A zero-fire wire communication circuit, communication system and air conditioning system

Abstract

The present invention discloses a zero - line and live - line communication circuit, a communication system and an air - conditioning system. Among them, the zero - line and live - line communication circuit includes: a logic operation module, whose input end is connected to the input end of the communication loop, and whose output end is connected to the control end of the first switching tube, and is used to output a control signal according to the voltage input at the input end of the communication loop; the first switching tube, whose input end is connected to the control end of the current adjustment module, and whose output end is grounded, and is used to change its own on - off state according to the control signal, and further control the switching conduction of two parallel - connected switching branches in the current adjustment module, so as to adjust the current of the communication loop; the current adjustment module, which is arranged between the input end and the output end of the communication loop. Through the present invention, it is possible to control the current of the communication loop to increase when the mains voltage drops significantly, so as to ensure the communication quality.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic communication, and more particularly, to a zero-fire communication circuit, a communication system, and an air conditioning system. Background Art

[0002] Currently, for communication between different communication entities in a home appliance system (such as an air conditioning system), a zero-fire communication method is generally adopted. This communication method is relatively simple and does not require a dedicated communication chip. The communication signal forms a signal communication loop through a COM line and a zero line, which can greatly reduce the hardware usage cost. However, when using zero-fire communication, the 220V AC power is divided and rectified to obtain a voltage signal, and the communication signal is loaded onto this voltage signal. Different communication entities use this voltage signal as a medium to transmit signals. If the mains voltage is unstable or interfered with, resulting in the mains voltage value being lower than 220V and having a large deviation, the voltage value of the communication voltage signal will also decrease significantly, thereby causing the current in the communication loop to decrease, and thus affecting the quality of the communication signal between the communication entities.

[0003] Regarding the problem in the prior art that a large decrease in the mains voltage affects the quality of the communication signal, no effective solution has been proposed yet. Summary of the Invention

[0004] An embodiment of the present invention provides a zero-fire communication circuit, a communication system, and an air conditioning system to solve the problem in the prior art that a large decrease in the mains voltage affects the quality of the communication signal.

[0005] To solve the above technical problems, the present invention provides a zero-fire communication circuit, which includes:

[0006] A logic operation module, whose input end is connected to the input end of the communication loop, and whose output end is connected to the control end of the first switch tube, for outputting a control signal according to the voltage input at the input end of the communication loop;

[0007] The first switch tube, whose input end is connected to the control end of the current adjustment module, and whose output end is grounded, for changing its own on-off state according to the control signal, thereby controlling the switching conduction of two parallel switch branches in the current adjustment module, and further adjusting the current in the communication loop;

[0008] The current adjustment module is arranged between the input end and the output end of the communication loop.

[0009] Further, the current adjustment module includes:

[0010] A first switch branch, which includes a second switch tube and a first resistor connected in series;

[0011] A second switching branch, which includes a third switching transistor and a second resistor connected in series;

[0012] The resistance value of the first resistor is greater than that of the second resistor, and the types of the second switching transistor and the third switching transistor are different.

[0013] Further, the second switching transistor is a PNP type switching transistor, and the third switching transistor is an NPN type switching transistor.

[0014] Further, the logic operation module includes:

[0015] A first voltage dividing unit, whose first end is connected to the input end of the communication loop, whose second end is grounded, and whose third end is connected to the non-inverting input end of a first comparator;

[0016] The first comparator, whose inverting input end inputs a first reference voltage, and whose output end is connected to the control end of the first switching transistor.

[0017] Further, the first voltage dividing unit includes:

[0018] A third resistor and a fourth resistor connected in series, wherein the third resistor is connected to the input end of the communication loop, the fourth resistor is grounded, and the line between the third resistor and the fourth resistor is connected to the non-inverting input end of the first comparator.

