Control chip, communication circuit and air conditioning system

Abstract

The application provides a control chip, a communication circuit and an air conditioning system. The control chip is internally provided with a signal transceiving module and a signal conversion module. The signal transceiving module and the signal conversion module are electrically connected. The signal conversion module is used for electrical connection with an external device. The signal transceiving module sends a first digital signal to the signal conversion module according to configuration information. The signal conversion module converts the first digital signal into a first differential signal and outputs the first differential signal to the external device. The signal conversion module also converts a second differential signal output by the external device into a second digital signal and outputs the second digital signal to the signal transceiving module. The signal transceiving module also receives the second digital signal. The application integrates the signal transceiving module and the signal conversion module in the control chip, solves the problem that the existing external chip occupies additional layout space of a substrate, causes the substrate design to be crowded and restricts product iteration efficiency.

Description

Technical Field

[0001] This application belongs to the field of air conditioning system technology, and in particular relates to a control chip, a communication circuit and an air conditioning system. Background Technology

[0002] In the field of air conditioning system control, the RS485 bus has become the core communication method for data interaction between indoor and outdoor units, or between indoor units and a centralized controller, due to its advantages of multi-node communication and long-distance transmission. In existing technologies, RS485 communication solutions generally adopt an architecture of "main control chip + external RS485 communication chip," that is, a separate external RS485 chip is used to convert digital signals to RS485 differential signals. However, the external chip requires additional layout space on the substrate, leading to a crowded substrate design and hindering product iteration efficiency. Utility Model Content

[0003] This application provides a control chip, communication circuit, and air conditioning system, which can solve the problem that the existing use of external chips occupies additional layout space on the substrate, resulting in a crowded substrate design and restricting product iteration efficiency.

[0004] In a first aspect, embodiments of this application provide a control chip, which includes a signal transceiver module and a signal conversion module. The signal transceiver module and the signal conversion module are electrically connected, and the signal conversion module is used to be electrically connected to an external device. The signal transceiver module is used to send a first digital signal to the signal conversion module according to the configuration information. The signal conversion module is used to convert the first digital signal into a first differential signal and output the first differential signal to the external device. The signal conversion module is also used to convert the received second differential signal output by the external device into a second digital signal and output the second digital signal to the signal transceiver module. The signal transceiver module is also used to receive the second digital signal.

[0005] In one possible implementation of the first aspect, the signal transceiver module is further configured to output a control signal to the signal conversion module, wherein the signal conversion module is configured to convert the first digital signal into the first differential signal or the second differential signal into the second digital signal according to the control signal. In one possible implementation of the first aspect, the signal conversion module includes a signal conversion unit, a filtering unit, and a sampling unit. The signal conversion unit is electrically connected to the signal transceiver module and the filtering unit, respectively. The sampling unit is electrically connected to the filtering unit and the signal transceiver module, respectively. The signal conversion unit is used to be electrically connected to the external device. The signal conversion unit is used to convert the second differential signal into an initial digital signal according to the control signal, and output the initial digital signal to the filtering unit; the filtering unit is used to filter the initial digital signal and output a filtered signal to the sampling unit; the sampling unit is used to sample the filtered signal to obtain the second digital signal. In one possible implementation of the first aspect, the signal conversion unit includes a differential comparator and a differential driver. The first input terminal, the second input terminal, the first output terminal, and the second output terminal of the differential driver are all electrically connected to the external device. The output terminal of the differential comparator is electrically connected to the filtering unit. The input terminal of the differential driver is electrically connected to the signal transceiver module. The control terminals of the differential comparator and the differential driver are both electrically connected to the signal transceiver module. In one possible implementation of the first aspect, the generation time of the control signal is the same as the generation time of the first digital signal.

[0006] In one possible implementation of the first aspect, the signal transceiver module includes an asynchronous transceiver electrically connected to the signal conversion module. Secondly, embodiments of this application provide a communication circuit including the control chip described in any one of the first aspects.

