CN115397079B

CN115397079B - Communication impedance matching circuit, lamp and lamp control system

Info

Publication number: CN115397079B
Application number: CN202211330726.2A
Authority: CN
Inventors: 黄毅; 童鹍; 周向军
Original assignee: Aputure Imaging Industries Co Ltd
Current assignee: Shenzhen Aitushi Innovation Technology Co ltd
Priority date: 2022-10-28
Filing date: 2022-10-28
Publication date: 2023-04-28
Anticipated expiration: 2042-10-28
Also published as: CN115397079A

Abstract

The application discloses communication impedance matching circuit, lamps and lanterns and lamps and lanterns control system, the circuit includes: the input unit is connected with the communication bus and is used for acquiring a mode selection signal input by a user; the control unit is used for generating a corresponding control signal according to the mode selection signal; the resistance switching unit is respectively connected with the control unit and the communication bus, and comprises a plurality of functional resistors which are used for being adjusted into corresponding working modes according to the control signals, wherein the working modes comprise at least one of the following steps: accessing a preset functional resistance, removing the preset functional resistance and switching the preset functional resistance. The application realizes quick and convenient switching connection of different functional resistors so as to meet application requirements in various scenes.

Description

Communication impedance matching circuit, lamp and lamp control system

Technical Field

The application relates to the technical field of lighting driving, and further relates to a communication impedance matching circuit, a lamp and a lamp control system.

Background

The existing LED lamp adopts DMX (Digital Multiplex, namely a standard protocol for lamplight communication) for communication, is generally based on an RS-485 circuit, and when a plurality of nodes are connected and work simultaneously, if communication instability occurs, an impedance matching resistor is manually added on a communication bus of the last node.

In the application scenario of multi-node connection communication, the functional resistor is sometimes required and sometimes not required due to different requirements on the functional resistor under the matching of different wiring modes and different devices, and some means are manual replacement of the functional resistor, and other means are manual access or manual removal of the functional resistor. The mode needs to additionally prepare the functional resistor, so that the lamp cannot work normally once the functional resistor is lost or the functional resistor is forgotten to prepare, meanwhile, the resistance value inside the lamp also needs to be changed in some severe environments, and the mode is not easy to meet the application requirements of different lamps and efficient adaptation in various environments.

Disclosure of Invention

An objective of the embodiments of the present application is to provide a communication impedance matching circuit, a lamp and a lamp control system, so as to solve the problem that functional resistors need to be manually replaced, connected or removed, and the requirements of fast and convenient switching and application under various environments cannot be met.

In a first aspect, to achieve the above object, an embodiment of the present application provides a communication impedance matching circuit, including:

the input unit is used for acquiring a mode selection signal input by a user;

the control unit is connected with the input unit and is used for generating a corresponding control signal according to the mode selection signal;

The resistance switching unit is respectively connected with the control unit and the communication bus, and comprises a plurality of functional resistors which are used for being adjusted into corresponding working modes according to the control signals, wherein the working modes comprise at least one of the following steps: accessing a preset functional resistance, removing the preset functional resistance and switching the preset functional resistance.

The embodiment of the application provides a communication impedance matching circuit, a lamp and a lamp control system, wherein a control unit generates and sends a corresponding control signal to a resistance switching unit according to a mode selection signal manually input by a user through an input unit, and the resistance switching unit correspondingly adjusts the circuit connection state between each functional resistor and a communication bus after receiving the control signal, so that the functional resistor and the communication bus are switched to a connection state or a disconnection state, and different functional resistors are quickly and conveniently switched and connected to meet application requirements under various scenes.

Drawings

The above features, technical features, advantages and implementation of the present application will be further described in the following description of preferred embodiments in a clear and easily understood manner with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of an internal structure of a communication impedance matching circuit according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an internal structure of a resistance switching unit according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of another internal structure of a resistance switching unit according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of an exemplary circuit of a pull-down switching module and a pull-up switching module provided in an embodiment of the present application;

FIG. 5 is a schematic circuit diagram of an exemplary impedance switching module according to an embodiment of the present application;

FIG. 6 is another exemplary schematic circuit diagram of a pull-down switching module and a pull-up switching module provided in an embodiment of the present application;

FIG. 7 is another exemplary schematic circuit diagram of an impedance switching module provided in an embodiment of the present application;

FIG. 8 is an exemplary circuit schematic of a power-on reset module and an external clock module provided in an embodiment of the present application;

fig. 9 is an exemplary schematic circuit diagram of a master control module according to an embodiment of the present application;

fig. 10 is a schematic circuit diagram of an example of a burning module, an overvoltage protection module, and a filtering module provided in an embodiment of the present application;

FIG. 11 is an exemplary circuit schematic of a communication module provided in an embodiment of the present application;

FIG. 12 is an exemplary schematic circuit diagram of a first power module and a second power module provided in an embodiment of the present application;

Fig. 13 is a schematic structural diagram of a lamp control system according to an embodiment of the present application.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

For simplicity of the drawing, only the parts relevant to the present application are schematically shown in each drawing, and they do not represent the actual structure thereof as a product. Additionally, in order to simplify the drawing for ease of understanding, components having the same structure or function in some of the drawings are shown schematically with only one of them, or only one of them is labeled. Herein, "a" means not only "only this one" but also "more than one" case.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

In addition, in the description of the present application, the terms "first," "second," and the like are used merely to distinguish between descriptions and are not to be construed as indicating or implying relative importance.

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following description will explain specific embodiments of the present application with reference to the accompanying drawings. It is obvious that the drawings in the following description are only examples of the present application, and that other drawings and other embodiments may be obtained from these drawings by those skilled in the art without undue effort.

Referring to fig. 1, fig. 1 is a schematic diagram illustrating an internal structure of a communication impedance matching circuit according to an embodiment of the present application, where the communication impedance matching circuit includes:

the input unit 200 is used for acquiring a mode selection signal input by a user;

a control unit 300 connected to the input unit 200, the control unit 300 being configured to generate a corresponding control signal according to the mode selection signal;

The resistance switching unit 100 is connected to the control unit 300 and the communication bus 400, and the resistance switching unit 100 includes a plurality of functional resistors, and is configured to adjust a line connection state between the plurality of functional resistors and the communication bus 400 according to a control signal to adjust to a required operation mode, where the operation mode includes at least one of: accessing a preset functional resistance, removing the preset functional resistance and switching the preset functional resistance.

Specifically, the input unit 200 may be integrated on a console, and display, through a man-machine interaction interface of the console, description information of the operation mode and a touch button for selecting the operation mode, where the description information may be displayed in a pop-up window form or a list box form. Or the table surface of the console is printed with the description information of the working mode, the mechanical rocker or the mechanical key used for poking and selecting the working mode, and the like, so that a user manually selects the working mode by touching any one of the buttons, the mechanical rocker or the mechanical key according to the application requirement or the scene requirement of the lighting lamp by referring to the description information to acquire a mode selection signal.

The control unit 300 may generate and send a corresponding control signal to the resistance switching unit 100 according to a mode selection signal manually input by the user through the input unit 200, and after receiving the control signal, the resistance switching unit 100 correspondingly adjusts a line connection state between each functional resistor and the communication bus, so that the functional resistor and the communication bus are switched to a connection state or a disconnection state, and the different functional resistors are quickly and conveniently switched and connected to meet application requirements in various scenes.

The method and the device can solve the problem that the lamp cannot work normally due to the fact that the functional resistor is required to be manually replaced or manually connected or manually removed and the functional resistor is lost or forgotten to be prepared in advance, and meet the application requirements of rapidness and convenience and the use requirements of various lamp application scenes.

Referring to fig. 2, fig. 2 is a schematic diagram of an internal structure of a resistance switching unit 100 according to an embodiment of the present application, where the functional resistor includes: a plurality of impedance matching resistors; the resistance switching unit 100 includes a plurality of impedance switching modules 21;

the plurality of impedance switching modules 21 are respectively connected with the plurality of impedance matching resistors in a one-to-one correspondence manner, and are used for controlling the connection or disconnection between the impedance matching resistors and the communication bus 400 according to the first control signal P2 so as to realize at least one of the following in the circuit: accessing, removing and switching the impedance matching resistor;

the first control signal P2 is generated by the control unit 300 according to the mode selection signal acquired by the input unit 200.

Specifically, the types of functional resistors include, but are not limited to, a pull-up resistor for pulling high, a pull-down resistor for pulling low, and an impedance matching resistor for matching the load, such as a lamp impedance, with the internal impedance of the excitation source. The number of functional resistors in the resistance switching unit 100 is not limited, and the number of different types of functional resistors can be set according to the application scenario and the requirement.

Specifically, the number of impedance matching resistors in the resistance switching unit 100 may be different from or the same as the number of impedance switching modules 21, and if the number of impedance matching resistors and the number of impedance switching modules 21 are one, one impedance switching module 21 controls the connected state or the disconnected state between the connected impedance matching resistor and the communication bus 400 to implement the connection or the disconnection of the impedance matching resistor in the circuit. Of course, if the number of the impedance matching resistors is the same as the number of the impedance switching modules 21 and is at least two, the at least two impedance switching modules 21 are respectively connected with the at least two impedance matching resistors in a one-to-one correspondence manner, and the at least two impedance switching modules 21 control the connected impedance matching resistors to be in a connection state or a disconnection state with the communication bus 400 so as to realize the connection, the removal and the switching of the impedance matching resistors in the circuit.