[0019] Further, the logic operation module further includes:

[0020] An AND gate calculator, whose first input end is connected to the output end of the first comparator, whose second input end is connected to the output end of a second comparator, and whose output end is connected to the control end of the first switching transistor;

[0021] A second voltage dividing unit, whose first end is connected to a voltage source, whose second end is grounded, and whose third end is connected to the inverting input end of the second comparator;

[0022] The second comparator, whose non-inverting input end inputs a second reference voltage.

[0023] Further, the second voltage dividing unit includes:

[0024] A fifth resistor and a sixth resistor connected in series, wherein the fifth resistor is connected to the voltage source, the sixth resistor is grounded, the line between the fifth resistor and the sixth resistor is connected to the inverting input end of the second comparator, the fifth resistor is a fixed value resistor, and the sixth resistor is the total resistance of the communication loop.

[0025] Further, the circuit further includes:

[0026] A seventh resistor and an eighth resistor connected in series, wherein the seventh resistor is connected to the output end of the logic operation module, the eighth resistor is grounded, and the line between the seventh resistor and the eighth resistor is connected to the control end of the first switching tube.

[0027] The present invention also provides another zero - live wire communication circuit, and the circuit includes:

[0028] A logic operation module, whose input end is connected to a voltage source, and whose output end is connected to the control end of a first switching tube, and is used to output a control signal according to the total resistance of the communication loop; the logic operation module includes: a second voltage - dividing unit, and the second voltage - dividing unit includes a fifth resistor and a sixth resistor connected in series, wherein the fifth resistor is connected to the voltage source, the sixth resistor is grounded, the line between the fifth resistor and the sixth resistor is connected to the inverting input end of a second comparator, the fifth resistor is a fixed - value resistor, and the sixth resistor is the total resistance of the communication loop;

[0029] The second comparator, whose non - inverting input end inputs a reference voltage, and whose output end is connected to the first switching tube;

[0030] The first switching tube, whose input end is connected to the control end of a current adjustment module, and whose output end is grounded, and is used to change its on - off state according to the control signal, and further control the switching conduction of two parallel - connected switching branches in the current adjustment module, and further adjust the current of the communication loop;

[0031] The current adjustment module is arranged between the input end and the output end of the communication loop.

[0032] The present invention also provides a communication system, including a first communication entity and a second communication entity, and is characterized in that it further includes the above - mentioned first zero - live wire communication circuit, the first communication entity is connected to the input end of the communication loop, and the second communication entity is connected to the output end of the communication loop.

[0033] The present invention also provides another communication system, including a first communication entity and a second communication entity, and is characterized in that it further includes the above - mentioned second zero - live wire communication circuit, the first communication entity is connected to the input end of the communication loop, and the second communication entity is connected to the output end of the communication loop.

[0034] Further, the communication system is an air - conditioning system, the first communication entity is an indoor unit of the air conditioner, and the second communication entity is an outdoor unit of the air conditioner.

[0035] Applying the technical solution of the present invention, through the logic operation module, a control signal is output according to the magnitude of the voltage carried by the carrier signal input at the input end of the communication loop. The control signal is used to control the switching conduction of two parallel switch branches in the current control module, thereby adjusting the current of the communication loop. It can achieve that when the mains voltage drops significantly, the current of the communication loop is controlled to increase, ensuring the communication quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural block diagram of a zero - fire wire communication circuit according to an embodiment of the present invention;

[0037] Figure 2 It is a structural diagram of a zero - fire wire communication circuit according to another embodiment of the present invention;

[0038] Figure 3 It is a structural diagram of a zero - fire wire communication circuit according to yet another embodiment of the present invention;

[0039] Figure 4 It is a structural diagram of a zero - fire wire communication circuit according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms of "a", "the" and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0042] It should be understood that the term " / " used herein is only a description of the associated relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0043] It should be understood that although terms such as first, second, and third may be used to describe resistors in the embodiments of the present invention, these resistors should not be limited to these terms. These terms are only used to distinguish different resistors. For example, without departing from the scope of the embodiments of the present invention, the first resistor may also be referred to as the second resistor, and similarly, the second resistor may also be referred to as the first resistor.