[0007] In one possible implementation of the second aspect, the communication circuit further includes a communication protection module connected between the control chip and the external device; The communication protection module is used to clamp the voltage on the transmission line between the control chip and the external device within a preset range. In one possible implementation of the second aspect, the communication protection module includes a first diode, a second diode, a third diode, a fourth diode, a first resistor, a second resistor, a third resistor, and a fourth resistor. The cathodes of the first diode, the second diode, and the first terminal of the second resistor are all electrically connected to a power supply. The anode of the first diode is electrically connected to the second terminal of the second resistor, the second terminal of the first resistor, the cathode of the third diode, and the external device. The cathode of the fourth diode is electrically connected to the anode of the second diode, the first terminal of the fourth resistor, the second terminal of the third resistor, and the external device. The anodes of the fourth diode, the third diode, and the second terminal of the fourth resistor are all grounded. The first terminals of the first resistor and the first terminals of the third resistor are both electrically connected to the control chip. Thirdly, embodiments of this application provide an air conditioning system, including a centralized control module and multiple indoor air conditioning units, wherein each indoor air conditioning unit includes the communication circuit described in any one of the second aspects, and the centralized control module and the multiple indoor air conditioning units are all connected to a bus.

[0008] The beneficial effects of the embodiments in this application compared with the prior art are: The control chip provided in this application embodiment includes a signal transceiver module and a signal conversion module, which are electrically connected. The signal conversion module is used for electrical connection with external devices. The signal transceiver module can output a first digital signal according to configuration information, and the signal conversion module can convert the first digital signal into a first differential signal for transmission to the external device. Furthermore, the signal conversion module can also convert a received second differential signal into a second digital signal, which the signal transceiver module receives, thus fully realizing bidirectional communication between the control chip and the external device. Therefore, this application integrates the signal transceiver module and the signal conversion module within the control chip, achieving the same communication function as the traditional "main control chip + external chip" solution without relying on an external communication chip. This significantly reduces the space occupied on the substrate layout, alleviating PCB (Printed Circuit Board) wiring pressure, reducing hardware design complexity, and supporting the rapid iteration of products such as air conditioners towards miniaturization and lightweighting, thereby enhancing the market competitiveness of the products. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art 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.

[0010] Figure 1 This is a schematic diagram of an existing solution for implementing RS485 communication; Figure 2 This is a schematic diagram of another existing scheme for implementing RS485 communication; Figure 3 This is a schematic block diagram of a control chip provided in one embodiment of this application; Figure 4 This is a schematic block diagram of a control chip provided in another embodiment of this application; Figure 5 This is a schematic block diagram of a control chip provided in another embodiment of this application; Figure 6 This is a circuit connection diagram of a control chip provided in an embodiment of this application; Figure 7 This is a circuit connection diagram of a signal conversion unit provided in an embodiment of this application; Figure 8 This is a schematic diagram of the transmission signal conversion provided in an embodiment of this application; Figure 9 This is a schematic diagram of received signal conversion provided in an embodiment of this application; Figure 10 This is a schematic block diagram of a communication protection module provided in one embodiment of this application; Figure 11 This is a schematic diagram of an air conditioning system provided in one embodiment of this application.

[0011] In the diagram: 101, signal transceiver module; 102, signal conversion module; 1021, signal conversion unit; 1022, filtering unit; 1023, sampling unit; 103, communication protection module; 200, external device. Detailed Implementation

[0012] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0013] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0014] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0015] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0016] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0017] In the field of air conditioning system control, the RS485 bus, due to its advantages of multi-node communication and long-distance transmission, has become the core communication method for data interaction between indoor and outdoor units, or between indoor units and centralized controllers. For example... Figure 1 and Figure 2 As shown, in existing technologies, RS485 communication solutions generally adopt an architecture of "main control chip + external RS485 communication chip," that is, the conversion between digital signals and RS485 differential signals is completed by a separate external RS485 chip. However, the external chip requires additional layout space on the substrate, resulting in a crowded substrate design and restricting product iteration efficiency.

[0018] To address the aforementioned issues, the control chip provided in this application includes a signal transceiver module and a signal conversion module, which are electrically connected. The signal conversion module is used for electrical connection with external devices. The signal transceiver module can output a first digital signal based on configuration information, and the signal conversion module can convert the first digital signal into a first differential signal for transmission to the external device. Furthermore, the signal conversion module can also convert a received second differential signal into a second digital signal, which the signal transceiver module receives, thus fully realizing bidirectional communication between the control chip and external devices. Therefore, this application integrates the signal transceiver module and the signal conversion module within the control chip, achieving the same communication functionality as the traditional "main control chip + external chip" solution without relying on an external communication chip. This significantly reduces the space occupied on the substrate layout, alleviating PCB routing pressure, reducing hardware design complexity, and supporting the rapid iteration of products such as air conditioners towards miniaturization and lightweight design, thereby enhancing the market competitiveness of the products. To illustrate the technical solution described in this application, specific embodiments are provided below.

