Terminal resistance adjusting circuit, communication system and household appliance

Abstract

The utility model relates to a terminal resistor adjusting circuit, a communication system and a household appliance, one end of a terminal resistor is directly connected with a communication bus, the other end of the terminal resistor is connected with the communication bus through a switching device, the switching device is connected with a processing device, and the processing device is connected with a voltage acquisition device. The bus voltage of the communication bus is acquired by the voltage acquisition device. Therefore, when the communication bus is connected with the load equipment with the terminal resistor, the resistance value connected to the communication bus is changed, and the bus voltage of the communication bus is reduced, the condition can be detected in time. Through the mode, the phenomenon that the bus voltage is reduced due to repeated installation of the terminal resistors can be relieved, and the bus communication quality is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a terminal resistance adjustment circuit, a communication system and a household appliance. Background Art

[0002] In bus communication solutions, it is usually necessary to set terminal resistors on the upper or lower computer side. For example, in CAN (Controller Area Network) bus communication, terminal resistors need to be connected at both ends of the communication line to ensure the load during normal communication.

[0003] In actual communication scenarios, different types and numbers of load devices will be connected to the communication bus according to different communication requirements, and it is inevitable that load devices equipped with terminal resistors will be connected. The connection of the terminal resistor of the load device will cause the resistance value of the connected communication bus to change, thus affecting the quality of bus communication. Utility Model Content

[0004] Based on this, it is necessary to provide a terminal resistance adjustment circuit, a communication system and a household appliance to improve the quality of bus communication.

[0005] A terminal resistance adjustment circuit comprises: a voltage acquisition device, a processing device and a switch device, wherein the voltage acquisition device is connected to a communication bus and is used to acquire the bus voltage of the communication bus; the processing device is connected to the voltage acquisition device and is used to output a disconnection control signal when the bus voltage is less than a preset communication voltage; a first end of the switch device is connected to the processing device, a second end of the switch device is connected to the communication bus via a terminal resistor, and a third end of the switch device is connected to the communication bus, and the switch device enters a disconnection operation state when receiving the disconnection control signal.

[0006] In one embodiment, the processing device includes a first comparator, a first input terminal of the first comparator is connected to the voltage acquisition device, a second input terminal of the first comparator is used to connect to a reference voltage source, an output terminal of the first comparator is connected to the switching device, a power supply terminal of the first comparator is used to connect to a power supply, and a ground terminal of the first comparator is grounded; wherein the output voltage of the reference voltage source is the preset communication voltage.

[0007] In one embodiment, the processing device is a hysteresis comparison circuit, which includes: a second comparator, a first resistor component, a second resistor component and a third resistor component, the first input end of the second comparator is connected to the voltage acquisition device, the second input end of the second comparator is connected to the first end of the first resistor component, the first end of the second resistor component and the first end of the third resistor component, the second end of the first resistor component is used to connect to a power supply, the second end of the second resistor component is connected to a ground end of the second comparator, the second end of the third resistor component is connected to the output end of the second comparator, the power supply end of the second comparator is used to connect to a power supply, and the ground end of the second comparator is grounded.

[0008] In one embodiment, the upper threshold voltage of the hysteresis comparison circuit is: The lower threshold voltage of the hysteresis comparison circuit is: Among them, the lower threshold voltage is the preset communication voltage, UfH represents the upper threshold voltage, UfL represents the lower threshold voltage, R1 represents the resistance value of the first resistor component, R2 represents the resistance value of the second resistor component, R3 represents the resistance value of the third resistor component, and VCC represents the voltage value of the voltage source.

[0009] In one embodiment, the processing device includes a processor, an input end of the processor is connected to the voltage acquisition device, and an output end of the processor is connected to the switch device.

[0010] In one of the embodiments, the voltage acquisition device includes a resistor voltage divider circuit, and the resistor voltage divider circuit connects the communication bus and the processing device.