[0044] Depending on the context, the words "if", "when" as used herein may be interpreted as "when...", "while...", "in response to determining", or "in response to detecting". Similarly, depending on the context, the phrases "if determined" or "if detecting (stated condition or event)" may be interpreted as "when determined", "in response to determining", "when detecting (stated condition or event)", or "in response to detecting (stated condition or event)".

[0045] It should also be noted that the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, such that a commodity or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such commodity or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the commodity or device comprising said element.

[0046] The optional embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] Embodiment 1

[0048] This embodiment provides a zero-fire wire communication circuit. Figure 1 As shown in the structural block diagram of the zero-fire wire communication circuit according to the embodiments of the present invention, Figure 1 the zero-fire wire circuit includes:

[0049] A logic operation module 10, whose input terminal is connected to the input terminal of the communication loop. The input terminal of the communication loop inputs a carrier signal formed after 220V mains voltage is divided and rectified. The output terminal of the logic operation module 10 is connected to the control terminal (base) of the first switching transistor Q1. The function of the logic operation module 10 is to output a control signal according to the magnitude of the voltage Vt carried by the carrier signal input at the input terminal of the communication loop.

[0050] The above-mentioned first switching transistor Q1, whose input terminal (collector) is connected to the control terminal of the current adjustment module 20, and whose output terminal is grounded, is used to change its on-off state according to the above control signal, and then control the switching conduction of two parallel switching branches in the current adjustment module, thereby adjusting the current of the communication loop; the above-mentioned current adjustment module 20 is arranged between the input terminal and the output terminal COM of the communication loop.

[0051] For the zero - line and live - line communication circuit of this embodiment, a logic operation module 10 is provided, which outputs a control signal according to the magnitude of the voltage Vt carried by the carrier signal input at the input end of the communication loop, and controls the switching conduction of two parallel - connected switch branches in the current control module 20 through this control signal, thereby adjusting the current of the communication loop. It can achieve that when the mains voltage drops significantly, the current of the communication loop is controlled to increase, ensuring the communication quality.

[0052] Embodiment 2

[0053] This embodiment provides another zero - line and live - line communication circuit. Figure 2 As shown in the structural diagram of the zero - line and live - line communication circuit according to another embodiment of the present invention, in order to realize the switching conduction of two switch branches, Figure 2 as shown, the above - mentioned current adjustment module 20 includes: a first switch branch, which includes a second switch tube Q2 and a first resistor R1 connected in series; a second switch branch, which includes a third switch tube Q3 and a second resistor R2 connected in series; the resistance value of the first resistor R1 is greater than that of the second resistor R2, and the types of the second switch tube Q2 and the third switch tube Q3 are different. In a specific embodiment of the present invention, the first switch tube Q1 is a PNP - type switch tube, the second switch tube Q2 is a PNP - type switch tube, and the third switch tube Q3 is an NPN - type switch tube.

[0054] In order to output different control signals according to the magnitude of the voltage Vt carried by the carrier signal input at the input end of the communication loop, the logic operation module 10 includes: a first voltage - dividing unit, whose first end is connected to the input end of the communication loop, whose second end is grounded, and whose third end is connected to the non - inverting input end of the first comparator U1; a first comparator U1, whose inverting input end inputs a first reference voltage V01, and whose output end is connected to the control end of the first switch tube Q1.

[0055] Since the input voltage of the comparator cannot be too high, therefore, it is necessary to divide the voltage Vt carried by the carrier signal. In order to achieve the voltage - dividing effect, the first voltage - dividing unit includes: a third resistor R3 and a fourth resistor R4 connected in series, where the third resistor R3 is connected to the input end of the communication loop, the fourth resistor R4 is grounded, and the line between the third resistor R3 and the fourth resistor R4 is connected to the non - inverting input end of the first comparator U1.