[0019] Figure 3 A schematic block diagram of a control chip according to an embodiment of this application is shown. See also... Figure 3As shown, the control chip includes a signal transceiver module 101 and a signal conversion module 102, which are electrically connected. The signal conversion module 102 is used to electrically connect to an external device 200.

[0020] Specifically, the signal transceiver module 101 can output a first digital signal according to the configuration information, and the signal conversion module 102 can convert the first digital signal into a first differential signal for transmission to the external device 200. Furthermore, the signal conversion module 102 can also convert the received second differential signal into a second digital signal, which the signal transceiver module 101 receives, thus fully realizing bidirectional communication between the control chip and the external device 200 (such as an RS485 device). Therefore, this application integrates the signal transceiver module 101 and the signal conversion module 102 within the control chip, achieving the same communication function as the traditional "main control chip + external chip" solution without relying on an external communication chip. This significantly reduces the space occupied on the substrate layout, alleviating PCB routing pressure, reducing hardware design complexity, and supporting the rapid iteration of products such as air conditioners towards miniaturization and lightweight design, thereby enhancing the product's market competitiveness.

[0021] It should be noted that, as Figure 4 As shown, the signal transceiver module 101 and the signal conversion module 102 can be collectively referred to as the 485 module. The control chip has a built-in 485 module, which simplifies the traditional dual-chip architecture of "main control chip + external RS485 communication chip" to a single-chip integrated architecture. There is no need to deploy an independent RS485 communication chip on the substrate, nor is there a need to design complex connection circuits between the external chip and the main control chip. At the same time, the signal conversion module 102 in the 485 module is directly connected to the external device 200 through the RS485 bus (two differential signal lines A and B). This not only meets the requirements of RS485 bus multi-node communication and long-distance transmission, but also, through the collaborative work within the module (the signal transceiver module 101 processes digital signals, and the signal conversion module 102 realizes bidirectional conversion between digital signals and differential signals), it can stably complete RS485 data interaction between the control chip and the external device 200. Ultimately, it achieves the same communication function as the external RS485 chip solution, and has the dual advantages of hardware simplification and cost optimization.

[0022] It should be noted that the configuration information used by the transceiver module is a set of key parameters that ensure RS485 communication adapts to the air conditioning system's requirements and achieves stable data transmission. Specifically, it may include basic communication timing parameters (such as baud rate), data bit length, parity bit type, stop bit count, functional configuration parameters (such as data transmission enable conditions), and signal filtering parameters. This configuration information is typically written by software through the control chip's registers and can be flexibly adjusted according to the communication requirements of different air conditioning models. This ensures that the first digital signal output by the transceiver module 101 is compatible with the reception rules of external RS485 devices while also ensuring the real-time and accuracy requirements of the air conditioning system for control command transmission, laying the foundation for subsequent signal conversion and data interaction.

[0023] In one embodiment of this application, such as Figure 5 As shown, the signal transceiver module 101 is also used to output a control signal DE to the signal conversion module 102. The signal conversion module 102 is used to convert the first digital signal into a first differential signal or convert the second differential signal into a second digital signal according to the control signal DE.

[0024] Specifically, the control signal DE includes a first control signal and a second control signal. The signal conversion module 102 is used to convert the first digital signal into a first differential signal according to the first control signal, and also to convert the second differential signal into a second digital signal according to the second control signal. Therefore, the signal conversion module 102 can achieve precise and synchronous switching of the working mode according to different control signals.

