CN218570251U - A differential communication circuit, a lighting fixture and a lighting fixture communication system - Google Patents

Abstract

The present application discloses a differential communication circuit, a lighting lamp and a lamp communication system. The circuit includes: a single-wire differential conversion unit for converting a first single-wire signal into a first differential signal pair; a first differential transmission line pair connected to the single-wire The differential conversion unit is connected to another differential communication circuit for sending the first differential signal pair to the other differential communication circuit; the second differential transmission line pair is connected to the other differential communication circuit for receiving the The second differential signal pair sent by the other differential communication circuit; a differential single-wire conversion unit connected to the second differential transmission line pair and used to restore the second differential signal pair to a second single-wire signal. The present application realizes long-distance differential communication at low cost, and improves communication efficiency between devices.

Description

A differential communication circuit, a lighting fixture and a lighting fixture communication system

technical field

The present application relates to the technical field of communication, and further relates to a differential communication circuit, a lighting lamp and a lamp communication system.

Background technique

Differential communication technology is often used in application scenarios that require long-distance communication control, because the differential transmission method can effectively suppress various interferences during the transmission process, which is conducive to long-distance transmission of signals. The mainstream differential communication technology currently used in the market uses a dedicated serial communication protocol chip such as an RS485 protocol chip to convert a single-wire signal into a differential signal. When using serial communication, it is necessary to convert the received and sent signals into a differential signal. The line realizes half-duplex transmission.

The existing differential communication technology needs to use a serial communication protocol chip at the signal sending end and the signal receiving end respectively, and a total of two serial communication protocol chips are required, and two connecting lines are used for half-duplex transmission during long-distance communication. The high cost of communication protocol chips does not meet the application requirements of some ultra-low-cost products, and the half-duplex transmission mode reduces the communication efficiency between devices.

Therefore, reducing the cost of differential communication between devices and improving communication efficiency between devices is a problem that needs to be solved at present.

Contents of the invention

The purpose of the embodiments of the present application is to provide a differential communication circuit, a lighting fixture, and a lighting fixture communication system, so as to solve the problems of high cost and low communication efficiency of differential communication of equipment.

In the first aspect, in order to achieve the above purpose, the embodiment of the present application provides a differential communication circuit, including:

a single-wire differential conversion unit, configured to convert the first single-wire signal into a first differential signal pair;

A first differential transmission line pair, connected to the single-wire differential conversion unit and another differential communication circuit, for sending the first differential signal pair to the another differential communication circuit;

A second differential transmission line pair, connected to the other differential communication circuit, for receiving a second differential signal pair sent by the other differential communication circuit;

A differential single-wire conversion unit, connected to the second differential transmission line pair, and configured to restore the second differential signal pair to a second single-wire signal.

In the second aspect, in order to achieve the above purpose, the embodiment of the present application provides a lighting fixture, including the above-mentioned differential communication circuit and a housing for packaging the differential communication circuit; the differential communication circuit includes:

a single-wire differential conversion unit, configured to convert the first single-wire signal into a first differential signal pair;

A first differential transmission line pair, connected to the single-wire differential conversion unit and another differential communication circuit, for sending the first differential signal pair to the another differential communication circuit;

A second differential transmission line pair, connected to the other differential communication circuit, for receiving a second differential signal pair sent by the other differential communication circuit;

A differential single-wire conversion unit, connected to the second differential transmission line pair, and configured to restore the second differential signal pair to a second single-wire signal.

In the third aspect, in order to achieve the above purpose, the embodiment of the present application provides a lamp communication system, which includes several lighting lamps, each of which includes the differential communication circuit and a device for packaging the differential communication circuit. The shell, several lighting fixtures are connected to each other through the differential communication circuit, the differential communication circuit includes:

a single-wire differential conversion unit, configured to convert the first single-wire signal into a first differential signal pair;

A first differential transmission line pair, connected to the single-wire differential conversion unit and another differential communication circuit, for sending the first differential signal pair to the another differential communication circuit;

A second differential transmission line pair, connected to the other differential communication circuit, for receiving a second differential signal pair sent by the other differential communication circuit;

A differential single-wire conversion unit, connected to the second differential transmission line pair, and configured to restore the second differential signal pair to a second single-wire signal.

The embodiment of the present application provides a differential communication circuit, a lighting lamp and a lamp communication system. A single-wire differential conversion unit is used to effectively convert a single-wire signal into a pair of differential signals that meet differential transmission requirements, and the differential single-wire conversion unit converts the received A single pair of differential signals can be restored to obtain a single signal, which can allow the communication parties to transmit effective information through differential at low cost.

Description of drawings

In the following, preferred embodiments will be described in a clear and understandable manner with reference to the accompanying drawings, and the above-mentioned characteristics, technical features, advantages and implementation methods of the present application will be further described.

FIG. 1 is a schematic diagram of the internal structure of a differential communication circuit provided by an embodiment of the present application;

FIG. 2 is a schematic diagram of the internal structure of the single-line differential conversion unit provided by the embodiment of the present application;

FIG. 3 is a schematic circuit diagram of an example of a single-line differential conversion unit provided in an embodiment of the present application;

FIG. 4 is another example circuit schematic diagram of the single-line differential conversion unit provided by the embodiment of the present application;

FIG. 5 is a schematic circuit diagram of an example of a differential single-line conversion unit provided in an embodiment of the present application;

FIG. 6 is an example circuit schematic diagram of the connection and communication between the current differential communication circuit and another differential communication circuit provided by the embodiment of the present application;

FIG. 7 is a communication waveform diagram of a simulation circuit of a differential communication circuit provided in an embodiment of the present application.

Detailed ways

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be practiced in other embodiments without 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 when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and/or components, but does not exclude one or more other Presence or addition of characteristics, wholes, steps, operations, elements, components and/or collections.

In order to keep the drawings concise, each drawing only schematically shows the parts relevant to the present application, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, in some drawings, only one of the components having the same structure or function is schematically shown, or only one of them is marked. Herein, "a" not only means "only one", but also means "more than one".

It should be further understood that the term "and/or" used in the description of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations .

In addition, in the description of the present application, the terms "first", "second" and the like are only used to distinguish descriptions, and cannot be understood 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 specific implementation manners of the present application will be described below with reference to the accompanying drawings. Apparently, the accompanying drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other accompanying drawings based on these drawings and obtain other implementations.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of the internal structure of a differential communication circuit 100 provided in an embodiment of the present application. The differential communication circuit 100 includes:

The single-wire differential conversion unit 50 is configured to convert the first single-wire signal G1 into a first differential signal pair.

Specifically, serial port communication is a widely used single-bus data communication, and is widely used in serial interfaces with computers and data communication between devices. UART, RS232, RS485, etc. follow the serial communication protocol and are collectively referred to as serial ports.