According to the method, the impedance switching module 21 is connected with the control unit 300 in a one-to-one correspondence manner, a plurality of impedance switching modules 21 and a plurality of impedance matching resistors are connected in a one-to-one correspondence manner, under the scene that the resistance value of an internal circuit of the lamp is selected and adjusted according to the requirement, after the mode selection signal input by a user is obtained, the mode selection signal is transmitted to the control unit through the communication bus by the input unit, the control unit 300 generates a first control signal P2 according to the mode selection signal and sends the first control signal P2 to the impedance switching module in the resistance switching unit 100, and the impedance switching module receives the first control signal P2 and adjusts the line connection state between the impedance matching resistors and the communication bus 400, so that the plurality of impedance matching resistors in the internal circuit of the lamp and the communication bus 400 are switched to be in a connection state or a disconnection state, the connection state or the removal of one or the plurality of impedance matching resistors can be switched quickly and conveniently, the application requirements of different lamps and the efficient adaptation under various environments can be adapted.

Referring to fig. 2, fig. 2 is a schematic diagram of an internal structure of a resistance switching unit 100 according to an embodiment of the present application, where the functional resistor includes: a plurality of pull-up resistors and a plurality of pull-down resistors; the resistance switching unit 100 includes a plurality of pull-up and pull-down switching modules 22;

the plurality of up-down switching modules 22 are respectively connected with the plurality of pull-down resistors and the plurality of pull-up resistors in a one-to-one correspondence manner, and are configured to control the connection or disconnection between the plurality of pull-down resistors and the plurality of pull-up resistors and the communication bus 400 according to the second control signal P1, so as to implement at least one of the following in the circuit: accessing, removing and switching a plurality of pull-up resistors and/or a plurality of pull-down resistors;

the second control signal P1 is generated by the control unit 300 according to the mode selection signal acquired by the input unit 200.

Specifically, the number of pull-down resistors in the resistance switching unit 100 may be the same as or different from the number of pull-up switching modules 22, and the number of pull-up resistors may be the same as or different from the number of pull-up switching modules 22. If there is only one pull-down resistor or pull-up resistor and one pull-up and pull-down switching module 22, then one pull-up and pull-down switching module 22 controls the connected pull-down resistor or pull-up resistor to be connected to or disconnected from the communication bus 400 to enable the connection or removal of this pull-down resistor or pull-up resistor in the circuit. If the number of pull-down resistors, the number of pull-up resistors and the number of pull-up/down switching modules 22 are one, then one pull-up/down switching module 22 controls the connected pull-down resistors, the connected state or the disconnected state between the pull-up resistors and the communication bus 400, so as to achieve the purpose of simultaneously connecting the pull-down resistors and the pull-up resistors in the circuit, or simultaneously removing the pull-down resistors and the pull-up resistors, or connecting the pull-down resistors and the pull-up resistors to achieve the purpose of switching the resistors, or removing the pull-down resistors and connecting the pull-up resistors to achieve the purpose of switching the resistors. Of course, if the number of pull-down resistors and pull-up resistors is the same as the number of pull-up and pull-down switching modules 22 and is at least two, the at least two pull-up and pull-down switching modules 22 are respectively connected with the at least two pull-down resistors and the pull-up resistors in a one-to-one correspondence manner, and the at least two pull-up and pull-down switching modules 22 control the connected pull-down resistors, the connected state or the disconnected state between the pull-up resistors and the communication bus 400 so as to realize the connection, the removal, the switching of the pull-down resistors and the pull-up resistors in the circuit.

According to the method, the up-down switching module 22 is connected with the control unit 300, the up-down switching module 22 is connected with the down-pull resistors and the up-pull resistors in a one-to-one correspondence manner, the down-pull resistors and the communication bus 400 in the lamp internal circuit can be respectively switched to a communication state or a disconnection state according to the mode selection signal input by the user, the input unit transmits the mode selection signal to the control unit through the communication bus, the control unit 300 generates a second control signal P1 according to the mode selection signal and transmits the second control signal P1 to the up-down switching module 22 in the resistance switching unit 100, the up-down switching module 22 receives the second control signal P1 and then adjusts the connection state of the down-pull resistors and/or the up-pull resistors and the communication bus 400, so that the down-pull resistors and the communication bus 400 in the lamp internal circuit can be respectively switched to the communication state or the disconnection state, or one or more down-pull resistors can be quickly and conveniently switched to be connected, connected or removed, and one or more up-pull resistors can be quickly and conveniently switched to adapt to various requirements of different applications under various scenes.

Referring to fig. 3, fig. 3 is a schematic diagram of another internal structure of a resistance switching unit 100 according to an embodiment of the present application, where the functional resistor includes: a plurality of impedance matching resistors, a plurality of pull-up resistors and a plurality of pull-down resistors; the resistance switching unit 100 includes:

the first control signal P2 is generated by the control unit 300 according to the mode selection signal acquired by the input unit 200, and the second control signal P1 is generated by the control unit 300 according to the mode selection signal acquired by the input unit 200.

Specifically, the primary impedance matching resistor and the secondary impedance matching resistor in fig. 3 function substantially the same, and are used herein only for differences in connection relationship with the pull-up switching circuit and the pull-down switching circuit. The number of the impedance switching modules 21 and the number of the pull-up and pull-down switching modules 22 may be the same or different, wherein one pull-up and pull-down switching module 22 may include a plurality of pull-up switching circuits and a plurality of pull-down switching circuits, one impedance switching module 21 may include a plurality of primary impedance switching circuits and a plurality of secondary impedance switching circuits, the number of the pull-up switching circuits and the number of the pull-up resistors in the resistance switching unit 100 are the same, the number of the pull-down switching circuits and the number of the pull-down resistors are the same, the number of the primary impedance switching circuits and the number of the primary impedance matching resistors are the same, and the number of the secondary impedance switching circuits and the number of the secondary impedance matching resistors are the same. If the number of the impedance matching resistor, the pull-down resistor or the pull-up resistor, the impedance switching module 21 and the pull-up/down switching module 22 is one, that is, there is one pull-down resistor zero pull-up resistor or one pull-up resistor zero pull-down resistor in the circuit, then one impedance switching module 21 controls the connection state or disconnection state between the connected impedance matching resistor and the communication bus 400 to enable the connection or disconnection of the impedance matching resistor in the circuit, and one pull-up/down switching module 22 controls the connection state or disconnection state between the connected pull-down resistor or pull-up resistor and the communication bus 400 to enable the connection or disconnection of the pull-down resistor in the circuit.

Of course, if the number of the impedance matching resistors, the pull-down resistors, the pull-up resistors, the impedance switching modules 21 and the pull-up and pull-down switching modules 22 is the same and is at least two, the at least two impedance switching modules 21 are respectively connected with the at least two impedance matching resistors in a one-to-one correspondence manner, the at least two impedance switching modules 21 control the connected state or the disconnected state between the connected impedance matching resistors and the communication bus 400 to realize the connection, the removal and the switching of the impedance matching resistors in the circuit, the at least two pull-up and pull-down switching modules 22 are respectively connected with the at least two pull-down resistors and the pull-up resistors in a one-to-one correspondence manner, and the at least two pull-up and pull-down switching modules 22 control the connected state or the disconnected state between the connected pull-down resistors and the communication bus 400 to realize the connection, the removal and the switching of the pull-down resistors and the pull-up resistors in the circuit. In summary, the number of the impedance matching resistor, the pull-down resistor, the pull-up resistor, the impedance switching module 21 and the pull-up/down switching module 22 set in the circuit can be set according to the size and the application scene of the lamp.

Referring to fig. 4 and 6, fig. 4 is a schematic circuit diagram of an example of the pull-up/down switching module 22 according to an embodiment of the present application, and fig. 6 is a schematic circuit diagram of another example of the pull-up/down switching module 22 according to an embodiment of the present application. The pull-up/down switching module 22 includes: at least one of a pull-up switching circuit and a pull-down switching circuit, wherein the pull-down switching circuit comprises a first transistor Q1 and a first photoelectric coupler PH1; the pull-up switching circuit comprises a second transistor Q2 and a second photoelectric coupler PH2;

The first poles of the first transistor Q1 and the second transistor Q2 are respectively connected with a first ground GND;

the second poles of the first transistor Q1 and the second transistor Q2 are respectively connected with a second control signal P1;

the second pin 2 of the first photo coupler PH1 is connected with the third pole of the first transistor Q1, and the second pin 2 of the second photo coupler PH2 is connected with the third pole of the second transistor Q2;

the first pins 1 of the first photoelectric coupler PH1 and the second photoelectric coupler PH2 are respectively connected with a second power supply voltage of 3.3V;

the fourth pin 4 of the first photo coupler PH1 is connected to one end of the first pull-down resistor R1, and the other end of the first pull-down resistor R1 is connected to the communication bus 400 or directly connected to the communication bus 400 through the impedance switching module 21, and the third pin 3 of the first photo coupler PH1 is connected to the second ground GND 2;

the third pin 3 of the second photo coupler PH2 is connected to one end of the first pull-up resistor R5, the other end of the first pull-up resistor R5 is connected to the communication bus 400 through the impedance switching module 21 or directly connected to the communication bus 400, and the fourth pin 4 of the second photo coupler PH2 is connected to the first power supply voltage +5vc and to the second ground GND2.

