Control circuit, controller and air conditioner

Abstract

The application provides a control circuit, which comprises a first resistor, a first end of the first resistor being connected with a VCC power supply, and a second end of the first resistor being connected with a first end of a switch module; a second resistor, a first end of the second resistor being connected with a second end of the switch module, and a second end of the second resistor being grounded; a third resistor, a first end of the third resistor being connected with the first end of the switch module, and a second end of the third resistor being connected with the second end of the switch module; and the switch module, a third end of the switch module being connected with a first bus, and a fourth end of the switch module being connected with a second bus, the switch module being used for switching on the connection between the second end of the first resistor and the first bus and the connection between the first end of the second resistor and the second bus. Thus, the control circuit can reduce signal distortion as much as possible, improve anti-interference performance, and enhance the reliability of the control circuit. Meanwhile, a small number of dial switches or relays and other components are used in the control circuit, so that low cost and easy maintenance can be achieved.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and in particular to a control circuit, controller, and air conditioner. Background Technology

[0002] With the development of electronic technology and the popularization of automation control, communication technology plays an irreplaceable role in data interaction, network construction, and remote control among various control devices. In particular, RS485 communication, as one of the earliest and most mature communication technologies, has been widely applied in various fields such as air conditioning, industrial control, and building automation due to its advantages such as low cost and ease of maintenance.

[0003] Therefore, how to design a control circuit to improve the versatility, anti-interference ability and reliability of RS485 and other communication processes has become an urgent problem to be solved. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] Therefore, the first objective of this application is to propose a control circuit that improves the versatility, anti-interference capability, and reliability of the communication process by designing a control circuit.

[0006] The second objective of this application is to propose a controller.

[0007] The third objective of this application is to propose an air conditioner.

[0008] To achieve the above objectives, a first aspect of this application provides a control circuit disposed in the controller. The control circuit includes: a first resistor, a first terminal of which is connected to a VCC power supply, and a second terminal of which is connected to a first terminal of a switching module; a second resistor, a first terminal of which is connected to a second terminal of the switching module, and the second terminal of which is grounded; a third resistor, a first terminal of which is connected to the first terminal of the switching module, and a second terminal of which is connected to the second terminal of the switching module; a third terminal of the switching module is connected to a first bus, and a fourth terminal of the switching module is connected to a second bus. The switching module is used to switch between connecting the second terminal of the first resistor to the first bus and between connecting the first terminal of the second resistor to the second bus.

[0009] The control circuit proposed in this application uses three resistors connected in series between VCC and GND (the grounding terminal of the wire), namely, a first resistor R1, a second resistor R2, and a third resistor R3, so that none of the three resistors are directly connected to the bus (the first bus). Furthermore, both ends of the third resistor R3 are connected to the first terminal of the switch module 10, and the second terminal of the switch module 10 is connected to the first bus. This allows the first resistor R1 to be connected to the first terminal of the first bus through the switch module 10, and the second resistor R2 to be connected to the second terminal of the first bus through the switch module 10, which minimizes signal distortion, improves anti-interference capability, and enhances the reliability of the control circuit. At the same time, using a smaller number of DIP switches or relays in the control circuit achieves low cost and ease of maintenance.

[0010] According to one embodiment of this application, the switch module includes: a DIP switch, the first terminal of which is connected to the second terminal of the first resistor and the second terminal of the third resistor respectively, the second terminal of which is connected to the first terminal of the second resistor and the second terminal of the third resistor respectively, the third terminal of which is connected to the first bus, and the fourth terminal of which is connected to the second bus.

[0011] According to one embodiment of this application, the switching module includes: a first solid-state relay, a first terminal of which is connected to a control signal input terminal, a second terminal of which is grounded, a third terminal of which is connected to a second terminal of a first resistor and a first terminal of a third resistor, and a fourth terminal of which is connected to a first bus; and a second solid-state relay, a first terminal of which is connected to the control signal input terminal, a second terminal of which is grounded, a third terminal of which is connected to a second bus, and a fourth terminal of which is connected to a first terminal of a second resistor and a second terminal of a third resistor.