Wherein, the single-wire signal is a serial port signal transmitted by the serial port sending pin TX. For example, a single-wire signal is a UART (Universal Asynchronous Receiver/Transmitter, Universal Asynchronous Receiver/Transmitter) signal transmitted by a serial port sending pin TX. Also for example, a single-wire signal is an RS485 signal transmitted by the serial port sending pin TX.

After the single-line differential conversion unit 50 obtains the first single-line signal G1 from the serial port sending pin TX, it converts the first single-line signal G1 and outputs two signals to obtain the first differential signal pair, and the first differential signal pair is the amplitude Two signals that are equal and opposite in phase, the voltage amplitudes of the two signals at the same time are equal but the direction of one signal is opposite to that of the other signal at the same time. The first single-wire signal G1 can be obtained by the current differential communication circuit 110 from the main control chip connected to the current differential communication circuit 110, that is, the main control chip converts the data to be sent into a single-line signal, and sends it through the serial port of the main control chip. TX is sent to the single-wire differential conversion unit 50. The main control chip is not shown in this application. In the prior art, a single-line signal in which the main control chip converts the data to be transmitted into a digital signal form is within the protection scope of this application.

The first differential transmission line pair 20 is connected to the single-wire differential conversion unit 50 and another differential communication circuit 120 for sending the first differential signal pair to another differential communication circuit 120 .

The second differential transmission line pair 40 is connected to another differential communication circuit 120 for receiving a second differential signal pair sent by another differential communication circuit 120 .

Specifically, the first differential transmission line pair 20 includes a first differential transmission line TL1 and a second differential transmission line TL2, and the second differential transmission line pair 40 includes a third differential transmission line RL1 and a fourth differential transmission line RL2. The first differential transmission line TL1 , the second differential transmission line TL2 , the third differential transmission line RL1 and the fourth differential transmission line RL2 are essentially single-ended or unidirectional transmission lines for transmitting signals.

As shown in FIG. 1 , the first differential transmission line pair 20 includes a first differential transmission line TL1 and a second differential transmission line TL2 , and the second differential transmission line pair 40 includes a third differential transmission line RL1 and a fourth differential transmission line RL2 . The first differential transmission line pair 20 and the second differential transmission line pair 40 can be used as signal transmission lines or as signal reception transmission lines. For example, assuming that the current differential communication circuit 110 is connected to another differential communication circuit 120, for the current differential communication circuit 110, the first differential transmission line pair 20 is used by the current differential communication circuit 110 to send the first differential communication circuit 120 to another differential communication circuit 120. The transmission transmission line of the differential signal pair, the second differential transmission line pair 40 is the reception transmission line used by the current differential communication circuit 110 to receive the second differential signal pair sent by another differential communication circuit 120 . Conversely, for another differential communication circuit 120, the first differential transmission line pair 20 is a receiving transmission line used by another differential communication circuit 120 to receive the first differential signal pair sent by the current differential communication circuit 110, and the second differential transmission line pair 40 is a sending transmission line used by another differential communication circuit 120 to send the second differential signal pair to the current differential communication circuit 110 .

The differential single-wire conversion unit 30 is connected to the second differential transmission line pair 40 and used for restoring the second differential signal pair to the second single-wire signal G2.

Specifically, the first single-line signal G1 is a digital signal obtained by the current differential communication circuit 110 from the main control chip connected to the current differential communication circuit 110 and converted based on the data to be sent, and the second single-line signal G2 is another digital signal obtained by the differential communication circuit 110. 120 acquires a digital signal converted based on the data to be sent from a main control chip connected to another differential communication circuit 120 , and the first single-wire signal G1 and the second single-wire signal G2 are only used to distinguish different signal sources. In addition, the first differential signal pair is two signals sent by the current differential communication circuit 110 to another differential communication circuit 120 , and the second differential signal pair is two signals sent by another differential communication circuit 120 to the current differential communication circuit 110 .

Since the identity of the differential communication circuit can be both the sending end and the receiving end, of course, the identity of the differential communication circuit can also be only the sending end, and the identity of the differential communication circuit can also be only the receiving end. When the front differential communication circuit 110 serves as the sending end, it converts the first single-wire signal G1 into a first differential signal pair, and transmits the first differential signal pair to another differential communication circuit 120 serving as the receiving end through the first differential transmission line pair 20 . When the front differential communication circuit 110 is used as the receiving end, it is connected to another differential communication circuit 120 as the sending end through the second differential transmission line pair 40, so as to convert and restore the second differential signal received from the other differential communication circuit 120 into the second single line Signal G2.

As we all know, the serial port receiving pin is used to receive data, and the serial port sending pin is used to send data. Two differential communication circuits 100 can be connected to each other through a two-wire serial port, so as to initiate data sending and receiving at the same time. Among them, the differential communication circuit 100 can use a two-wire serial port for serial communication. The two-wire serial port means that the serial port sending pin and the serial port receiving pin are separately arranged on two lines. For example, the differential communication circuit 100 includes a first positive terminal, a first Negative terminal, second positive terminal, second negative terminal, the first positive terminal is used to send the first differential signal in the first differential signal pair, and the first negative terminal is used to receive the first differential signal in the second differential signal pair . The second positive terminal is used for sending the second differential signal of the first differential signal pair, and the second negative terminal is used for receiving the second differential signal of the second differential signal pair. The first differential signal pair is the two-way differential signal obtained by converting the first single-wire signal G1 by the current differential communication circuit 110, and the second differential signal pair is sent to the current differential communication circuit 120 connected to the current differential communication circuit 110. The two differential signals of the circuit 110. The first positive terminal and the first negative terminal form a first two-wire serial port, and the second positive terminal and the second negative terminal form a second two-wire serial port.

In the prior art, two transmission lines are used for differential transmission for both reception and transmission, so a special serial communication protocol chip is required to switch the direction of transmission and reception. The differential communication circuit of the present application provides four differential transmission lines, a single-wire differential conversion unit and a differential single-wire conversion unit, which can enable two connected differential communication circuits to communicate with each other through full-duplex transmission and simultaneously realize sending and receiving signals, all The duplex mode can control the transmission of data in two directions at the same time without switching the direction. Therefore, there is no time delay caused by the switching operation, thereby improving the communication efficiency. In addition, this application directly converts single-wire signal to differential signal through the single-wire differential conversion unit, and directly performs conversion from differential signal to single-wire signal through the differential single-wire conversion unit, without additional serial communication protocol chips such as RS485 protocol chips for signal conversion. , to reduce the cost of differential communication of the device.

