.

[0066] Figure 15a This is a waveform diagram of a first voltage with a peak voltage of 115V and a frequency of 60Hz, as disclosed in an embodiment of this application.

[0067] Figure 15b This is a waveform diagram of a fifth voltage obtained after full-wave rectification of a first voltage with a peak voltage of 115V and a frequency of 60Hz, as disclosed in an embodiment of this application.

[0068] Figure 15c This is a waveform diagram of a zero-crossing signal corresponding to an AC voltage with a peak voltage of 115V and a frequency of 60Hz, as disclosed in an embodiment of this application.

[0069] Figure 16This is a schematic diagram of the structure of a first control module disclosed in an embodiment of this application;

[0070] Figure 17 This is a schematic diagram of another first control module disclosed in an embodiment of this application;

[0071] Figure 18 This is the fourth schematic diagram of the communication circuit of an indoor unit disclosed in the embodiments of this application. Detailed Implementation

[0072] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0074] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0075] It is understood that in the following embodiments, "connection" should be interpreted as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., transmit electrical signals or data to each other. Meanwhile, in the following embodiments, "connection" can indicate either an indirect connection or a direct connection.

[0076] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0077] Figure 1A schematic diagram of the structure of an air conditioner provided in the related art is shown. For example... Figure 1 As shown, the air conditioner includes an indoor unit 110 and an outdoor unit 120. The indoor unit 110 includes an indoor unit communication circuit 111, and the outdoor unit 120 includes an outdoor unit communication circuit 121. The indoor unit communication circuit 111 may include a step-down resistor 111a and a first communication unit 111b. The outdoor unit communication circuit 121 may include a second communication module 121a. The step-down resistor 111a is used to connect to a power supply 130 and step down the voltage provided by the power supply 130 through the step-down resistor 111a, and then provides the stepped-down voltage to the first communication unit 111b to power the first communication unit 111b, so as to realize the communication between the first communication unit 111b and the second communication module 121a, that is, to realize the transmission of communication signals.

[0078] In related technologies, communication circuits 111 of various specifications of indoor units are typically provided to meet the needs of power supplies 130 of different power types. The resistance value of the step-down resistor 111a in the communication circuits 111 of different specifications of indoor units is different, and the peak voltage corresponding to the AC voltage provided by the power supply 130 of different power types is different. It can be understood that the peak voltage corresponding to the AC voltage can refer to the maximum voltage value of the AC voltage.

[0079] For example, in some regions, there are two different types of power supplies 130, including a power supply 130 that provides an AC voltage with a peak voltage of 230V and a frequency of 60Hz, and a power supply 130 that provides an AC voltage with a peak voltage of 115V and a frequency of 60Hz. In order to adapt to the two types of power supplies 130, two types of communication circuits 111 for indoor units are provided. When using the power supply 130 with a peak voltage of 230V and a frequency of 60Hz, the communication circuit 111 of the indoor unit with a resistance of 24KΩ is selected. When using the power supply 130 with a peak voltage of 115V and a frequency of 60Hz, the communication circuit 111 of the indoor unit with a resistance of 10.6KΩ is selected, so as to balance the circuit drive current and reduce the circuit power consumption.

[0080] The developers of this application discovered that if the resistance value of the step-down resistor 111a in the communication circuit 111 of the indoor unit is too large, it may not be able to provide sufficient drive current to the first communication unit 111b, thus failing to drive the first communication unit 111b to work normally and resulting in a communication failure. If the resistance value of the step-down resistor 111a in the communication circuit 111 of the indoor unit is too small, it may cause excessive power consumption of the first communication unit 111b, or even damage the components of the first communication unit 111b, resulting in a communication failure. Furthermore, a circuit structure that is incompatible with two different types of power supplies 130 is detrimental to circuit versatility.

[0081] Figure 2 This illustration shows one of the structural schematic diagrams of a communication circuit for an indoor unit according to an embodiment of this application. For example... Figure 2 As shown, the communication circuit 210 of the indoor unit may include a first communication module 211 and a first control module 212. The first communication module 211 is connected to the communication circuit of the outdoor unit of the air conditioner, and the first control module 212 is connected to the first communication module 211. The first communication module 211 is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit. The first control module 212 is used to control the first communication module 211 to be in a receiving state or a sending state. The first communication module 211 may include a first communication unit 211b and a step-down resistor unit 211a. The first communication unit 211b is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit. The step-down resistor unit 211a is connected to the power supply 220 and the first communication unit 211b respectively. The step-down resistor unit 211a is used to step down the first voltage provided by the power supply 220 to obtain a second voltage, which is used to power the first communication unit 211b. The first control module 212 is also used to output the level signal corresponding to the power supply type according to the power supply type of the power supply 220.

[0082] The voltage level signal is used to control the first communication module 211 to adjust the resistance value of the step-down resistor unit 211a. It should be noted that if the first communication module 211 is in a receiving state, the first communication unit 211b is used to receive communication signals; if the first communication module 211 is in a transmitting state, the first communication unit 211b is used to transmit communication signals. The first control module 212 is also connected to the first communication unit 211b. The first control module 212 can be used to control the first communication unit 211b to be in a receiving state, so as to receive communication signals transmitted by the communication circuit of the outdoor unit through the first communication unit 211b; or the first control module 212 can be used to control the first communication unit 211b to be in a transmitting state, so as to transmit communication signals to the communication circuit of the outdoor unit through the first communication unit 211b. It is understood that the outdoor unit may also include a second control module. When the first communication module 211 is in a receiving state, the second control module can be used to control the second communication module to be in a transmitting state; when the first communication module 211 is in a transmitting state, the second control module can also be used to control the second communication module to be in a receiving state, so as to ensure the communication reliability between the indoor and outdoor units of the air conditioner.

[0083] It should be noted that the second voltage needs to be greater than or equal to the operating voltage required by the first communication unit 211b in order to meet the working requirements of the first communication unit 211b. If the second voltage is too high, it may easily lead to excessive power consumption of the indoor unit, or even damage the components of the first communication unit 211b and the second communication module. If the second voltage is too low, it will not be able to drive the first communication unit 211b to work normally, that is, it will not be possible to achieve communication between the indoor unit and the outdoor unit.

[0084] In this embodiment, the first control module 212 outputs a power level signal corresponding to the power type of the power supply 220 to control the step-down resistor unit 211a to adjust its resistance value, so that the resistance value of the step-down resistor unit 211a is adapted to the power type. For example, the larger the peak voltage corresponding to the AC voltage provided by the power supply 220, the larger the adjusted resistance value of the step-down resistor unit 211a; conversely, the smaller the peak voltage corresponding to the AC voltage provided by the power supply 220, the smaller the adjusted resistance value of the step-down resistor unit 211a, thus balancing the circuit drive current and reducing circuit power consumption.

[0085] Figure 3 A schematic diagram of the structure of a first communication unit provided in an embodiment of this application is shown. Figure 3 As shown, the first communication unit may include a second optocoupler E2, a third optocoupler E3, and a first rectifier circuit 310. The first control module may include a first controller 320, which may include a first communication transmitter and a first communication receiver. The first rectifier circuit 310 is connected to the step-down resistor unit 330 and the transistor of the second optocoupler E2, respectively. The diode of the second optocoupler E2 is connected to the first communication transmitter of the first controller 320. The diode of the third optocoupler E3 is connected to the transistor of the second optocoupler E2 and the second communication module 340, respectively. The transistor of the third optocoupler E3 is connected to the first communication receiver of the first controller 320. The second communication module 340 is connected to the second control module 350.

[0086] It should be noted that the first voltage provided by power supply 360 can be AC ​​voltage. The step-down resistor unit 330 is used to step down the first voltage provided by power supply 360 to obtain a second voltage. The first rectifier circuit 310 is used to rectify the second voltage output by the step-down resistor unit 330 to obtain a DC voltage, which powers the second optocoupler E2 and the third optocoupler E3. When the first communication module is in the transmitting state and the second communication module 340 is in the receiving state, the first controller 320 outputs a third-level signal through the first communication transmitting terminal to make the second optocoupler E2 in the conducting state, or outputs a fourth-level signal through the first communication transmitting terminal to make the second optocoupler E2 in the conducting and disconnecting states, thereby controlling whether the second communication module 340 can receive current, that is, controlling the second control module 350 to receive the communication signal through the second communication module 340, thereby realizing the indoor unit's communication circuit sending communication signals to the outdoor unit's communication circuit. When the first communication module is in the receiving state and the second communication module 340 is in the transmitting state, the first controller 320 outputs a third-level signal through the first communication transmitting end to make the second optocoupler E2 in the conducting state. The on / off state (conducting state or disconnected state) of the third optocoupler E3, that is, whether current flows through the third optocoupler E3, is determined by the second communication module 340. The first controller 320 receives the communication signal transmitted by the third optocoupler E3 through the first communication receiving end, so as to realize that the communication circuit of the indoor unit receives the communication signal sent by the communication circuit of the outdoor unit.