[0011] In one embodiment, the resistor divider circuit includes a fourth resistor component and a fifth resistor component, the first end of the fourth resistor component is connected to the communication bus, the second end of the fourth resistor component is connected to the first end of the fifth resistor component and the processing device, and the second end of the fifth resistor component is grounded.

[0012] In one embodiment, the switching device includes a power switching device, a control end of the power switching device is connected to the processing device, an input end of the power switching device is connected to the communication bus through the terminal resistor, and an output end of the power switching device is connected to the communication bus.

[0013] A communication system comprises a communication bus and the above-mentioned terminal resistance adjustment circuit.

[0014] A household appliance comprises the above communication system.

[0015] In the above-mentioned terminal resistance adjustment circuit, communication system and household appliance, one end of the terminal resistance is directly connected to the communication bus, and the other end of the terminal resistance is connected to the communication bus through a switching device, the switching device is connected to a processing device, and the processing device is connected to a voltage acquisition device to receive the bus voltage of the communication bus acquired by the voltage acquisition device. In this way, when a load device of the type with a built-in terminal resistance is connected to the communication bus, the resistance value connected to the communication bus changes, causing the bus voltage of the communication bus to decrease, which can be detected in time. Specifically, when a load device with a built-in terminal resistance is connected, so that the bus voltage is less than or equal to the preset communication voltage, the processing device will output a disconnection control signal to the switch device to control the switch device to enter a disconnection operation state, thereby interrupting the connection between the terminal resistance and the communication bus and increasing the resistance value connected to the communication bus. In this way, the phenomenon of bus voltage reduction caused by repeated installation of terminal resistances can be alleviated, and the quality of bus communication can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a schematic diagram of the structure of a terminal resistance adjustment circuit in an embodiment of the present application;

[0018] Figure 2 This is a schematic diagram of the structure of a terminal resistance adjustment circuit in another embodiment of the present application;

[0019] Figure 3 This is a schematic diagram of the structure of a terminal resistance adjustment circuit in another embodiment of the present application;

[0020] Figure 4 This is a schematic diagram of the structure of a terminal resistance adjustment circuit in another embodiment of the present application;

[0021] Figure 5 This is a schematic diagram of the structure of a terminal resistance adjustment circuit in another embodiment of the present application;

[0022] Figure 6 This is a schematic diagram of the structure of a terminal resistance adjustment circuit in another embodiment of the present application;

[0023] Figure 7 This is a schematic diagram of the terminal resistance adjustment circuit structure in another embodiment of the present application.

[0024] Description of reference numerals:

[0025] 110-voltage acquisition device, 120-processing device, 130-switch device, R-terminal resistor, L1-first bus, L2-second bus, 200-communication bus; U1-first comparator, U2-second comparator, R1-first resistor component, R2-second resistor component, R3-third resistor component, R4-fourth resistor component, R5-fifth resistor component, Q1-power switch device; VCC-power supply, Vf-reference voltage source; 121-processor. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0027] The terminal resistance adjustment circuit provided in the embodiment of the present application is applied to a device that needs to set a terminal resistance between communication buses and communicate through such a communication bus, which can be a household appliance or other types of equipment, such as an air conditioner, a refrigerator, etc., without specific limitation. Among them, the type of communication bus is not unique, as long as it is a communication bus that needs to connect terminal resistances at both ends during the communication process, such as a CAN bus, without specific limitation.

[0028] See also Figure 1 The present application provides a terminal resistance adjustment circuit, including: a voltage acquisition device 110, a processing device 120 and a switch device 130, the voltage acquisition device 110 is connected to the communication bus 200, and is used to acquire the bus voltage of the communication bus 200; the processing device 120 is connected to the voltage acquisition device 110, and is used to output a disconnection control signal when the bus voltage is less than a preset communication voltage; the first end of the switch device 130 is connected to the processing device 120, the second end of the switch device 130 is connected to the communication bus 200 through a terminal resistor R, and the third end of the switch device 130 is connected to the communication bus 200. When the switch device 130 receives the disconnection control signal, it enters a disconnection operation state.

