Half-duplex communication circuit and communication system

Abstract

The utility model provides a half-duplex communication circuit and a communication system. The half-duplex communication circuit comprises a first level conversion module, a transceiving control module, a 485 communication module and a pull-up and pull-down module. The first level conversion module comprises a first MOS tube, a first resistor unit and a second resistor unit. According to the invention, automatic transceiving control can be realized, so that the control circuit does not need to control the transceiving state of the 485 communication module through an independent IO end, and the number of IO ends used when the control circuit realizes half-duplex communication can be reduced. Meanwhile, safe, stable and reliable operation of the half-duplex communication circuit in a large-current scene can be ensured.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a half-duplex communication circuit and a communication system. Background Art

[0002] Half-duplex communication refers to a communication method in which data can be sent and received using the same channel, but a channel only supports receiving data or sending data at the same time. Since half-duplex communication does not support sending and receiving data at the same time, a half-duplex communication circuit is provided with a transceiver control terminal to determine the transceiver state based on the level of the transceiver control terminal.

[0003] In the prior art, when a half-duplex communication circuit is used for data transmission, the control circuit needs to connect the signal sending end, signal receiving end and IO (Input / Output) end of the circuit to the half-duplex communication circuit, so as to control the receiving and sending state of the half-duplex communication circuit by controlling the output level of the IO end. It can be seen that the control circuit needs to use more IO ends to realize half-duplex communication.

[0004] At the same time, since half-duplex communication supports data transmission and reception and has the advantages of low cost, it is widely used in various scenarios. However, the inventors have found that in high current scenarios, existing half-duplex communication circuits cannot work stably, safely and reliably.

[0005] In summary, there is an urgent need to provide a half-duplex communication circuit that can reduce the number of IO terminals used in the control circuit and can operate safely and stably in high current scenarios. Utility Model Content

[0006] The purpose of this application is to solve at least one of the above-mentioned technical defects and to provide a half-duplex communication circuit and communication system that can reduce the number of IO terminals used in the control circuit and can operate safely and stably in high current scenarios.

[0007] In some embodiments, the present application provides a half-duplex communication circuit, including:

[0008] a first level conversion module, the first level conversion module comprising a first MOS tube, a first resistance unit and a second resistance unit; a source of the first MOS tube is connected to a first end of the first resistance unit and is used to connect to a signal sending end of a control circuit; a gate of the first MOS tube is connected to a second end of the first resistance unit and is used to connect to a first voltage source; a drain of the first MOS tube is connected to a first end of the second resistance unit, and a second end of the second resistance unit is used to connect to a second voltage source;

[0009] a transceiver control module, connected to the drain of the first MOS tube, and used to connect a target voltage source and ground; the transceiver control module is used to output a low level voltage when the drain voltage of the first MOS tube is a high level voltage, and to output a high level voltage when the drain voltage of the first MOS tube is a low level voltage; wherein the target voltage source is the first voltage source or the second voltage source;

[0010] 485 communication module, the transceiver control terminal of the 485 communication module is connected to the transceiver control module, and the driver input terminal of the 485 communication module is used for grounding; the 485 communication module is used to determine the transceiver state according to the high level voltage or low level voltage output by the transceiver control module, and perform signal transceiver based on the transceiver state;

[0011] The pull-up and pull-down modules include a third resistor unit and a fourth resistor unit; the first end of the third resistor unit is connected to the inverting signal receiving and transmitting end of the 485 communication module, and the second end of the third resistor unit is used for grounding; the first end of the fourth resistor unit is connected to the inverting signal receiving and transmitting end of the 485 communication module, and the second end of the fourth resistor unit is used for connecting to the target voltage source.

[0012] In one of the embodiments, the half-duplex communication circuit further includes:

[0013] The second level conversion module is connected to the receiver output end of the 485 communication module and is used to connect to the signal receiving end of the control circuit.