[0056] In order to avoid the voltage input to the control end of the first switch tube Q1 from being too large, the above - mentioned zero - line and live - line communication circuit further includes: a seventh resistor R7 and an eighth resistor R8 connected in series, where the seventh resistor R7 is connected to the output end of the logic operation module 10, the eighth resistor R8 is grounded, and the line between the seventh resistor R7 and the eighth resistor R8 is connected to the control end of the first switch tube Q1. The seventh resistor R7 and the eighth resistor R8 are used to divide the voltage output by the logic operation module 10.

[0057] The working principle of the above-mentioned live-neutral communication circuit is as follows: when the mains voltage is about 220V, the voltage Vt carried by the carrier signal is within the normal range. After the voltage Vt is divided by the third resistor R3 and the fourth resistor R4, the voltage V1 is obtained. The first reference voltage V01 is preset at the non-inverting input terminal of the first comparator U1. By default, V1 is higher than V01, and the first comparator U1 outputs a high level "1", driving the first switching transistor Q1 to turn on, and then enabling the second switching transistor Q2 to turn on and the third switching transistor Q3 to turn off. The second switching transistor Q2 and the first resistor R1 are connected to the communication loop. The resistance value of the first resistor R1 is relatively large, which can effectively reduce the current in the communication loop of the communication circuit and prevent large current from damaging the devices through the communication circuit.

[0058] When the mains voltage is lower than 220V and the deviation is large, resulting in a significant decrease in the voltage Vt carried by the carrier signal, after the voltage Vt carried by the carrier signal is divided by the third resistor R3 and the fourth resistor R4, the fluctuated voltage V1 is obtained. At this time, V1 is lower than V01, and U1 outputs a low level "0", driving the first switching transistor Q1 to turn off, and then enabling the second switching transistor Q2 to turn off and the third switching transistor Q3 to turn on. The third switching transistor Q3 and the second resistor R2 are connected to the communication loop. The resistance value of the second resistor R2 is relatively small, which can effectively avoid the situation that the current in the communication loop is too small due to the too low working voltage, prevent the communication quality from deteriorating due to the decrease in the current in the communication loop, and improve the communication quality.

[0059] Embodiment 3

[0060] This embodiment provides another live-neutral communication circuit. Figure 3 As shown in the structural diagram of the live-neutral communication circuit according to another embodiment of the present invention, as mentioned above, when the mains voltage decreases significantly, the current in the communication loop will decrease and the communication quality will be affected. In practical applications, if the communication line is too long, resulting in an increase in the total resistance of the communication loop, the current in the communication loop will also decrease, thereby affecting the communication quality. Therefore, in order to further ensure the communication quality, such as Figure 3As shown in the figure, the above-mentioned logic operation module 10 further includes: an AND gate calculator U3, whose first input terminal is connected to the output terminal of the first comparator U1, whose second input terminal is connected to the output terminal of the second comparator U2, and whose output terminal is connected to the control terminal of the first switching transistor Q1; a second voltage dividing unit, whose first terminal is connected to a voltage source (which can be 3.3V), whose second terminal is grounded, and whose third terminal is connected to the inverting input terminal of the second comparator U2; a second comparator U2, whose non-inverting input terminal inputs a second reference voltage V02. The second voltage dividing unit includes: a fifth resistor R5 and a sixth resistor R6 connected in series, wherein the fifth resistor R5 is connected to the voltage source, the sixth resistor R6 is grounded, the line between the fifth resistor R5 and the sixth resistor R6 is connected to the inverting input terminal of the second comparator U2, the fifth resistor R5 is a fixed-value resistor, and the sixth resistor R6 is the total resistance of the communication loop.