[0029] Specifically, the voltage acquisition device 110 is a device that can realize the voltage acquisition function, which can be a voltage sensor, a voltage transformer, etc., or other circuits or devices with voltage acquisition function, and there is no specific limitation. The bus voltage is the voltage value of the electrical signal flowing through the communication bus 200 when the communication bus 200 is transmitting the communication signal. The preset communication voltage is the preset minimum voltage value that needs to be satisfied on the communication bus 200 when the communication bus 200 realizes the communication function. The processing device 120 is a device that has the function of comparing the bus voltage with the preset communication voltage, and outputs different control signals according to different comparison results. The switching device 130 is a device that can enter the on-state or off-state when receiving different control signals.

[0030] During the communication process of the communication bus 200, the terminal resistor R is connected to both ends of the communication bus 200, for example Figure 1 As shown, the communication bus 200 includes a first bus L1 and a second bus L2 (for example, it can be CAN high and CAN low), and the terminal resistor R is connected between the first bus and the second bus to ensure the load during normal communication. When the communication bus 200 is connected to a load device, it is often difficult for the communication bus 200 to determine whether the connected load device has its own terminal resistor R. If too many terminal resistors R are connected, the resistance value connected at both ends of the communication bus 200 will be reduced due to the parallel connection between the terminal resistors R. At this time, due to the voltage division of the terminal resistors R, the bus voltage on the communication bus 200 will be reduced, affecting the communication reliability, and even causing communication failure in severe cases.

[0031] Therefore, in the solution of this embodiment, the voltage acquisition device 110 is connected to the communication bus 200. When the communication bus 200 is connected to the load device and the communication of the load function is turned on, the bus voltage of the communication bus 200 is collected by the voltage acquisition device 110 and sent to the processing device 120. The processing device 120 stores a preset communication voltage, or the processing device 120 can input (or generate) a preset communication voltage. After the processing device 120 obtains the bus voltage, it compares and analyzes it with the preset communication voltage. When it is detected that the bus voltage is less than the preset communication voltage, the processing device 120 outputs a disconnection control signal to the switch device 130. Correspondingly, when it is detected that the bus voltage is greater than the preset voltage, the processing device 120 outputs a conduction control signal to the switch device 130.

[0032] In this way, the terminal resistors R at both ends of the communication bus 200 are connected or disconnected by turning on and off the switch device 130. When the connected load device has its own terminal resistor R, which causes the bus voltage to drop and cannot meet normal communication needs, the bus voltage of the communication bus 200 can be increased by cutting off the terminal resistor R, thereby ensuring the communication quality.

[0033] In the above-mentioned terminal resistance adjustment circuit, one end of the terminal resistance R is directly connected to the communication bus 200, and the other end of the terminal resistance R is connected to the communication bus 200 through the switch device 130, the switch device 130 is connected to the processing device 120, and the processing device 120 is connected to the voltage acquisition device 110 to receive the bus voltage of the communication bus 200 collected by the voltage acquisition device 110. In this way, when the communication bus 200 is connected to a load device of the type with a terminal resistance R, the resistance value of the communication bus 200 changes, causing the bus voltage of the communication bus 200 to decrease, which can be detected in time. Specifically, when the load device with a terminal resistance R is connected, so that the bus voltage is less than or equal to the preset communication voltage, the processing device 120 will output a disconnection control signal to the switch device 130 to control the switch device 130 to enter the disconnection operation state, thereby interrupting the connection between the terminal resistance R and the communication bus 200 and adjusting the resistance value of the communication bus 200. In this way, the phenomenon of bus voltage reduction caused by repeated installation of the terminal resistance R can be alleviated, and the quality of bus communication can be effectively improved.

[0034] See also Figure 2 In one embodiment, the processing device 120 includes a first comparator U1, a first input terminal of the first comparator U1 is connected to the voltage acquisition device 110, a second input terminal of the first comparator U1 is used to connect to a reference voltage source (Vf shown in the figure), an output terminal of the first comparator U1 is connected to a switching device 130, a power terminal of the first comparator U1 is used to connect to a power supply (VCC shown in the figure), and a ground terminal of the first comparator U1 is grounded; wherein the output voltage of the reference voltage source is a preset communication voltage.