[0087] Understandably, in this embodiment, driving the first communication unit 211b to work normally can be understood as the current flowing through the third optocoupler E3 triggering the diode of the third optocoupler E3 to light up when the third optocoupler needs to be in a conducting state. Optionally, the first controller can be the controller of an air conditioner.

[0088] Figure 4 A schematic diagram of another first communication unit provided in an embodiment of this application is shown. Figure 4 As shown, the first communication unit may further include a first current-limiting resistor R41. The first current-limiting resistor R41 is connected to the cathode of the diodes of the first communication transmitter and the second optocoupler E2, respectively, to prevent excessive current from flowing into the first communication transmitter.

[0089] Optionally, the positive terminal of the diode of the second optocoupler E2 is connected to the first voltage input terminal V1, and the negative terminal of the diode of the second optocoupler E2 is connected to the first current-limiting resistor R41. Optionally, the voltage provided by the first voltage input terminal V1 is 5V.

[0090] Please continue to refer to this. Figure 4The first communication unit may also include a pull-down resistor R42. The first end of the pull-down resistor R42 is connected to the emitter of the transistor of the third optocoupler E3 and the first communication receiver, respectively. The second end of the pull-down resistor R42 is connected to the ground terminal GND. The collector of the transistor of the third optocoupler is connected to the first voltage input V1.

[0091] Please continue to refer to this. Figure 4 The first communication unit may also include a first diode D1, the positive terminal of the first diode D1 is connected to the negative terminal of the diode of the third optocoupler E3, and the negative terminal of the first diode D1 is connected to the second communication module 410 to prevent the current of the second communication module 410 from flowing back into the first communication unit, thereby improving the safety of the communication circuit.

[0092] In some embodiments, please refer to Figure 4 The first communication module may further include a first Zener diode D2, which is connected to both the step-down resistor unit 420 and the first communication unit. The second voltage is greater than or equal to the breakdown voltage of the first Zener diode D2. For example, the breakdown voltage of the first Zener diode D2 can range from 12V to 24V. Optionally, the breakdown voltage of the Zener diode D2 can be 12V, 18V, or 24V. It should be noted that the breakdown voltage of the Zener diode refers to the voltage at which the Zener diode begins to conduct and stabilizes the clamping voltage under reverse bias conditions. The second voltage being greater than or equal to the breakdown voltage of the first Zener diode D2 clamps the supply voltage of the first communication unit to the breakdown voltage of the first Zener diode D2, preventing damage to the first communication unit due to excessive voltage and ensuring the operational stability of the first communication unit.

[0093] Please continue to refer to this. Figure 4 The first communication module may also include a first capacitor C1 and a third resistor R3. For example, the step-down resistor unit 420 is connected to the live wire L, the step-down resistor unit 420 is connected to the first rectifier circuit, the Zener diode D2 is connected to the first rectifier circuit and the neutral wire N, the third resistor R3 is connected in parallel with the Zener diode D2, and the first capacitor C1 is connected in parallel with the Zener diode D2.

[0094] It should be noted that the step-down resistor unit 420 is connected to the power supply via the live wire L and the neutral wire N. When the voltage difference between the live wire L and the neutral wire N is greater than the breakdown voltage of the Zener diode D2, current flows into the power supply through the step-down resistor unit 420 and the first rectifier circuit. The Zener diode D2, the first capacitor C1, and the third resistor R3, with the neutral wire N as the reference, provide a stable power supply voltage for the first communication unit. Optionally, please refer to [further details]. Figure 4 The first rectifier circuit may include rectifier diode D3.

[0095] Figure 5A schematic diagram of the structure of a second communication module and a second control module provided in an embodiment of this application is shown. Figure 5 As shown, the second communication module may include a fourth optocoupler E4 and a fifth optocoupler E5. The second control module may include a second controller 510, which may include a second communication transmitter and a second communication receiver. The transistor of the fourth optocoupler E4 is connected to the positive terminal of the diode of the first communication unit and the fifth optocoupler, respectively. The negative terminal of the diode of the fifth optocoupler E5 is connected to the neutral line N. The diode of the fourth optocoupler E4 is connected to the second communication transmitter, and the transistor of the fifth optocoupler E5 is connected to the second communication receiver.

[0096] It should be noted that the second controller 510 can be used to output a fifth-level signal to the second communication transmitter to turn on the fourth optocoupler E4. The second controller 510 can also be used to output a sixth-level signal to the second communication transmitter to turn off the fourth optocoupler E4. The second controller 510 can output a fifth-level signal to the second communication transmitter so that, when the second communication module is in a receiving state, it can receive communication signals sent by the first communication module through the second communication receiver. The second controller 510 can output either a fifth-level or sixth-level signal to the second communication transmitter to control whether current flows through the diode of the third optocoupler E3, thereby enabling the second communication module to send communication signals to the first communication module.

[0097] In some embodiments, please refer to Figure 5 The second communication module may further include a fourth resistor R4, a second capacitor C2, a fourth diode D4, a third capacitor C3, and a second Zener diode D5. One end of the fourth resistor R4 is connected to the first communication unit, and the other end of the fourth resistor R4 is connected to the anode of the fourth diode D4. The cathode of the fourth diode D4 is connected to the collector of the transistor in the fourth optocoupler E4. The anode of the second Zener diode D5 is connected to both the cathode of the fourth diode D4 and the collector of the transistor in the fourth optocoupler E4. The cathode of the second Zener diode D5 is connected to the neutral line N. The second capacitor C2 and the third capacitor C3 are both connected in parallel with the second Zener diode D5. In this embodiment, the fourth resistor R4, the second capacitor C2, the fourth diode D4, the third capacitor C3, and the second Zener diode D5 are arranged between the fourth optocoupler E4 and the first communication unit to improve the stability of the communication circuit and ensure operational reliability.

[0098] In some embodiments, please refer to Figure 5The second communication module may further include a fifth resistor R5. The fifth resistor R5 is connected to both the second communication transmitter and the anode of the diode in the fourth optocoupler E4, to prevent excessive current from flowing into the diode of the fourth optocoupler E4. For example, the anode of the diode in the fourth optocoupler E4 is connected to the fifth resistor R5, and the cathode of the diode in the fourth optocoupler E4 is connected to the ground terminal GND.

[0099] Please continue to refer to this. Figure 5 The second communication module may also include a sixth resistor R6 and a seventh resistor R7. The first end of the sixth resistor R6 is connected to the emitter of the transistor of the fifth optocoupler E5 and the first end of the seventh resistor R7, respectively. The second end of the sixth resistor R6 is connected to the second communication receiver. The second end of the seventh resistor R7 is connected to the ground terminal GND. The collector of the transistor of the third optocoupler is connected to the first voltage input V1.

[0100] In this embodiment, the communication circuit of the indoor unit includes a first communication module and a first control module. The first communication module is connected to the communication circuit of the outdoor unit of the air conditioner. The first communication module is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit. The first control module is used to control the first communication module to be in a receiving state or a sending state. The first communication module includes a step-down resistor unit and a first communication unit. The step-down resistor unit is connected to the power supply and the first communication unit respectively. The step-down resistor unit is used to step down the first voltage provided by the power supply to obtain a second voltage to power the first communication unit. The first control module is also used to output a power level signal corresponding to the power type of the power supply. This power level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit so that the resistance value of the step-down resistor unit matches the power type of the power supply. This avoids the second voltage after stepping down by the step-down resistor unit being too high or too low when different power types are connected due to the fixed resistance value of the step-down resistor unit. This prevents damage to the first communication unit due to excessive voltage. At the same time, it ensures that the operating voltage required for the first communication unit can be provided to drive the first communication unit to work, thereby ensuring the communication reliability of the indoor unit's communication circuit.