Differential transmission is a signal transmission technology, which is different from the traditional method of transmitting a single-wire signal with one signal line and one ground line. Differential transmission uses two signal lines and two signal lines in one ground line. To transmit a pair of signals, that is, a differential signal pair, the differential signal pair is two signals with equal amplitude and opposite phase (that is, equal voltage amplitude and opposite direction). A pair of signals transmitted on the two signal lines is a differential signal, and the differential signal transmits the level difference between the two signals on the two signal lines. In this application, the third differential transmission line RL1 and the fourth differential transmission line RL2, as well as the first differential transmission line TL1 and the second differential transmission line TL2 are essentially signal lines. It should be noted that the differential signal requires two signal lines of equal length, equal width, equal width, close proximity (generally, the line spacing exceeds 4 times the line width), and signal lines on the same level for differential transmission. In this way, when the interference noise is loaded on the two differential transmission lines in the differential transmission line pair, that is, the signal lines, at the same time, because the two differential transmission lines in the differential transmission line pair, that is, the signal lines are very close to each other and the two differential signal lines in the differential signal pair The amplitudes of the differential signals are equal, and the amplitudes of the coupling electromagnetic fields between the two signal wires and the ground wires are also equal. At the same time, the phases of the two differential signals in the differential signal pair are opposite, and their electromagnetic fields will cancel each other out. Therefore, the differential transmission Signal anti-interference ability is strong. Therefore, the EMI (abbreviation for Electromagnetic Interference, that is, electromagnetic interference) to the outside world is also small, which can effectively suppress electromagnetic interference. Therefore, in application scenarios that require long-distance communication control, differential transmission is used to effectively suppress various interferences during transmission, which is beneficial to long-distance transmission of signals. Therefore, the present application enables the communication parties to transmit effective information in a differential manner at low cost by means of differential signal transmission.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of the internal structure of the single-line differential conversion unit 50 provided by the embodiment of the present application. The single-line differential conversion unit 50 includes: a resistor voltage divider module 11, a signal separation module 12 and a first comparison module 13;

The resistor divider module 11 is configured to output a constant DC level V0 after being connected to the power supply; the value of the constant DC level V0 is equal to half of the voltage value of the power supply, and the voltage value of the power supply is equal to the first single-wire signal G1 the peak voltage.

Specifically, the power supply is the working power provided to the differential communication circuit, and the power supply is determined according to the maximum working power supported by the differential communication circuit, and the power supply is provided by an additional power conversion circuit (not shown in the figure). Power supply conversion circuits in the technology, including DC-DC circuits, AC-DC circuits, step-down circuits, etc., are within the protection scope of this application.

Exemplarily, an additional power conversion circuit (not shown in the figure) is used to provide a power supply to the differential communication circuit, and the voltage value of the power supply may include, for example, 1.5V, 3.3V, 5.0V and so on. Since the resistance voltage divider module 11 divides the connected power supply to output a constant DC level V0, generally the value of the constant DC level V0 is equal to half of the voltage value of the power supply. Among them, if the decimal place of half of the voltage value of the power supply is the same as the decimal place of the power supply, there is no need to perform rounding calculation on half of the voltage value of the power supply, and directly divide the voltage value of the power supply by 2. As the value of the constant DC level V0, for example, if the voltage value of the power supply is 5.0V, then the value of the constant DC level V0 is 2.5V. If the decimal place of half of the voltage value of the power supply is different from the decimal place of the power supply, the last decimal place of half the voltage value of the power supply is rounded to an integer. For example, if the voltage value of the power supply is 1.5V, The calculation result of dividing the voltage value of the power supply by 2 is 0.75, and the last decimal place of half of the voltage value of the power supply is 0.05. If it is rounded and calculated, the value of the constant DC level V0 can be 0.7V or 0.8 V. For example, if the voltage value of the power supply is 3.3V, the calculation result of dividing the voltage value of the power supply by 2 is 1.65, and the last decimal place of half of the voltage value of the power supply is 0.05. The value of the DC level V0 can be 1.6V or 1.7V.

The signal separation module 12 is configured to output the first single-wire sub-signal N1 and the second single-wire sub-signal N2 after receiving a first single-wire sub-signal G1; the amplitude of the first single-wire sub-signal N1 and the second single-wire sub-signal N2 equal.

Specifically, the signal separation module 12 is connected to the serial port sending pin TX, and is used to separate or cut one first single-wire signal G1 to obtain two single-wire sub-signals. Wherein, the signal separation module 12 provides two identical lines to separate one first single-wire signal G1 into two single-wire sub-signals in the form of digital signals with the same level and magnitude. Wherein, the two single-wire sub-signals include a first single-wire sub-signal N1 and a second single-wire sub-signal N2, and the levels of the first single-wire sub-signal N1 and the second single-wire sub-signal N2 are the same.

The first comparison module 13 is connected to the resistance voltage divider module 11 and the signal separation module 12 respectively, and is configured to output a pair of amplitudes after receiving a constant DC level V0, the first single-wire sub-signal N1 and the second single-wire sub-signal N2 Signals that are equal and opposite in phase serve as a first differential signal pair.

Specifically, the first input end of the first comparison module 13 is connected to the resistance voltage divider module 11 to access a constant DC level V0, and the second input end of the first comparison module 13 is connected to the signal separation module 12 to access two The first single-wire sub-signal N1 in the first single-wire sub-signal, compares the level amplitude of the first single-wire sub-signal N1 with the constant DC level V0, and outputs the first differential signal. In addition, the third input terminal of the first comparison module 13 is connected to the resistance voltage divider module 11 to access a constant DC level V0, and the fourth input terminal of the first comparison module 13 is connected to the signal separation module 12 to access two channels The second single-wire sub-signal N2 of the single-wire sub-signals compares the level and amplitude of the second single-wire sub-signal N2 with the constant DC level V0 to output a second differential signal.

Please refer to FIG. 3. FIG. 3 is another example circuit schematic diagram of the single-wire differential conversion unit 50 provided by the embodiment of the present application. The resistor voltage divider module 11 includes a first voltage divider resistor R10 and a second voltage divider resistor R13; signal separation The module 12 includes a third resistor R4, a fourth resistor R9 and a fifth resistor R11; the first comparison module 13 includes a first operational amplifier U1 and a second operational amplifier U3.

One end of the third resistor R4 and the fourth resistor R9 are respectively connected to the serial port sending pin TX to receive a first single-wire signal G1.

The inverting input pin 4 of the first operational amplifier U1 is connected to the other end of the third resistor R4 to access the first single-wire sub-signal N1.

The non-inverting input pin 3 of the second operational amplifier U3 is connected to the other end of the fourth resistor R9 to receive the second single-wire sub-signal N2.

Specifically, both ends of the third resistor R4 are respectively connected to the serial port sending pin TX and the reverse input pin 4 of the first operational amplifier U1, so that the first single-wire signal G1 transmitted by the serial port sending pin TX passes through the third The resistor R4 is separated to obtain the first single-wire sub-signal N1 and input to the inverting input pin 4 of the first operational amplifier U1. In addition, both ends of the fourth resistor R9 are respectively connected to the serial port sending pin TX and the same-direction input pin 3 of the second operational amplifier U3, so that the first single-wire signal G1 transmitted by the serial port sending pin TX passes through the fourth resistor R9 is separated to obtain the second single-wire sub-signal N2 and input to the non-inverting input pin 3 of the second operational amplifier U3.