[0061] The operation logic of the AND gate calculator is simply "if there is a 0, it is 0", that is, if either the first comparator U1 or the second comparator U2 outputs "0", then the AND gate calculator U3 outputs "0", if both the first comparator U1 and the second comparator U2 output "1", then the AND gate calculator U3 outputs "1". Based on the above content, the working principle of the zero-fire communication circuit in this embodiment is as follows:

[0062] When the mains voltage is about 220V and the voltage Vt carried by the carrier signal is within the normal range, the voltage Vt carried by the carrier signal is divided by the third resistor R3 and the fourth resistor R4 to obtain a voltage V1. The first reference voltage V01 set in advance is input to the non-inverting input terminal of the first comparator U1. By default, V1 is higher than V01, and the first comparator U1 outputs a high level "1". At this time, considering the change of the total resistance R6 of the communication loop, there are the following two situations:

[0063] The first situation: If the communication loop resistance R6 is normal at this time, the second reference voltage V02 set in advance is input to the inverting input terminal of the second comparator U2. The voltage of the voltage source is divided by the fifth resistor R5 and the sixth resistor R6 to obtain a voltage V2. By default, V02 is higher than V2, and the second comparator U2 outputs a high level "1", then the AND gate calculator U3 outputs a high level "1", driving the first switching transistor Q1 to turn on, and further enabling the second switching transistor Q2 to turn on and the third switching transistor Q3 to turn off. The second switching transistor Q2 and the first resistor R1 are connected to the communication loop. The resistance value of the first resistor R1 is relatively large, which can effectively reduce the current in the communication loop of the communication circuit and avoid damage to the devices due to large current passing through the communication circuit.

[0064] The second case: If the total resistance R6 of the communication circuit has a large increase at this time (the total resistance of the communication circuit increases as the length of the communication line increases), after the voltage of the voltage source is divided by the fifth resistor R5 and the sixth resistor R6, the voltage V2 is obtained. At this time, V2 is higher than V02, the second comparator U2 outputs a low level "0", then the AND gate arithmetic unit U3 outputs a low level "0", driving the first switching transistor Q1 to turn off, and further causing the second switching transistor Q2 to turn off and the third switching transistor Q3 to turn on. The third switching transistor Q3 and the second resistor R2 are connected to the communication circuit. The resistance value of the second resistor R2 is small, which can effectively avoid the situation that the current of the communication circuit becomes too small due to the increase of the total resistance of the communication circuit, avoid the decline of the communication quality due to the decrease of the current of the communication circuit, and improve the communication quality.

[0065] When the mains voltage is lower than 220V and the deviation is large, resulting in a large decrease in the voltage Vt carried by the carrier signal, after the voltage Vt carried by the carrier signal is divided by the third resistor R3 and the fourth resistor R4, the fluctuated voltage V1 is obtained. At this time, V1 is lower than V01, and U1 outputs a low level "0". At this time, regardless of whether the second comparator U2 outputs a low level "0" or a high level "1", the AND gate arithmetic unit U3 outputs a low level "0", driving the first switching transistor Q1 to turn off, and further causing the second switching transistor Q2 to turn off and the third switching transistor Q3 to turn on. The third switching transistor Q3 and the second resistor R2 are connected to the communication circuit. The resistance value of the second resistor R2 is small, which can effectively avoid the situation that the current of the communication circuit becomes too small, avoid the decline of the communication quality due to the decrease of the current of the communication circuit, and improve the communication quality.

[0066] Embodiment 4

[0067] This embodiment provides another zero-fire wire communication circuit. Figure 4 It is a structural diagram of a zero-fire wire communication circuit according to another embodiment of the present invention, as Figure 4 shown. The zero-fire wire communication circuit includes:

[0068] A fifth resistor R5 and a sixth resistor R6 are arranged in series. Among them, the fifth resistor R5 is connected to a voltage source, the sixth resistor R6 is grounded, and the line between the fifth resistor R5 and the sixth resistor R6 is connected to the inverting input terminal of a second comparator. The fifth resistor R5 is a fixed-value resistor, and the sixth resistor R6 is the total resistance of the communication loop; a comparator U, whose non-inverting input terminal inputs a reference voltage V0, and whose output terminal is connected to a first switching transistor Q1; a first switching transistor Q1, whose input terminal is connected to the control terminal of a current adjustment module, and whose output terminal is grounded, and is used to change its on-off state according to a control signal, thereby controlling the switching conduction of two parallel switching branches in the current adjustment module, and further adjusting the current of the communication loop; a current adjustment module is arranged between the input terminal and the output terminal of the communication loop. The specific structure of the above current adjustment module is the same as that of the above embodiment, and includes: a first switching branch, which includes a second switching transistor Q2 and a first resistor R1 arranged in series; a second switching branch, which includes a third switching transistor Q3 and a second resistor R2 arranged in series; the resistance value of the first resistor R1 is greater than that of the second resistor R2, and the types of the second switching transistor Q2 and the third switching transistor Q3 are different. Specifically, the first switching transistor Q1 is a PNP-type switching transistor, the second switching transistor Q2 is a PNP-type switching transistor, and the third switching transistor Q3 is an NPN-type switching transistor.

[0069] The working principle of the zero-fire communication circuit of this embodiment is as follows:

[0070] When the total resistance R6 of the communication loop is a normal value, the inverting input terminal of the comparator U inputs a preset reference voltage V0. After the voltage of the voltage source is divided by the fifth resistor R5 and the sixth resistor R6, a voltage V is obtained. By default, V0 is higher than V. The comparator U outputs a high level "1", driving the first switching transistor Q1 to turn on, and further enabling the second switching transistor Q2 to turn on and the third switching transistor Q3 to turn off. The second switching transistor Q2 and the first resistor R1 are connected to the communication loop. The resistance value of the first resistor R1 is relatively large, which can effectively reduce the current of the communication loop in the communication circuit and avoid damage to devices caused by large current passing through the communication circuit.

[0071] When the total resistance R6 of the communication loop rises significantly, after the voltage of the voltage source is divided by the fifth resistor R5 and the sixth resistor R6, a voltage V is obtained. At this time, V is higher than V0. The comparator U outputs a low level "0", driving the first switching transistor Q1 to turn off, and further enabling the second switching transistor Q2 to turn off and the third switching transistor Q3 to turn on. The third switching transistor Q3 and the second resistor R2 are connected to the communication loop. The resistance value of the second resistor R2 is relatively small, which can effectively avoid the situation that the current of the communication loop becomes too small due to the increase of the total resistance of the communication loop, and avoid the decline of the communication quality due to the decrease of the current of the communication loop, and improve the communication quality.

[0072] Embodiment 5

[0073] This embodiment provides a communication system, including a first communication entity and a second communication entity. It is characterized in that it further includes any one of the zero-fire communication circuits in the above-mentioned Embodiments 1 to 4, which is used to improve the communication quality between the first communication entity and the second communication entity. The first communication entity is connected to the input end of the communication loop, and the second communication entity is connected to the output end of the communication loop. In this embodiment, the communication system is an air-conditioning system, the first communication entity is an indoor unit of the air conditioner, and the second communication entity is an outdoor unit of the air conditioner.

[0074] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0075] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A zero-fire wire communication circuit, characterized in that, The circuit includes: A logic operation module, whose input terminal is connected to the input terminal of the communication loop, and whose output terminal is connected to the control terminal of the first switching transistor, for outputting a control signal according to the voltage input at the input terminal of the communication loop; the logic operation module includes: a first voltage dividing unit, whose first terminal is connected to the input terminal of the communication loop, whose second terminal is grounded, and whose third terminal is connected to the non-inverting input terminal of the first comparator; the first comparator, whose inverting input terminal inputs a first reference voltage, and whose output terminal is connected to the control terminal of the first switching transistor; an AND gate calculator, whose first input terminal is connected to the output terminal of the first comparator, whose second input terminal is connected to the output terminal of the second comparator, and whose output terminal is connected to the control terminal of the first switching transistor; a second voltage dividing unit, whose first terminal is connected to a voltage source, whose second terminal is grounded, and whose third terminal is connected to the inverting input terminal of the second comparator; the second comparator, whose non-inverting input terminal inputs a second reference voltage; the second voltage dividing unit includes: a fifth resistor and a sixth resistor connected in series, wherein, the fifth resistor is connected to the voltage source, the sixth resistor is grounded, the line between the fifth resistor and the sixth resistor is connected to the inverting input terminal of the second comparator, the fifth resistor is a fixed-value resistor, and the sixth resistor is the total resistance of the communication loop; The first switching transistor, whose input terminal is connected to the control terminal of the current adjustment module, and whose output terminal is grounded, for changing its on-off state according to the control signal, thereby controlling the switching conduction of two parallel-connected switching branches in the current adjustment module, and further adjusting the current of the communication loop; The current adjustment module is arranged between the input terminal and the output terminal of the communication loop.