Specifically, the communication impedance matching circuit may include only one pull-up/pull-down switching module 22, where one pull-up/pull-down switching module 22 may include only one pull-up switching circuit, or one pull-up/pull-down switching module 22 may include only one pull-down switching circuit, and of course, one pull-up/pull-down switching module 22 may include both a pull-up switching circuit and a pull-down switching circuit.

The pull-down switching circuit includes a first transistor Q1 and a first photo coupler PH1, and of course, the pull-down switching circuit may further include a first capacitor C1, a first primary resistor R2, and a first secondary resistor R3, where a second pin 2 of the first photo coupler PH1 is connected to a third pole of the first transistor Q1 through the first primary resistor R2, and a first pin 1 of the first photo coupler PH1 is connected to a first ground GND through the first capacitor C1, and a second pole of the first transistor Q1 is connected to the first secondary resistor R3 and then connected to a second control signal P1.

The pull-up switching circuit includes a second transistor Q2 and a second photo coupler PH2, and of course, the pull-up switching circuit may further include a second capacitor C9, a tenth capacitor C10, a second primary resistor R4, and a second secondary resistor R6, where a second pin 2 of the second photo coupler PH2 is connected to a third pole of the second transistor Q2 through the second primary resistor R4, a first pin 1 of the second photo coupler PH2 is connected to the first ground GND through the first capacitor C1, a second pole of the second transistor Q2 is connected to the second secondary resistor R6, and then connected to the second control signal P1, a fourth pin 4 of the second photo coupler PH2 is connected to the first power supply voltage +5vc, and a fourth pin 4 of the second photo coupler PH2 is connected to the second ground GND2 through the tenth capacitor C10.

That is, as shown in fig. 4 and 6, C1, R2, R3, Q1, and PH1 form a pull-down switching circuit, C1 is a filter capacitor powered by pin 1 of PH1, R3 is an input current limiting resistor of a control pin Q1, R2 is a current limiting resistor of an internal light emitting diode of an optocoupler PH1, and R1 is connected to a communication bus as a first pull-down resistor. Similarly, as shown in fig. 4 and 6, C9, C10, R4, R6, Q2, and PH2 form a pull-up switching circuit, C9 is a filter capacitor powered by pin 1 of PH2, C10 is a filter capacitor powered by pin 4 of PH2, R6 is an input current limiting resistor of the Q2 control pin, R4 is a current limiting resistor of the light emitting diode in the PH2 optocoupler, and R5 is connected to the communication bus as a pull-up resistor.

Of course, the communication impedance matching circuit may further include at least two pull-up and pull-down switching modules 22, so that the at least two pull-up and pull-down switching modules 22 include at least two pull-down switching circuits and/or pull-up switching circuits, and only the at least two pull-down switching circuits and/or the pull-up switching circuits are connected in parallel to each other and commonly connected to the same second control signal P1, which is not described herein again. It should be noted that, if the communication impedance matching circuit only includes the pull-up/down switching module 22, a plurality of pull-up resistors and a plurality of pull-down resistors in the pull-up/down switching module 22 are directly connected to the communication bus. For example, the communication impedance matching circuit includes two pull-up resistors and two pull-up switching circuits, which are a first pull-up resistor, a second pull-up resistor, a first pull-up switching circuit and a second pull-up switching circuit, respectively, and then the first pull-up switching circuit is directly connected to the communication bus after being connected to the first pull-up resistor, and the second pull-up switching circuit is directly connected to the communication bus after being connected to the second pull-up resistor. Or the communication impedance matching circuit comprises two pull-up resistors, one pull-down resistor, one pull-down switching circuit and two pull-up switching circuits, wherein the pull-up resistors are respectively a first pull-up resistor, a second pull-up resistor, a first pull-down switching circuit, a first pull-up switching circuit and a second pull-up switching circuit, and then the first pull-up switching circuit is connected with the first pull-up resistor and then is directly connected to a communication bus, the second pull-up switching circuit is connected with the second pull-up resistor and then is directly connected to the communication bus, and the first pull-down switching circuit is connected with the first pull-down resistor and then is directly connected to the communication bus.

Referring to fig. 5 and fig. 7, fig. 5 is a schematic circuit diagram of an example of the impedance switching module 21 according to an embodiment of the present application, and fig. 7 is a schematic circuit diagram of another example of the impedance switching module 21 according to an embodiment of the present application. The impedance switching module 21 includes a third transistor Q3, a fourth transistor Q4, a third photo coupler PH3, and a fourth photo coupler PH4;

the first poles of the third transistor Q3 and the fourth transistor Q4 are respectively connected with the first ground GND;

the second poles of the third transistor Q3 and the fourth transistor Q4 are respectively connected with a first control signal P2;

the second pin 2 of the third photo coupler PH3 is connected to the third pole of the third transistor Q3, and the second pin 2 of the fourth photo coupler PH4 is connected to the third pole of the fourth transistor Q4;

the first pins 1 of the third photoelectric coupler PH3 and the fourth photoelectric coupler PH4 are respectively connected with a second power supply voltage of 3.3V;

the third pin 3 of the third photo coupler PH3 is connected with one end of a primary impedance matching resistor R9, the other end of the primary impedance matching resistor R9 is connected with the other end of a first pull-down resistor R1, and the fourth pin 4 of the third photo coupler PH3 is connected with the other end of a first pull-up resistor R5;

The third pin 3 of the fourth photo coupler PH4 is connected to one end of the secondary impedance matching resistor R13, the other end of the secondary impedance matching resistor R13 is connected to the other end of the first pull-up resistor R5, and the fourth pin 4 of the fourth photo coupler PH4 is connected to the other end of the first pull-down resistor R1.

Specifically, the communication impedance matching circuit may include only one impedance switching module 21, where one impedance switching module 21 may include only one primary impedance switching circuit, or one impedance switching module 21 may include only one secondary impedance switching circuit, and of course, one impedance switching module 21 may include both one primary impedance switching circuit and one secondary impedance switching circuit.

The primary impedance switching circuit includes a third transistor Q3 and a third photo coupler PH3, and of course, the primary impedance switching circuit may further include an eleventh capacitor C11, a third primary resistor R8, and a third secondary resistor R11, where a second pin 2 of the third photo coupler PH3 is connected to a third pole of the third transistor Q3 through the third primary resistor R8, a first pin 1 of the third photo coupler PH3 is connected to the first ground GND through the eleventh capacitor C11, and a second pole of the third transistor Q3 is connected to the third secondary resistor R11 and then connected to the first control signal P2.

The secondary impedance switching circuit includes a fourth transistor Q4 and a fourth photo coupler PH4, and of course, the secondary impedance switching circuit may further include a third grounding capacitor C13, a fourth primary resistor R12, and a fourth secondary resistor R14, where a second pin 2 of the fourth photo coupler PH4 is connected to a third pole of the fourth transistor Q4 through the fourth primary resistor R12, and a first pin 1 of the fourth photo coupler PH4 is connected to the first ground GND through the third grounding capacitor C13, and a second pole of the fourth transistor Q4 is connected to the fourth secondary resistor R14 and then connected to the first control signal P2.

That is, as shown in fig. 5 and 7, C11, R8, R11, Q3, and PH3 form a primary impedance switching circuit, C11 is a filter capacitor powered by pin 1 of PH3, R11 is an input current limiting resistor of a control pin Q3, R8 is a current limiting resistor of an internal light emitting diode of the optical coupler PH3, and R9 is connected to the communication bus and is used as an impedance matching resistor between a positive signal line a and a negative signal line B of the communication bus. Similarly, as shown in fig. 5 and 7, C13, R12, R14, Q4, and PH4 form a secondary impedance switching circuit, C13 is a filter capacitor powered by pin 1 of PH4, R14 is an input current limiting resistor of a control pin Q4, R12 is a current limiting resistor of an internal light emitting diode of an optocoupler PH3, and when the P2 signal is at the second level; when the second level is higher than the first level, Q4 is conducted and PH4 is conducted, and at the moment, R13 is connected into the communication bus to serve as an impedance matching resistor between the negative electrode signal line B and the positive electrode signal line A of the communication bus.

Of course, the communication impedance matching circuit may further include at least two impedance switching modules 21, so that the at least two impedance switching modules 21 include at least two paths of secondary impedance switching circuits and/or primary impedance switching circuits, and only the at least two paths of secondary impedance switching circuits and/or primary impedance switching circuits are connected in parallel to each other to be commonly connected to the same first control signal P2, which is not described herein again.

It should be noted that, if the communication impedance matching circuit includes only the impedance switching module 21, a plurality of impedance matching resistors in the impedance switching module 21 are directly connected to the communication bus. If the communication impedance matching circuit includes not only the impedance switching module 21 but also the pull-up/pull-down switching module 22, the plurality of pull-up resistors and the plurality of pull-down resistors in the pull-up/pull-down switching module 22 are directly connected with the plurality of impedance matching resistors in the impedance switching module 21 respectively and then connected with the communication bus. For example, as shown in fig. 4 and 5 or fig. 6 and 7, the other end of the first pull-down resistor R1 is connected to the other end of the primary impedance matching resistor R9 and the fourth pin 4 of the fourth photo coupler PH4 to form a second node SN2, and the other end of the primary impedance matching resistor R9 is connected to the negative electrode signal line B of the communication bus to form a fourth node SM2. The other end of the first pull-up resistor R5 is connected to the other end of the secondary impedance matching resistor R13 and the fourth pin 4 of the third optocoupler PH3 to form a first node SN1, and the other end of the secondary impedance matching resistor R13 is connected to the positive signal line a of the communication bus to form a third node SM1.