[0101] Please refer to Figures 6a to 6b , Figure 6a This illustration shows one of the structural schematic diagrams of a first communication module provided in an embodiment of this application. Figure 6b This is a second schematic diagram of the structure of a first communication module provided in an embodiment of this application. For example... Figures 6a to 6bAs shown, the first communication module 610 may include a first resistor 611, a selection unit 612, and a first communication unit 613. The selection unit 612 may include a second resistor 612a. The first resistor 611 is connected to the power supply 620, the selection unit 612, and the first communication unit 613. The selection unit 612 is also connected to the first control module 630. The second resistor 612a is connected to the first resistor 611. The selection unit 612 is used to determine whether the current supplied by the power supply 620 passes through the second resistor 612a based on the level signal.

[0102] The step-down resistor unit consists of a first resistor 611, or a first resistor 611 and a second resistor 612a. When the current supplied by the power supply 620 passes through the second resistor 612a, the resistance value of the step-down resistor unit is determined based on the resistance values ​​of the first resistor 611 and the second resistor 612a. When the current supplied by the power supply 620 does not pass through the second resistor 612a, the resistance value of the step-down resistor unit is equal to the resistance value of the first resistor 611.

[0103] It should be noted that the current supplied by the power supply 620 flows through the first resistor 611 at a constant current. The first control module 630 is connected to the selection unit 612 and outputs a level signal corresponding to the power supply type to the selection unit 612. The selection unit 612 causes the current supplied by the power supply 620 to pass through or not pass through the second resistor 612a, thereby adjusting the total current of the path between the power supply 620 and the first communication unit 613.

[0104] In some embodiments, when the current supplied by the power supply 620 passes through the second resistor 612a, the current path of the current supplied by the power supply 620 becomes longer, relative to the current supplied by the power supply not passing through the second resistor 612a, so that the resistance value of the step-down resistor unit is greater than the resistance value of the first resistor 611.

[0105] For example, please refer to Figure 6a Taking the connection of the first terminal B of the first resistor 611 to the power supply 620, the second terminal C of the first resistor 611 to the first terminal D of the second resistor 612a, and the second terminal E of the second resistor 612a to the first terminal A of the first communication unit 613 as an example, if the selection unit 612 opens the path between the second terminal C of the first resistor 611 and the first terminal A of the first communication unit 613, then the current supplied by the power supply 620 does not flow through the second resistor 612a, and the step-down resistor unit is composed of the first resistor 611. If the selection unit 612 does not open the path between the second terminal C of the first resistor 611 and the first terminal A of the first communication unit 613, then the current supplied by the power supply 620 flows through the second resistor 612a, and the first resistor 611 and the second resistor 612a are connected in series. The resistance value of the step-down resistor unit is equal to the resistance value corresponding to the series resistance formed by the first resistor 611 and the second resistor 612a.

[0106] It should be noted that, Figure 6a The diagram illustrates the case where the first resistor 611 and the second resistor 612a are connected in series, with the second resistor 612a connected between the first resistor 611 and the first communication unit 613. It is understood that the second resistor 612a can also be connected to both the power supply 620 and the first resistor 611, with the second resistor 612a connected in series between the power supply 620 and the first resistor 611 when the current supplied by the power supply 620 passes through it.

[0107] In other embodiments, when the current supplied by the power supply 620 passes through the second resistor 612a, the cross-sectional area of ​​the current flow path supplied by the power supply 620 may become larger, so that the resistance of the step-down resistor unit is smaller than the resistance of the first resistor 611, compared to the current supplied by the power supply 620 not passing through the second resistor 612a.

[0108] It should be noted that, with Figure 6a The difference shown is that, Figure 6b This illustrates the connection between the first terminal D of the second resistor 612a and the first terminal B of the first resistor 611. The selection unit 612 can selectively connect or disconnect the path between the second terminal E of the second resistor 612a and the first terminal A of the first communication unit 613, or selectively connect or disconnect the path between the first terminal B of the first resistor 611 and the first terminal D of the second resistor 612a. Figure 6b This illustrates a scenario where the selection unit 612 can selectively turn on or off the path between the second terminal E of the second resistor 612a and the first terminal A of the first communication unit 613.

[0109] like Figure 6b As shown, if the selection unit 612 connects the second terminal E of the second resistor 612a to the first terminal A of the first communication unit 613, the current supplied by the power supply 620 flows through the second resistor 612a. The first resistor 611 and the second resistor 612a are connected in parallel, and the resistance of the step-down resistor unit is equal to the resistance of the parallel resistor formed by the first resistor 611 and the second resistor 612a. If the selection unit 612 disconnects the second terminal E of the second resistor 612a from the first terminal A of the first communication unit 613, the current supplied by the power supply 620 does not flow through the second resistor 612a, and the resistance of the step-down resistor unit is equal to the resistance of the first resistor 611.

[0110] In other embodiments, when the selection unit 612 is used to selectively connect or disconnect the path between the first terminal B of the first resistor 611 and the first terminal D of the second resistor 612a, if the selection unit 612 connects the path between the first terminal B of the first resistor 611 and the first terminal D of the second resistor 612a, the current supplied by the power supply 620 flows through the second resistor 612a, the first resistor 611 and the second resistor 612a are connected in parallel, and the resistance of the step-down resistor unit is equal to the resistance of the parallel resistance formed by the first resistor 611 and the second resistor 612a. If the selection unit 612 disconnects the path between the first terminal B of the first resistor 611 and the first terminal D of the second resistor 612a, the current supplied by the power supply 620 does not flow through the second resistor 612a, and the resistance of the step-down resistor unit is equal to the resistance of the first resistor 611.

[0111] In some embodiments, the first communication module 610 may include a plurality of selection units 612, wherein the resistance value of the second resistor 612a in each selection unit 612 may be equal or unequal, so that the step-down resistor unit of the first communication module 610 can provide more resistance values ​​to be compatible with more different types of power supplies 620.

[0112] In this embodiment, the first communication module 610 includes a first resistor 611 and a selection unit 612. The selection unit 612 includes a second resistor 612a. The selection unit 612 selectively allows the current supplied by the power supply 620 to pass through or not pass through the second resistor 612a, so that the resistance value of the step-down resistor unit is equal to the resistance value of the first resistor 611, or determined by the resistance values ​​of the first resistor 611 and the second resistor 612a. In other words, the resistance value of the step-down resistor unit can be the resistance value of the first resistor 611, or deviate from the resistance value of the first resistor 611. The first communication module 610 can provide step-down resistor units with at least two resistance values, and the circuit structure is simple, which can reduce the cost and area of ​​the first communication module 610.

[0113] Figure 7 This is shown as a third schematic diagram of the structure of a first communication module provided in an embodiment of this application. Figure 7 As shown, the selection unit 710 is connected in parallel with the first resistor 720, and the selection unit 710 is connected to the power supply 740 and the first communication unit 730 respectively. The selection unit 710 may also include a first switch 711, and the first switch 711 is connected in series with the second resistor 712.

[0114] When the first switch 711 is closed, the current supplied by the power supply 740 passes through the second resistor 712. When the first switch 711 is open, the current supplied by the power supply 740 does not pass through the second resistor 712. It should be noted that, compared to when the first switch 711 is open, when the first switch 711 is closed, the first resistor 720 and the second resistor 712 are connected in parallel, increasing the total cross-sectional area of ​​the step-down resistor unit and reducing its resistance to the current supplied by the power supply 740. When the peak voltage of the AC voltage supplied by the power supply 740 is high, the first switch 711 should be open; when the peak voltage of the AC voltage supplied by the power supply 740 is low, the first switch 711 should be closed. This ensures that the second voltage after being stepped down by the step-down resistor unit is close to the operating voltage required by the first communication unit, thus balancing the circuit drive current and reducing circuit power consumption, and improving the versatility of the first communication module.

[0115] For example, the first control module is connected to the first switch 711, and the first control module is also used to control the first switch 711 to be in a closed state or an open state.

[0116] In some embodiments, such as Figure 7 As shown, the first switch 711 is connected to the second resistor 712 and the first communication unit 730, respectively. In other embodiments, the first switch 711 is connected to the power supply 740 and the second resistor 712, respectively.

[0117] Optionally, the first switch 711 may include, but is not limited to, transistors, field-effect transistors, optocouplers, and other electronically controlled switches. The level signal may include a first level signal and a second level signal. The first switch 711 may be in an off state based on the second level signal, in which case the current supplied by the power supply 740 does not pass through the second resistor 712, or the power supply 740 may be in an on state based on the first level signal, in which case the current supplied by the power supply 740 passes through the second resistor 712.