[0035] Specifically, the specific type of the processing device 120 is not unique. In the solution of this embodiment, the processing device 120 is a first comparator U1. Specifically, the first input end of the first comparator U1 is connected to the voltage acquisition device 110, and the second input end of the first comparator U1 is connected to the reference voltage source, and the voltage value output by the reference voltage source is used as the preset communication voltage. In this way, the processing device 120 can output different signals according to the magnitude relationship between the bus voltage and the preset communication voltage to control the operation of the switch device 130.

[0036] Specifically, the first input terminal of the first comparator U1 can be a positive input terminal, and the second input terminal can be a negative input terminal. In this way, when the sampled voltage is less than the preset voltage threshold, the first comparator U1 outputs a low-level signal to the switch device 130, and uses the low-level signal as a disconnection control signal to control the switch device 130 to disconnect. The first input terminal of the first comparator U1 can also be a negative input terminal, and the second input terminal is used as a positive input terminal. In this way, when the sampled voltage is less than the preset voltage threshold, the first comparator U1 outputs a high-level signal to the switch device 130, and uses the high-level signal as a disconnection control signal to control the switch device 130 to disconnect. In this solution, the comparator is directly used as the processing device 120, the circuit structure is simple, and the circuit volume and hardware cost can be effectively saved.

[0037] See also Figure 3 In one embodiment, the processing device 120 is a hysteresis comparison circuit, which includes: a second comparator U2, a first resistor component R1, a second resistor component R2 and a third resistor component R3, a first input end of the second comparator U2 is connected to the voltage acquisition device 110, a second input end of the second comparator U2 is connected to a first end of the first resistor component R1, a first end of the second resistor component R2 and a first end of the third resistor component R3, a second end of the first resistor component R1 is used to connect to a power supply (VCC shown in the figure), a second end of the second resistor component R2 is connected to a ground end of the second comparator U2, a second end of the third resistor component R3 is connected to an output end of the second comparator U2, a power supply end of the second comparator U2 is used to connect to a power supply, and a ground end of the second comparator U2 is grounded.

[0038] Specifically, the first resistor component R1, the second resistor component R2 and the third resistor component R3 can all be separate resistor devices, or components formed by connecting multiple resistor devices in series and / or in parallel, and are not specifically limited. The solution of this embodiment uses a hysteresis comparison circuit as the processing device 120, so that after the terminal resistor R is cut off from the communication bus 200 (that is, the connection loop with the communication bus 200 is disconnected) due to the bus voltage being less than the preset communication voltage, even if the bus voltage rises, it will not cause the terminal resistor R to be reconnected to the communication bus 200, thereby effectively preventing the communication bus 200 from level fluctuations.

[0039] Specifically, the hysteresis comparison circuit of this embodiment can provide an upper threshold voltage and a lower threshold voltage, wherein the upper threshold voltage is set to be greater than the highest operating voltage of the communication chip where the communication bus 200 is located, and the lower threshold voltage is set to the lowest safe voltage that the communication chip can recognize.

[0040] In this way, the lower threshold voltage is used as the preset communication voltage, and when the hysteresis comparison circuit detects that the bus voltage is less than the lower threshold voltage, it will output a disconnection control signal to the switch device 130 to remove the terminal resistor R from the communication bus 200. In the subsequent process, even if the bus voltage rises, as long as it does not rise to a level greater than the upper threshold voltage, the hysteresis comparison circuit will continue to output a disconnection control signal to the switch device 130 to maintain the disconnected state of the switch device 130.

[0041] It should be noted that the resistance value of each resistance component in the hysteresis comparison circuit is not unique. In one embodiment, the upper threshold voltage of the hysteresis comparison circuit is: The lower threshold voltage of the hysteresis comparator circuit is: Among them, the lower threshold voltage is the preset communication voltage, UfH represents the upper threshold voltage, UfL represents the lower threshold voltage, R1 represents the resistance value of the first resistor component R1, R2 represents the resistance value of the second resistor component R2, R3 represents the resistance value of the third resistor component R3, and VCC represents the voltage value of the voltage source.