As shown in the schematic diagrams of the example circuits shown in fig. 4 to 7, only a scenario including a pair of impedance matching resistors, a first pull-up resistor and a first pull-down resistor together with four functional resistors is shown, however, the communication impedance matching circuit may also include at least two impedance switching modules 21 and at least two pull-up and pull-down switching modules 22, so that the at least two impedance switching modules 21 include at least two secondary impedance switching circuits and/or primary impedance switching circuits, the at least two pull-up and pull-down switching modules 22 include at least two pull-down switching circuits and/or pull-up switching circuits, only the at least two pull-down switching circuits and/or pull-up switching circuits are connected in parallel with each other to commonly access the same second control signal P1, the at least two secondary impedance switching circuits and/or primary impedance switching circuits are connected in parallel with each other to commonly access the same first control signal P2, and the at least two first pull-up resistors and the at least two pull-down resistors respectively include at least two primary impedance matching resistors and at least two secondary impedance matching circuits are connected in series, and each secondary impedance is not connected in parallel with each secondary impedance matching circuit.

In some embodiments, the control unit 300 includes:

a main control chip U2 and a tenth resistor R10;

an external clock module for providing an external clock signal;

and the power-on reset module is used for ensuring that the reset is realized after the power-on and before the power-off is initialized to the locking state.

Specifically, referring to fig. 8 and fig. 9, fig. 8 includes an exemplary schematic circuit diagram of a power-on reset module and an external clock module provided in an embodiment of the present application, and fig. 9 is an exemplary schematic circuit diagram of a master control module provided in an embodiment of the present application. The power-on reset module comprises a seventh resistor R7 and a twelfth capacitor C12; the starting configuration module comprises a tenth resistor R10, and the external clock module comprises a crystal oscillator Y1, a fifteenth resistor R15, a fourteenth capacitor C14 and a fifteenth capacitor C15.

The starting control pin BOOT0 of the main control chip U2 is connected with the tenth resistor R10 and then connected to the first ground wire GND, one end of the seventh resistor R7 is connected with the second power supply voltage of 3.3V, the other end of the seventh resistor R7 is connected with one end of the twelfth capacitor C12 to form a first junction NRT1, the reset control pin NRST of the main control chip U2 is connected with the first junction NRT1, and the other end of the twelfth capacitor C12 is connected with the first ground wire GND. The first pin 1 of the crystal oscillator Y1 is connected with the fifteenth capacitor C15 and then connected to the fourth pin 4 of the crystal oscillator Y1, the third pin 3 of the crystal oscillator Y1 is connected with the fourteenth capacitor C14 and then connected to the second pin 2 of the crystal oscillator Y1, and the second pin 2 and the fourth pin 4 of the crystal oscillator Y1 are connected with the first ground wire GND. One end of the fifteenth resistor R15 is respectively connected with the third pin 3 of the crystal oscillator Y1 and the crystal oscillator input pins PD0-OSC_IN of the main control chip U2, and the other end of the fifteenth resistor R15 is respectively connected with the first pin 1 of the crystal oscillator Y1 and the crystal oscillator output pins PD1-OSC_OUT of the main control chip U2.

Because the internal clock is generated by an RC oscillating circuit, the internal clock signal provided by the internal RC oscillating circuit can be affected by temperature to become unstable in frequency, and because the external clock module generally uses quartz crystal oscillator, the precision is high, and the external clock signal with high precision and stable frequency is provided by the external clock module. The power-on reset module monitors that the circuit is powered on and then controls the main control chip U2 to carry out power-on initialization so as to realize reset, meanwhile, the main control chip U2 receives an external clock signal provided by the external clock module in real time, so that the main control chip can realize the time synchronization of the internal clock signal and the external clock signal of the lamp, the time of a plurality of lamps cascaded between every two lamps is consistent with the external clock signal, the lamps are globally synchronized in time, and the working modes of synchronously controlling the lamps are realized.

In some embodiments, the communication impedance matching circuit further comprises:

a burning module for writing data in the writable memory;

and the overvoltage protection module is used for limiting the line voltage input to the main control chip U2 within a preset range.

Specifically, referring to fig. 9 and fig. 10, fig. 9 is an exemplary schematic circuit diagram of a main control module provided in an embodiment of the present application, and fig. 10 includes an exemplary schematic circuit diagram of a burning module, an overvoltage protection module, and a filtering module provided in an embodiment of the present application. The burning module comprises a first connector J1, a seventeenth resistor R17 and an eighteenth resistor R18. The overvoltage protection module comprises a first diode D1 and a second diode D2.

The fifth pin 5 of the first connector J1 is connected to the reset control pin NRST of the main control chip U2, the first pin 1 of the first connector J1 is connected to one end of the seventeenth resistor R17 and the second power supply voltage 3.3V, and the fourth pin 4 of the first connector J1 is connected to one end of the eighteenth resistor R18 and the first ground GND. The other end of the seventeenth resistor R17 is respectively connected with the second pin 2 of the first connector J1, the third pin 3 of the first diode D1 and the debugging data pin PA13 of the main control chip U2, and the other end of the eighteenth resistor R18 is respectively connected with the third pin 3 of the first connector J1, the third pin 3 of the second diode D2 and the debugging clock pin PA14 of the main control chip U2. The second pins 2 of the first diode D1 and the second diode D2 are respectively connected to the second power supply voltage of 3.3V, and the first pins 1 of the first diode D1 and the second diode D2 are respectively connected to the first ground line GND. The burning module can write data or programs into a storage space inside the main control chip U2, and in addition, the overvoltage protection module can clamp line voltage input to the main control chip U2 in a preset range through two diodes, namely, the line voltage input to the main control chip U2 does not exceed a preset maximum value, so that the main control chip U2 and other elements are prevented from being damaged.

the communication module 500 is respectively connected with the control unit 300 and the communication bus 400, and is used for transmitting the control signal generated by the control unit 300 to the communication bus 400 and transmitting the control signal to the rest of communication impedance matching circuits in a wireless mode.

Specifically, the communication bus may be a serial port line capable of realizing balanced transmission and differential reception, such as an RS485 communication bus and an RS232 communication bus, and the communication bus includes a positive signal line a, a negative signal line B and a ground signal line G, and signal transmission is realized through a voltage difference between the positive signal line a and the negative signal line B.

Illustratively, when the communication module 500 belongs to a communication chip conforming to the RS485 communication protocol, the communication bus is an RS485 communication bus. Referring to fig. 9 and 11, fig. 9 is an exemplary circuit schematic diagram of a master control module provided in an embodiment of the present application, and fig. 11 is an exemplary circuit schematic diagram of a communication module 500 provided in an embodiment of the present application as an RS485 communication module. The communication module 500 includes an RS485 communication chip U4, a twenty-ninth capacitor C29, a nineteenth resistor R19, a twentieth resistor R20, a twenty-second resistor R22, a twenty-eighth resistor R28, and a twenty-seventh resistor R27. The first pin 1 of the RS485 communication chip U4 is respectively connected with one end of a twenty-ninth capacitor C29, one end of a nineteenth resistor R19 and one end of a twentieth resistor R20 and is connected with a second power supply voltage of 3.3V; the second pin 2 of the RS485 communication chip U4 is respectively connected with the other end of the twenty-ninth capacitor C29 and the first ground GND; the third pin 3 of the RS485 communication chip U4 is respectively connected with the other ends of the illumination receiving pin PB11 and the twentieth resistor R20 of the main control chip U2; the fourth pin 4 of the RS485 communication chip U4 is respectively connected with the fifth pin 5 of the RS485 communication chip U4, the illumination driving pin PB12 of the main control chip U2 and one end of the twenty-eighth resistor R28, and the other end of the twenty-eighth resistor R28 is connected with the first ground wire GND; the sixth pin 6 of the RS485 communication chip U4 is respectively connected with the other ends of the illumination transmitting pin PB10 and the nineteenth resistor R19 of the main control chip U2; the seventh pin 7 and the eighth pin 8 of the RS485 communication chip U4 are connected with the first ground wire GND after being short-circuited; the sixteenth pin 16 of the RS485 communication chip U4 is connected with a first power supply voltage +5Vc; the fifteenth pin 15 of the RS485 communication chip U4 is connected with the second ground wire GND 2; the thirteenth pin 13 and the twelfth pin 12 of the RS485 communication chip U4 are respectively connected with the first signal line RS-485_N and the second signal line RS-485_P of the communication bus 400; and the tenth pin 10 and the ninth pin 9 of the RS485 communication chip U4 are connected with the second ground wire GND2 after being short-circuited.

Specifically, the RS485 communication chip U4 may be an isolated chip or a non-isolated chip. The isolation type chip is preferably adopted for the RS485 communication chip U4 in the application, and a system RS485 signal on the left side and a bus RS485 signal on the right side of the RS485 communication chip U4 in the diagram 11 can be effectively isolated, so that the effects of lightning surge resistance, static electricity and interference signal isolation are achieved.