[0014] In one embodiment, the second level conversion module includes a second MOS tube, a fifth resistance unit and a sixth resistance unit;

[0015] The source of the second MOS tube is connected to the first end of the fifth resistance unit and is used to connect to the signal receiving end of the control circuit; the gate of the second MOS tube is connected to the second end of the fifth resistance unit and is used to connect to the first voltage source; the drain of the second MOS tube is respectively connected to the receiver output end of the 485 communication module and the first end of the sixth resistance unit, and the second end of the sixth resistance unit is used to connect to the second voltage source.

[0016] In one of the embodiments, the transceiver control module includes a first transistor, a seventh resistor unit and an eighth resistor unit;

[0017] The base of the first transistor is connected to the first end of the seventh resistor unit, and the second end of the seventh resistor unit is connected to the drain of the first MOS tube; the collector of the first transistor is respectively connected to the transceiver control end of the 485 communication module and the first end of the eighth resistor unit, and the second end of the eighth resistor unit is used to connect to the target voltage source; the emitter of the first transistor is used to be grounded.

[0018] In one embodiment, the transceiver control module includes a third MOS tube, a ninth resistor unit and a tenth resistor unit;

[0019] The gate of the third MOS tube is connected to the first end of the ninth resistance unit, and the second end of the ninth resistance unit is connected to the drain of the first MOS tube; the drain of the third MOS tube is respectively connected to the transceiver control end of the 485 communication module and the first end of the tenth resistance unit, and the second end of the tenth resistance unit is used to connect to the target voltage source; the source of the third MOS tube is used to be grounded.

[0020] In one embodiment, the 485 communication module includes a 485 communication chip and a first capacitor;

[0021] The transceiver control end of the 485 communication chip is connected to the transceiver control module, the inverting signal transceiver end of the 485 communication chip is connected to the first end of the third resistor unit, the in-phase signal transceiver end of the 485 communication chip is connected to the first end of the fourth resistor unit, and the driver input end of the 485 communication chip is used for grounding;

[0022] The power supply end of the 485 communication chip is connected to the first end of the first capacitor, and the second end of the first capacitor is used to connect to the second voltage source.

[0023] In one embodiment, the 485 communication chip is a MAX 485 communication chip.

[0024] In one embodiment, the 485 communication module further includes an eleventh resistor unit, a first end of the eleventh resistor unit is used to connect to the second voltage source, and a second end of the eleventh resistor unit is connected to a receiver output end of the 485 communication chip.

[0025] In one embodiment, the pull-up and pull-down module further includes a twelfth resistor unit, a first end of the twelfth resistor unit is connected to the inverting signal transceiver end of the 485 communication module, and a second end of the twelfth resistor unit is connected to the inverting signal transceiver end of the 485 communication module.

[0026] In some embodiments, the present application provides a communication system, including:

[0027] The half-duplex communication circuit described in any one of the above embodiments, wherein the half-duplex communication circuit comprises a first level conversion module, and the first level conversion module comprises a first MOS tube;

[0028] A control circuit, wherein a signal sending end of the control circuit is connected to the source of the first MOS tube.

[0029] It can be seen from the above technical solutions that the embodiments of the present application have at least the following advantages:

[0030] (1) The half-duplex communication circuit can automatically determine the receiving and sending state according to the level of the signal sending end of the control circuit, thereby realizing automatic control of receiving and sending. In this way, the control circuit does not need to control the receiving and sending state of the 485 communication module through a separate IO terminal, thereby reducing the number of IO terminals used by the control circuit to realize half-duplex communication;

[0031] (2) The half-duplex communication circuit can use the first level conversion module to perform bidirectional level conversion to match the input and output levels of the control circuit with the input and output levels of the 485 communication module, thereby improving the reliability of half-duplex communication and the operating safety of the control circuit;

[0032] (3) MOS tubes are used as switch tubes in the first level conversion module, thereby ensuring the safe, stable and reliable operation of the half-duplex communication circuit in high current scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be 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 paying creative labor.