[0042] Specifically, the upper threshold voltage and the lower threshold voltage required by the hysteresis comparison circuit are determined according to the working voltage of the communication chip corresponding to the communication bus 200. When the communication chip is fixed, the specific values ​​of the upper threshold voltage and the lower threshold voltage are also determined accordingly. Accordingly, in order to make the upper threshold voltage and the lower threshold voltage of the hysteresis comparison circuit reach the required values, it is necessary to set matching resistance values ​​for each resistor component in the hysteresis comparison circuit. The solution of this embodiment, combined with and By performing analysis and calculation, the resistance values ​​of the first resistance component R1, the second resistance component R2 and the third resistance component R3 required in the end can be determined. Through this solution, combined with the upper threshold voltage and the lower threshold voltage required by the hysteresis comparison circuit, a suitable voltage value can be configured for each resistance component of the hysteresis comparison circuit, thereby effectively improving the operation accuracy of the terminal resistance adjustment circuit.

[0043] It should be noted that the voltage value of the voltage source, the upper threshold voltage and the lower threshold voltage are not unique, and their sizes may vary according to the type of the second comparator U2 and the communication chip in the actual scenario. For example, in a more detailed embodiment, the voltage value of the voltage source may be set to 5V (volts), the upper threshold voltage may be set to be greater than or equal to 5.5V, and the lower threshold voltage may be set to 3V.

[0044] See also Figure 4In one embodiment, the processing device 120 includes a processor 121 , an input end of the processor 121 is connected to the voltage acquisition device 110 , and an output end of the processor 121 is connected to the switch device 130 .

[0045] Specifically, in the solution of this embodiment, the processing device 120 can also be set as a processor 121, and the processor 121 has a data comparison function, and a preset communication voltage is pre-stored in the processor 121. After the processor 121 receives the bus voltage, it will compare and analyze it with the preset communication voltage, and output different control signals to the switch device 130 according to the comparison and analysis results to control the operation of the switch device 130, with high comparison accuracy. It should be pointed out that the processor 121 can be an MCU (Microcontroller Unit), a CPU (Central Process Unit) or a single-chip microcomputer, etc., and is not specifically limited.

[0046] In one embodiment, the voltage acquisition device 110 includes a resistor voltage divider circuit, and the resistor voltage divider circuit connects the communication bus 200 and the processing device 120 .

[0047] Specifically, the type of voltage acquisition device 110 is not unique. This embodiment uses a resistor voltage divider circuit to acquire voltage from the communication bus 200, uses the voltage value after resistor voltage division as the bus voltage, and transmits it to the processing device 120 for comparative analysis. This solution uses resistor voltage division to acquire bus voltage, which has high acquisition accuracy.

[0048] See also Figure 5 , Figure 6 and Figure 7 In one embodiment, the resistor divider circuit includes a fourth resistor component R4 and a fifth resistor component R5, a first end of the fourth resistor component R4 is connected to the communication bus 200, a second end of the fourth resistor component R4 is connected to a first end of the fifth resistor component R5 and the processing device 120, and a second end of the fifth resistor component R5 is grounded.

[0049] Specifically, the voltage divider resistor specifically includes a fourth resistor component R4 and a fifth resistor component R5 connected in series, and the common end of the fourth resistor component R4 and the fifth resistor component R5 is used as an output end and connected to the processing device 120. In this way, the voltage of the communication bus 200 is collected through the resistor voltage divider circuit, and the bus voltage is obtained as follows: Wherein, R4 represents the resistance value of the fourth resistance component R4, and R5 represents the resistance value of the fifth resistance component R5.