The non-inverting input pin 3 of the first operational amplifier U1 and the inverting input pin 4 of the second operational amplifier U3 are jointly connected to one end of the fifth resistor R11 to access a constant DC level;

Specifically, the non-inverting input pin 3 of the first operational amplifier U1 is connected to the fifth resistor R11, so as to access the constant DC level generated by the voltage division of the first voltage dividing resistor R10 and the second voltage dividing resistor R13 through the fifth resistor R11 V0. The non-inverting input pin 3 of the first operational amplifier U1 is connected to a constant DC level V0, and the inverting input pin 4 of the first operational amplifier U1 is connected to the single-wire signal transmitted through the third resistor R4. In this way, the first operational amplifier U1 compares the constant DC level V0 input at the non-inverting input pin 3 of the first operational amplifier U1 with the first single-wire sub-signal N1 input at the inverting input pin 4 of the first operational amplifier U1. The magnitude between the level amplitudes, so as to output the first differential signal according to the comparison result.

In addition, the inverting input pin 4 of the second operational amplifier U3 is connected to the fifth resistor R11, so as to access the constant DC level V0 generated by the division of the first voltage dividing resistor R10 and the second voltage dividing resistor R13 through the fifth resistor R11 . The inverting input pin 4 of the second operational amplifier U3 is connected to a constant DC level V0, and the non-inverting input pin 3 of the second operational amplifier U3 is connected to the second single-wire sub-signal N2 transmitted through the fourth resistor R9. The second operational amplifier U3 compares the level amplitude of the second single-wire sub-signal N2 input at the same direction input pin 3 of the second operational amplifier U3 with the constant direct current input at the reverse input pin 4 of the second operational amplifier U3 The magnitude between V0, so as to output the second differential signal according to the comparison result.

The other end of the first voltage dividing resistor R10 is connected to the power supply, and one end of the second voltage dividing resistor R13 is grounded; one end of the first voltage dividing resistor R10 and the other end of the second voltage dividing resistor R13 are respectively connected to the other end of the fifth resistor R11 Connected at one end to output a constant DC level V0;

Wherein, the first differential signal M1 of the first level and the second differential signal M2 of the first level have equal amplitudes and opposite phases to form a first differential signal pair.

Specifically, one end of the first voltage-dividing resistor R10 is connected to the other end of the second voltage-dividing resistor R13 to form a converging point P1, and the first voltage-dividing resistor R10 and the second voltage-dividing resistor R13 are connected in series to form a resistor voltage-dividing module. The first voltage-dividing resistor R10 and the second voltage-dividing resistor R13 are connected in series to divide the connected power supply, and the first voltage-dividing resistor R10 and the second voltage-dividing resistor R13 output the constant DC level in the above embodiment from the converging point P1 V0.

The output pin 1 of the first operational amplifier U1 is used to output the first differential signal M1 of the first level; the output pin 1 of the second operational amplifier U3 is used to output the second differential signal M2 of the first level; wherein, The first differential signal M1 of the first level and the second differential signal M2 of the first level have equal amplitudes and opposite phases to form a first differential signal pair.

Specifically, since the value of the constant DC level V0 is equal to half of the voltage value of the power supply, when the level amplitudes of the first single-line sub-signal N1 and the second single-line sub-signal N2 are not equal to or higher than or lower than the constant DC level When V0, the two operational amplifiers will respectively output a pair of signals with equal amplitude but opposite phase (that is, the voltage amplitude is equal but opposite in direction), and this pair of signals will be divided into two channels and respectively enter the first differential transmission line pair 20 differential signal.

That is to say, if the level amplitude of the first single-wire sub-signal N1 is higher or lower than the constant DC level V0, the output pin of the first operational amplifier U1 in the current differential communication circuit 110 outputs the first level For the first differential signal M1, if the level amplitude of the second single-wire sub-signal N2 is higher or lower than the constant DC level V0, the output pin of the second operational amplifier U3 in the current differential communication circuit 110 outputs the first voltage flat second differential signal M2. Since the output pin of the first operational amplifier U1 in the current differential communication circuit 110 is connected to the first differential transmission line TL1, the first differential signal can be sent to another differential communication circuit 120 as a receiving end through the first differential transmission line TL1. In addition, the output pin of the second operational amplifier U3 in the current differential communication circuit 110 is connected to the second differential transmission line TL2, so the second differential signal can be sent to another differential communication circuit 120 at the receiving end through the second differential transmission line TL2.

In some embodiments, the resistance values of the third resistor R4 , the fourth resistor R9 and the fifth resistor R11 are equal. Wherein, the resistance values of the third resistor R4, the fourth resistor R9 and the fifth resistor R11 may also be unequal. The present application preferably selects the third resistor R4, the fourth resistor R9 and the fifth resistor R11 with the same resistance value, so that the first operational amplifier U1 compares the level amplitude of the first single-wire sub-signal N1 with the constant DC level V0 The efficiency is higher when the size is larger, and the second operational amplifier U3 is more efficient when comparing the level amplitude of the second single-line sub-signal N2 with the magnitude of the constant DC level V0, so that it can compare and output the first differential signal pair more quickly .

Please refer to FIG. 3. FIG. 3 is an example circuit schematic diagram of the single-line differential conversion unit 50 provided by the embodiment of the present application. If the first operational amplifier U1 and the second operational amplifier U3 are both push-pull output structures, the first operational The power supply pins (6) of the amplifier U1 and the second operational amplifier U3 are connected to the power supply.

Specifically, the push-pull output structure is composed of two transistors (including MOS transistors or triodes), and the two transistors are respectively two MOS transistors or two triodes. Generally, one transistor is always turned off while the other is turned on. The biggest feature of push-pull output is that it can really output high level and low level, and it has driving ability at both levels. The so-called driving ability refers to the ability to output current. Since the first operational amplifier U1 and the second operational amplifier U3 both have a push-pull output structure, the voltages of the first differential signal and the second differential signal output by the output pin 1 of the first operational amplifier U1 and the second operational amplifier U3 The average value depends on the size of the power supply connected to the power supply pin 6 of the first operational amplifier U1 and the second operational amplifier U3. In other words, the so-called push-pull output mode is named according to the working mode of these two MOS tubes. When the operational amplifier of the push-pull output structure inputs a high level, it outputs a high level to the outside, and vice versa, when it inputs a low level, it outputs a low level to the outside.

Please refer to FIG. 4. FIG. 4 is another example circuit schematic diagram of the single-line differential conversion unit 50 provided by the embodiment of the present application. The single-line differential conversion unit 50 also includes: a first bias module and a second bias module;

The first bias module is configured to output the first differential signal M3 of the second level when receiving the first differential signal M1 of the first level; the second level is greater than the first level;

The second bias module is configured to output the second differential signal M4 of the second level when receiving the second differential signal M2 of the first level;

If both the first operational amplifier U1 and the second operational amplifier U3 have an open-drain output structure, the output pin 10 of the first operational amplifier U1 is connected to the first bias module, and the output pin 10 of the second operational amplifier U3 is connected to the first bias module. Two bias module connections;

Wherein, the first differential signal M3 of the second level and the second differential signal M4 of the second level have equal amplitudes and opposite phases to form a first differential signal pair.