[0034] Figure 1 is one of the circuit schematic diagrams of a half-duplex communication circuit in one embodiment;

[0035] Figure 2 The second circuit diagram of a half-duplex communication circuit in one embodiment;

[0036] Figure 3 FIG. 4 is a system schematic diagram of a communication system in an embodiment. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] In one embodiment, the present application provides a half-duplex communication circuit 10. Figure 1 As shown, the half-duplex communication circuit 10 may include a first level conversion module 110, a transceiver control module 120, a 485 communication module 130, and a pull-up and pull-down module 140. The first level conversion module 110 may include a first MOS transistor Q1, a first resistor unit R1 and a second resistor unit R2, and the pull-up and pull-down module 140 may include a third resistor unit R3 and a fourth resistor unit R4.

[0039] Among them, the first level conversion module 110 refers to a circuit for performing bidirectional level conversion. In practical applications, the power supply voltage of the 485 communication module 130 may be different from the power supply voltage of the control circuit 20, resulting in the input and output voltages of the 485 communication module 130 being different from the input and output voltages of the control circuit 20. In order to improve communication reliability and circuit safety, the first level conversion module 110 can be used to perform bidirectional level conversion between the 485 communication module 130 and the control circuit 20 to achieve data transmission between circuit modules with different power supply voltages.

[0040] like Figure 1 As shown, the first level conversion module 110 may include a first MOS tube Q1, a first resistance unit R1 and a second resistance unit R2. It can be understood that the first MOS tube Q1 can be selected according to actual conditions, and this document does not impose specific restrictions on this. In order to more clearly describe the circuit operation process of the half-duplex communication circuit 10, this document takes the first MOS tube Q1 as an NMOS tube as an example. The first resistance unit R1 may include at least one resistor, for example, it may include 1, 2, 5 resistors, etc. When the first resistance unit R1 includes multiple resistors, the specific connection relationship of each resistor can be determined according to actual conditions, and this application does not impose specific restrictions on this. Similarly, the second resistance unit R2 may include at least one resistor. When the second resistance unit R2 includes multiple resistors, the specific connection relationship of each resistor can be determined according to actual conditions, and this application does not impose specific restrictions on this.

[0041] The source of the first MOS transistor Q1 is respectively connected to the signal transmission terminal TX of the control circuit 20 and the first end of the first resistor unit R1, the second end of the first resistor unit R1 is respectively connected to the first voltage source U1 and the gate of the first MOS transistor Q1, the drain of the first MOS transistor Q1 is respectively connected to the transceiver control module 120 and the first end of the second resistor unit R2, and the second end of the second resistor unit R2 is used to connect the second voltage source U2. Among them, the first voltage source U1 can be used to provide the power supply voltage required by the control circuit 20, and the second voltage source U2 can be used to provide the power supply voltage required by the 485 communication module 130. In an example, the first voltage source can be used to provide a 3.3V voltage, and the second voltage source can be used to provide a 5V voltage.

[0042] The transceiver control module 120 may be a circuit for automatically controlling the transceiver state of the communication module 130 according to the level of the signal transmitting terminal TX of the control circuit 20. The transceiver control module 120 may be used to connect the target voltage source and the ground respectively, wherein the target voltage source may be the first voltage source U1 or the second voltage source U2. In one example, to further improve the communication reliability, the target voltage source may be the second voltage source U2.

[0043] The transceiver control module 120 can be connected to the transceiver control terminal of the 485 communication module 130, and the driver input terminal of the 485 communication module 130 is used for grounding. The inverting signal transceiver terminal of the 485 communication module 130 can be connected to the first end of the third resistor unit R3, and the in-phase signal transceiver terminal of the 485 communication module 130 can be connected to the first end of the fourth resistor unit R4. The second end of the third resistor unit R3 can be used for grounding, and the second end of the fourth resistor unit R4 can be used for connecting to the target voltage source.