[0012] According to one embodiment of this application, the first terminal of the first solid-state relay and the first terminal of the second solid-state relay are both connected to the control signal input terminal through a sixth resistor.

[0013] According to one embodiment of this application, it further includes: a fourth resistor, the first end of which is connected to the first end of the first resistor, and the second end of which is connected to the first bus.

[0014] According to one embodiment of this application, it further includes: a fifth resistor, the first end of which is connected to the second bus, and the second end of which is grounded.

[0015] According to one embodiment of this application, it further includes: a first protection module, the protection module including a first transient voltage suppression diode and a second transient voltage suppression diode; wherein, a first terminal of the first transient voltage suppression diode is connected to the first bus, and a second terminal of the first transient voltage suppression diode is grounded; a first terminal of the second transient voltage suppression diode is connected to the second bus, and a second terminal of the second transient voltage suppression diode is grounded.

[0016] According to one embodiment of this application, the protection module further includes: a second protection module, the second protection module including a third transient voltage suppression diode; wherein, a first terminal of the third transient voltage suppression diode is connected to the first bus, and a second terminal of the third transient voltage suppression diode is connected to the second bus.

[0017] To achieve the above objectives, a second aspect of this application provides a controller, including a control circuit as described in the first aspect of this application.

[0018] To achieve the above objectives, a third aspect of this application provides an air conditioner including a controller as described in the second aspect of this application. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a control circuit according to an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of a control circuit according to another embodiment of this application;

[0021] Figure 3 This is a schematic diagram of a control circuit according to another embodiment of this application;

[0022] Figure 4 This is a schematic diagram of a control circuit;

[0023] Figure 5 This is a schematic diagram of another control circuit;

[0024] Figure 6 This is a schematic diagram of yet another type of control circuit;

[0025] Figure 7 This is a schematic diagram of another type of control circuit;

[0026] Figure 8 This is a schematic diagram of a controller according to an embodiment of this application.

[0027] Figure 9 This is a schematic diagram of an air conditioner according to one embodiment of this application. Detailed Implementation

[0028] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0029] The control circuit, controller, and air conditioner of the present application embodiments are described below with reference to the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of the structure of a control circuit according to an embodiment of this application.

[0031] like Figure 1 As shown, the control circuit 100 in this embodiment is disposed in the controller 200. The control circuit 100 may specifically include: a first resistor R1, a second resistor R2, a third resistor R3, and a switch module 10.

[0032] Among them, the first resistor R1 has its first end connected to the VCC power supply (Circuit means circuit, i.e., the voltage connected to the circuit) and its second end connected to the first end of the switch module 10; the second resistor R2 has its first end connected to the second end of the switch module 10 and its second end grounded (connected to GND); the third resistor R3 has both ends connected to the switch module 10, that is, the first end of the third resistor R3 is connected to the first end of the switch module 10 and the second end is connected to the second end of the switch module 10; the third resistor R3 is connected in series with the first resistor R1 and the second resistor R2.

[0033] In this embodiment, the switch module 10 has its third terminal connected to the first bus (485A) and its fourth terminal connected to the second bus (485B). Optionally, the switch module 10 is used to switch the connection between the second terminal of the first resistor and the first bus, and between the first terminal of the second resistor and the second bus. It should be noted that in this application, the switch module 10 can be a software switch such as a signal relay or a solid-state relay, or a hardware switch such as a DIP switch or a jumper.

[0034] In this embodiment of the application, the first bus can be any bus, for example, the first bus can be an RS485A bus (abbreviated as 485A); the second bus can be any other bus, for example, the second bus can be an RS485B bus (abbreviated as 485B).

[0035] It should be noted that in this application, the first resistor R1, the second resistor R2, and the third resistor R3 are arranged on both sides of the first bus and the second bus, so that the configuration of the first resistor R1, the second resistor R2, and the third resistor R3 can be realized by controlling the switch module 10 (e.g., a 2-position DIP switch or two solid-state relays). In other words, the configuration of three resistors can be realized through two switches.