The communication module 500 is formed by C29, R19, R20, R22, R27, R28 and U4, the differential signal of the RS-485 communication bus, namely the communication bus 400 of the application, can be converted into a single-ended signal to be sent to the control unit 300, or the single-ended signal of the control unit 300 can be converted into a differential signal, so that communication is realized, C29 is the filter capacitor of the first pin 1 of U4, R19 and R20 are respectively the sixth pin 6 of the U4 chip and the pull-up resistor of the third pin 3, R28 is the pull-down resistor of the fourth pin 4 of U4, R22 and R27 are respectively used as the pull-down resistor of the first signal line RS-485_N and the pull-up resistor of the second signal line RS-485_P, U4 is the isolated RS-485 communication chip U4, the first pin 1 of the RS485 communication chip U4 is the primary power supply positive electrode, the sixteenth pin 16 of the RS485 communication chip U4 is the secondary power supply positive electrode, the second pin 2, the seventh pin 7 and the eighth pin 8 of the RS485 communication chip U4 are cathodes of primary power supply, the ninth pin 9, the tenth pin 10 and the fifteenth pin 15 of the RS485 communication chip U4 are cathodes of secondary power supply, the eleventh pin 11 and the fourteenth pin 14 of the RS485 communication chip U4 are not electrically connected, the twelfth pin 12 and the thirteenth pin 13 of the RS485 communication chip U4 are connected with an RS-485 communication bus which is a differential signal of the communication bus 400 of the application, the third pin 3 of the RS485 communication chip U4 is a signal receiving pin, the sixth pin 6 of the RS485 communication chip U4 is a signal transmitting pin, when the fourth pin 4 of the RS485 communication chip U4 is at a first level, the RS485 communication chip U4 converts a signal received from the RS-485 communication bus into a single-ended signal and outputs the single-ended signal by the third pin 3 of the RS485 communication chip U4, the third pin 3 of the RS485 communication chip U4 is connected to the main control chip U2 of the control unit 300, the main control chip U2 analyzes the received signal, and similarly, when the fifth pin 5 of the RS485 communication chip U4 is at the second level, the RS485 communication chip U4 converts the signal of the sixth pin 6 of the RS485 communication chip U4 into a differential signal, and sends out the differential signal through the RS-485 communication bus, wherein the second level is higher than the first level.

In some embodiments, the RS485 bus, i.e. the communication bus 400 of the present application, may be affected by the pull-up resistor, the pull-down resistor. According to the relevant standard of the RS485 bus, the RS485 transceiver, i.e. the communication module 500, outputs the second level when the differential voltage of the RS485 bus is larger than the first differential voltage value, e.g. +200 mV. When the RS485 bus differential voltage is less than a second differential voltage value, for example-200 mV, the RS485 transceiver, i.e. the communication module 500, outputs a first level. When the voltage on the RS485 bus is greater than the second differential voltage value and less than the first differential voltage value, for example, between-200 mV and +200mV, the RS485 transceiver, i.e. the communication module 500, may output the second level and may also output the first level, but for a specific node, the RS485 transceiver, i.e. the output of the communication module 500, is always in a level state, if the output of the RS485 transceiver, i.e. the communication module 500, is in the first level, this is an initial position for serial communication, and the communication will be abnormal, which will naturally affect the normal use of the lamp, so it is necessary to use a pull-up pull-down resistor to clamp the voltage difference between-200 mV and +200mV of the first signal line RS-485_n and the second signal line RS-485_p on the RS485 bus.

In some embodiments, C21, C22, C23, C24, C25, C26, C27, and C28 are filter capacitances of the first pin 1, the first pin 13, the first pin 19, the first pin 32, the first pin 48, and the first pin 64 of the master control chip U2 for accessing the second power supply voltage of 3.3V.

the first power supply module is configured to convert the dc power supply 5V into a first power supply voltage +5vc to supply power to the control unit 300, the communication module 500, and the pull-up/pull-down switching module 22.

The second power supply module is configured to convert the dc power supply 5V into a second power supply voltage 3.3V to supply power to the communication module 500, the impedance switching module 21, and the pull-up/down switching module 22.

Specifically, referring to fig. 12, fig. 12 is a schematic circuit diagram of an example of a first power supply module and a second power supply module provided in an embodiment of the present application, where the first power supply module includes a first power conversion chip U3, a plurality of first input filter capacitors, and a plurality of first output filter capacitors. The second pin 2 of the first power conversion chip U3 is connected with one ends of a plurality of first input filter capacitors and then connected with a direct current power supply 5V, and the other ends of the plurality of first input filter capacitors are respectively connected with a first ground wire GND. The fourth pin 4 of the first power conversion chip U3 is connected with one ends of a plurality of first output filter capacitors to output a first power supply voltage +5Vc, and the other ends of the plurality of first output filter capacitors are respectively connected with the second ground wire GND 2. The first pin 1 of the first power conversion chip U3 is connected to the first ground GND, and the third pin 3 of the first power conversion chip U3 is connected to the second ground GND 2. The third pin 3 of the second power conversion chip U1 is connected with one end of a plurality of second input filter capacitors and is connected with a direct current power supply 5V. The first pin 1 of the second power conversion chip U1 is connected with the other ends of the second input filter capacitors and then connected with the first ground wire GND. The second pin 2 of the second power conversion chip U1 is respectively connected with the fourth pin 4 of the second power conversion chip U1 and one ends of a plurality of second output filter capacitors to output a second power supply voltage of 3.3V. The other ends of the second output filter capacitors are connected with the first ground GND.

Specifically, C2, C3, C4, C5, C6, C7, C8 and U1 form a first power supply module for converting the direct current power supply 5V into the second power supply voltage 3.3V, C2, C3 and C4 are input filter capacitors, C5, C6, C7 and C8 are output filter capacitors, and U1 is a voltage conversion chip. And C16, C17, C18, C19, C20, FB1, FB2 and U3 form a second power supply module for converting the direct current power supply 5V into the first power supply voltage +5Vc, wherein C16, C17 and C20 are input filter capacitors, and C18 and C19 are output filter capacitors.

In some embodiments, the first magnetic bead FB1 is respectively connected to the second pin 2 of the first power conversion chip U3 and a plurality of first input filter capacitors (for example, fig. 12 includes C16, C17, and C20), the second magnetic bead FB2 is respectively connected to the fourth pin 4 of the first power conversion chip U3 and a plurality of first output filter capacitors (for example, fig. 12 includes C18 and C9), the first magnetic bead FB1 and the second magnetic bead FB2 are magnetic beads with input ends and output ends for filtering high-frequency interference signals, and whether the first magnetic bead FB1 and the second magnetic bead FB2 are arranged in a circuit according to requirements or a circuit board size can be determined.

a plurality of expansion connector pairs, each expansion connector pair comprising a first expansion connector J2 and a second expansion connector J3;

The communication impedance matching circuit is connected with the rest of the communication impedance matching circuits in cascade through a plurality of expansion connector pairs.

Specifically, as shown in fig. 11, each of the first expansion connector J2 and each of the second expansion connectors J3 includes three interfaces, which are a first pin 1 connected to the positive signal line a, a second pin 2 connected to the negative signal line B, and a third pin 3 connected to the ground signal line G, respectively. Note that the ground signal line G is connected to the second ground GND2. Further, each expansion connector pair divides the communication bus 400 into a first bus for connection with the up-down switching module 22, the impedance switching module 21, and the communication module 500, and a second bus for connection with other communication impedance matching circuits or for interfacing with a communication bus of a console. Taking a single communication impedance matching circuit as an example, the first expansion connector J2 may be used as an input end of a signal, the second expansion connector J3 may be used as an output end of the signal, and the second expansion connector J3 may be electrically connected with the first expansion connector J2 of the next communication impedance matching circuit (or the next lamp).

According to the communication impedance matching circuit, the first pins 1 and the second pins 2 of the plurality of expansion connector pairs are connected in one-to-one correspondence, so that cascade connection is formed by the plurality of communication impedance matching circuits, the plurality of communication impedance matching circuits are connected with each other to achieve the effects of data transmission and control signal sharing, the plurality of communication impedance matching circuits in cascade connection between the two pairs are enabled to realize synchronous switching of working modes, the application requirements of synchronous and efficient switching of the plurality of communication impedance matching circuits in cascade connection are met, and the communication impedance matching circuit is simple to operate and convenient to use.

In some embodiments, as shown in fig. 4-7, comprising:

if the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are all N-channel MOS transistors, the first pole, the second pole, and the third pole are respectively a source, a gate, and a drain, and the first control signal and the second control signal are both high levels; or alternatively, the first and second heat exchangers may be,

if the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are all N-type transistors, the first pole, the second pole, and the third pole are respectively a collector, a base, and an emitter, and the first control signal and the second control signal are both high levels; or alternatively, the first and second heat exchangers may be,

if the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are P-channel MOS transistors, the first pole, the second pole, and the third pole are drain, gate, and source, respectively, and the first control signal and the second control signal are low levels; or alternatively, the first and second heat exchangers may be,

if the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are P-type transistors, the first pole, the second pole, and the third pole are an emitter, a base, and a collector, respectively, and the first control signal and the second control signal are low levels.