Specifically, the open-drain output structure is the opposite of the push-pull output structure. The difference between the open-drain output structure and the push-pull output structure is that the open-drain output structure cannot really output high levels, that is, there is no driving capability at high levels. The external pull-up resistor completes the external drive. This feature of the open-drain output structure can easily adjust the output level, because the output level is completely determined by the power supply level connected to the pull-up resistor. That is to say, when the first operation When the structure of the amplifier is an open-drain output structure, the level of the first differential signal obtained depends on the power supply connected to the first bias module connected to the output pin 10 of the first operational amplifier. Similarly, when the structure of the second operational amplifier is an open-drain output structure, the level of the second differential signal obtained depends on the power supply connected to the second bias module connected to the output pin 10 of the second operational amplifier. .

The operational amplifier with an open-drain output structure is composed of internal components such as resistors and transistors. When the operational amplifier is working normally, the internal transistors always need a certain voltage to provide bias. Therefore, in this embodiment, the first differential signal M1 of the first level is configured as the second differential signal M4 of the second level through the first bias module connected to the first operational amplifier U1, and the first bias module can The influence of the DC bias on the first operational amplifier U1 is suppressed. The second differential signal is configured as a high level through a second bias module connected to the second operational amplifier U3, and the second bias module can suppress the influence of the DC bias on the second operational amplifier U3.

In some embodiments, since the operational amplifier has a push-pull output structure, the signal level of the output pin of the operational amplifier cannot exceed the voltage value of the power supply input at the power supply pin 6 of the operational amplifier. Therefore, the present application preferably An operational amplifier using an open-drain output structure.

Please refer to FIG. 1 and FIG. 4. FIG. 1 is a schematic diagram of the internal structure of the differential communication circuit 100 provided in the embodiment of the present application, and FIG. 4 is another example circuit schematic diagram of the single-line differential conversion unit 50 provided in the embodiment of the present application. The first differential transmission line pair 20 shown in FIG. 1 includes a first differential transmission line TL1 and a second differential transmission line TL2 . As shown in Figure 4,

The first bias module includes: a first pull-up resistor R2, a first bias capacitor C1;

The second bias module includes: a second pull-up resistor R8, a second bias capacitor C3;

One end of the first pull-up resistor R2 is respectively connected to the output pin 1 of the first operational amplifier U1 and one end of the first bias capacitor C1 to access the first differential signal M1 of the first level;

One end of the second pull-up resistor R8 is respectively connected to the output pin 1 of the second operational amplifier U3 and one end of the second bias capacitor C3 to access the second differential signal M2 of the first level;

The other end of the first pull-up resistor R2 and the other end of the second pull-up resistor R8 are respectively connected to the power supply;

The other end of the first bias capacitor C1 is connected to the first differential transmission line TL1, so as to send the first differential signal M3 of the second level to the differential single-line conversion unit 30 of another differential communication circuit 120;

The other end of the second bias capacitor C3 is connected to the second differential transmission line TL2 to transmit the second differential signal M4 of the second level to the differential single-wire conversion unit 30 of another differential communication circuit 120 .

Specifically, when the operational amplifier used has an open-drain output structure, it is necessary to configure the output signal of the output pin 1 of the first operational amplifier U1 and the second operational amplifier U3 to be at a high level, otherwise the differential signal cannot be effectively output. The reason why the output pin 1 of the amplifier is connected to a pull-up resistor is because the serial port communication requires the ability to output a high level, because the general open-drain output cannot output a high level, so in this embodiment, the first pull-up resistor R2 and the second The two pull-up resistors R8 are respectively used to configure the level at the output pin 1 of the first operational amplifier U1 and the second operational amplifier U3 to be high level, that is, through the first pull-up resistor R2 connected to the first operational amplifier U1 The first differential signal M1 of the first level is configured as the second differential signal M4 of the second level. The second differential signal is configured at a high level through the second pull-up resistor R8 connected to the second operational amplifier U3.

The first bias capacitor C1 and the second bias capacitor C3 can prevent the current differential communication circuit 110 as the transmitting end from another differential communication circuit 120 as the receiving end, because the DC bias current is different for the first operational amplifier U1, the second operational amplifier U1, and the second operational amplifier U1. Amplifier U3 has an effect. As we all know, since the DC bias current will affect the performance of the operational amplifier, in this embodiment, the first bias capacitor C1 is connected to the output pin 1 of the first operational amplifier U1, and the output of the second operational amplifier U3 The second bias capacitor C3 is connected to the pin 1, and the DC bias current can be averaged through the first bias capacitor C1 and the second bias capacitor C3, so as not to interfere with the DC bias of the operational amplifier, so as to achieve The influence of the DC bias on the second operational amplifier U3 is suppressed.

In some embodiments, the differential single-wire conversion unit 30 includes: a third bias module, a fourth bias module, and a third operational amplifier U2;

The third bias module is configured to output the third differential signal K3 of the first level after receiving the third differential signal K1 of the second level sent by another differential communication circuit 120;

The fourth bias module is configured to output the fourth differential signal K4 of the first level after receiving the fourth differential signal K2 of the second level sent by another differential communication circuit 120; the second level is greater than first level;

The third operational amplifier U2 is connected to the third bias module and the fourth bias module respectively, configured to receive the third differential signal K3 of the first level and the fourth differential signal K4 of the first level, The second single-line signal G2 is output.

Specifically, this embodiment is opposite to the single-line differential conversion unit 50 in the above-mentioned embodiments. The current differential communication circuit 110 is connected to another differential communication circuit 120 through the second differential transmission line pair 40, so that the current differential communication circuit 110 receives another differential communication circuit 110. The second differential signal pair sent by the communication circuit 120, wherein the second differential signal pair includes a third differential signal K1 of a second level and a fourth differential signal K2 of a second level. The third operational amplifier U2 of the current differential communication circuit 110 configures the third differential signal K1 of the second level sent by another differential communication circuit 120 to the first level through a third bias module connected to the third operational amplifier U2 The third differential signal K3 of the current differential communication circuit 110, the third operational amplifier U2 of the current differential communication circuit 110 transmits the fourth differential signal of the second level sent by another differential communication circuit 120 through the fourth bias module connected to the third operational amplifier U2 K2 is configured as the fourth differential signal K4 of the first level.