[0050] See also Figure 5 , Figure 6 and Figure 7In one embodiment, the switch device 130 includes a power switch device Q1, a control end of the power switch device Q1 is connected to the processing device 120, an input end of the power switch device Q1 is connected to the communication bus 200 through a terminal resistor R, and an output end of the power switch device Q1 is connected to the communication bus 200.

[0051] Specifically, the specific type of the switch device 130 is not limited, as long as it can achieve the shutdown function when receiving the disconnection control signal, and achieve the conduction function when receiving the conduction control signal. The solution of this embodiment specifically adopts a power switch device Q1, such as a field effect transistor, a triode, and an insulated gate field effect transistor, etc., which is not specifically limited.

[0052] It is understandable that in other embodiments, the switch device 130 may also be a relay, a photoelectric switch, etc., which can be selected based on actual needs.

[0053] The present application also provides a communication system, including a communication bus and the above-mentioned terminal resistance adjustment circuit.

[0054] Specifically, the structure and operation principle of the terminal resistance adjustment circuit are as shown in the above-mentioned embodiments and the accompanying drawings. In the communication system of the embodiment of the present application, during the communication of the communication bus 200, the terminal resistance R is connected to both ends of the communication bus 200, for example Figure 1 As shown, the communication bus 200 includes a first bus L1 and a second bus L2 (for example, it can be CAN high and CAN low), and the terminal resistor R is connected between the first bus and the second bus to ensure the load during normal communication. When the communication bus 200 is connected to a load device, it is often difficult for the communication bus 200 to determine whether the connected load device has its own terminal resistor R. If too many terminal resistors R are connected, the resistance value connected at both ends of the communication bus 200 will be reduced due to the parallel connection between the terminal resistors R. At this time, due to the voltage division of the terminal resistors R, the bus voltage on the communication bus 200 will be reduced, affecting the communication reliability, and even causing communication failure in severe cases.

[0055] Therefore, in the solution of this embodiment, the voltage acquisition device 110 is connected to the communication bus 200. When the communication bus 200 is connected to the load device and the communication of the load function is turned on, the bus voltage of the communication bus 200 is collected by the voltage acquisition device 110 and sent to the processing device 120. The processing device 120 stores a preset communication voltage, or the processing device 120 can input (or generate) a preset communication voltage. After the processing device 120 obtains the bus voltage, it compares and analyzes it with the preset communication voltage. When it is detected that the bus voltage is less than the preset communication voltage, the processing device 120 outputs a disconnection control signal to the switch device 130. Correspondingly, when it is detected that the bus voltage is greater than the preset voltage, the processing device 120 outputs a conduction control signal to the switch device 130.

[0056] In this way, the terminal resistors R at both ends of the communication bus 200 are connected or disconnected by turning on and off the switch device 130. When the connected load device has its own terminal resistor R, which causes the bus voltage to drop and cannot meet normal communication needs, the bus voltage of the communication bus 200 can be increased by cutting off the terminal resistor R, thereby ensuring the communication quality.

[0057] For further information, see Figure 2 In one embodiment, the processing device 120 includes a first comparator U1, a first input end of the first comparator U1 is connected to the voltage acquisition device 110, a second input end of the first comparator U1 is used to connect to a reference voltage source (Vf in the figure), an output end of the first comparator U1 is connected to a switch device 130, a power supply end of the first comparator U1 is used to connect to a power supply (VCC in the figure), and a ground end of the first comparator U1 is grounded; wherein the output voltage of the reference voltage source is a preset communication voltage. This solution directly uses a comparator as the processing device 120, has a simple circuit structure, and can effectively save circuit volume and hardware costs.

[0058] In another embodiment, see Figure 3 The processing device 120 is a hysteresis comparison circuit, which includes: a second comparator U2, a first resistor component R1, a second resistor component R2 and a third resistor component R3. The first input end of the second comparator U2 is connected to the voltage acquisition device 110, the second input end of the second comparator U2 is connected to the first end of the first resistor component R1, the first end of the second resistor component R2 and the first end of the third resistor component R3, the second end of the first resistor component R1 is used to connect to a power supply (VCC shown in the figure), the second end of the second resistor component R2 is connected to the ground end of the second comparator U2, the second end of the third resistor component R3 is connected to the output end of the second comparator U2, the power supply end of the second comparator U2 is used to connect to the power supply, and the ground end of the second comparator U2 is grounded.