[0036] In summary, the control circuit proposed in this application uses three resistors connected in series between VCC and GND (the grounding terminal of the wire), namely, the first resistor R1, the second resistor R2, and the third resistor R3, so that none of the three resistors are directly connected to the bus (the first bus). Furthermore, both ends of the third resistor R3 are connected to the switch module 10. This allows the first resistor R1 to be connected to the first bus through the switch module 10, and the second resistor R2 to be connected to the second bus through the switch module 10, which minimizes signal distortion, improves anti-interference capability, and enhances the reliability of the control circuit. At the same time, using a smaller number of DIP switches or relays in the control circuit achieves low cost and ease of maintenance.

[0037] Furthermore, as one possible implementation, in this application, the first resistor R1 is a pull-up resistor, the second resistor R2 is a pull-down resistor, and the third resistor R3 is a terminating resistor.

[0038] In this case, the first resistor R1 and the second resistor R2 can both be bias resistors. In this way, the first resistor R1 is a pull-up bias resistor and the second resistor R2 is a pull-down bias resistor.

[0039] It's important to note that a pull-up resistor is a resistor connected between an I / O (Input / Output) interface and the power supply, which keeps an uncertain or insufficiently driven high-level potential at a high level. A larger pull-up resistor value results in stronger driving capability and better noise immunity, but also higher power consumption. In high-speed circuits, it provides some suppression of signal rising edges. A pull-down resistor, on the other hand, does the opposite.

[0040] It should be noted that the first resistor R1 and the second resistor R2 in this application are equal. In practical applications, a smaller resistance value results in stronger anti-interference capability, but an excessively small resistance value leads to a larger bias current supplied to the bus. In particular, when the bias current exceeds the chip's driving capability, it will affect normal communication. Therefore, the values ​​of the first resistor R1 and the second resistor R2 should be within a reasonable range. For example, the value range of the first resistor R1 and the second resistor R2 is 200~1K, or 10~40K. The value range can be set based on the principle of ensuring normal communication and according to the actual situation.

[0041] Among them, the third resistor R3 can be a terminating (matching) resistor.

[0042] It should be noted that the specific resistance value of the third resistor R3 is not limited in this application and can be set according to the actual situation. As one possible implementation, it can be set according to the impedance of the cable used. Optionally, the resistance value of the third resistor R3 can be set to a range of 100 to 120Ω, for example, 120Ω.

[0043] It should be noted that for RS485 communication applications, if the transmission distance is long or the communication rate is too high, communication quality may deteriorate. The main reason for this is that the signal is reflected on the bus and superimposed on the original signal, causing distortion. Therefore, the control circuit in this application adds a 120Ω terminating resistor to absorb the reflected signal.

[0044] It should be noted that, for RS-485 communication applications, one characteristic of RS-485 communication is that one bus corresponds to multiple RS-485 communication nodes, and the number of communication nodes is not fixed. This often makes it difficult to accurately determine the selection, total number, and resistance value of the bias resistors, thus hindering effective interference suppression and consequently compromising normal communication. Therefore, the control circuit in this application, in addition to adding a 120Ω terminating resistor, adds a first resistor R1 as a pull-up bias resistor and a second resistor R2 as a pull-down bias resistor. This prevents interference signals from entering the RX (Receive) terminal of the RS-485 chip from the bus due to significant environmental interference, thereby avoiding software errors and communication failures.

[0045] It should be noted that this application does not impose any restrictions on the specific selection of the switch module 10, which can be set according to the actual situation. Optionally, the switch module 10 may include a DIP switch or a solid-state relay.

[0046] The following explanation describes the switch module 10 in the control circuit 100 proposed in this application, focusing on the different types of switch units included in the switch module 10.

[0047] Regarding the switch module 10, which includes a DIP switch, one possible implementation is as follows: Figure 2 As shown, the switch module 10 includes a DIP switch. The first terminal of the DIP switch is the first terminal of the switch module 10, the second terminal of the DIP switch is the second terminal of the switch module 10, the third terminal of the DIP switch is the third terminal of the switch module 10, and the fourth terminal of the DIP switch is the fourth terminal of the switch module 10.