[0025] It should be noted that the generation time of the control signal is the same as the generation time of the first digital signal. When the signal transceiver module 101 outputs the first digital signal in preparation for transmission, the control signal can synchronously trigger the signal conversion module 102 to start the differential drive function, avoiding control signal lag and ensuring that the digital signal is efficiently converted into a differential signal and transmitted through the RS485 bus. When it is necessary to receive signals from the external device 200, the control signal can promptly switch the signal conversion module 102 to the differential receiving function, accurately converting the second differential signal from the external RS485 bus into a digital signal, avoiding signal interference or data loss caused by transmission and reception conflicts, and ensuring the timing accuracy of RS485 communication between the control chip and the external device 200. In addition, this design eliminates the need to build an additional mode switching circuit outside the control chip, which simplifies the hardware structure, reduces the space occupied by the substrate layout, and avoids timing deviations caused by external circuit delays. Meanwhile, the control signal is directly output by the signal transceiver module 101, which shortens the transmission path of the control command, reduces signal loss and interference risk, and further improves the stability and response speed of RS485 communication, ensuring that the transmission of control commands (such as temperature adjustment and on / off) and status feedback (such as equipment operating parameters) in the air conditioning system is efficient and error-free.

[0026] The following is combined with Figures 6 to 10 The circuit diagrams provided for each unit describe in detail the working process and working principle of the control chip and communication circuit provided in the embodiments of this application.

[0027] In one embodiment of this application, such as Figure 6 As shown, the signal transceiver module 101 includes an asynchronous transceiver UART, which is electrically connected to the signal conversion module 102.

[0028] Specifically, the asynchronous transceiver is a key functional unit for data interaction between the control chip and the external device 200. It can send and receive data. When sending data, the asynchronous transceiver can send a first digital signal (TXD) according to preset configuration information (such as baud rate and data bit length) and simultaneously output a first control signal to the signal conversion module 102, triggering the signal conversion module 102 to convert the first digital signal into a first differential signal. When receiving data, the asynchronous transceiver can receive the second digital signal (RXD) output by the signal conversion module 102 under the trigger of the second control signal. Through built-in timing detection and data verification logic, it can parse the valid information fed back by the external device 200 (such as the outdoor unit operating status and bus communication status) and transmit the parsing results to the core control unit of the control chip, providing data support for the operation and control of the air conditioning system. At the same time, the asynchronous transceiver can achieve synchronous data transmission without relying on an external clock signal, adapting to multi-node, long-distance communication scenarios of RS485 bus, ensuring the accuracy of data transmission between the control chip and the external device 200, and simplifying the design of the communication link.

[0029] In one embodiment of this application, such as Figure 6 As shown, the signal conversion module 102 includes a signal conversion unit 1021, a filtering unit 1022, and a sampling unit 1023. The signal conversion unit 1021 is electrically connected to the signal transceiver module 101 and the filtering unit 1022, respectively. The sampling unit 1023 is electrically connected to the filtering unit 1022 and the signal transceiver module 101, respectively. The signal conversion unit 1021 is used to electrically connect to the external device 200.

[0030] Specifically, the signal conversion unit 1021 converts the second differential signal into an initial digital signal RXD_raw according to the second control signal, and outputs the initial digital signal RXD_raw to the filtering unit 1022, completing the physical signal form conversion from "differential signal to digital signal" and providing a foundation for subsequent processing. The filtering unit 1022 addresses potential bus interference (such as electromagnetic noise and signal glitches) carried in the initial digital signal RXD_raw by using preset filtering rules (such as limiting signal transition thresholds and smoothing high-frequency fluctuations) to reduce noise, outputting a more stable filtered signal and preventing interference signals from entering subsequent stages and causing data misjudgment. The sampling unit 1023 accurately samples the filtered signal, filters out valid level states that conform to the communication protocol, and finally generates a second digital signal that the signal transceiver module 101 can directly parse, ensuring that the information fed back by the external device 200 can be accurately recognized by the control chip.

[0031] It should be noted that the initial digital signal RXD_raw is continuously sampled based on the system clock. When N consecutive identical level signals are acquired, it is determined to be a valid signal and retained; if the condition of N consecutive identical level signals cannot be met, it is determined to be a glitch signal and filtered. The filter width corresponding to the number of consecutive samples (N) used to determine a valid signal can be flexibly configured through registers. The software can design adaptive filtering algorithms according to the actual application scenario (such as the field electromagnetic environment, bus interference intensity, etc.), thereby effectively suppressing noise interference and ensuring the accuracy of signal transmission under different operating conditions.