[0044] In the process of sending data, the signal transmitting end TX of the control circuit 20 will use a high level to represent 1 and a low level to represent 0. When the signal transmitting end TX sends 0, the first MOS tube Q1 is turned on, and the drain voltage of the first MOS tube Q1 is pulled down, that is, the drain voltage of the first MOS tube Q1 is a low level voltage. In this case, the transceiver control module 120 outputs a high level voltage to the transceiver control end of the 485 communication module 130, so that the 485 communication module 130 is in a data sending state. In the case of being in the data sending state, the 485 communication module 130 will react the level of the driver input end to the in-phase signal transceiver end and the inverted signal transceiver end. In the present application, since the driver input end is grounded, therefore, when in the data sending state, the in-phase signal transceiver end of the 485 communication module 130 outputs a low level, and the inverted signal transceiver end outputs a high level to transmit 0 to the next level circuit.

[0045] In the process of sending data, when the signal transmitting end TX sends 1, the first MOS tube Q1 is turned off, and the drain voltage of the first MOS tube Q1 is pulled up to a high level through the second resistor unit R2. In this case, the transceiver control module 120 outputs a low-level voltage to the transceiver control end of the 485 communication module 130, so that the 485 communication module 130 is in a data receiving state, and then the in-phase signal transceiver end and the inverted signal transceiver end of the 485 communication module 130 are both in a high-impedance state. Since the in-phase signal transceiver end is connected to the target voltage source through the fourth resistor unit R4, and the inverted signal transceiver end is grounded through the third resistor unit R3, the in-phase signal transceiver end can output a high level, and the inverted signal transceiver end can output a low level, so as to transmit 1 to the next level circuit.

[0046] In the process of receiving data, the signal transmitting end TX always outputs a high level, so that the 485 communication module 130 is in a data receiving state. In this case, the 485 communication module 130 can receive the data transmitted by the next level circuit through the in-phase signal transceiver and the anti-phase signal transceiver, and transmit the received data to the control circuit 20.

[0047] It can be seen that the half-duplex communication circuit 10 provided in the present application can realize automatic control of transmission and reception. During application, the half-duplex communication circuit 10 only needs to connect the signal sending end TX and the signal receiving end RX of the control circuit 20 to realize communication, so that the control circuit 20 does not need to control the transmission and reception status of the 485 communication module 130 through a separate IO end, thereby reducing the number of IO ends used by the control circuit 20 to realize half-duplex communication.

[0048] In one embodiment, the half-duplex communication circuit 10 may also include a second level conversion module, which is respectively connected to the receiver output end of the 485 communication module 130 and the signal receiving end RX of the control circuit 20, and is used to perform level conversion between the 485 communication module 130 and the control circuit 20 to further improve the reliability of half-duplex communication and the operation safety of the control circuit 20.

[0049] It can be understood that the second level conversion module of the present application can be implemented by a circuit of any structure. In one embodiment, in order to further improve the operating safety, stability and reliability of the half-duplex communication circuit 10 in a high current scenario, the second level conversion module may include a second MOS tube Q2, a fifth resistor unit R5 and a sixth resistor unit R6. It can be understood that the second MOS tube Q2 can be selected according to actual conditions. In order to more clearly describe the circuit working process of the half-duplex communication circuit 10, this article takes the second MOS tube Q2 as an NMOS tube as an example. The specific description of the fifth resistor unit R5 and the sixth resistor unit R6 can refer to the relevant description of the first resistor unit R1 and the second resistor unit R2 mentioned above, which will not be repeated here.

[0050] like Figure 2 As shown, the source of the second MOS tube Q2 is respectively connected to the signal receiving end RX of the control circuit 20 and the first end of the fifth resistance unit R5, the second end of the fifth resistance unit R5 is respectively connected to the first voltage source U1 and the gate of the second MOS tube Q2, the drain of the second MOS tube Q2 is respectively connected to the receiver output end of the 485 communication module 130 and the first end of the sixth resistance unit R6, and the second end of the sixth resistance unit R6 is used to connect the second voltage source U2.