[0118] Figure 8 A schematic diagram of the structure of a selection unit provided in an embodiment of this application is shown. Figure 8 As shown, the first switch may include a first optocoupler E1, the collector of the transistor of the first optocoupler E1 is connected to the second resistor R2, the emitter of the first optocoupler E1 is connected to the first communication unit and the first resistor R1 respectively, the anode of the diode of the first optocoupler E1 is connected to the first voltage input terminal V1, and the cathode of the diode of the first optocoupler E1 is connected to the first control module 810.

[0119] It should be noted that when the first control module outputs a low-level signal, the first optocoupler E1 is in a closed state, the transistor of the first optocoupler E1 is turned on, and the resistance of the step-down resistor unit is equal to the resistance of the parallel resistor formed by the first resistor and the second resistor connected in parallel. When the first control module outputs a high-level signal, the first optocoupler E1 is in a closed state, and the resistance of the step-down resistor unit is equal to the resistance of the first resistor.

[0120] Please continue to refer to this. Figure 8 The selection unit may also include a second current-limiting resistor R8, which is connected to the negative terminal of the diode of the first optocoupler E1 and the first control module 810 respectively. The second current-limiting resistor R8 determines the magnitude of the driving current of the diode of the first optocoupler E1 to avoid excessive current flowing into the first control module 810.

[0121] In this embodiment, the first switch includes a first optocoupler, which can isolate the power supply (high voltage side) from the first control module, ensuring the safety and reliability of the first control module and improving the safety and reliability of the communication circuit of the indoor unit.

[0122] In this embodiment, when the first switch is closed, the current supplied by the power supply passes through the second resistor, and the resistance of the step-down resistor unit is the resistance value corresponding to the parallel resistance formed by the first resistor and the second resistor connected in parallel. When the first switch is open, the current supplied by the power supply does not pass through the second resistor, and the resistance of the step-down resistor unit is the resistance value of the first resistor. By adjusting the open and closed state of the first switch (open state and closed state), the parallel connection of the second resistor and the first resistor can be dynamically adjusted, thereby adjusting the resistance value of the step-down resistor unit, ensuring the reliability of the resistance value adjustment, and at the same time, the adjustment method is simple.

[0123] Figure 9 This is shown as a fourth schematic diagram of a first communication module provided in an embodiment of this application. For example... Figure 9 As shown, the selection unit 910 may further include a second switch 911, a second resistor 912 connected in series with the first resistor 920, and the second resistor 912 connected to the power supply 940 or the first communication unit 930, and the second switch 911 and the second resistor 912 connected in parallel.

[0124] Specifically, when the second switch 911 is in the open state, the current supplied by the power supply 940 passes through the second resistor 912. When the second switch 911 is in the closed state, the second resistor 912 is short-circuited, and the current supplied by the power supply 940 does not pass through the second resistor 912.

[0125] Please refer to the following for further explanation. Figure 9When the second resistor 912 is connected to the first communication unit 930, the second resistor 912 is also connected to the first resistor 920 and the first communication unit 930. If the second switch 911 is in the open state, the current supplied by the power supply 940 passes through the first resistor 920 and the second resistor 912 in sequence. When the second resistor 912 is connected to the power supply 940, the second resistor 912 is also connected to the power supply 940 and the first resistor 920 in sequence. If the second switch 911 is in the open state, the current supplied by the power supply 940 passes through the second resistor 912 and the first resistor 920 in sequence.

[0126] It should be noted that when the second switch 911 is open, compared to when it is closed, the current supplied by the power supply 940 flows through the first resistor 920 and the second resistor 912. The total conductor length of the step-down resistor unit increases, thus enhancing its resistance to the current supplied by the power supply 940. When the peak voltage of the AC voltage supplied by the power supply 940 is high, the second switch 911 should be open; when the peak voltage of the AC voltage supplied by the power supply 940 is low, the second switch 911 should be closed. This ensures that the second voltage after being stepped down by the step-down resistor unit is close to the operating voltage required by the first communication unit, thereby balancing the circuit drive current and reducing circuit power consumption.

[0127] For example, the first control module is connected to the second switch 911, and the first control module is also used to control the second switch 911 to be in a closed state or an open state.

[0128] In some embodiments, the second switch 911 may include a sixth optocoupler. The collector of the transistor in the sixth optocoupler is connected to both the first resistor 920 and the second resistor 912. The emitter of the transistor in the sixth optocoupler is connected to both the second resistor 912 and the first communication unit 930. The anode of the diode in the sixth optocoupler is connected to the first voltage input terminal, and the cathode of the diode in the sixth optocoupler is connected to the first control module. It should be noted that when the control module outputs a low-level signal, the sixth optocoupler is in a closed state, and the resistance of the step-down resistor unit is equal to the resistance of the first resistor 920. When the control module outputs a high-level signal, the sixth optocoupler is in an open state, and the resistance of the step-down resistor unit is the resistance corresponding to the series resistance formed by the first resistor 920 and the second resistor 912.

[0129] In this embodiment, the second switch 911 includes a sixth optocoupler, which can isolate the power supply (high voltage side) from the first control module, ensuring the safety and reliability of the first control module and improving the safety and reliability of the communication circuit of the indoor unit.

[0130] In this embodiment, when the second switch is in the open state, the current supplied by the power supply passes through the second resistor, and the resistance of the step-down resistor unit is the resistance value corresponding to the series resistance formed by the first resistor and the second resistor connected in series. When the second switch is in the closed state, the current supplied by the power supply does not pass through the second resistor, and the resistance of the step-down resistor unit is the resistance value of the first resistor. By adjusting the open and closed state of the second switch (open state and closed state), the series connection between the second resistor and the first resistor can be dynamically adjusted, thereby adjusting the resistance value of the step-down resistor unit, ensuring the reliability of the resistance value adjustment, and at the same time, the adjustment method is simple.

[0131] In some embodiments, the AC voltage of the power supply includes a third voltage or a fourth voltage, wherein the resistance values ​​of the first resistor and the second resistor are determined based on the peak voltage corresponding to the third voltage and the peak voltage corresponding to the fourth voltage.

[0132] It should be noted that by reasonably selecting the resistance values ​​of the first resistor and the second resistor, the resistance value of the first resistor can be matched with one of the third voltage and the fourth voltage, and the resistance value of the step-down resistor unit formed by the first resistor and the second resistor can be matched with the other of the third voltage and the fourth voltage. This ensures that when the first communication module is connected to a power supply of different types, the second voltage after being stepped down by the step-down resistor unit is close to the operating voltage required by the first communication module, thereby balancing the needs of circuit drive current and reducing circuit power consumption.

[0133] In some embodiments, the resistance value of the first resistor can be in the range of 10.6KΩ to 24KΩ, and the resistance value of the second resistor can be in the range of 13.4KΩ to 19KΩ.

[0134] by Figure 8 Taking the first communication module as an example, the resistance of the first resistor can be 24KΩ, and the resistance of the second resistor can be 19KΩ. It should be noted that when the peak voltage of the first voltage supplied by the power supply is 230V, the first control module outputs a high-level signal, the first optocoupler E1 is cut off, the resistance r11 of the step-down resistor unit is 24KΩ, and the average drive current I0 of the first communication unit is I0 = Um1 / r11 = (230V-24V) / 24KΩ = 8.58mA, where Um1 is the voltage difference across the step-down resistor unit, and the breakdown voltage of the first Zener diode is 24V.

[0135] When the peak voltage of the first voltage supplied by the power supply is 115V, the first control module outputs a low-level signal, the first optocoupler E1 is turned on, the first resistor R1 and the second resistor R2 are connected in parallel, the resistance value r11 of the step-down resistor unit is 10.6KΩ, and the average driving current I0 of the second optocoupler E2 is I0 = Um1 / r11 = (115V-24V) / 10.6KΩ = 8.58mA, which is equal to the average driving current when the peak voltage is 230V, thus meeting the working requirements of the first communication unit.

[0136] by Figure 9 Taking the first communication module shown as an example, with the second switch including a sixth optocoupler, the resistance of the first resistor can be 10.6KΩ, and the resistance of the second resistor can be 13.4KΩ. It should be noted that the peak voltage of the first voltage supplied by the power supply is 115V. When the first control module outputs a low-level signal, the sixth optocoupler is turned on. The resistance of the step-down resistor unit r11 is 10.6KΩ. The average drive current of the first communication unit I0 = Um1 / r11 = (115V - 24V) / 10.6KΩ = 8.58mA.

