CN108534298B

CN108534298B - Slave communication circuit, slave, electrical equipment, master-slave communication circuit and method

Info

Publication number: CN108534298B
Application number: CN201810413923.8A
Authority: CN
Inventors: 刘文斌; 王星; 贺小林; 李洋
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2018-05-03
Filing date: 2018-05-03
Publication date: 2023-11-14
Anticipated expiration: 2038-05-03
Also published as: WO2019210689A1; CN108534298A

Abstract

The invention discloses a slave communication circuit, a slave, electrical equipment, a master-slave communication circuit and a method. The slave communication circuit comprises a slave universal asynchronous receiving and transmitting transmitter and an optical coupling output conversion circuit, wherein the slave universal asynchronous receiving and transmitting transmitter comprises a slave signal transmitting end; the first input end of the optical coupler output conversion circuit is connected with a power supply, and the second input end of the output photoelectric coupler is connected with the slave signal transmitting end; the first output end of the output photoelectric coupler is connected with a power supply, the second output end of the output photoelectric coupler is connected with the input end of the relay, and the output end of the relay is connected with the host signal receiving end of the host communication circuit. The invention can eliminate the influence of high low level caused by the transmission bit property of the optocoupler, thereby improving the communication reliability and enabling the host side chip to identify high and low levels under various conditions.

Description

Slave communication circuit, slave, electrical equipment, master-slave communication circuit and method

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a slave communication circuit, a slave, an electrical apparatus, a master-slave communication circuit, and a method.

Background

For an electrical device having a master and at least one slave, the master is to control the operation of a plurality of slaves simultaneously when the electrical device is operating. For example: the air conditioner has a main control board and a plurality of compressors, and the main control board is to control the operation of the plurality of compressors simultaneously during the operation of the air conditioner.

At present, two communication modes exist in the industries of electrical equipment such as air conditioners and the like: 485 communication and UART (Universal Asynchronous Receiver/Transmitter, universal asynchronous receiver Transmitter) optocoupler communication. Based on 485 communication, centralized communication can be performed between one host computer and a plurality of slaves, so that multiple sets of units are connected together. But the 485 based communication has high cost and needs a special chip.

Communication quality based on UART optocoupler communication mode is easily affected by the characteristics of optocoupler components. The minimum level of the optocoupler changes at high or low temperatures. In particular, the communication failure, which is unrecognizable by the chip, is more likely to occur due to the minimum level being too high, when the current transmission is higher than the upper limit or the lower limit.

Disclosure of Invention

In view of at least one of the above technical problems, the present invention provides a slave communication circuit, a slave, an electrical device, a master-slave communication circuit and a method, which can eliminate the influence of high low level caused by the transmission bit of an optocoupler.

According to one aspect of the present invention, there is provided a slave communication circuit comprising a slave universal asynchronous receiver-transmitter and an optocoupler output conversion circuit, wherein:

the slave universal asynchronous receiving and transmitting transmitter comprises a slave signal transmitting end;

the slave universal asynchronous receiving and transmitting transmitter is connected with the optical coupling output conversion circuit;

the optical coupler output conversion circuit comprises an output photoelectric coupler and a relay, wherein a first input end of the output photoelectric coupler is connected with a power supply, and a second input end of the output photoelectric coupler is connected with a slave signal transmitting end; the first output end of the output photoelectric coupler is connected with a power supply, the second output end of the output photoelectric coupler is connected with the input end of the relay, and the output end of the relay is connected with the host signal receiving end of the host communication circuit.

In some embodiments of the present invention, the relay is a triode, the base of the triode is the relay input, the collector of the triode is the relay output, and the emitter of the triode is grounded.

In some embodiments of the invention, the relay comprises a relay coil, a relay moving contact, and a relay stationary contact, wherein:

the relay coil is a relay input end, the relay movable contact is a relay output end, and the relay fixed contact is grounded;

Or,

the relay coil is a relay input end, the relay static contact is a relay output end, and the relay movable contact is grounded.