Specifically, the transistor is a simple element, the working principle of the transistor is similar to an electronic switch, a circuit can be opened and closed, and two most common transistors comprise a triode and a MOS tube, wherein the triode is a current type device and the MOS tube is a voltage type device. The triode and the MOS tube respectively comprise three pins, wherein the three pins of the triode are a base electrode b, a collector electrode c and an emitter electrode e, the three pins of the MOS tube are a grid electrode G, a drain electrode D and a source electrode S, and the source electrode S, the grid electrode G and the drain electrode D of the MOS tube respectively correspond to the emitter electrode e, the base electrode b and the collector electrode c of the triode. The triode comprises a PNP triode, a P triode and an N triode, and the MOS tube comprises an N channel triode, namely an NPN MOS tube, and a P channel triode, namely a PNP MOS tube.

The emitter e of the N-type triode is grounded, the collector c is connected with high level, and when Vc > Vb > Ve, the N-type triode is conducted, and current flows from the collector c to the emitter e. In addition, the source electrode S of the N-channel MOS tube is grounded at a low potential, the grid electrode G of the N-channel MOS tube is connected with a positive voltage, namely VG > VS leads the N-channel MOS tube to be conducted when |VGS| > Vth, and current flows from the drain electrode D to the source electrode S.

The emitter e of the P-type triode is connected with high level, the collector c is connected with low level, and when Vc is smaller than Vb < Ve, the P-type triode is conducted, and current flows from the emitter e to the collector c. In addition, the source electrode S of the P channel MOS tube is connected with high level, the grid electrode G of the N channel MOS tube is connected with the voltage of negative voltage and the voltage of VDD, namely VG < VS drain electrode makes the P channel MOS tube conducted when |VGS| > Vth, and current flows from the source electrode S to the drain electrode D.

From the above analysis, the conduction principles of the N-channel MOS transistor and the N-type triode are similar, and the conduction principles of the P-channel MOS transistor and the P-type triode are similar, so that the schematic diagrams of the example circuits of the impedance switching module 21, the pull-up/down switching module 22 and the pull-up/down switching module 22 have four structural scenarios.

The first structural scene is: fig. 4 is a schematic circuit diagram of an example of the pull-up/pull-down switching module 22 according to the embodiment of the present application, fig. 5 is a schematic circuit diagram of an example of the impedance switching module 21 according to the embodiment of the present application, and the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 in fig. 4 and 5 are all N-type transistors, the first pole, the second pole, and the third pole are respectively a collector, a base, and an emitter, and the first control signal P2 and the second control signal P1 are both at a second level; the second level is higher than the first level. As shown in fig. 4, collectors of the first transistor Q1 and the second transistor Q2 are respectively connected to the first ground GND, and bases of the first transistor Q1 and the second transistor Q2 are respectively connected to the first control signal. The second pin 2 of the first photo coupler PH1 is connected to the emitter of the first transistor Q1, and the second pin 2 of the second photo coupler PH2 is connected to the emitter of the second transistor Q2. Referring to fig. 5, collectors of the third transistor Q3 and the fourth transistor Q4 are respectively connected to the first ground GND, and bases of the third transistor Q3 and the fourth transistor Q4 are respectively connected to the second control signal. The second pin 2 of the third photo coupler PH3 is connected to the emitter of the third transistor Q3, and the second pin 2 of the fourth photo coupler PH4 is connected to the emitter of the fourth transistor Q4. Because the first control signal P2 and the second control signal P1 are both at the second level (for example, 1V or 5V is higher than the high level of the voltage at the emitter), according to the N-type triode conduction principle, Q1 is turned on and simultaneously enables PH1 to be turned on, at this time, R1 is connected to the RS-485 communication bus to serve as the pull-down resistor of the RS-485_n line, Q2 is turned on and simultaneously enables PH2 to be turned on, and at this time, R5 is connected to the RS-485 communication bus to serve as the pull-up resistor of the RS-485_p line. Q3 is conducted and PH3 is conducted simultaneously, at the moment, R9 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_P to RS-485_N, Q4 is conducted and PH4 is conducted simultaneously, at the moment, R13 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_N to RS-485_P. Of course, since the emitter is grounded and thus the voltage at the emitter is 0V, if the first control signal P2 and the second control signal P1 are both at the first level (for example, -1.5V or-3.3V, etc. are lower than the low level of the voltage at the emitter), none of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 is turned on, thereby achieving the effects of removing the first pull-down resistor R1, removing the first pull-up resistor R5, removing the primary impedance matching resistor R9, and removing the secondary impedance matching resistor R13 from the RS-485 communication bus.

The second structural scene is: if the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are all N-channel MOS transistors, the first pole, the second pole, and the third pole are respectively a source, a gate, and a drain, and the first control signal P2 and the second control signal P are both at the second level; the second level is higher than the first level. The first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 shown in fig. 4 and 5 may be replaced with N-channel MOS transistors with reference to the first structural scenario, and other elements remain unchanged. The sources of the first transistor Q1 and the second transistor Q2 are respectively connected with the first ground GND, and the gates of the first transistor Q1 and the second transistor Q2 are respectively connected with a first control signal. The second pin 2 of the first photo coupler PH1 is connected to the drain of the first transistor Q1, and the second pin 2 of the second photo coupler PH2 is connected to the drain of the second transistor Q2. The sources of the third transistor Q3 and the fourth transistor Q4 are respectively connected with the first ground GND, and the gates of the third transistor Q3 and the fourth transistor Q4 are respectively connected with the second control signal. The second pin 2 of the third photo coupler PH3 is connected to the drain of the third transistor Q3, and the second pin 2 of the fourth photo coupler PH4 is connected to the drain of the fourth transistor Q4. Because the first control signal P2 and the second control signal P1 are both at the second level (for example, 1V or 5V is higher than the high level of the voltage at the emitter), according to the conduction principle of the N-channel MOS transistor, it is known that Q1 is turned on and simultaneously enables PH1 to be turned on, at this time, R1 is connected to the RS-485 communication bus to serve as the pull-down resistor of the RS-485_n line, Q2 is turned on and simultaneously enables PH2 to be turned on, and at this time, R5 is connected to the RS-485 communication bus to serve as the pull-up resistor of the RS-485_p line. Q3 is conducted and PH3 is conducted simultaneously, at the moment, R9 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_P to RS-485_N, Q4 is conducted and PH4 is conducted simultaneously, at the moment, R13 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_N to RS-485_P. Of course, since the emitter is grounded and thus the voltage at the emitter is 0V, if the first control signal P2 and the second control signal P1 are both at the first level (for example, -1.5V or-3.3V, etc. are lower than the low level of the voltage at the emitter), none of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 is turned on, thereby achieving the effects of removing the first pull-down resistor R1, removing the first pull-up resistor R5, removing the primary impedance matching resistor R9, and removing the secondary impedance matching resistor R13 from the RS-485 communication bus.

The third structural scene is: based on the case that the transistors in the first structural scenario are N-type transistors, the impedance switching module 21 and the pull-up/down switching module 22 can be replaced with transistors. If the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 in fig. 6 and fig. 7 are P-type transistors, the first pole, the second pole, and the third pole are an emitter, a base, and a collector, respectively, and the first control signal and the second control signal are both at the first level. Emitters of the first transistor, the second transistor Q2, the third transistor Q3 and the fourth transistor Q4 are respectively connected with the first ground GND, and bases of the first transistor and the second transistor Q2 are respectively connected with a first control signal. The second pin 2 of the first photo coupler PH1 is connected to the collector of the first transistor Q1, and the second pin 2 of the second photo coupler PH2 is connected to the collector of the second transistor Q2. The bases of the third transistor Q3 and the fourth transistor Q4 are respectively connected with a second control signal. The second pin 2 of the third photo coupler PH3 is connected to the collector of the third transistor Q3, and the second pin 2 of the fourth photo coupler PH4 is connected to the collector of the fourth transistor Q4. As the first control signal P2 and the second control signal P1 are both in the second level and are in the first level (for example, -1.5V or-3.3V is lower than the low level of the voltage at the emitter), according to the conduction principle of the P-type triode, Q1 is conducted and simultaneously enables PH1 to be conducted, at the moment, R1 is connected into the RS-485 communication bus to serve as a pull-down resistor of the RS-485_N line, Q2 is conducted and simultaneously enables PH2 to be conducted, at the moment, R5 is connected into the RS-485 communication bus to serve as a pull-up resistor of the RS-485_P line. Q3 is conducted and PH3 is conducted simultaneously, at the moment, R9 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_P to RS-485_N, Q4 is conducted and PH4 is conducted simultaneously, at the moment, R13 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_N to RS-485_P. Of course, since the emitter is grounded and thus the voltage at the emitter is 0V, if the first control signal P2 and the second control signal P1 are both at the second level (e.g., 1V or 5V is higher than the high level of the voltage at the emitter), none of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 is turned on, thereby achieving the effects of removing the first pull-down resistor R1, removing the first pull-up resistor R5, removing the primary impedance matching resistor R9, and removing the secondary impedance matching resistor R13 from the RS-485 communication bus.