[0137] The peak voltage of the first voltage supplied by the power supply is 230V. The control module outputs a high-level signal, the sixth optocoupler is cut off, and the resistance value r11 of the step-down resistor unit is 10.6KΩ + 13.4KΩ = 24KΩ. The average drive current I0 of the first communication unit is I0 = Um1 / r11 = (230V-24V) / 24KΩ = 8.58mA, which is equal to the average drive current when the peak voltage is 115V, thus reducing the energy consumption of the first communication unit.

[0138] In this embodiment, the resistance values ​​of the first resistor and the second resistor of the first communication module are determined based on the peak voltage corresponding to the AC voltage that the power supply connected to the first communication module may provide, thereby ensuring that the resistance value range of the step-down resistor unit can match the peak voltage corresponding to different AC voltages, further ensuring the reliability of the resistance value adjustment of the step-down resistor unit.

[0139] Figure 10 This is a second schematic diagram of the communication circuit structure of an indoor unit according to an embodiment of this application. For example... Figure 10 As shown, the communication circuit of the indoor unit may also include a zero-crossing detection circuit 1010. The zero-crossing detection circuit 1010 is connected to the power supply 1020. The first control module 1030 is also connected to the zero-crossing detection circuit 1010. The zero-crossing detection circuit 1010 is used to output a zero-crossing signal based on the first voltage. The first control module 1030 is used to determine the power supply type corresponding to the power supply 1020 based on the zero-crossing signal.

[0140] The zero-crossing signal can be used to characterize the zero-point information of the first voltage. The zero-crossing signal is different depending on the peak voltage corresponding to the first voltage. It should be noted that the first voltage can be an AC voltage, and the zero-point information can refer to the time information of the first voltage when its voltage value transitions from positive to negative or from negative to positive and crosses the zero voltage (reference level), or in other words, the time information of the intersection of the AC voltage and the zero voltage (reference level).

[0141] Different power types correspond to different zero-crossing signals output by the zero-crossing detection circuit. In this embodiment, the communication circuit of the indoor unit is also equipped with a zero-crossing detection circuit. The zero-crossing detection circuit is connected to the power supply and the first control module respectively. The first control module is also used to obtain the zero-crossing signal output by the zero-crossing detection circuit based on the first voltage provided by the power supply, and determine the power type corresponding to the power supply according to the zero-crossing signal, so as to ensure the accuracy of the obtained power type, thereby ensuring the accuracy of adjusting the resistance value of the step-down resistor unit.

[0142] In some embodiments, the first control module 1030 can also be used to determine the power supply type corresponding to the power supply 1020 based on the pulse width of the zero-crossing signal. The pulse width refers to the duration of a certain state (such as a high level or a low level) in the zero-crossing signal. For example, the zero-crossing signal may include a pulse signal, and the pulse width refers to the duration of the high level of each pulse. It should be noted that the pulse width of the zero-crossing signal is related to the peak voltage corresponding to the first voltage provided by the power supply 1020. For example, the pulse width of the zero-crossing signal is negatively correlated with the peak voltage corresponding to the first voltage. In another example, the pulse width of the zero-crossing signal is positively correlated with the peak voltage corresponding to the first voltage.

[0143] Since the AC voltages provided by different power supplies 1020 have different peak voltages, the pulse widths of the zero-crossing detection signals obtained are different. The first control module 1030 detects the pulse width and outputs a level signal corresponding to the power supply type to dynamically adjust the resistance value of the step-down resistor unit 1041. This enables the resistance value of the step-down resistor unit 1041 of the first communication module 1040 to be adapted to the first voltage provided by the power supply when different power supply types are connected.

[0144] Figure 11This is shown as a third schematic diagram of the communication circuit of an indoor unit according to an embodiment of this application. The communication circuit of the indoor unit may further include a second rectifier circuit 1111, which is connected to both the power supply 1120 and the zero-crossing detection circuit 1112. The second rectifier circuit 1111 rectifies the first voltage provided by the power supply 1120 to obtain a fifth voltage. It should be noted that in this embodiment, the first voltage is an AC voltage, and the fifth voltage is a DC voltage. By setting the second rectifier circuit 1111 between the zero-crossing detection circuit 1112 and the power supply 1120 to obtain a DC voltage, the design of the zero-crossing detection circuit 1112 does not require consideration of AC voltage polarity reversal, level reversal, or other processing logic, thus simplifying the design of the zero-crossing detection circuit 1112 and reducing its design difficulty.

[0145] Optionally, the second rectifier circuit 1111 may include at least one of a half-wave rectifier circuit and a full-wave rectifier circuit. The half-wave rectifier circuit is connected to both the power supply 1120 and the zero-crossing detection circuit 1112. It should be noted that a half-wave rectifier circuit refers to rectifying the AC current using one half-cycle, while the other half-cycle is wasted. Through the unidirectional conductivity of a diode, half a cycle of the AC current is converted into a unidirectional pulsating DC voltage. A full-wave rectifier circuit may include two diodes, which can alternately conduct to form a complete rectified waveform.

[0146] Please continue to refer to this. Figure 11 The second rectifier circuit 1111 can be a full-wave rectifier circuit. Specifically, the second rectifier circuit 1111 may include a sixth diode D6 and a seventh diode D7. The positive terminal of the sixth diode D6 is connected to the live wire L, and the negative terminal of the sixth diode D6 is connected to the zero-crossing detection circuit 1112. The positive terminal of the seventh diode D7 is connected to the neutral wire N, and the negative terminal of the seventh diode D7 is connected to the zero-crossing detection circuit 1112.

[0147] Figure 12 A schematic diagram of a zero-crossing detection circuit provided in an embodiment of this application is shown. The zero-crossing detection circuit 1210 may include a seventh optocoupler E7, a ninth resistor R9, and a tenth resistor R10. The first terminal of the tenth resistor R10 is connected to the power supply 1220. The anode of the diode of the seventh optocoupler E7 is connected to the second terminal of the tenth resistor R10. The collector of the transistor of the seventh optocoupler E7 is connected to the second voltage input terminal V2. The emitter of the transistor of the seventh optocoupler E7 is connected to the ninth resistor R9 and the first control module 1230, respectively. The ninth resistor R9 is connected to the third voltage input terminal.

[0148] It should be noted that when the current output from the tenth resistor R10 is insufficient to turn on the diode of the seventh optocoupler E7, the transistor of the seventh optocoupler E7 is in the off state, and the voltage at point F is determined by the voltage provided by the third voltage input terminal. When the current output from the tenth resistor R10 is sufficient to turn on the diode of the seventh optocoupler E7, the transistor of the seventh optocoupler E7 is in the on state, and the voltage at point F is determined by the voltage provided by the second voltage input terminal V2. Therefore, the voltage at point F differs depending on whether the current output from the tenth resistor R10 is greater than or equal to the on-state current of the diode of the seventh optocoupler E7, or when the current output from the tenth resistor R10 is less than the on-state current of the diode of the seventh optocoupler E7. Taking the pulse width as an example, the longer the duration for which the current output from the tenth resistor R10 is greater than or equal to the on-state current of the diode of the seventh optocoupler E7, the longer the pulse width. Taking the pulse width as an example, which indicates the time length determined by the voltage provided by the third voltage input terminal, the longer the current output by the tenth resistor R10 is less than the conduction current of the diode of the seventh optocoupler E7, the longer the pulse width.

[0149] The driving current I1 of the seventh optocoupler E7 in the zero-crossing detection circuit 1210 can be calculated as follows: I1 = [Um0 * Sin(2πft + θ) - U1 - U2] / r12, where Um0 is the peak voltage corresponding to the first voltage provided by the power supply, U1 is the voltage drop of the sixth diode D6 or the seventh diode D7, U2 is the voltage drop of the diode of the seventh optocoupler E7, r12 is the resistance of the tenth resistor R10, f is the frequency of the first voltage provided by the power supply, t is time, and θ is the phase angle. When the driving current I1 ≥ I2, the diode of the seventh optocoupler E7 is turned on, where I2 is the conduction current of the diode of the seventh optocoupler E7; conversely, when I1 < I2, the seventh optocoupler E7 is turned off.