[0051] Specifically, in the process of receiving data, the 485 communication module 130 can receive the data transmitted by the next-level circuit through the in-phase signal transceiver and the inverted signal transceiver, and output the received data through the receiver output. When the receiver output outputs a high level, the drain voltage of the second MOS tube Q2 is a high level voltage, the body diode of the second MOS tube Q2 is not turned on, and the source voltage of the second MOS tube Q2 is pulled up to a high level through the fifth resistor unit R5 to output a high level voltage to the control circuit 20.

[0052] When the receiver output terminal outputs a low level, the drain voltage of the second MOS tube Q2 is a low level voltage, the body diode of the second MOS tube Q2 is turned on, and the source voltage of the second MOS tube Q2 is gradually pulled down to a low level voltage via the body diode. When the voltage difference between the gate voltage and the source voltage of the second MOS tube Q2 is greater than the turn-on voltage threshold of the MOS tube, the second MOS tube Q2 is turned on to further lower the source voltage of the second MOS tube Q2, so as to output a low level voltage to the control circuit 20.

[0053] In one embodiment, Figure 2 As shown, the transceiver control module 120 may include a first transistor Q3, a seventh resistor unit R7, and an eighth resistor unit R8. It can be understood that the first transistor Q3 can be selected according to actual conditions. In order to more clearly describe the circuit operation process of the half-duplex communication circuit 10, this article takes the first transistor Q3 as an NPN transistor as an example. The specific description of the seventh resistor unit R7 and the eighth resistor unit R8 can refer to the relevant description of the first resistor unit R1 and the second resistor unit R2 mentioned above, which will not be repeated here.

[0054] The base of the first transistor Q3 is connected to the first end of the seventh resistor unit R7, and the second end of the seventh resistor unit R7 is connected to the drain of the first MOS transistor Q1. The emitter of the first transistor Q3 is used for grounding, and the collector of the first transistor Q3 is respectively connected to the transceiver control end of the 485 communication module 130 and the first end of the eighth resistor unit R8, and the second end of the eighth resistor unit R8 is used for connecting to the target voltage source.

[0055] When the drain voltage of the first MOS transistor Q1 is a low level voltage, the base voltage of the first transistor Q3 is also a low level voltage, and the first transistor Q3 is turned off. The collector of the first transistor Q3 is pulled up to a high level voltage via the eighth resistor unit R8, thereby outputting a high level voltage to the transceiver control terminal of the 485 communication module 130. When the drain voltage of the first MOS transistor Q1 is a high level voltage, the base voltage of the first transistor Q3 is a high level voltage, the first transistor Q3 is turned on, and the collector voltage of the first transistor Q3 is pulled down to a low level voltage, thereby outputting a low level voltage to the transceiver control terminal of the 485 communication module 130.

[0056] In this embodiment, the transceiver control module 120 is implemented by using a resistor unit and a transistor, so that the cost of the half-duplex communication circuit 10 can be reduced.

[0057] In one embodiment, the transceiver control module 120 can be implemented using a MOS tube and a resistor unit to further improve the operational safety, stability and reliability of the half-duplex communication circuit 10 in a high current scenario. Specifically, the transceiver control module 120 may include a third MOS tube, a ninth resistor unit and a tenth resistor unit. The gate of the third MOS tube is connected to the first end of the ninth resistor unit, and the second end of the ninth resistor unit is connected to the drain of the first MOS tube Q1. The source of the third MOS tube is used for grounding, and the drain of the third MOS tube is respectively connected to the transceiver control end of the 485 communication module 130 and the first end of the tenth resistor unit, and the second end of the tenth resistor unit is used to connect to the target voltage source.

[0058] The circuit operation process of this embodiment can refer to the above description of using a transistor and a resistor unit to implement the transceiver control module 120, which will not be described in detail herein.

[0059] In one embodiment, Figure 2 As shown, the 485 communication module 130 may include a 485 communication chip U3 and a first capacitor C1. It can be understood that the 485 communication chip U3 can be selected according to actual conditions, and this document does not make specific restrictions on this. In some examples, the 485 communication chip U3 may be a MAX 485 communication chip to achieve low-power communication. When the MAX 485 communication chip is used, the transceiver control end of the 485 communication chip may include a transmission enable end DE and a reception enable end RE, wherein the transmission enable end DE is a high-level enable, and the reception enable end RE is a low-level enable.