The fourth structural scenario is: similarly, based on the case that the transistor in the second structural scenario is an N-channel MOS transistor, the impedance switching module 21 and the pull-up/down switching module 22 may be replaced with transistors. If the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are P-channel MOS transistors, the first pole, the second pole, and the third pole are drain, gate, and source, respectively, and the first control signal and the second control signal are both at the first level. The first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 shown in fig. 6 and fig. 7 may be replaced with P-channel MOS transistors with reference to the first structural scenario, and other elements remain unchanged. The drains of the first transistor Q1, the second transistor Q2, the third transistor Q3 and the fourth transistor Q4 are respectively connected to the first ground GND, and the gates of the first transistor Q1 and the second transistor Q2 are respectively connected to the first control signal. The second pin 2 of the first photo coupler PH1 is connected to the source of the first transistor Q1, and the second pin 2 of the second photo coupler PH2 is connected to the source of the second transistor Q2. The gates of the third transistor Q3 and the fourth transistor Q4 are respectively connected to the second control signals. The second pin 2 of the third photo coupler PH3 is connected to the source of the third transistor Q3, and the second pin 2 of the fourth photo coupler PH4 is connected to the source of the fourth transistor Q4. As the first control signal P2 and the second control signal P1 are both in the second level and are in the first level (for example, -1.5V or-3.3V and other low levels smaller than the voltage at the emitter), according to the conduction principle of the P-channel MOS tube, Q1 is conducted and simultaneously enables PH1 to be conducted, at the moment, R1 is connected into the RS-485 communication bus to serve as a pull-down resistor of the RS-485_N line, Q2 is conducted and simultaneously enables PH2 to be conducted, and at the moment, R5 is connected into the RS-485 communication bus to serve as a pull-up resistor of the RS-485_P line. Q3 is conducted and PH3 is conducted simultaneously, at the moment, R9 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_P to RS-485_N, Q4 is conducted and PH4 is conducted simultaneously, at the moment, R13 is connected to the RS-485 communication bus to serve as an impedance matching resistor from RS-485_N to RS-485_P. Of course, since the emitter is grounded and thus the voltage at the emitter is 0V, if the first control signal P2 and the second control signal P1 are both at the second level (e.g., 1V or 5V is higher than the high level of the voltage at the emitter), none of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 is turned on, thereby achieving the effects of removing the first pull-down resistor R1, removing the first pull-up resistor R5, removing the primary impedance matching resistor R9, and removing the secondary impedance matching resistor R13 from the RS-485 communication bus.

Because the source and drain directions of the P-channel MOS tube and the N-channel MOS tube are opposite, the NMOS is conducted when Vgs is larger than a certain value, and the MOS transistor is suitable for low-end driving under the condition that the source electrode is grounded, and only the grid voltage reaches 4V or 10V. The P-channel MOS transistor is conducted because Vgs is smaller than a certain value, and is suitable for high-end driving under the condition that the source electrode is connected with VCC. However, although the P-channel MOS transistor can be conveniently used for high-end driving, the N-channel MOS transistor is preferably used in the embodiment of the present application because the on-resistance of the P-channel MOS transistor is small and easy to manufacture due to the fact that the on-resistance of the P-channel MOS transistor is large, the cost is high, the number of replacement types is small, and the like.

The present application switches the impedance matching resistor and the pull-up and pull-down resistors on the communication bus 400 through the control unit 300, so as to solve the problems of the prior art. In the present application, the control unit 300 sends the first control signal P2 to the impedance switching module 21 according to the mode selected by the user, the control unit 300 sends the second control signal P1 to the pull-up/pull-down switching module 22 according to the mode selected by the user, and the impedance switching module 21 correspondingly turns off or turns on the transistor after receiving the first control signal P2, so as to achieve the effect of accessing, removing or removing the impedance matching resistor on the communication bus 400. Similarly, the pull-up/down switching module 22 receives the second control signal P1 and then correspondingly turns off or on the transistor, so as to achieve the effect of switching in, removing or switching on the communication bus 400 to change the pull-up/down resistor.

According to the lamp, the problems that the resistor needs to be manually replaced or the impedance matching accessory is manually accessed or manually removed, and the lamp cannot work normally due to the fact that the lamp is lost or forgets to prepare the lamp can be solved, the problem that the resistance value of the pull-up resistor and the resistance value of the pull-down resistor cannot be changed in some severe environments is solved, and the problem that the resistance value cannot be solved through external accessories is solved, so that the requirements of quick and convenient application and the application requirements under various scenes are met.

According to the light source, the resistance values of the multipath functional resistors can be increased through adjustment of the switching unit, the strong light and weak light of the lamp can be set, the luminous intensity of the light source can be adjusted under different light intensity demands, so that the light intensity of different demands can be enough, and the application demands under various scenes can be met. By setting the corresponding modes in the lighting system, the control unit 300 generates and sends corresponding control signals to the resistance switching unit 100 according to the mode selected and input by the user, and after the resistance switching unit 100 receives the control signals, the impedance matching resistor, the first pull-up resistor and the line connection state between the first pull-down resistor and the communication bus 400 are correspondingly adjusted, so that the impedance matching resistor, the first pull-up resistor and the first pull-down resistor are switched to the connection state or the disconnection state with the communication bus 400, the purpose of automatically configuring and controlling each lighting lamp in the lighting system in batches is achieved, and the scene switching efficiency of the lighting system is greatly improved.

An embodiment of the present application provides a lamp, including a communication impedance matching circuit in the corresponding embodiment of fig. 1-12 and a housing for packaging the communication impedance matching circuit, the communication impedance matching circuit includes:

the resistance switching unit 100 is connected to the control unit 300 and the communication bus 400, respectively, and the resistance switching unit 100 includes a plurality of functional resistors, and is configured to adjust to a corresponding operation mode according to a control signal, where the operation mode includes implementing at least one of: accessing a preset functional resistance, removing the preset functional resistance and switching the preset functional resistance.

In order to better implement the communication impedance matching circuit in the embodiment of the application, the embodiment of the application also provides a lamp based on the communication impedance matching circuit, which comprises the communication impedance matching circuit in all the embodiments and a shell for packaging the communication impedance matching circuit. The specific structure of the communication impedance matching circuit refers to the above embodiments, and because all the technical solutions of all the embodiments are adopted, the communication impedance matching circuit at least has all the beneficial effects brought by the technical solutions of the embodiments, and will not be described in detail herein.

Referring to fig. 13, fig. 13 is a schematic diagram of an internal structure of a lamp control system provided in an embodiment of the present application, as shown in fig. 13, the lamp control system includes a plurality of lamps, two by two, sequentially connected in cascade through a communication bus 400, each lamp is integrated with a communication impedance matching circuit in the corresponding embodiment of fig. 1-12, and the communication impedance matching circuit includes:

In order to better implement the communication impedance matching circuit in the embodiment of the present application, on the basis of the communication impedance matching circuit, the embodiment of the present application further provides a lamp control system including a plurality of lamps, where the plurality of lamps includes a lamp 1000, a lamp 2000, a lamp … …, and a lamp n, and the plurality of lamps includes the communication impedance matching circuit in the corresponding embodiment of fig. 1-12, where other elements may be the same or different, and the housing may be the same or different. The specific structure of the communication impedance matching circuit refers to the above embodiments, and because all the technical solutions of all the embodiments are adopted, the communication impedance matching circuit at least has all the beneficial effects brought by the technical solutions of the embodiments, and will not be described in detail herein.

The foregoing details of the communication impedance matching circuit, the lamp and the lamp control system provided in the embodiments of the present application are described in detail, and specific examples are applied to illustrate the principles and implementations of the present application, and the description of the foregoing examples is only for helping to understand the technical solution and the core idea of the present application, but is not used for limiting the protection scope of the present application; those skilled in the art will appreciate that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A communication impedance matching circuit, comprising:

an input unit (200) for acquiring a mode selection signal input by a user;

a control unit (300) connected with the input unit (200), wherein the control unit (300) is used for generating a corresponding control signal according to the mode selection signal;

the resistance switching unit (100) is respectively connected with the control unit (300) and the communication bus (400), the resistance switching unit (100) comprises a plurality of functional resistors, and the resistance switching unit is used for adjusting the line connection states between the functional resistors and the communication bus (400) respectively according to the control signals so as to adjust the line connection states to a required working mode, and the working mode comprises at least one of the following: accessing a preset functional resistor, removing the preset functional resistor and switching the preset functional resistor;

A communication module (500) respectively connected with the control unit (300) and the communication bus (400) and used for transmitting the control signal generated by the control unit (300) to the communication bus (400);

the functional resistors comprise a plurality of impedance matching resistors, a plurality of pull-up resistors and a plurality of pull-down resistors; the plurality of impedance matching resistors comprise a plurality of primary impedance matching resistors and a plurality of secondary impedance matching resistors; the resistance switching unit (100) comprises a plurality of impedance switching modules (21) and a plurality of pull-up and pull-down switching modules (22); the plurality of pull-up resistors comprises a first pull-down resistor (R1), and the plurality of pull-down resistors comprises a first pull-up resistor (R5);

the plurality of impedance switching modules (21) are respectively connected with the plurality of impedance matching resistors and the plurality of secondary impedance matching resistors in a one-to-one correspondence manner, and are used for controlling the connection or disconnection between the impedance matching resistors and the communication bus (400) according to a first control signal (P2) so as to realize at least one of the following in a circuit: accessing, removing and switching the impedance matching resistor;

the plurality of pull-up and pull-down switching modules (22) are respectively connected with the plurality of pull-down resistors and the plurality of pull-up resistors in a one-to-one correspondence manner and are used for controlling the connection or disconnection between the plurality of pull-down resistors and the plurality of pull-up resistors and the communication bus (400) according to a second control signal (P1) so as to realize at least one of the following in a circuit: accessing, removing and switching the plurality of pull-up resistors and/or the plurality of pull-down resistors;

The control signals comprise the first control signal (P2) and the second control signal (P1) which are generated by the control unit (300) according to the mode selection signal acquired by the input unit (200); the method comprises the steps of,

the other end of the primary impedance matching resistor (R9) is connected with the other end of the first pull-down resistor (R1), and the other end of the primary impedance matching resistor (R9) is also connected with a second pin of the first expansion connector (J2);

the other end of the secondary impedance matching resistor (R13) is connected with the other end of the first pull-up resistor (R5), and the other end of the secondary impedance matching resistor (R13) is also connected with a first pin of the first expansion connector (J2).