[0150] As can be seen from the calculation formula of the drive current of the seventh optocoupler E7, when the zero-crossing detection circuit is connected to a power supply providing AC voltages with different peak values, the proportions of the conduction and cutoff times of the seventh optocoupler E7 are different, resulting in different pulse widths of the zero-crossing signal output by the zero-crossing detection circuit 1210. Therefore, based on the pulse width, the peak voltage of the AC voltage provided by the power supply 1220 can be determined, and thus the power supply type of the power supply 1220 can be determined.

[0151] In some embodiments, such as Figure 12 As shown, the voltage provided by the second voltage input terminal V2 is higher than the voltage provided by the third voltage input terminal. The voltage provided by the second voltage input terminal V2 is 12V, and the voltage provided by the third voltage input terminal is 0V.

[0152] In some embodiments, such as Figure 12As shown, the negative terminal of the diode of the seventh optocoupler E7 is connected to the signal ground SGND, and the third input terminal is the common ground GND. It can be understood that the signal ground SGND is the reference ground line for analog signals or sensitive signals, mainly used for low-noise signal paths, and the common ground GND is the system common ground line, usually referring to the power supply ground or circuit reference ground.

[0153] Figure 13 A schematic diagram of another zero-crossing detection circuit provided in an embodiment of this application is shown. Figure 13 As shown, the zero-crossing detection circuit 1310 may further include a first transistor Q1, an eleventh resistor R11, a twelfth resistor R12, and a thirteenth resistor R13. The first terminal of the first transistor Q1 is connected to the thirteenth resistor R13, which is also connected to the fourth voltage input terminal V4. The second terminal of the first transistor Q1 is connected to the third voltage input terminal and the eleventh resistor R11. The eleventh resistor R11 is also connected to the twelfth resistor R12 and the emitter of the transistor in the seventh optocoupler E7. The twelfth resistor R12 is also connected to the third terminal of the first transistor Q1.

[0154] It should be noted that the twelfth resistor R12 prevents excessive current from flowing into the third terminal of the first transistor Q1, and the thirteenth resistor R13 prevents excessive current from flowing into the first control module 1320. The descriptions of the seventh optocoupler E7 and the third voltage input terminal can be found in the above embodiments and will not be repeated here.

[0155] Optionally, the voltage provided by the fourth voltage input terminal V4 may be less than or equal to the voltage provided by the second voltage input terminal. For example, the voltage provided by the fourth voltage input terminal V4 is 5V, and the voltage provided by the second voltage input terminal V2 is 12V. In another example, both the fourth voltage input terminal V4 and the second voltage input terminal V2 provide a voltage of 5V.

[0156] Optionally, the first transistor Q1 is an NPN transistor, with its first terminal being the collector, its second terminal being the emitter, and its third terminal being the base.

[0157] In this embodiment, the zero-crossing signal is a pulse signal, and the pulse width is the duration for which the pulse signal remains in a high-level state.

[0158] For example, using AC peak voltages of 230V and 115V, and a frequency of 60Hz, please refer to... Figures 14a to 15c , Figure 14a This illustration shows a waveform diagram of a first voltage with a peak voltage of 230V and a frequency of 60Hz, provided in an embodiment of this application. Figure 14bThe diagram illustrates a waveform of a fifth voltage obtained by full-wave rectification of a first voltage with a peak voltage of 230V and a frequency of 60Hz, according to an embodiment of this application. Figure 14c The diagram shows a waveform of a zero-crossing signal corresponding to an AC voltage with a peak voltage of 230V and a frequency of 60Hz, provided in an embodiment of this application. Figure 15a This illustration shows a waveform diagram of a first voltage with a peak voltage of 115V and a frequency of 60Hz, provided in an embodiment of this application. Figure 15b The diagram illustrates a waveform of a fifth voltage obtained by full-wave rectification of a first voltage with a peak voltage of 115V and a frequency of 60Hz, according to an embodiment of this application. Figure 15c The diagram shows a waveform of a zero-crossing signal corresponding to an AC voltage with a peak voltage of 115V and a frequency of 60Hz, provided in an embodiment of this application.

[0159] according to Figures 14a to 15c With the tenth resistor R10 unchanged, the peak voltage corresponding to the first voltage supplied by the power supply is different, and the pulse width of the corresponding zero-crossing signal is different. When the pulse width of the zero-crossing signal is L1, it can be determined that the peak voltage of the first voltage supplied by the power supply is 230V and the frequency is 60Hz. When the pulse width of the zero-crossing signal is L2, it can be determined that the peak voltage of the first voltage supplied by the power supply is 115V and the frequency is 60Hz. Based on this, when the pulse width is large, the output level signal can be used to make the resistance of the step-down resistor unit the first resistance value, and when the pulse width is small, the output level signal can be used to make the resistance of the step-down resistor unit the second resistance value, wherein the first resistance value is smaller than the second resistance value.

[0160] It is understandable that a second rectifier circuit may not be provided in the zero-crossing detection circuit. For example, a device with bidirectional detection capability may be used to output a zero-crossing signal based on the first voltage provided by the power supply. This embodiment does not limit this.

[0161] In some embodiments, the first control module is further configured to determine the power supply type as a first power supply type if the pulse width of the zero-crossing signal is greater than or equal to a pulse width threshold. If the pulse width of the zero-crossing signal is less than the pulse width threshold, the power supply type is determined as a second power supply type, wherein the peak voltage corresponding to the AC voltage provided by the first power supply type is less than the peak voltage corresponding to the AC voltage provided by the second power supply type. It should be noted that the pulse width threshold can be determined based on the pulse widths of the zero-crossing signals corresponding to various power supplies that may be connected to the zero-crossing detection circuit. For example, the pulse width threshold can be less than L2 and greater than L1. If the pulse width of the zero-crossing signal is greater than or equal to the pulse width threshold, it indicates that the peak voltage of the first voltage provided by the power supply is relatively small. In this case, the resistance value of the step-down resistor unit should be adjusted to a smaller first resistance value. If the pulse width of the zero-crossing signal is less than the pulse width threshold, it indicates that the peak voltage of the AC voltage of the power supply is relatively large. In this case, the resistance value of the step-down resistor unit should be adjusted to a larger second resistance value so that after connecting different types of power supplies, the second voltage obtained by the step-down resistor unit after resistance adjustment is close to the first resistance value, ensuring the accuracy of the obtained zero-crossing signal.

[0162] Understandably, the first control module can be used to detect the pulse width of the zero-crossing signal, compare the pulse width with the pulse width threshold, and output the corresponding level signal based on the comparison result. This function can be implemented by a controller with this software function available on the market, or it can be implemented by hardware circuitry.

[0163] The pulse width threshold of the zero-crossing signal is positively correlated with the peak voltage corresponding to the first voltage provided by the power supply. In this embodiment, when the pulse width of the zero-crossing signal is greater than or equal to the pulse width threshold, that is, when the first voltage provided by the power supply is small, the resistance of the step-down resistor unit is small to ensure that the current output by the step-down resistor unit is large enough to ensure that the first communication unit can work normally (such as the third optocoupler can be lit normally). When the pulse width is less than the pulse width threshold, that is, when the first voltage provided by the power supply is large, the resistance of the step-down resistor unit is large, which helps to suppress the current, protect the first communication unit, and reduce the power consumption of the first communication unit.

[0164] Figure 16 A schematic diagram of the structure of a first control module provided in an embodiment of this application is shown. Figure 16 As shown, the first control module 1610 may include a fourth capacitor C4 and a first comparator U1. The fourth capacitor C4 is connected to the zero-crossing detection circuit 1620. The first input terminal of the first comparator U1 is connected to the fourth capacitor C4, the second input terminal of the first comparator U1 is used to input the first target voltage Vref, and the output terminal of the first comparator U1 is connected to the first communication module 1630. The fourth capacitor C4 is used to charge based on the zero-crossing signal to obtain a pulse width-dependent sixth voltage of the zero-crossing signal. The first comparator U1 is used to compare the sixth voltage with the first target voltage Vref and output a level signal.

[0165] The first target voltage Vref is generated based on a pulse width threshold. For example, the first target voltage Vref is positively correlated with the pulse width threshold; that is, the larger the pulse width threshold, the larger the reference voltage. It should be noted that in this embodiment, the pulse width of the zero-crossing signal is converted into a sixth voltage via the fourth capacitor C4. Then, the sixth voltage and the first target voltage Vref are compared via the first comparator U1, and a corresponding level signal is output based on the comparison result. The sixth voltage is correlated with the pulse width of the zero-crossing signal. If the pulse width of the zero-crossing signal refers to the length of time the zero-crossing signal remains in a high-level state, the sixth voltage is positively correlated with the pulse width of the zero-crossing signal. If the pulse width of the zero-crossing signal refers to the length of time the zero-crossing signal remains in a low-level state, the sixth voltage is negatively correlated with the pulse width of the zero-crossing signal.