[0060] The transceiver control terminal of the 485 communication chip U3 is connected to the transceiver control module 120, so that the transceiver state can be determined according to the level output by the transceiver control module 120, and data is transmitted and received accordingly. The inverting signal transceiver terminal B of the 485 communication chip U3 is connected to the first end of the third resistor unit R3, the in-phase signal transceiver terminal A of the 485 communication chip U3 is connected to the first end of the fourth resistor unit R4, and the driver input terminal DI of the 485 communication chip U3 is used for grounding. In an example, the receiver output terminal RO of the 485 communication chip U3 can be connected to the second level conversion module, and the ground terminal GND can be used for grounding.

[0061] The power supply terminal VCC of the 485 communication chip U3 is connected to the first terminal of the first capacitor C1, and the second terminal of the first capacitor C1 is used to connect to the second voltage source U2. In this way, the first capacitor C1 can be used for filtering and power supply to further improve communication reliability.

[0062] In one embodiment, the 485 communication module 130 may further include an eleventh resistor unit R11. The specific description of the eleventh resistor unit R11 can refer to the relevant description of the first resistor unit R1, which will not be repeated herein. The first end of the eleventh resistor unit R11 is used to connect to the second voltage source U2, and the second end of the eleventh resistor unit R11 is connected to the receiver output end of the 485 communication chip U3.

[0063] In one embodiment, the pull-up / pull-down module 140 further includes a twelfth resistor unit R12. The specific description of the twelfth resistor unit R12 can refer to the related description of the first resistor unit R1, which will not be repeated herein. The first end of the twelfth resistor unit R12 is connected to the inverting signal transceiver end of the 485 communication module 130, and the second end of the twelfth resistor unit R12 is connected to the inverting signal transceiver end of the 485 communication module 130.

[0064] In one embodiment, Figure 3 As shown, the present application provides a communication system, including a control circuit 20 and the half-duplex communication circuit 10 described in any of the above embodiments, wherein the signal transmitting end TX of the control circuit 20 is connected to the source of the first MOS tube Q1. Among them, the control circuit 20 can be a circuit that needs to perform 485 communication, and the specific description of the half-duplex communication circuit 10 can refer to the description of any of the above embodiments, which will not be repeated herein.

[0065] The communication system of the embodiment of the present application can reduce the number of IO terminals used by the control circuit 20 to implement half-duplex communication, and can improve the reliability of half-duplex communication and the operational safety of the control circuit 20, as well as ensure operational safety, stability, and reliability in high current scenarios.

[0066] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. Herein, "one", "one", "said", "the" and "it" may also include plural forms, unless the context clearly indicates another way. A plurality refers to at least two cases, such as 2, 3, 5 or 8, etc. "And / or" includes any and all combinations of the relevant listed items.

[0067] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can refer to each other.

[0068] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A half-duplex communication circuit, characterized in that: include: a first level conversion module, the first level conversion module comprising a first MOS tube, a first resistance unit and a second resistance unit; a source of the first MOS tube is connected to a first end of the first resistance unit and is used to connect to a signal sending end of a control circuit; a gate of the first MOS tube is connected to a second end of the first resistance unit and is used to connect to a first voltage source; a drain of the first MOS tube is connected to a first end of the second resistance unit, and a second end of the second resistance unit is used to connect to a second voltage source; a transceiver control module, connected to the drain of the first MOS tube, and used to connect a target voltage source and ground; the transceiver control module is used to output a low level voltage when the drain voltage of the first MOS tube is a high level voltage, and to output a high level voltage when the drain voltage of the first MOS tube is a low level voltage; wherein the target voltage source is the first voltage source or the second voltage source; 485 communication module, the transceiver control terminal of the 485 communication module is connected to the transceiver control module, and the driver input terminal of the 485 communication module is used for grounding; the 485 communication module is used to determine the transceiver state according to the high level voltage or low level voltage output by the transceiver control module, and perform signal transceiver based on the transceiver state; The pull-up and pull-down modules include a third resistor unit and a fourth resistor unit; the first end of the third resistor unit is connected to the inverting signal receiving and transmitting end of the 485 communication module, and the second end of the third resistor unit is used for grounding; the first end of the fourth resistor unit is connected to the inverting signal receiving and transmitting end of the 485 communication module, and the second end of the fourth resistor unit is used for connecting to the target voltage source.