[0032] It should be noted that the sampling unit 1023 has a sampling point adjustment function to adapt to different signal waveform scenarios. Theoretically, the ideal sampling point for an RS485 signal is the middle position of the high / low level transition (i.e., 50% of the time within 1 bit). This point minimizes the impact of signal edge jitter and ensures sampling accuracy. However, in practical applications, due to factors such as bus interference and transmission distance, signal waveforms are prone to distortion and edge delays. If sampling is fixed at the 50% point, incorrect values ​​may be acquired. Therefore, a flexible sampling point adjustment mechanism can be designed, with a minimum step size of one-sixteenth of the 1 bit time. The sampling position can be freely set within the range of 1 / 16 to 16 / 16 of the 1 bit time (i.e., from the start to the end of the signal). The software can select the most stable point for sampling based on the actual state of the signal waveform, effectively improving sampling reliability under non-ideal waveforms.

[0033] It should be noted that, Figure 6The system also includes an I / O control unit connected to the signal conversion unit. The core function of this I / O control is to connect an external LED (Light-Emitting Diode) and precisely control it. Specifically, the I / O control receives the initial digital signal RXD_raw and outputs corresponding control commands to drive the LED to light up, providing a clear indication of normal communication. When a communication anomaly occurs, the I / O control module can turn the LED off or flash it, indicating a problem with the current communication link. This design, through the visual status of the LED, helps technicians quickly assess the operating condition of the control chip, simplifying subsequent debugging and troubleshooting processes and improving the convenience of circuit maintenance.

[0034] It should be noted that, as Figure 7 As shown, the signal conversion unit 1021 includes a differential comparator and a differential driver. The first input terminal of the differential comparator, the second input terminal of the differential comparator, the first output terminal of the differential driver, and the second output terminal of the differential driver are all used for electrical connection with the external device 200. The output terminal of the differential comparator is electrically connected to the filtering unit 1022. The input terminal of the differential driver is electrically connected to the signal transceiver module 101. The control terminals of the differential comparator and the differential driver are both electrically connected to the signal transceiver module 101.

[0035] Specifically, the differential comparator and differential driver, as core components of the signal conversion unit 1021, respectively undertake the signal conversion functions during RS485 communication data transmission and reception, working together to achieve bidirectional data interaction between the control chip and the external device 200. The core function of the differential driver is to complete the conversion from digital signal to RS485 differential signal. Its input receives the first digital signal output from the signal transceiver module 101. Triggered by the first control signal output from the signal transceiver module 101, it outputs the corresponding first differential signal (A / B line differential signal) to the external device 200 through its first and second output terminals, adapting to the differential transmission characteristics of the RS485 bus. For specific signal conversion relationships, please refer to [link to relevant documentation]. Figure 8 As shown. The core function of the differential comparator is to convert the RS485 differential signal into an initial digital signal RXD_raw. Its first and second input terminals receive the second differential signal transmitted from the external device 200 via the RS485 bus. Under the control of the second control signal output by the signal transceiver module 101, it compares the level difference between the two differential signals and converts it into an initial digital signal RXD_raw that the control chip can process. When A > B, the initial digital signal RXD_raw is high; when A < B, the initial digital signal RXD_raw is low. For specific signal conversion relationships, please refer to [reference needed]. Figure 9As shown. Furthermore, the control terminals of both the differential comparator and the differential driver are connected to the signal transceiver module 101, allowing for precise switching of operating modes based on control signals (operating modes include a first operating mode and a second operating mode; the first control signal disables the differential comparator and activates the differential driver, operating in the first mode; the second control signal disables the differential driver and activates the differential comparator, operating in the second mode. The control signals received by the differential driver and differential comparator are mutually exclusive; when the control signal received by the differential driver is high, the control signal received by the differential comparator is low; and when the control signal received by the differential driver is low, the control signal received by the differential comparator is high). This avoids transmission and reception conflicts and ensures the timeliness and accuracy of RS485 differential signal to digital signal conversion, providing hardware support for stable communication between the control chip and the external device 200.

[0036] In summary, after the differential signal is converted into the initial digital signal RXD_raw by the signal conversion unit 1021, the noise is filtered by the filtering unit 1022, and the effective signal is extracted by the sampling unit 1023, the RS485 differential signal can be accurately converted into an RXD signal that meets the parsing requirements of the signal transceiver module 101, enabling the signal transceiver module 101 to parse it normally, and finally realizing the effective conversion of the feedback information from the external device 200 into data that the control chip can recognize.