In some embodiments of the present invention, the optocoupler output conversion circuit further includes a first resistor and a second resistor, where the first resistor is disposed in series between the second output terminal of the output optocoupler and the relay input terminal, one end of the second resistor is connected to the power supply, and the other end of the second resistor is connected to the relay output terminal.

In some embodiments of the present invention, in the case where the transmission signal of the slave signal transmission terminal is at a low level, the output voltage of the relay output terminal is less than a predetermined value.

In some embodiments of the invention, the output optocoupler comprises a light emitting diode in a primary loop and a phototransistor in a secondary loop;

the positive electrode of the light-emitting diode is a first input end of the output photoelectric coupler, and the negative electrode of the light-emitting diode is a second input end of the output photoelectric coupler; the collector electrode of the phototriode is a first output end of the output photoelectric coupler, and the emitter electrode of the phototriode is a second output end of the output photoelectric coupler.

According to another aspect of the present invention, there is provided a master-slave communication circuit comprising a master communication circuit and at least one slave communication circuit, wherein,

The slave communication circuit is the slave communication circuit according to any one of the above embodiments;

the host communication circuit includes a host communication interface that is connected to the slave communication interface of the at least one slave communication circuit by parallel lines.

In some embodiments of the present invention, the host communication interface includes a host signal transmitting interface and a host signal receiving interface, wherein the host signal transmitting interface is connected to the host signal transmitting end, and the host signal receiving interface is connected to the host signal receiving end;

the slave asynchronous receiving and transmitting transmitter comprises a slave signal sending interface and a slave signal receiving interface;

the host signal transmitting interface is connected with the slave signal receiving interface of at least one slave machine through parallel lines, and the host signal receiving interface is connected with the slave signal transmitting interface of at least one slave machine through parallel lines.

In some embodiments of the invention, the host communication circuit comprises a host universal asynchronous receiver transmitter and a power amplification circuit, wherein:

the host universal asynchronous receiving and transmitting transmitter comprises a host signal transmitting end;

the input end of the power amplifying circuit is connected with the host signal transmitting end and is used for amplifying the current of the host signal;

The output of the power amplifying circuit is connected to at least one slave to transmit a master signal to the at least one slave.

According to another aspect of the present invention there is provided a slave comprising a slave communications circuit as described in any one of the embodiments above.

According to another aspect of the present invention, there is provided an electrical device comprising a master and at least one slave, wherein the slave is a slave as described in any of the above embodiments.

According to another aspect of the present invention, there is provided an electrical device comprising a master, at least one slave, and a master-slave communication circuit as described in any of the above embodiments.

According to another aspect of the present invention, there is provided a master-slave communication method, comprising:

in the slave communication circuit according to any one of the above embodiments, in the case where the slave signal transmitting terminal outputs a low level signal,

the second output end of the output photoelectric coupler is provided with current output;

outputting the current output by the second output end of the photoelectric coupler to enable the input end of the relay to be electrified;

and under the condition that the input end of the relay is powered on, the output end of the relay outputs a low level.

In some embodiments of the present invention, the master-slave communication method further includes:

In the host communication circuit according to any one of the above embodiments, the host signal transmitting terminal transmits the host signal to the power amplifying circuit;

the power amplifying circuit amplifies the current of the host signal;

the master universal asynchronous receiver transmitter transmits the amplified master signal to at least one slave.

The invention can eliminate the influence of high low level caused by the transmission bit property of the optocoupler, thereby improving the communication reliability and enabling the host side chip to identify high and low levels under various conditions.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of some embodiments of UART optocoupler communication circuits.

FIG. 2 is a schematic diagram of a master-slave communication circuit according to some embodiments of the present invention.

Fig. 3 is a schematic diagram of an optocoupler output conversion circuit according to some embodiments of the invention.