[0166] Optionally, the first comparator U1 can be an operational amplifier. If the first level signal is a high level signal and the second level signal is a low level signal, then the first input terminal of the first comparator U1 can be the non-inverting input terminal of the operational amplifier, and the second output terminal of the first comparator U1 can be the inverting input terminal of the operational amplifier. If the first level signal is a low level signal and the second level signal is a high level signal, then the first input terminal of the first comparator U1 can be the inverting input terminal of the operational amplifier, and the second output terminal of the first comparator U1 can be the non-inverting input terminal of the operational amplifier.

[0167] Figure 17 A schematic diagram of another first control module provided in an embodiment of this application is shown. Figure 17 As shown, the first control module may further include a fourth capacitor C4, a first comparator U1, a first controller 1711, and an isolation element 1712. The first controller 1711 is connected to the zero-crossing detection circuit 1713, and the isolation element 1712 is connected to the fourth capacitor C4, the zero-crossing detection circuit 1713, and the first controller 1711. The first controller 1711 controls the load based on the zero-crossing signal output by the zero-crossing detection circuit 1713, and the isolation element 1712 allows the zero-crossing signal to flow to the fourth capacitor C4 and blocks the current flowing from the fourth capacitor C4 into the first controller 1711.

[0168] It should be noted that by setting an isolation element 1712 between the fourth capacitor C4 and the first controller 1711, and between the fourth capacitor C4 and the zero-crossing detection circuit 1713, the charging and discharging process of the fourth capacitor C4 can be prevented from affecting the zero-crossing signal received by the first controller 1711, thus ensuring that the signal received by the first controller 1711 is more stable and reliable.

[0169] Optionally, the isolation element 1712 may include an eighth diode D8. The positive terminal of the eighth diode D8 is connected to both the zero-crossing detection circuit 1713 and the first controller 1711, and the negative terminal of the eighth diode D8 is connected to the fourth capacitor C4. It should be noted that the eighth diode D8 has unidirectional conduction and reverse cutoff characteristics. This feature effectively prevents the charging and discharging process of the fourth capacitor C4 from affecting the zero-crossing signal received by the first controller 1711. Furthermore, the eighth diode D8 is a passive component, which, compared to active components, reduces the price and size of the control module.

[0170] It is understood that the first controller 1711 used in this embodiment can be a commercially available controller that can control the load 1330 according to the zero-crossing signal. The circuit structure of the control module provided in the above embodiment is only an example. Other hardware circuits that can achieve this function can also be used. This embodiment does not limit this.

[0171] In this embodiment, the first control module further includes a first controller and an isolation element. The isolation element limits the flow of the zero-crossing signal, which can effectively prevent the interference current generated during the charging and discharging of the fourth capacitor from affecting the level stability of the input terminal of the first controller. That is, it ensures the accuracy of the zero-crossing signal obtained by the first controller. Thus, while adjusting the resistance value of the step-down resistor unit, it can ensure the accuracy and reliability of the first controller controlling the load based on the zero-crossing signal.

[0172] In this embodiment, the first control module includes a fourth capacitor and a first comparator. The fourth capacitor is connected to a zero-crossing detection circuit. The fourth capacitor is charged based on the zero-crossing signal to obtain a sixth voltage related to the pulse width of the zero-crossing signal. The first input terminal of the first comparator is connected to the fourth capacitor. The first comparator compares the sixth voltage with a first target voltage and outputs a level signal corresponding to the comparison result. By setting hardware circuits to realize the output of a corresponding level signal based on the pulse width of the zero-crossing signal, the software design complexity of the first control module is reduced.

[0173] In some embodiments, the communication circuit of the indoor unit may further include a voltage detection unit, and the first control module may further include a second comparator. The voltage detection unit is connected to a power supply and is used to detect a first voltage to obtain a voltage detection signal. The first input terminal of the second comparator is connected to the voltage detection unit, the second input terminal of the second comparator is used to input a second target voltage, and the output terminal of the second comparator is connected to the first communication module. The second comparator is used to compare the voltage detection signal with the second target voltage and output a level signal.

[0174] It should be noted that the voltage detection signal can be used to reflect the peak voltage corresponding to the first voltage. Optionally, the voltage detection unit can be used to detect the peak voltage corresponding to the first voltage, and the obtained voltage detection signal is correlated with the peak voltage corresponding to the first voltage. For example, the voltage detection signal is positively correlated with the peak voltage corresponding to the first voltage, that is, the larger the peak voltage corresponding to the first voltage, the larger the voltage detection signal.

[0175] For example, the second target voltage can be greater than or equal to the peak voltage corresponding to the third voltage, and less than the peak voltage corresponding to the fourth voltage. When the voltage detection signal is less than or equal to the second target voltage, the first control module outputs a first level signal; when the voltage detection signal is greater than the second target voltage, the first control module outputs a second level signal. The first level signal controls the first communication module to adjust the resistance value of the step-down resistor unit to a first resistance value, and the second level signal controls the first communication module to adjust the resistance value of the step-down resistor unit to a second resistance value, wherein the first resistance value is less than the second resistance value.

[0176] In this embodiment, a voltage detection unit is set in the communication circuit of the indoor unit. The first control module includes a second comparator. The voltage detection unit detects the first voltage provided by the power supply to obtain a voltage detection signal. The first input terminal of the second comparator is connected to the voltage detection unit, and the second input terminal of the second comparator is input with a second target voltage. The second comparator compares the voltage detection signal with the second target voltage and outputs a level signal to adjust the resistance value of the step-down resistor unit. Since the voltage detection signal reflects the power supply type, the level signal obtained by comparing the voltage detection signal with the second target voltage through the second comparator adjusts the resistance value of the step-down resistor unit, ensuring that the adjusted resistance value of the step-down resistor unit is compatible with the power supply type.

[0177] In some embodiments, the power supply type may include a first power supply type and a second power supply type. The peak voltage corresponding to the first voltage provided by the power supply of the first power supply type is less than the peak voltage corresponding to the first voltage provided by the power supply of the second power supply type. The level signal includes a first level signal and a second level signal. The first level signal corresponds to the first power supply type and is used to control the first communication module to adjust the resistance value of the step-down resistor unit to a first resistance value. The second level signal corresponds to the second power supply type and is used to control the first communication module to adjust the resistance value of the step-down resistor unit to a second resistance value, wherein the first resistance value is less than the second resistance value.

[0178] It should be noted that the peak voltage corresponding to the first voltage provided by the power supply of the first power type is relatively small, while the peak voltage corresponding to the first voltage provided by the power supply of the second power type is relatively large. The first control module is also used to output a first level signal if the power supply corresponds to the first power type, and to output a second level signal if the power supply corresponds to the second power type.

[0179] For example, if the peak voltage corresponding to the first voltage provided by the power supply is 230V, the resistance of the step-down resistor unit is adjusted to 24KΩ. If the peak voltage corresponding to the first voltage provided by the power supply is 115V, the resistance of the step-down resistor unit is adjusted to 10.6KΩ.

[0180] In some embodiments, when the voltage detection signal is less than or equal to the target voltage, the first control module outputs a first level signal, and when the voltage detection signal is greater than the target voltage, the first control module outputs a second level signal.

[0181] In some embodiments, when the pulse width of the zero-crossing signal is greater than or equal to the pulse width threshold, the first control module outputs a first level signal; when the pulse width of the zero-crossing signal is less than the pulse width threshold, the first control module outputs a second level signal.

[0182] In this embodiment, when the power supply type is the first power supply type, i.e., the peak voltage of the first voltage is relatively small, the first control module outputs a first level signal to make the resistance of the step-down resistor unit relatively small, so as to ensure that the first communication unit can be driven to work. When the power supply type is the second power supply type, i.e., the peak voltage of the first voltage is relatively large, the first control module outputs a second level signal to make the resistance of the step-down resistor unit relatively large, thereby reducing the power consumption of the first communication unit.