[0037] This application also discloses a communication circuit, including the aforementioned control chip. Using this control chip, the communication circuit can directly achieve bidirectional conversion between digital signals and RS485 differential signals, enabling RS485 bus communication with external devices without relying on an external communication chip. This design simplifies the hardware structure of the communication circuit, reduces the number of components and layout space on the PCB substrate, and lowers wiring difficulty and hardware costs.

[0038] Since the RS485 signal is output directly from the chip, in order to protect the chip, in one embodiment of this application, such as Figure 10 As shown, the communication circuit also includes a communication protection module 103, which is connected between the signal conversion module 102 and the external device 200. The communication protection module 103 is used to clamp the voltage on the transmission line between the signal conversion module 102 and the external device 200 within a preset range.

[0039] Specifically, in practical applications, the start / stop of external device 200, bus interference, or lightning strikes may cause abnormally high or low voltages in the transmission line between signal conversion module 102 and external device 200. If these abnormal voltages directly act on signal conversion module 102, they can easily damage the chip interface or internal circuitry, thus interrupting communication. Communication protection module 103 can monitor voltage changes in the transmission line in real time. Once it detects that the voltage exceeds the preset safety range, it will quickly clamp the line voltage within the safe range using built-in clamping elements (such as Zener diodes). This prevents abnormal voltages from causing hardware damage to signal conversion module 102 and control chip, and also prevents voltage fluctuations from causing differential signal distortion. This ensures that the RS485 signal transmitted between signal conversion module 102 and external device 200 is always at a stable and safe level, providing crucial protection for the reliable operation of the entire communication circuit.

[0040] In one embodiment of this application, such as Figure 10 As shown, the communication protection module 103 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The cathodes of the first diode D1, the second diode D2, and the first terminal of the second resistor R2 are all electrically connected to the power supply. The anode of the first diode D1 is electrically connected to the second terminal of the second resistor R2, the second terminal of the first resistor R1, the cathode of the third diode D3, and the external device 200. The cathode of the fourth diode D4 is electrically connected to the anode of the second diode D2, the first terminal of the fourth resistor R4, the second terminal of the third resistor R3, and the external device 200. The anodes of the fourth diode D4, the anodes of the third diode D3, and the second terminal of the fourth resistor R4 are all grounded. The first terminals of the first resistor R1 and the first terminals of the third resistor R3 are both electrically connected to the signal conversion module 102.

[0041] Specifically, diodes D1, D2, D3, and D4 act as clamping elements, forming a bidirectional clamping circuit through a specific connection of their anodes and cathodes. When an excessively high voltage occurs on the transmission line between the external device 200 and the signal conversion module 102, the diodes reverse-bias breakdown and clamp the voltage to near the power supply level. When an excessively low voltage occurs (close to ground level), the diodes forward-bias conduct and limit the voltage to near the ground level, thereby ensuring that the RS485 bus level is always within the safe range that the control chip can withstand, preventing abnormal voltage from impacting the chip. Furthermore, resistors R1 and R2 are connected in series between the signal conversion module 102 and the bus to limit the current flowing through the chip interface, preventing current overload from damaging the chip's internal circuitry. Resistors R3 and R4 are connected to the bus and the power supply, and the bus and ground, respectively. Through reasonable impedance configuration, a stable positive and negative level is maintained when there is no data transmission on the bus, preventing misjudgment by the signal conversion module 102 due to level drift, ultimately achieving hardware protection for the chip and ensuring the stability of bus communication.

[0042] It should be noted that, Figure 10 CN4 in the configuration is an RS485 port used to connect external device 200.

[0043] This application also discloses an indoor air conditioner unit, including the aforementioned communication circuit. Using this communication circuit, the indoor air conditioner unit can efficiently achieve 485 bus communication with external devices such as the outdoor air conditioner unit and a centralized controller. This allows for stable transmission of control data such as temperature adjustment commands and power-on / off signals from the indoor unit, while also accurately receiving operating status feedback from external devices, providing reliable data support for the coordinated operation of the air conditioning system. Simultaneously, it significantly simplifies the hardware layout of the indoor unit's control board, reducing the board's footprint. This not only lowers the hardware cost and PCB wiring complexity of the indoor unit but also aligns with the design trend towards miniaturization and thinner designs for indoor units. like Figure 11 As shown in the illustration, this application also discloses an air conditioning system, including a centralized control module (such as a central controller) and multiple indoor air conditioning units as described above. The centralized control module and the multiple indoor air conditioning units are all connected to a bus. By using multiple indoor air conditioning units, the air conditioning system can achieve efficient and unified coordination with the centralized control module by relying on the control chips built into each indoor unit.