[0048] In this case, when the DIP switch is closed, i.e., switched to the ON position, the bias resistors (first resistor and second resistor) can be connected to the bus, thereby achieving high anti-interference capability of the control circuit.

[0049] It should be noted that in this application, the DIP switch can be replaced by a jumper.

[0050] It should be noted that, in this application, if the switch module 10 includes a DIP switch, the control circuit proposed in this application also includes a communication module and a capacitor C1. Optionally, the first terminal (Receive, RX) of the communication module is used for signal reception, the fourth terminal (Transmit, TX) is used for signal transmission, the fifth terminal is grounded, the sixth terminal is connected to the first bus, the seventh terminal is connected to the second bus, and the eighth terminal is connected to VCC; one end of the capacitor C1 is connected to VCC, and the other end is grounded.

[0051] It should be noted that if the switch module 10 includes a DIP switch, a 2-position DIP switch can be selected; if the switch module 10 includes a jumper, a 2-pin jumper can be selected.

[0052] It should be noted that in this application, if the switch module 10 includes a DIP switch, after the controller located at the end is configured when configuring the network, the controller can automatically turn on the DIP switches located at both ends of the bus if it detects that communication is not possible.

[0053] For the switch module 10, which includes a solid-state relay, as one possible implementation, such as Figure 3 As shown, the switch module 10 also includes: a first solid-state relay IC2 and a second solid-state relay IC3.

[0054] Among them, the third terminal K2A ​​of the first solid-state relay IC2 is the first terminal of the switching module, and the fourth terminal K2B is the third terminal of the switching module; the first terminal of the first solid-state relay IC2 is connected to the control signal input terminal, the second terminal is grounded, the third terminal is connected to the second terminal of the first resistor R1 and the first terminal of the third resistor R3 respectively, and the fourth terminal is connected to the first bus.

[0055] Among them, the third terminal K3B of the second solid-state relay IC3 is the fourth terminal of the switch module 10, and the fourth terminal K3A is the second terminal of the switch module 10; the first terminal of the second solid-state relay IC3 is connected to the control signal input terminal, the second terminal is grounded, the third terminal is connected to the second bus, and the fourth terminal is connected to the first terminal of the second resistor R2 and the second terminal of the third resistor R3 respectively.

[0056] It should be noted that in this application, the first solid-state relay and the second solid-state relay can be replaced by electromagnetic relays, transistors, MOSFETs, or other devices.

[0057] It should be noted that in this application, if the switch module 10 uses a solid-state relay, it can be configured remotely and intelligently through software.

[0058] Furthermore, the first terminal of both the first solid-state relay and the first terminal of the second solid-state relay are connected to the control signal input terminal through a sixth resistor.

[0059] Furthermore, the control circuit 100 also includes a fourth resistor R4.

[0060] Among them, the fourth resistor R4 has its first end connected to the first end of the first resistor R1, and its second end connected to the first bus.

[0061] Furthermore, the control circuit 100 also includes a fifth resistor R5.

[0062] Among them, the fifth resistor R5 has its first end connected to the second bus and its second end grounded.

[0063] It should be noted that if the relay is open, i.e. in the ON position, the bias resistors (first resistor R1 and second resistor R2) can be connected to the bus, thereby achieving high anti-interference capability of the control circuit.

[0064] Furthermore, when the switching module 10 includes a solid-state relay, the selection of the first resistor R1 and the second resistor R2 can be further optimized.

[0065] Optionally, the first resistor R1 and the second resistor R2 can both be strong bias resistors, that is, the first resistor R1 is a strong pull-up bias resistor and the second resistor R2 is a strong pull-down bias resistor, or both can be weak bias resistors, that is, the second resistor R2 is a weak pull-up bias resistor and the second resistor R2 is a weak pull-down bias resistor.

[0066] As one possible implementation, a first resistor R1 and a second resistor R2 that are both less than the first resistance threshold can be selected. In other words, the first resistor R1 can be selected as a strong pull-up bias resistor and the second resistor R2 can be selected as a strong pull-down bias resistor.