[0059] In this way, the hysteresis comparison circuit of this embodiment can provide an upper threshold voltage and a lower threshold voltage, wherein the upper threshold voltage is set to be greater than the highest operating voltage of the communication chip where the communication bus 200 is located, and the lower threshold voltage is set to the lowest safe voltage that the communication chip can recognize.

[0060] Furthermore, in one embodiment, see Figure 4 The processing device 120 includes a processor 121, an input end of the processor 121 is connected to the voltage acquisition device 110, and an output end of the processor 121 is connected to the switch device 130. In this way, after the processor 121 receives the bus voltage, it will compare and analyze it with the preset communication voltage, and output different control signals to the switch device 130 according to the comparison and analysis results to control the operation of the switch device 130, with high comparison accuracy.

[0061] In the communication system of the present application, the voltage acquisition device 110 may include a resistor voltage divider circuit, and the resistor voltage divider circuit connects the communication bus 200 and the processing device 120. For details, please refer to Figure 2-Figure 4 The resistor divider circuit includes a fourth resistor component R4 and a fifth resistor component R5, a first end of the fourth resistor component R4 is connected to the communication bus 200, a second end of the fourth resistor component R4 is connected to a first end of the fifth resistor component R5 and the processing device 120, and a second end of the fifth resistor component R5 is grounded.

[0062] In the communication system of the present application, the specific type of the switch device 130 is not limited, as long as it can achieve the shutdown function after receiving the disconnection control signal, and achieve the conduction function after receiving the conduction control signal. The solution of this embodiment specifically adopts a power switch device Q1, such as a field effect transistor, a triode, and an insulated gate field effect transistor, etc., which is not specifically limited.

[0063] It is understandable that in other embodiments, the switch device 130 may also be a relay, a photoelectric switch, etc., which can be selected based on actual needs.

[0064] In the communication system provided by the present application, one end of the terminal resistor R is directly connected to the communication bus 200, and the other end of the terminal resistor R is connected to the communication bus 200 through the switch device 130, the switch device 130 is connected to the processing device 120, and the processing device 120 is connected to the voltage acquisition device 110 to receive the bus voltage of the communication bus 200 collected by the voltage acquisition device 110. In this way, when the communication bus 200 is connected to a load device of the type with a terminal resistor R, the resistance value of the communication bus 200 changes, causing the bus voltage of the communication bus 200 to decrease, which can be detected in time. Specifically, when the load device with a terminal resistor R is connected, so that the bus voltage is less than or equal to the preset communication voltage, the processing device 120 will output a disconnection control signal to the switch device 130 to control the switch device 130 to enter the disconnection operation state, thereby interrupting the connection between the terminal resistor R and the communication bus 200 and adjusting the resistance value of the communication bus 200. In this way, the phenomenon of bus voltage reduction caused by repeated installation of the terminal resistor R can be alleviated, and the communication quality is high.

[0065] An embodiment of the present application also provides a household appliance, comprising the above-mentioned communication system.

[0066] Specifically, the communication system is as shown in the above embodiments and the accompanying drawings, and will not be described in detail here. The types of household appliances are not unique, as long as they are devices of this type that have bus communication requirements, such as air-conditioning units, refrigerators, etc., are all acceptable, and there is no specific limitation. In the household appliance, one end of the terminal resistor R is directly connected to the communication bus 200, and the other end of the terminal resistor R is connected to the communication bus 200 through the switch device 130, the switch device 130 is connected to the processing device 120, and the processing device 120 is connected to the voltage acquisition device 110 to receive the bus voltage of the communication bus 200 collected by the voltage acquisition device 110. In this way, when the communication bus 200 is connected to a load device of the type with its own terminal resistor R, the resistance value connected to the communication bus 200 changes, causing the bus voltage of the communication bus 200 to decrease, which can be detected in time. Specifically, when a load device with its own terminal resistor R is connected so that the bus voltage is less than or equal to the preset communication voltage, the processing device 120 will output a disconnection control signal to the switch device 130 to control the switch device 130 to enter a disconnection operation state, thereby interrupting the connection between the terminal resistor R and the communication bus 200 and adjusting the resistance value of the communication bus 200. In this way, the phenomenon of bus voltage reduction caused by repeated installation of the terminal resistor R can be alleviated, and the operation reliability is high.