[0044] The centralized control module can send operating instructions (such as uniform temperature setting, on / off sequence, and fan speed setting) to all indoor units synchronously via the bus. Each indoor unit can accurately receive and execute the instructions through its own control chip, and at the same time, feed back its own operating status (such as actual room temperature, fan operating parameters, and fault codes) to the centralized control module in real time. This makes it easier for managers to monitor and flexibly schedule multiple indoor units in batches, greatly improving the management efficiency of the air conditioning system.

[0045] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A control chip, characterized in that, The control chip includes a signal transceiver module and a signal conversion module, which are electrically connected. The signal conversion module is used to electrically connect to external devices. The signal transceiver module is used to send a first digital signal to the signal conversion module according to the configuration information. The signal conversion module is used to convert the first digital signal into a first differential signal and output the first differential signal to the external device. The signal conversion module is also used to convert the received second differential signal output by the external device into a second digital signal and output the second digital signal to the signal transceiver module. The signal transceiver module is also used to receive the second digital signal.

2. The control chip according to claim 1, characterized in that, The signal transceiver module is further configured to output a control signal to the signal conversion module, and the signal conversion module is configured to convert the first digital signal into the first differential signal or the second differential signal into the second digital signal according to the control signal.

3. The control chip according to claim 2, characterized in that, The signal conversion module includes a signal conversion unit, a filtering unit, and a sampling unit. The signal conversion unit is electrically connected to the signal transceiver module and the filtering unit, respectively. The sampling unit is electrically connected to the filtering unit and the signal transceiver module, respectively. The signal conversion unit is used to electrically connect to the external device. The signal conversion unit is used to convert the second differential signal into an initial digital signal according to the control signal, and output the initial digital signal to the filtering unit; the filtering unit is used to filter the initial digital signal and output a filtered signal to the sampling unit; the sampling unit is used to sample the filtered signal to obtain the second digital signal.

4. The control chip according to claim 3, characterized in that, The signal conversion unit includes a differential comparator and a differential driver. The first input terminal, the second input terminal, the first output terminal, and the second output terminal of the differential driver are all electrically connected to the external device. The output terminal of the differential comparator is electrically connected to the filtering unit. The input terminal of the differential driver is electrically connected to the signal transceiver module. The control terminals of the differential comparator and the differential driver are both electrically connected to the signal transceiver module.

5. The control chip according to claim 2, characterized in that, The generation time of the control signal is the same as the generation time of the first digital signal.

6. The control chip according to claim 1, characterized in that, The signal transceiver module includes an asynchronous transceiver, which is electrically connected to the signal conversion module.

7. A communication circuit, characterized in that, Includes the control chip described in any one of claims 1-6.

8. The communication circuit according to claim 7, characterized in that, The communication circuit also includes a communication protection module, which is connected between the control chip and the external device. The communication protection module is used to clamp the voltage on the transmission line between the control chip and the external device within a preset range.

9. The communication circuit according to claim 8, characterized in that, The communication protection module includes a first diode, a second diode, a third diode, a fourth diode, a first resistor, a second resistor, a third resistor, and a fourth resistor. The cathodes of the first diode, the second diode, and the first terminal of the second resistor are all electrically connected to the power supply. The anode of the first diode is electrically connected to the second terminal of the second resistor, the second terminal of the first resistor, the cathode of the third diode, and the external device. The cathode of the fourth diode is electrically connected to the anode of the second diode, the first terminal of the fourth resistor, the second terminal of the third resistor, and the external device. The anodes of the fourth diode, the third diode, and the second terminal of the fourth resistor are all grounded. The first terminals of the first resistor and the first terminals of the third resistor are both electrically connected to the control chip.

10. An air conditioning system, characterized in that, It includes a centralized control module and multiple indoor air conditioning units, wherein each indoor air conditioning unit includes the communication circuit described in any one of claims 7-9, and the centralized control module and the multiple indoor air conditioning units are all connected to a bus.

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