Fig. 4 is a schematic diagram of an optocoupler output conversion circuit according to another embodiment of the invention.

Fig. 5 is a schematic diagram of an optocoupler output conversion circuit according to still another embodiment of the invention.

FIG. 6 is a schematic diagram of another embodiment of a master-slave communication circuit according to the present invention.

FIG. 7 is a schematic diagram of a master-slave communication circuit according to still another embodiment of the present invention.

FIG. 8 is a schematic diagram of another embodiment of a master-slave communication circuit according to the present invention.

Fig. 9 is a schematic diagram of some embodiments of the electrical device of the present invention.

Fig. 10 is a schematic diagram of some embodiments of the electrical device of the present invention.

FIG. 11 is a schematic diagram of a master-slave communication method according to some embodiments of the present invention.

FIG. 12 is a schematic diagram of another embodiment of a master-slave communication method according to the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.

Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.

In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

FIG. 1 is a schematic diagram of some embodiments of UART optocoupler communication circuits. As shown in fig. 1, the UART optocoupler of the related art isolates a communication circuit. The circuit has a simple structure and low cost, and can realize the inter-board communication of the thermal ground and the floating ground main board only by two optocouplers. Wherein, heat refers to: in the circuit, if the reference ground level is connected with an external power grid through a rectifier bridge or a diode, the reference ground level is directly and electrically connected with the power grid, and the ground level is called as thermal ground. The current can flow from the ground level to the power grid, and the voltage of the ground level meeting the ground is half of the voltage of the live wire of the power grid, so that the electric power grid is dangerous to a human body. Floating means: in the circuit, the reference ground level is not actually electrically connected with a power grid, the ground level is called floating ground, for example, the ground level is connected with an isolated component such as a transformer, the ground level is suspended, passive assimilation is realized when the ground level is communicated with any level, for example, the ground level is connected with a human body, the whole floating ground level is kept consistent with the human body level, and the human body is free from electric shock hazard.

The circuit structure of the embodiment of fig. 1 has limited output power, cannot realize long-distance and multi-node communication, can only perform one-to-one communication, and has communication quality related to the transmission ratio of the optocoupler. When the optical coupler is in transmission bias limit or in ambient temperature bias limit, the actual low level is higher than 0.8V, and the chip cannot recognize the low level to cause communication failure.

For example: due to the characteristics of the optocoupler, under the condition that the current transmission ratio is lower than the lower limit, the circuit structure shown in fig. 1 easily enables the secondary side of the optocoupler not to enter deep saturation, and the output voltage of the secondary side is higher. The output low level of the secondary side occurs higher than 0.8V, and thus the chip cannot recognize the low level, resulting in communication failure.

FIG. 2 is a schematic diagram of a master-slave communication circuit according to some embodiments of the present invention. As shown in fig. 2, the master-slave communication circuit may include a master communication circuit 10 and a slave communication circuit 20, wherein:

the master-slave communication circuit of the embodiment of fig. 2 may be provided in an electrical device comprising a master and at least one slave to enable communication between the master and the slave. Specifically, the master communication circuit 10 may be provided on the master side, and the slave communication circuit 20 may be provided on the slave side.

For example: the master-slave communication circuit of the embodiment of fig. 2 may be disposed in an air conditioner including a master control board and at least one compressor, wherein a master of the air conditioner is the master control board, and a slave of the air conditioner is the compressor. The master communication circuit 10 may be disposed on an air conditioner main control board, and the slave communication circuit 20 may be disposed on a compressor driving board.

As shown in fig. 2, the master communication circuit 10 includes a master communication interface 11, the slave communication circuit 20 includes a slave communication interface 21, and the master communication interface 11 is connected to the slave communication interface 21 of at least one slave communication circuit 20 through parallel lines 30.

As shown in fig. 2, the parallel lines 30 sequentially include a power line, a host signal transmission line, a host signal reception line, and a ground line from top to bottom.