Please refer to FIG. 1 and FIG. 5. FIG. 1 is a schematic diagram of the internal structure of the differential communication circuit 100 provided by the embodiment of the present application, and FIG. 5 is an example circuit schematic diagram of the differential single-wire conversion unit 30 provided by the embodiment of the present application, as shown in The second differential transmission line pair 40 shown in 1 includes a third differential transmission line RL1 and a fourth differential transmission line RL2. As shown in Figure 4,

The third bias module includes: a first pull-down resistor R3, a second pull-down resistor R12;

The fourth bias module includes: a third bias capacitor C2 and a fourth bias capacitor C4;

One end of the third bias capacitor C2 is connected to the third differential transmission line RL1 to receive the third differential signal K1 of the second level sent by another differential communication circuit 120;

One end of the fourth bias capacitor C4 is connected to the fourth differential transmission line RL2 to receive the fourth differential signal K2 of the second level sent by another differential communication circuit 120;

The other end of the third bias capacitor C2 is respectively connected to one end of the first pull-down resistor R3, and the other end of the first pull-down resistor R3 is grounded to output the third differential signal K3 of the first level;

The other end of the fourth bias capacitor C4 is respectively connected to one end of the second pull-down resistor R12, and the other end of the second pull-down resistor R12 is grounded to output the fourth differential signal K4 of the first level;

The non-inverting input pin 3 of the third operational amplifier U2 is connected to the third differential signal K3 of the first level, and the reverse input pin 4 of the third operational amplifier U2 is connected to the fourth differential signal K4 of the first level, The output pin 1 of the third operational amplifier U2 is used to output the second single-wire signal G2.

Specifically, the first pull-down resistor R3 is used to convert the third differential signal K1 of the second level input to the inverting input pin 4 of the third operational amplifier U2 into the third differential signal K3 of the first level , the second level is greater than the first level, that is, the third differential signal K1 of the second level input to the reverse input pin 4 of the third operational amplifier U2 is changed from high to high through the first pull-down resistor R3 The level is pulled down to a low level. Similarly, the second pull-down resistor R12 is used to convert the fourth differential signal K2 of the second level input to the non-inverting input pin 3 of the third operational amplifier U2 into a fourth differential signal K4 of the first level, The second level is greater than the first level, that is to say, the fourth differential signal K2 of the second level input to the non-inverting input pin 3 of the third operational amplifier U2 is changed from a high level to a high level through the second pull-down resistor R12 Pulled low. In addition, the third bias capacitor C2 and the fourth bias capacitor C4 can prevent the current differential communication circuit 110 as the receiving end and another differential communication circuit 120 as the transmitting end from affecting the third operational amplifier U2 due to the difference in DC bias current. . As we all know, the operational amplifier is one of the operational amplifiers. Since the DC bias current will affect the performance of the operational amplifier, in this embodiment, the fourth bias capacitor is connected to the non-inverting input pin 3 of the third operational amplifier U2 C4, and the third bias capacitor C2 is connected to the inverting input pin 4 of the third operational amplifier U2, and the DC bias current can be averaged through the third bias capacitor C2 and the fourth bias capacitor C4, so that there is no Interference will be generated to the DC bias of the operational amplifier, so as to suppress the impact of the DC bias on the third operational amplifier U2.

In some embodiments, as shown in FIG. 5 , one end of the sixth resistor R5 is respectively connected to the other end of the third bias capacitor C2 and one end of the first pull-down resistor R3, and the other end of the sixth resistor R5 is connected to the third The inverting input of op amp U2 is connected to pin 4. One end of the seventh resistor R7 is respectively connected to the other end of the fourth bias capacitor C4 and one end of the second pull-down resistor R12, and the other end of the seventh resistor R7 is connected to the inverting input pin 4 of the third operational amplifier U2.

In some embodiments, as shown in FIG. 5 , the differential single-wire conversion unit 30 further includes a third pull-up resistor R6, one end of the third pull-up resistor R6 is connected to the power supply, and the other end of the third pull-up resistor R6 is respectively connected to the The output pin 1 of the third operational amplifier U2 is connected to the serial port receiving pin RX of the main control chip, and the output pin 1 of the third operational amplifier U2 outputs the second single-wire signal G2 and sends it to the serial port receiving pin RX of the main control chip , the serial port receiving pin RX of the main control chip transmits the second single-wire signal G2 through the antenna after receiving the second single-wire signal G2.

In some embodiments, as shown in FIG. 6, FIG. 6 is an example circuit schematic diagram of the connection and communication between the current differential communication circuit 110 and another differential communication circuit 120. The components in the current differential communication circuit 110 are the same as those in the above-mentioned FIGS. The components and connections are the same in the illustrated embodiment. Similarly, through four capacitors namely C5, C6, C7 and C8, three operational amplifiers namely U4, U5 and U6, and twelve resistors R14, R16, R18, R23, R17, R1, R19, R15, R20, R22 , R21 , and R24 constitute another differential communication circuit 120 having the same structure as the current differential communication circuit 110 .

The serial receiving pin RX of the main control chip connected to the current differential communication circuit 110 receives the output pin 1 of U2 and outputs G2, and the serial receiving pin RX of the main control chip connected to the current differential communication circuit 110 receives G2 and passes the current differential communication The antenna in circuit 110 transmits G2. The serial port receiving pin RXD of the main control chip connected to another differential communication circuit 120 receives the output pin 1 of U2 and outputs G3, and the serial port receiving pin RXD of the main control chip connected to another differential communication circuit 120 receives G3 and passes through another An antenna in the differential communication circuit 120 transmits G3. The serial port sending pin TX of the main control chip connected to the current differential communication circuit 110 sends G1 to U1 and U3, and the serial port sending pin TXD of the main control chip connected to the other differential communication circuit 120 sends G4 to U4 and U6. In this way, as shown in FIG. 7 is the communication waveform diagram of the simulation circuit of the differential communication circuit. By observing the communication waveform diagram shown in FIG. 7 and FIGS. 120 each includes a single-wire differential conversion unit 50 and a differential single-wire conversion unit 30. The current differential communication circuit 110 and another differential communication circuit 120 communicate with each other through the first differential transmission line pair 20 and the second differential transmission line pair 40. Due to the single-wire differential Both the conversion unit 50 and the differential single-wire conversion unit 30 use operational amplifiers. The single-wire differential conversion unit 50 can effectively convert a single-wire signal into a pair of differential signals that meet the differential requirements through two operational amplifiers, and the differential single-wire conversion unit 30 uses a An operational amplifier can restore an effective single-wire signal.

In this application, operational amplifiers with different response speeds can be selected to meet the requirements of different communication rates. For example, conventional operational amplifiers can be used in scenarios where the communication rate is not high. Conventional operational amplifiers are convenient for selection and lower in cost. For scenarios requiring a high communication rate, an operational amplifier with a high response speed can be selected correspondingly, and even if an operational amplifier with a high response speed is used, the cost will not be higher than that of the two mainstream differential communication technologies in the prior art. This application requires coordinated adjustment of the software serial port communication protocol, and the communication protocol needs to set a self-sending and self-receiving mode to cooperate with the realization of the circuit scheme.