[0067] As another possible implementation, a first resistor R1 and a second resistor R2 greater than the first resistor threshold can be selected. That is, the first resistor R1 can be selected as a weak pull-up bias resistor and the second resistor R2 can be selected as a weak pull-down bias resistor.

[0068] Furthermore, when the switching module 10 includes a solid-state relay, the selection of the fifth resistor R5 and the sixth resistor R6 can be further optimized.

[0069] As one possible implementation, when the first resistor R1 and the second resistor R2 are strong pull-up and pull-down bias resistors respectively, the fifth resistor R5 and the sixth resistor R6 can be set as weak pull-up and pull-down bias resistors respectively.

[0070] The values ​​of the fifth resistor R5 and the sixth resistor R6 (weak pull-up and pull-down bias resistors) are between 10K and 100K. Furthermore, based on the principle that the more bus nodes there are, the larger the resistance value should be, preferably, the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 can be set to 47K to ensure that a weak bias resistor is provided for the bus before the strong pull-up and pull-down bias resistors are configured, in order to mitigate the impact of signal delay caused by the TVS junction capacitance of the protection device.

[0071] In this case, when the switching module 10 includes a solid-state relay, optionally, a strong pull-up bias first resistor R1 is connected to VCC and the output K2A of the first solid-state relay IC2, and the output K2B of IC2 is connected to the non-inverting input A of the 485 bus (i.e., the first bus 485A). Similarly, a strong pull-down bias second resistor R2 is connected to GND and the output K3A of the second solid-state relay IC3, and the output K3B of IC3 is connected to the inverting input B of the 485 bus (i.e., the second bus 485B). In this way, the resistors are controlled by the MOS output of the relays, further improving the anti-interference capability of the control circuit.

[0072] Furthermore, a third resistor R3 with a resistance of 120Ω is connected between the output K2A of IC2 and the output K3A of IC3. When the strong pull-up and pull-down bias resistors are enabled, the 120-ohm terminating resistor also takes effect. Moreover, the switching unit controls the two relays as inputs via software-controlled microcontroller pins. The strong pull-up and pull-down bias resistors and the terminating resistor are connected to the outputs of the two relays, thereby enabling the bias resistors to be turned on or off.

[0073] It should be noted that in this application, strong pull-up and pull-down bias resistors can be configured in combination with fixed pull-up and pull-down bias resistors. Furthermore, in order to facilitate mass production, the strong pull-up and pull-down bias resistors can be set to be generally set at both ends of the 485 bus before the switch is turned on.

[0074] Furthermore, the control circuit 100 proposed in this application also includes: a first protection module 20.

[0075] The first protection module 20 includes at least: a first transient voltage suppressor diode TVS (Transient Voltage Suppressor) 1 and a second transient voltage suppressor diode TVS 2.

[0076] Among them, the first transient voltage suppression diode TVS1 has its first terminal connected to the first bus and its second terminal grounded.

[0077] Among them, the second transient voltage suppression diode TVS2 has its first end connected to the second bus and its second end grounded.

[0078] Furthermore, the control circuit 100 proposed in this application also includes a second protection module 30.

[0079] The second protection module 30 includes a third transient voltage suppression diode, TVS3.

[0080] Among them, the third transient voltage suppressor diode TVS3 has its first terminal connected to the first bus and its second terminal connected to the second bus.

[0081] In summary, the control circuit proposed in this application, by adding a protection module consisting of at least two protection diodes (transient voltage suppression diodes), can quickly and effectively protect the precision components in the circuit, preventing damage from various surge pulses.

[0082] It should be noted that the following methods are commonly used in related technologies to improve the anti-interference capability of 485 communication.

[0083] The first type, such as Figure 4 As shown, the circuit only uses a 120Ω terminating resistor. However, using only a 120Ω terminating resistor often increases the bus load, consumes more drive current, and thus reduces the driving capability of the 485 chip. Furthermore, the lack of pull-up and pull-down bias resistors can easily lead to software errors and communication failures.