[0183] In some embodiments, please refer to Figure 18 The communication circuit of the indoor unit may further include a power conversion module 1801, a rectifier bridge 1802, and a fifth capacitor C5. One end of the power conversion module 1801 is connected to the rectifier bridge 1802 and the fifth capacitor C5, and the other end of the power conversion module 1801 is connected to the first controller 1803. The AC power (such as 230V / 60Hz or 115V / 60Hz) supplied by the power supply is rectified into DC power by the rectifier bridge 1802 and the fifth capacitor C5, and then converted into DC power (such as 12V and 5V DC power) used by the power conversion module 1801 to power the first controller 1803 and related circuits. Optionally, the fifth voltage input terminal V5 is 5V, and the first voltage input terminal V1 is 5V.

[0184] In some embodiments, the first controller 1803 can be the control center of an air conditioner. The first controller 1803 includes a zero-crossing detection terminal and a selection terminal. The zero-crossing detection terminal is connected to the collector of the first transistor Q1 to obtain the zero-crossing signal output by the zero-crossing detection circuit. The selection terminal is connected to the second current-limiting resistor R8 and is used to output a level signal. Optionally, the first controller 1803 may include, but is not limited to, an MCU (Microcontroller Unit).

[0185] It should be noted that when zero crosses, the voltages of the neutral line (N) and the live line (L) are equal. At this time, the diode of the seventh optocoupler E7 is cut off, and the output voltage of the emitter of the seventh optocoupler E7 becomes low due to the grounding pull-down of the eleventh resistor R11. At this time, the base voltage of the first transistor Q1 is low, and the first transistor Q1 is turned off. The zero-crossing detection terminal is pulled up by the thirteenth resistor R13 and inputs a high level. At this time, zero crossing is determined.

[0186] When the voltages of the neutral line (N) and the live line (L) are not equal, the diode of the seventh optocoupler (E7) is turned on, the emitter voltage of the seventh optocoupler (E7) becomes high, the base voltage of the first transistor (Q1) is high, the first transistor (Q1) is saturated and turned on, the collector output of the first transistor (Q1) is low, and the zero-crossing detection terminal inputs a low level.

[0187] When the first voltage supplied by the power supply is 230V / 60Hz, the selection terminal of the first controller 1803 outputs a high-level signal, the first optocoupler E1 is in the off state, and the resistance of the step-down resistor unit is the resistance of the first resistor R1.

[0188] When the first voltage supplied by the power supply is 115V / 60Hz, the selection terminal of the first controller 1803 outputs a low-level signal, the first optocoupler E1 is in the conducting state, and the resistance value of the step-down resistor unit is the resistance value corresponding to the parallel resistance formed by the parallel connection of the first resistor R1 and the second resistor R2.

[0189] In this embodiment, the power supply type is determined by the pulse width of the zero-crossing signal detected by the zero-crossing detection circuit. By adding a selection unit to control the resistance value of the step-down resistor unit of the zero-crossing detection circuit, the identification and resistance adjustment for different power supply types are realized. This achieves a balance between circuit drive current and reduced circuit power consumption, realizes a universal circuit design, and solves the problem of abnormal air conditioner operation caused by market after-sales personnel not paying attention to identifying the power supply type due to different zero-crossing detection circuits for different power supplies.

[0190] This application also provides an air conditioner, which may include an indoor unit and an outdoor unit. The indoor unit may include the communication circuit of any of the indoor units provided in the above embodiments.

[0191] In this embodiment, the communication circuit of the indoor unit provided in the above embodiment is provided in the indoor unit of the air conditioner. The communication circuit of the indoor unit can automatically adjust the resistance value of the step-down resistor unit according to the power supply type, so as to take into account both the normal operation of the first communication module and the need to reduce the power consumption of the circuit.

[0192] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0193] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0194] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A communication circuit for an indoor unit, characterized in that, An indoor unit used in an air conditioner, the communication circuit of the indoor unit includes: The first communication module is connected to the communication circuit of the outdoor unit of the air conditioner. The first communication module is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit. A first control module is connected to the first communication module, and the first control module is used to control the first communication module to be in a receiving state or a sending state. The first communication module includes: The first communication unit is used to receive communication signals sent by the communication circuit of the outdoor unit, or to send communication signals to the communication circuit of the outdoor unit. A step-down resistor unit is connected to the power supply and the first communication unit respectively. The step-down resistor unit is used to step down the first voltage provided by the power supply to obtain a second voltage, which is used to power the first communication unit. The first control module is further configured to output a level signal corresponding to the power type according to the power type of the power supply, and the level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit.

2. The communication circuit of the indoor unit according to claim 1, characterized in that, The first communication module includes a first resistor and a selection unit. The first resistor is connected to the power supply, the selection unit and the first communication unit respectively. The selection unit is also connected to the first control module. The selection unit includes a second resistor connected to the first resistor; the step-down resistor unit consists of the first resistor, or is composed of the first resistor and the second resistor. The selection unit is configured to, based on the level signal, allow the current supplied by the power supply to pass through or not pass through the second resistor. When the current supplied by the power source passes through the second resistor, the resistance value of the step-down resistor unit is determined based on the resistance values ​​of the first resistor and the second resistor. When the current supplied by the power source does not pass through the second resistor, the resistance value of the step-down resistor unit is equal to the resistance value of the first resistor.

3. The communication circuit of the indoor unit according to claim 2, characterized in that, The selection unit is connected in parallel with the first resistor, and the selection unit is connected to the power supply and the first communication unit respectively. The selection unit also includes a first switch, which is connected in series with the second resistor. When the first switch is closed, the current supplied by the power source passes through the second resistor; When the first switch is in the open state, the current supplied by the power source does not pass through the second resistor.

4. The communication circuit of the indoor unit according to claim 3, characterized in that, The first switch includes a first optocoupler; The collector of the transistor in the first optocoupler is connected to the second resistor, the emitter of the first optocoupler is connected to the first communication unit and the first resistor, the anode of the diode in the first optocoupler is connected to the first voltage input terminal, and the cathode of the diode in the first optocoupler is connected to the first control module.

5. The communication circuit of the indoor unit according to claim 2, characterized in that, The selection unit further includes a second switch, the second resistor is connected in series with the first resistor, and the second resistor is connected to the power supply or the first communication unit, and the second switch is connected in parallel with the second resistor; When the second switch is in the off state, the current supplied by the power source passes through the second resistor; When the second switch is closed, the second resistor is short-circuited, and the current supplied by the power source does not pass through the second resistor.

6. The communication circuit of the indoor unit according to claim 1, characterized in that, The first voltage is an AC voltage, and the communication circuit of the indoor unit also includes a zero-crossing detection circuit; The zero-crossing detection circuit is connected to the power supply. The zero-crossing detection circuit is used to output a zero-crossing signal based on the first voltage. The zero-crossing signal is used to characterize the zero-point information of the first voltage. The first control module is also connected to the zero-crossing detection circuit, and the first control module is used to determine the power supply type corresponding to the power supply based on the zero-crossing signal.

7. The communication circuit of the indoor unit according to claim 1, characterized in that, The communication circuit of the indoor unit also includes a voltage detection unit, and the first control module also includes a comparator; The voltage detection unit is connected to the power supply and is used to detect the first voltage to obtain a voltage detection signal. The comparator has a first input terminal connected to the voltage detection unit, a second input terminal for inputting a target voltage, and an output terminal connected to the first communication module. The comparator is used to compare the voltage detection signal with the target voltage and output a level signal.

8. The communication circuit of the indoor unit according to claim 1, characterized in that, The power supply type includes a first power supply type and a second power supply type, wherein the peak voltage corresponding to the first voltage provided by the power supply of the first power supply type is less than the peak voltage corresponding to the first voltage provided by the power supply of the second power supply type, and the level signal includes a first level signal and a second level signal. The first level signal corresponds to the first power supply type, and the first level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit to the first resistance value; The second level signal corresponds to the second power supply type, and the second level signal is used to control the first communication module to adjust the resistance value of the step-down resistor unit to the second resistance value; The first resistance value is less than the second resistance value.

9. The communication circuit of the indoor unit according to claim 1, characterized in that, The first communication module includes a Zener diode, which is connected to the step-down resistor unit and the first communication unit respectively, wherein the second voltage is greater than or equal to the breakdown voltage of the Zener diode.

10. An air conditioner, characterized in that, include: Outdoor unit; The indoor unit includes the communication circuitry of the indoor unit as described in any one of claims 1 to 9.

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