In order to adapt to ultra-low-cost product application requirements and establish a hierarchical product system, a simpler and more effective low-cost differential communication technology solution is needed to achieve this. This application uses both the single-line differential conversion unit 50 and the differential single-line conversion unit 30 The operational amplifier is used to convert the single-line signal into a differential signal through the two operational amplifiers in the single-line differential conversion unit 50, and restore the differential signal obtained by the single-line differential conversion unit 50 to a single-line signal through one operational amplifier in the differential single-line conversion unit 30 , can reduce the number of communication chips to further reduce the cost.

This application can choose operational amplifiers with different costs and specifications according to different communication rate requirements, so as to provide strong technical support for the establishment of a hierarchical product system. In addition, this application can significantly reduce the technical implementation cost of differential communication and realize long-distance differential communication. Communication, and signal conversion through operational amplifiers, compared with the use of special communication protocol chips or differential drivers for signal conversion in the prior art, greatly reduces the cost of long-distance differential communication.

In order to better implement the differential communication circuit in the embodiment of the present application, on the basis of the differential communication circuit, the embodiment of the present application also provides a lighting fixture, including the differential communication circuit in all the above-mentioned embodiments and the differential communication circuit for packaging shell. The specific structure of the differential communication circuit refers to the above-mentioned embodiments. Since this lighting fixture adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, and will not repeat them here. .

In some embodiments, mature and mass-produced lighting fixtures (such as LED fluorescent tubes, LED flat lamps, LED ceiling lamps, LED strips, LED strips, LED spotlights, LED string lights, LED downlights, etc.). The lighting fixture of the present application is the differential communication circuit 100 mentioned in the embodiment of the present application. The current lighting fixture as the sending end sends the first differential signal pair to another lighting fixture as the receiving end through the first differential transmission line pair 20, and the current lighting fixture as the receiving end receives the signal from another lighting fixture as the sending end through the second differential transmission line pair 40. Send the second differential signal pair.

Exemplarily, as shown in Figure 2-Figure 6, since the identity of the lighting fixture can be either a transceiver or a receiving end, if the current lighting fixture is a communication master and another lighting fixture is a communication slave, then, as shown in As shown in 2-6, when the current lighting fixture is used as the sending end, the single-line signal is converted into a differential signal, and is connected to another lighting fixture as the receiving end through the first differential transmission line pair 20, that is, the first differential transmission line TL1 and the second differential transmission line TL2 , so as to transmit the first differential signal pair to another lighting fixture as a receiving end. When the current lighting fixture is used as the receiving end, it is connected to another lighting fixture as the sending end through the second differential transmission line pair 40, that is, the third differential transmission line RL1 and the fourth differential transmission line RL2, so as to transmit the second differential signal received from another lighting fixture to the second single-wire signal G2. The above-mentioned embodiment describes that when the current lighting fixture is used as the sending end and the receiving end, and another lighting fixture is used as the sending end and the receiving end, the single-line differential conversion unit 50 and the differential single-line conversion unit 30 of the other lighting fixture can be connected with the current lighting fixture. The single-line differential conversion unit 50 and the differential single-line conversion unit 30 have the same circuit topology. For a detailed example circuit schematic diagram, see FIG. 6 , which will not be repeated here.

FIG. 6 is an example circuit schematic diagram of a connection relationship between two communication parties. The sending end transmits valid information to the receiving end through a differential transmission line. The transmission distance of the differential transmission line will be limited by the communication rate. The faster the communication rate, the shorter the effective transmission distance of the differential transmission line. You can choose a suitable operational amplifier to meet different communication rate requirements according to your needs. The effective transmission distance with low communication rate requirements Just long.

In order to better implement the differential communication circuit in the embodiment of the present application, on the basis of the differential communication circuit, the embodiment of the present application also provides a lamp communication system, including several lighting lamps, and each lighting lamp includes The differential communication circuit and the shell used to package the differential communication circuit, several lighting fixtures are connected to each other through the differential communication circuit, the differential communication circuit includes:

A single-line differential conversion unit 50, configured to convert the first single-line signal G1 into a first differential signal pair;

The first differential transmission line pair 20 is connected to the single-wire differential conversion unit 50 and another differential communication circuit 120 for sending the first differential signal pair to another differential communication circuit 120;

The second differential transmission line pair 40 is connected to another differential communication circuit 120 for receiving a second differential signal pair sent by another differential communication circuit 120;

The differential single-wire conversion unit 30 is connected to the second differential transmission line pair 40 and used for restoring the second differential signal pair to the second single-wire signal G2.