[0084] The second type, such as Figure 5 and 6 As shown, the circuit uses only a pull-up bias resistor R1 and a pull-down bias resistor R2. However, in this case, difficulties in resistor selection often result in low reliability of the bias resistor value, leading to communication failure.

[0085] The third type, such as Figure 7 As shown, the circuit uses a 120Ω terminating resistor as well as pull-up and pull-down bias resistors. However, in this case, multiple bias resistors are often used, such as three. This requires three switching units to be set simultaneously. If any one is omitted, the anti-interference function may not be achieved, and setting multiple switching units will inevitably increase the hardware material cost and complicate the layout.

[0086] Fourthly, the circuit uses twisted-pair shielded cable. However, in this case, since the 485 communication signal is a differential signal, using twisted-pair cable can reduce the bus coupling distributed capacitance, making the bus signal loop smaller and the anti-interference capability stronger. Using shielded cable and grounding can shield or reduce external interference noise and improve communication reliability. However, using shielded cable can only improve external electromagnetic interference, and has no effect on interference introduced through cable connection.

[0087] Therefore, the control circuit proposed in this application can uniformly configure the number of communication devices and their locations on the network, even for complex 485 communication systems. Besides using twisted-pair shielded cables to improve interference immunity, the 485 communication bus must be used in conjunction with a bias resistor when using a terminating matching resistor to ensure that signal reflection is eliminated without reducing drive capability. Furthermore, when the bus is idle, the difference between the differential signals A and B is greater than 0, improving noise immunity. Here, "network" refers to a network composed of devices with 485 communication capabilities.

[0088] Optionally, the control circuit 100 can configure three resistors (pull-up bias resistor, pull-down bias resistor, and 120Ω terminating resistor) using only two switching devices. The switching unit, such as a 2-position DIP switch, can simultaneously switch from OFF to ON, enabling the simultaneous opening or closing of the bias resistor and terminating resistor of a specific communication node, preventing the bias resistor or terminating resistor from being turned on only. This reduces setup complexity and cost, and ensures the correctness of resistor matching for multiple communication nodes under different networking conditions.

[0089] Furthermore, when software-controllable switching devices such as relays are used instead of DIP switches and jumpers as switching units, it is possible to achieve intelligent and remote configuration of bias resistors and terminal matching resistors, eliminating the need to disassemble the controller and manually set the DIP switches.

[0090] It should be noted that when the switching unit is not a relay, the switching unit (DIP switch or jumper) is in the OFF state by default. When the device is in a non-terminal (both ends) position of a network, the DIP switch does not need to be turned on. When the device is in the terminal position of the network, at least one device's two-position switching unit should be switched to the ON position. Preferably, the switching units of the two devices at the end should both be switched to the ON position. This can ensure that even when one device is not working, the bus still has a bias resistor to achieve the effect of anti-interference.

[0091] It should be noted that when the switching unit is a relay, the switching unit (first solid-state relay and second solid-state relay) is in the OFF state by default. When the device is in a non-terminal position of a network, the switching unit does not need to be turned on. When the device is in the terminal position of the network, at least one device's switching unit has both relays turned on at the same time. Preferably, both relays of the two devices at the end are in the ON state, which can ensure that the bus still has a bias resistor to achieve the effect of anti-interference when one of the devices is not working.

[0092] Furthermore, when the switching unit is a relay, optionally, in addition to setting strong pull-up and pull-down bias resistors (first resistor and second resistor), weak pull-up and pull-down bias resistors (fifth resistor and sixth resistor) can be set.

[0093] In summary, the control circuit proposed in this application ensures that when a 120-ohm terminating resistor is used on the bus, the strong bias resistor of the controller at the end of the bus is turned on, guaranteeing that the bias resistor provides sufficient current to compensate for the current consumption of the terminating matching resistor, thus improving the anti-interference performance of the 485 bus. Furthermore, the combination of strong and weak pull-up and pull-down bias resistors provides a more flexible and reliable configuration method. Optionally, the strong pull-up and pull-down bias resistors are used at both ends of the bus communication nodes, and the weak pull-up and pull-down bias resistors are used at all bus communication nodes, ensuring that the bus provides a weak bias resistor before the strong and pull-down bias resistors are configured, to mitigate the impact of signal delay caused by the TVS junction capacitance of the protection device. Furthermore, using relays enables intelligent and remote configuration of the terminating resistor and pull-up and pull-down resistors, making the field more flexible and convenient, and saving at least one switching unit, such as a 1-bit DIP switch, reducing the material cost of the product's bill of materials.