2. The half-duplex communication circuit according to claim 1, characterized in that: The half-duplex communication circuit also includes: The second level conversion module is connected to the receiver output end of the 485 communication module and is used to connect to the signal receiving end of the control circuit.

3. The half-duplex communication circuit according to claim 2, characterized in that: The second level conversion module includes a second MOS tube, a fifth resistance unit and a sixth resistance unit; The source of the second MOS tube is connected to the first end of the fifth resistance unit and is used to connect to the signal receiving end of the control circuit; the gate of the second MOS tube is connected to the second end of the fifth resistance unit and is used to connect to the first voltage source; the drain of the second MOS tube is respectively connected to the receiver output end of the 485 communication module and the first end of the sixth resistance unit, and the second end of the sixth resistance unit is used to connect to the second voltage source.

4. The half-duplex communication circuit according to claim 1, characterized in that: The transceiver control module includes a first transistor, a seventh resistor unit and an eighth resistor unit; The base of the first transistor is connected to the first end of the seventh resistor unit, and the second end of the seventh resistor unit is connected to the drain of the first MOS tube; the collector of the first transistor is respectively connected to the transceiver control end of the 485 communication module and the first end of the eighth resistor unit, and the second end of the eighth resistor unit is used to connect to the target voltage source; the emitter of the first transistor is used to be grounded.

5. The half-duplex communication circuit according to claim 1, characterized in that: The transceiver control module includes a third MOS tube, a ninth resistor unit and a tenth resistor unit; The gate of the third MOS tube is connected to the first end of the ninth resistance unit, and the second end of the ninth resistance unit is connected to the drain of the first MOS tube; the drain of the third MOS tube is respectively connected to the transceiver control end of the 485 communication module and the first end of the tenth resistance unit, and the second end of the tenth resistance unit is used to connect to the target voltage source; the source of the third MOS tube is used to be grounded.

6. The half-duplex communication circuit according to any one of claims 1 to 5, characterized in that: The 485 communication module includes a 485 communication chip and a first capacitor; The transceiver control end of the 485 communication chip is connected to the transceiver control module, the inverting signal transceiver end of the 485 communication chip is connected to the first end of the third resistor unit, the in-phase signal transceiver end of the 485 communication chip is connected to the first end of the fourth resistor unit, and the driver input end of the 485 communication chip is used for grounding; The power supply end of the 485 communication chip is connected to the first end of the first capacitor, and the second end of the first capacitor is used to connect to the second voltage source.

7. The half-duplex communication circuit according to claim 6, characterized in that: The 485 communication chip is a MAX 485 communication chip.

8. The half-duplex communication circuit according to claim 6, characterized in that: The 485 communication module further includes an eleventh resistor unit, a first end of the eleventh resistor unit is used to connect to the second voltage source, and a second end of the eleventh resistor unit is connected to a receiver output end of the 485 communication chip.

9. The half-duplex communication circuit according to any one of claims 1 to 5, characterized in that: The pull-up and pull-down module further includes a twelfth resistor unit, a first end of the twelfth resistor unit is connected to the inverting signal transceiver end of the 485 communication module, and a second end of the twelfth resistor unit is connected to the inverting signal transceiver end of the 485 communication module.

10. A communication system, characterized in that: include: The half-duplex communication circuit according to any one of claims 1 to 9, wherein the half-duplex communication circuit comprises a first level conversion module, wherein the first level conversion module comprises a first MOS tube; A control circuit, wherein a signal sending end of the control circuit is connected to the source of the first MOS tube.

Images