The above is a detailed introduction of a differential communication circuit, a lighting fixture and a lighting communication system provided by the embodiment of the present application. In this paper, a specific example is used to illustrate the principle and implementation of the present application. The description of the above embodiment is only used It is used to help understand the technical solutions and core ideas of the present application, and is not intended to limit the scope of protection of the present application; those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or modify them Part of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. A differential communication circuit (100), characterized in that, comprising: A single-wire differential conversion unit (50), configured to convert the first single-wire signal (G1) into a first differential signal pair; A first differential transmission line pair (20), connected to the single-line differential conversion unit (50) and another differential communication circuit, for sending the first differential signal pair to the another differential communication circuit; A second differential transmission line pair (40), connected to the other differential communication circuit, for receiving a second differential signal pair sent by the other differential communication circuit; A differential single-wire conversion unit (30), connected to the second differential transmission line pair (40), and configured to restore the second differential signal pair to a second single-wire signal (G2). 2. The differential communication circuit according to claim 1, characterized in that the single-wire differential conversion unit (50) comprises: a resistor voltage divider module (11), a signal separation module (12) and a first comparison module (13) ; The resistance voltage divider module (11) is configured to output a constant DC level (V0) after being connected to a power supply; the value of the constant DC level (V0) is equal to half of the voltage value of the power supply, And the voltage value of the power supply is equal to the peak voltage value of the first single-wire signal (G1); The signal separation module (12) is configured to output a first single-wire sub-signal (N1) and a second single-wire sub-signal (N2) after receiving one of the first single-wire signals (G1); A single-wire sub-signal (N1) and the second single-wire sub-signal (N2) have the same amplitude; The first comparison module (13) is respectively connected to the resistance voltage divider module (11) and the signal separation module (12), configured to receive the constant DC level (V0), the first After the single-line sub-signal (N1) and the second single-line sub-signal (N2), output a pair of signals with equal amplitude and opposite phase as the first differential signal pair. 3. The differential communication circuit according to claim 2, wherein: The resistance voltage dividing module (11) includes a first voltage dividing resistor (R10) and a second voltage dividing resistor (R13); The signal separation module (12) includes a third resistor (R4), a fourth resistor (R9) and a fifth resistor (R11); The first comparison module (13) includes a first operational amplifier (U1) and a second operational amplifier (U3); One end of the third resistor (R4) and the fourth resistor (R9) are respectively connected to the serial port sending pin (TX) to receive the first single-wire signal (G1); The reverse input pin (4) of the first operational amplifier (U1) is connected to the other end of the third resistor (R4) to access the first single-wire sub-signal (N1); The non-inverting input pin (3) of the second operational amplifier (U3) is connected to the other end of the fourth resistor (R9) to access the second single-wire sub-signal (N2); The non-inverting input pin (3) of the first operational amplifier (U1) and the reverse input pin (4) of the second operational amplifier (U3) are jointly connected with one end of the fifth resistor (R11), so as to accessing said constant DC level (V0); The other end of the first voltage dividing resistor (R10) is connected to the power supply, and one end of the second voltage dividing resistor (R13) is grounded; One end of the first voltage dividing resistor (R10) and the other end of the second voltage dividing resistor (R13) are respectively connected to the other end of the fifth resistor (R11) to output the constant DC level (V0 ); The output pin (1) of the first operational amplifier (U1) is used to output a first differential signal (M1) of a first level; The output pin (1) of the second operational amplifier (U3) is used to output the second differential signal (M2) of the first level; Wherein, the first differential signal (M1) of the first level and the second differential signal (M2) of the first level have equal amplitudes and opposite phases to form the first differential signal pair. 4. The differential communication circuit according to claim 3, wherein: If both the first operational amplifier (U1) and the second operational amplifier (U3) have a push-pull output structure, the power supply pins of the first operational amplifier (U1) and the second operational amplifier (U3) ( 6) Connect to the power supply. 5. The differential communication circuit according to claim 3, wherein the single-wire differential conversion unit (50) further comprises: a first bias module and a second bias module; The first bias module is configured to output a first differential signal (M3) of a second level when receiving the first differential signal (M1) of the first level; the second level is greater than said first level; A second bias module, configured to output a second differential signal (M4) of a second level when receiving the second differential signal (M2) of the first level; If both the first operational amplifier (U1) and the second operational amplifier (U3) have an open-drain output structure, the output pin (1) of the first operational amplifier (U1) is connected to the first bias module connected, the output pin (1) of the second operational amplifier (U3) is connected to the second bias module; Wherein, the first differential signal ( M3 ) of the second level and the second differential signal ( M4 ) of the second level have equal amplitudes and opposite phases to form the first differential signal pair. 6. The differential communication circuit according to claim 5, wherein the first differential transmission line pair (20) comprises a first differential transmission line (TL1) and a second differential transmission line (TL2); The first bias module includes: a first pull-up resistor (R2), a first bias capacitor (C1); The second bias module includes: a second pull-up resistor (R8), a second bias capacitor (C3); One end of the first pull-up resistor (R2) is respectively connected to the output pin (1) of the first operational amplifier (U1) and one end of the first bias capacitor (C1) to access the outputting the first differential signal (M3) of the second level after the first differential signal (M1) of the first level; One end of the second pull-up resistor (R8) is respectively connected to the output pin (1) of the second operational amplifier (U3) and one end of the second bias capacitor (C3) to access the outputting the second differential signal (M4) of the second level after the second differential signal (M2) of the first level; The other end of the first pull-up resistor (R2) and the other end of the second pull-up resistor (R8) are respectively connected to the power supply; The other end of the first bias capacitor (C1) is connected to the first differential transmission line (TL1) to send the first differential signal (M3) of the second level to the other differential communication circuit A differential single-wire conversion unit (30); The other end of the second bias capacitor (C3) is connected to the second differential transmission line (TL2) to send the second differential signal (M4) of the second level to the other differential communication circuit. A differential single-wire conversion unit (30). 7. The differential communication circuit according to claim 1, characterized in that, the second differential signal pair comprises a third differential signal (K1) of a second level and a fourth differential signal (K2) of a second level ; The differential single-wire conversion unit (30) includes: a third bias module, a fourth bias module and a third operational amplifier (U2); The third bias module is configured to output a third differential signal (K3) of the first level after receiving the third differential signal (K1) of the second level sent by the other differential communication circuit ); The fourth bias module is configured to output a fourth differential signal (K4) of the first level after receiving the fourth differential signal (K2) of the second level sent by the other differential communication circuit ); said second level is greater than said first level; The third operational amplifier (U2) is connected to the third bias module and the fourth bias module respectively, configured to receive the third differential signal (K3) of the first level and After the fourth differential signal (K4) of the first level, the second single-line signal (G2) is output. 8. The differential communication circuit according to claim 7, wherein the second differential transmission line pair (40) comprises a third differential transmission line (RL1) and a fourth differential transmission line (RL2); The third bias module includes: a first pull-down resistor (R3), a second pull-down resistor (R12); The fourth bias module includes: a third bias capacitor (C2), a fourth bias capacitor (C4); One end of the third bias capacitor (C2) is connected to the third differential transmission line (RL1) to receive a second level third differential signal (K1) sent by the other differential communication circuit; One end of the fourth bias capacitor (C4) is connected to the fourth differential transmission line (RL2) to receive the fourth differential signal (K2) of the second level sent by the other differential communication circuit; The other end of the third bias capacitor (C2) is respectively connected to one end of the first pull-down resistor (R3), and the other end of the first pull-down resistor (R3) is grounded to output the first voltage flat third differential signal (K3); The other end of the fourth bias capacitor (C4) is respectively connected to one end of the second pull-down resistor (R12), and the other end of the second pull-down resistor (R12) is grounded to output the first level The fourth differential signal (K4); The same direction input pin (3) of the third operational amplifier (U2) is connected to the third differential signal (K3) of the first level, and the reverse input pin of the third operational amplifier (U2) (4) Connecting the fourth differential signal (K4) of the first level, and the output pin (1) of the third operational amplifier (U2) is used to output the second single-wire signal (G2). 9. A lighting fixture, characterized in that it comprises the differential communication circuit according to any one of claims 1-8 and a casing for packaging the differential communication circuit; the differential communication circuit comprises: A single-wire differential conversion unit (50), configured to convert the first single-wire signal (G1) into a first differential signal pair; A first differential transmission line pair (20), connected to the single-line differential conversion unit (50) and another differential communication circuit, for sending the first differential signal pair to the another differential communication circuit; A second differential transmission line pair (40), connected to the other differential communication circuit, for receiving a second differential signal pair sent by the other differential communication circuit; A differential single-wire conversion unit (30), connected to the second differential transmission line pair (40), and configured to restore the second differential signal pair to a second single-wire signal (G2). 10. A lamp communication system, characterized in that it includes several lighting lamps, each of which includes a differential communication circuit as claimed in any one of claims 1-8 and a package for packaging the differential communication circuit The casing, and several lighting fixtures are connected to each other through the differential communication circuit, and the differential communication circuit includes: A single-wire differential conversion unit (50), configured to convert the first single-wire signal (G1) into a first differential signal pair; A first differential transmission line pair (20), connected to the single-line differential conversion unit (50) and another differential communication circuit, for sending the first differential signal pair to the another differential communication circuit; A second differential transmission line pair (40), connected to the other differential communication circuit, for receiving a second differential signal pair sent by the other differential communication circuit; A differential single-wire conversion unit (30), connected to the second differential transmission line pair (40), and configured to restore the second differential signal pair to a second single-wire signal (G2).

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