[0067] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0068] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A terminal resistance adjustment circuit, characterized in that: include: A voltage acquisition device, connected to the communication bus, for acquiring the bus voltage of the communication bus; A processing device, connected to the voltage acquisition device, configured to output a disconnection control signal when the bus voltage is less than a preset communication voltage; A switch device, wherein a first end of the switch device is connected to the processing device, a second end of the switch device is connected to the communication bus via a terminal resistor, a third end of the switch device is connected to the communication bus, and the switch device enters a disconnected operating state when receiving the disconnection control signal.

2. The terminal resistance adjustment circuit according to claim 1, characterized in that: The processing device includes a first comparator, a first input end of the first comparator is connected to the voltage acquisition device, a second input end of the first comparator is used to connect to a reference voltage source, an output end of the first comparator is connected to the switching device, a power supply end of the first comparator is used to connect to a power supply, and a ground end of the first comparator is grounded; wherein the output voltage of the reference voltage source is the preset communication voltage.

3. The terminal resistance adjustment circuit according to claim 1, characterized in that: The processing device is a hysteresis comparison circuit, which includes: a second comparator, a first resistor component, a second resistor component and a third resistor component, wherein the first input end of the second comparator is connected to the voltage acquisition device, the second input end of the second comparator is connected to the first end of the first resistor component, the first end of the second resistor component and the first end of the third resistor component, the second end of the first resistor component is used to connect to a power supply, the second end of the second resistor component is connected to a ground end of the second comparator, the second end of the third resistor component is connected to an output end of the second comparator, the power supply end of the second comparator is used to connect to a power supply, and the ground end of the second comparator is grounded.

4. The terminal resistance adjustment circuit according to claim 3, characterized in that: The upper threshold voltage of the hysteresis comparison circuit is: The lower threshold voltage of the hysteresis comparison circuit is: Among them, the lower threshold voltage is the preset communication voltage, UfH represents the upper threshold voltage, UfL represents the lower threshold voltage, R1 represents the resistance value of the first resistor component, R2 represents the resistance value of the second resistor component, R3 represents the resistance value of the third resistor component, and VCC represents the voltage value of the voltage source.

5. The terminal resistance adjustment circuit according to claim 1, characterized in that: The processing device comprises a processor, an input end of the processor is connected to the voltage acquisition device, and an output end of the processor is connected to the switch device.

6. The terminal resistance adjustment circuit according to any one of claims 1 to 5, characterized in that: The voltage acquisition device comprises a resistor voltage divider circuit, and the resistor voltage divider circuit is connected to the communication bus and the processing device.

7. The terminal resistance adjustment circuit according to claim 6, characterized in that: The resistor divider circuit includes a fourth resistor component and a fifth resistor component, wherein a first end of the fourth resistor component is connected to the communication bus, a second end of the fourth resistor component is connected to a first end of the fifth resistor component and the processing device, and a second end of the fifth resistor component is grounded.

8. The terminal resistance adjustment circuit according to any one of claims 1 to 5, characterized in that: The switch device comprises a power switch device, a control end of the power switch device is connected to the processing device, an input end of the power switch device is connected to the communication bus via the terminal resistor, and an output end of the power switch device is connected to the communication bus.

9. A communication system, characterized in that: It comprises a communication bus and a terminal resistance adjustment circuit as described in any one of claims 1 to 8.

10. A household appliance, characterized in that: A communication system comprising the method of claim 9.

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