[0094] To implement the above embodiments, this application also proposes a controller. For example... Figure 8 As shown, the controller 200 proposed in this application embodiment may specifically include: the control circuit 100 shown in any of the above embodiments.

[0095] To achieve the above embodiments, this application also proposes an air conditioner 300, such as... Figure 9 As shown, the air conditioner 300 proposed in this application embodiment may specifically include: Figure 9 The controller 200 shown.

[0096] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., 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 this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0097] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A control circuit, characterized by The control circuit is arranged in a controller, and the control circuit comprises: a first resistor, a first end of the first resistor being connected with a VCC power supply, and a second end of the first resistor being connected with a first end of a switch module; a second resistor, a first end of the second resistor being connected with a second end of the switch module, and a second end of the second resistor being grounded; a third resistor, a first end of the third resistor being connected with the first end of the switch module, and a second end of the third resistor being connected with the second end of the switch module; a third end of the switch module being connected with a first bus, and a fourth end of the switch module being connected with a second bus, the switch module being used for switching on the connection between the second end of the first resistor and the first bus and the connection between the first end of the second resistor and the second bus, wherein the first resistor is an upper pull bias resistor, the second resistor is a lower pull bias resistor, and the third resistor is a terminal resistor; the switch module comprises: a dial switch, a first end of the dial switch being connected with the second end of the first resistor and the second end of the third resistor respectively, a second end of the dial switch being connected with the first end of the second resistor and the second end of the third resistor respectively, a third end of the dial switch being connected with the first bus, and a fourth end of the dial switch being connected with the second bus.

2. The control circuit of claim 1, wherein, the switch module comprises: a first solid-state relay, a first end of the first solid-state relay being connected with a control signal input end, a second end of the first solid-state relay being grounded, a third end of the first solid-state relay being connected with the second end of the first resistor and the first end of the third resistor respectively, and a fourth end of the first solid-state relay being connected with the first bus; a second solid-state relay, a first end of the second solid-state relay being connected with the signal input end, a second end of the second solid-state relay being grounded, a third end of the second solid-state relay being connected with the second bus, and a fourth end of the second solid-state relay being connected with the first end of the second resistor and the second end of the third resistor respectively.

3. The control circuit of claim 2, wherein, the first end of the first solid-state relay and the first end of the second solid-state relay are both connected with the control signal input end through a sixth resistor.

4. The control circuit of claim 1, wherein, further comprising: a fourth resistor, a first end of the fourth resistor being connected with the first end of the first resistor, and a second end of the fourth resistor being connected with the first bus.

5. The control circuit of claim 1, wherein, further comprising: a fifth resistor, a first end of the fifth resistor being connected with the second bus, and a second end of the fifth resistor being grounded.

6. The control circuit of claim 1, wherein, further comprising: a first protection module, the protection module comprising a first transient voltage suppression diode and a second transient voltage suppression diode; wherein a first end of the first transient voltage suppression diode being connected with the first bus, and a second end of the first transient voltage suppression diode being grounded; a first end of the second transient voltage suppression diode being connected with the second bus, and a second end of the second transient voltage suppression diode being grounded.

7. The control circuit of claim 6, wherein, further comprising: a second protection module, the second protection module comprising a third transient voltage suppression diode; wherein A first end of the third transient voltage suppression diode is connected to the first bus and a second end of the third transient voltage suppression diode is connected to the second bus.

8. A controller characterized by comprising: Comprising: The control circuit of any one of claims 1-7.

9. An air conditioner characterized by comprising: Comprising: The controller of claim 8.

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