2. The zero-fire communication circuit according to claim 1, characterized in that, The current adjustment module includes: A first switching branch, which includes a second switching transistor and a first resistor connected in series; A second switching branch, which includes a third switching transistor and a second resistor connected in series; The resistance value of the first resistor is greater than that of the second resistor, and the types of the second switching transistor and the third switching transistor are different.

3. The zero-fire communication circuit according to claim 2, wherein The second switching transistor is a PNP-type switching transistor, and the third switching transistor is an NPN-type switching transistor.

4. The zero-fire communication circuit according to claim 1, wherein The first voltage dividing unit includes: A third resistor and a fourth resistor connected in series, wherein, the third resistor is connected to the input terminal of the communication loop, the fourth resistor is grounded, and the line between the third resistor and the fourth resistor is connected to the non-inverting input terminal of the first comparator.

5. The zero-fire communication circuit according to claim 1, characterized in that, The circuit further includes: A seventh resistor and an eighth resistor connected in series, wherein, the seventh resistor is connected to the output terminal of the logic operation module, the eighth resistor is grounded, and the line between the seventh resistor and the eighth resistor is connected to the control terminal of the first switching transistor.

6. A live-neutral communication circuit, characterized in that, The circuit includes: A logic operation module, whose input terminal is connected to a voltage source, and whose output terminal is connected to the control terminal of a first switching transistor, is configured to output a control signal according to the total resistance of the communication loop of the zero-fire wire communication circuit; the logic operation module includes: a second voltage division unit, the second voltage division unit includes a fifth resistor and a sixth resistor connected in series, wherein the fifth resistor is connected to the voltage source, the sixth resistor is grounded, and the line between the fifth resistor and the sixth resistor is connected to the inverting input terminal of a second comparator, the fifth resistor is a fixed-value resistor, and the sixth resistor is the total resistance of the communication loop; The second comparator, whose non-inverting input terminal inputs a reference voltage, and whose output terminal is connected to the first switching transistor; The first switching transistor, whose input terminal is connected to the control terminal of a current adjustment module, and whose output terminal is grounded, is configured to change its on-off state according to the control signal, thereby controlling the switching conduction of two parallel switching branches in the current adjustment module, and further adjusting the current of the communication loop; The current adjustment module is disposed between the input terminal and the output terminal of the communication loop.

7. A communication system, comprising a first communication entity and a second communication entity, characterized in that, It further includes the zero-fire wire communication circuit according to claim 6, the first communication entity is connected to the input terminal of the communication loop, and the second communication entity is connected to the output terminal of the communication loop.

8. A communication system, comprising a first communication entity and a second communication entity, characterized in that, It further includes the zero-fire wire communication circuit according to any one of claims 1 to 5, the first communication entity is connected to the input terminal of the communication loop, and the second communication entity is connected to the output terminal of the communication loop.

9. The communication system according to claim 7 or 8, characterized in that, The communication system is an air-conditioning system, the first communication entity is an indoor unit of the air conditioner, and the second communication entity is an outdoor unit of the air conditioner.

Images