2. The communication impedance matching circuit according to claim 1, wherein the pull-up and pull-down switching module (22) comprises: at least one of a pull-up switching circuit and a pull-down switching circuit, the pull-down switching circuit including a first transistor (Q1), a first photo coupler (PH 1); the pull-up switching circuit comprises a second transistor (Q2) and a second photoelectric coupler (PH 2);

the first poles of the first transistor (Q1) and the second transistor (Q2) are respectively connected with a first ground line (GND);

-the second diodes of the first transistor (Q1) and the second transistor (Q2) are each respectively connected to the second control signal (P1);

a second pin (2) of the first photoelectric coupler (PH 1) is connected with a third pole of the first transistor (Q1), and a second pin (2) of the second photoelectric coupler (PH 2) is connected with a third pole of the second transistor (Q2);

the first pins (1) of the first photoelectric coupler (PH 1) and the second photoelectric coupler (PH 2) are respectively connected with a second power supply voltage;

a fourth pin (4) of the first photoelectric coupler (PH 1) is connected with one end of a first pull-down resistor (R1), and a third pin (3) of the first photoelectric coupler (PH 1) is connected with a second ground wire (GND 2);

the third pin (3) of the second photoelectric coupler (PH 2) is connected with one end of the first pull-up resistor (R5), and the fourth pin (4) of the second photoelectric coupler (PH 2) is connected with the first power supply voltage and is connected to the second ground wire (GND 2);

if the first transistor (Q1) and the second transistor (Q2) are both N-channel MOS transistors, the first pole, the second pole, and the third pole are respectively a source, a gate, and a drain, and the first control signal and the second control signal are both high levels; or alternatively, the first and second heat exchangers may be,

If the first transistor (Q1) and the second transistor (Q2) are N-type transistors, the first pole, the second pole, and the third pole are respectively a collector, a base, and an emitter, and the first control signal and the second control signal are both high levels; or alternatively, the first and second heat exchangers may be,

if the first transistor (Q1) and the second transistor (Q2) are P-channel MOS transistors, the first pole, the second pole, and the third pole are drain, gate, and source, respectively, and the first control signal and the second control signal are both low levels; or alternatively, the first and second heat exchangers may be,

if the first transistor (Q1) and the second transistor (Q2) are P-type transistors, the first pole, the second pole, and the third pole are an emitter, a base, and a collector, respectively, and the first control signal and the second control signal are both low levels;

the first pin, the second pin, the third pin and the fourth pin of the first photoelectric coupler (PH 1) and the second photoelectric coupler (PH 2) are anodes of light emitting diodes respectively, cathodes of the light emitting diodes, emitting electrodes of triodes and collecting electrodes of the triodes.

3. The communication impedance matching circuit according to claim 2, wherein the impedance switching module (21) includes a third transistor (Q3), a fourth transistor (Q4), a third photo coupler (PH 3), and a fourth photo coupler (PH 4);

The first poles of the third transistor (Q3) and the fourth transistor (Q4) are respectively connected with a first Ground (GND);

the second poles of the third transistor (Q3) and the fourth transistor (Q4) are respectively connected with a first control signal (P2);

the second pin (2) of the third photoelectric coupler (PH 3) is connected with the third pole of the third transistor (Q3), and the second pin (2) of the fourth photoelectric coupler (PH 4) is connected with the third pole of the fourth transistor (Q4);

the first pins (1) of the third photoelectric coupler (PH 3) and the fourth photoelectric coupler (PH 4) are respectively connected with a second power supply voltage;

the third pin (3) of the third photoelectric coupler (PH 3) is connected with one end of a primary impedance matching resistor (R9), the other end of the primary impedance matching resistor (R9) is connected with the other end of the first pull-down resistor (R1), and the fourth pin (4) of the third photoelectric coupler (PH 3) is connected with the other end of the first pull-up resistor (R5);

the third pin (3) of the fourth photo coupler (PH 4) is connected with one end of a secondary impedance matching resistor (R13), the other end of the secondary impedance matching resistor (R13) is connected with the other end of the first pull-up resistor (R5), and the fourth pin (4) of the fourth photo coupler (PH 4) is connected with the other end of the first pull-down resistor (R1);

If the third transistor (Q3) and the fourth transistor (Q4) are N-channel MOS transistors, the first pole, the second pole and the third pole are respectively a source electrode, a grid electrode and a drain electrode; or alternatively, the first and second heat exchangers may be,

if the third transistor (Q3) and the fourth transistor (Q4) are N-type triodes, the first pole, the second pole and the third pole are respectively a collector electrode, a base electrode and an emitter electrode; or alternatively, the first and second heat exchangers may be,

if the third transistor (Q3) and the fourth transistor (Q4) are P-channel MOS transistors, the first pole, the second pole and the third pole are respectively a drain electrode, a grid electrode and a source electrode; or alternatively, the first and second heat exchangers may be,

if the third transistor (Q3) and the fourth transistor (Q4) are P-type triodes, the first pole, the second pole and the third pole are an emitter, a base and a collector respectively;

the first pin, the second pin, the third pin and the fourth pin of the third photoelectric coupler (PH 3) and the fourth photoelectric coupler (PH 4) are anodes of light emitting diodes respectively, cathodes of the light emitting diodes, emitting electrodes of triodes and collecting electrodes of the triodes.

4. The communication impedance matching circuit of claim 3, further comprising:

the communication module (500) is respectively connected with the control unit (300) and the communication bus (400) and is used for transmitting the control signal generated by the control unit (300) to the communication bus (400) and transmitting the control signal to the rest of communication impedance matching circuits in a wireless mode;

A first power supply module for converting a direct current power supply to a first power supply voltage to supply power to the control unit (300), the communication module (500) and the pull-up and pull-down switching module (22);

and the second power supply module is used for converting the direct-current power supply into a second power supply voltage to supply power to the communication module (500), the impedance switching module (21) and the pull-up and pull-down switching module (22).

5. The communication impedance matching circuit of claim 1, further comprising: a plurality of second expansion connectors;

the communication impedance matching circuit is connected with the rest of communication impedance matching circuits in cascade through the second expansion connector pair.

6. The communication impedance matching circuit according to claim 1, wherein the control unit (300) comprises a main control chip (U2); the communication impedance matching circuit further includes:

an external clock module connected with the main control chip (U2) and used for providing an external clock signal;

and the power-on reset module is connected with the main control chip (U2) and used for ensuring that the locked state before power failure is initialized after power-on to realize reset.

7. The communication impedance matching circuit of claim 6, further comprising:

A burning module for writing data in the writable memory;

and the overvoltage protection module is used for limiting the line voltage input to the main control chip (U2) within a preset range.

8. The communication impedance matching circuit according to claim 7, wherein the communication module (500) comprises an RS485 communication chip (U4);

the first pin of the RS485 communication chip (U4) is respectively connected with one end of a twenty-ninth capacitor (C29), one end of a nineteenth resistor (R19) and one end of a twentieth resistor (R20) and is connected with a second power supply voltage;

the second pin of the RS485 communication chip (U4) is respectively connected with the other end of the twenty-ninth capacitor (C29) and the first ground wire (GND);

the third pin of the RS485 communication chip (U4) is respectively connected with the other ends of the illumination receiving pin (PB 11) and the twentieth resistor (R20) of the main control chip (U2);

the fourth pin of the RS485 communication chip (U4) is respectively connected with the fifth pin 5 of the RS485 communication chip (U4), the illumination driving pin (PB 12) of the main control chip (U2) and one end of a twenty-eighth resistor (R28), and the other end of the twenty-eighth resistor (R28) is connected with a first ground wire (GND);

The sixth pin of the RS485 communication chip (U4) is respectively connected with the other ends of the lighting transmitting pin PB10 and the nineteenth resistor (R19) of the main control chip (U2);

the seventh pin and the eighth pin of the RS485 communication chip (U4) are connected with a first ground wire (GND) after being short-circuited;

a sixteenth pin of the RS485 communication chip (U4) is connected with a first power supply voltage;

the fifteenth pin of the RS485 communication chip (U4) is connected with a second ground wire (GND 2);

a thirteenth pin and a twelfth pin of the RS485 communication chip (U4) are respectively connected with a first signal line (RS-485_N) and a second signal line (RS-485_P) of the communication bus (400);

and a tenth pin and a ninth pin of the RS485 communication chip (U4) are connected with a second ground wire (GND 2) after being short-circuited.

9. A luminaire comprising the communication impedance matching circuit of any one of claims 1-8 and a housing for enclosing the communication impedance matching circuit.

10. A luminaire control system, characterized by comprising a number of luminaires, each luminaire being connected in series by a communication bus (400), each luminaire being integrated with a communication impedance matching circuit according to any one of claims 1-8.