In some embodiments of the present invention, as shown in fig. 2, the slave communication circuit 20 may include a slave communication interface 21, a slave universal asynchronous receiver transmitter 22, and an optical coupling output conversion circuit, where:

the slave universal asynchronous receiver transmitter 22 includes a slave signal receiving end RXS and a slave signal transmitting end TXS.

The slave communication interface 21 is connected with the optocoupler output conversion circuit.

The optocoupler output conversion circuit may be a high-low level conversion circuit.

The optocoupler output conversion circuit can comprise an output optocoupler U1 and a relay Q3, wherein a first input end of the output optocoupler U1 is connected with a power supply, and a second input end of the output optocoupler U1 is connected with a slave signal transmitting end; the first output end of the output photoelectric coupler U1 is connected with a power supply, the second output end of the output photoelectric coupler U1 is connected with the input end of a relay, and the output end of the relay is connected with the host signal receiving end of the host communication circuit.

In some embodiments of the invention, the output optocoupler U1 may include a light emitter in the primary loop and a light receiver in the secondary loop.

In some embodiments of the invention, as shown in fig. 2 and 3, the light emitter may be a light emitting diode U11 located in the primary loop; the light receiver may be a phototransistor U12 located in the secondary loop.

The anode of the light-emitting diode U11 is connected with a power supply; the negative electrode of the light-emitting diode U11 is connected with the signal transmitting end of the slave; the collector of the phototriode U12 is connected with a power supply, the emitter of the phototriode U12 is connected with the input end of the relay Q3, and the output end of the relay Q3 is connected with the host signal receiving end RX through the slave communication interface 21.

In some embodiments of the present invention, when the transmission signal of the slave signal transmitting end is at a low level, the output voltage of the output end of the relay Q3 is smaller than a predetermined value, so as to ensure that the low-level signal of the slave can be accurately identified under the condition of the optical coupler transmission offset limit or the ambient temperature offset limit.

In some embodiments of the invention, the predetermined value may be 0.8V.

In some embodiments of the invention, the relay Q3 may be a triode relay or a conventional relay.

Fig. 3 is a schematic diagram of an optocoupler output conversion circuit according to some embodiments of the invention. As shown in fig. 2 and 3, the relay Q3 may be a triode relay, i.e., the relay Q3 is a triode.

As shown in fig. 2 and 3, the base electrode of the triode is the input end of the relay Q3, the collector electrode of the triode is the output end of the relay Q3, and the emitter electrode of the triode is grounded.

In the process of sending signals from the slave to the host, the sending signals pass through the optocoupler and the level conversion circuit, as shown in figures 2 and 3,

when the low-level signal (0) is output from the slave signal transmitting terminal, the primary side (light emitting diode U11) of the output photocoupler U1 is turned on; in the case where the light emitting diode U11 is turned on, the secondary side (phototransistor U12) of the photocoupler U1 is turned on; the emitter current of phototransistor U12 flows through transistor Q3, causing transistor Q3 to be in an active state.

After the triode Q3 works, collector current of the triode Q3 flows through the triode through the R3, the collector of the triode outputs low level to the receiving side of the host, and the host receives the low level at the moment.

In the actual communication process, if the voltage of the secondary side of the optocoupler exceeds 0.8V or reaches 1V under the temperature limit caused by the characteristic of the optocoupler, the triode is normally conducted, the collector current < base current β is still true, the triode is still in a saturated state, the Vce of the triode Q3 is still lower than 0.7V, and the triode is at a normal low level.

Based on the master-slave communication circuit provided by the embodiment of the invention, in particular to a slave communication circuit, a relay or a triode is arranged at the second output end of the output photoelectric coupler, the high-low level conversion circuit is formed, so that under the condition of the optical coupler transmission bias limit or the environment temperature bias limit, the low level signal of the slave can be accurately identified. Therefore, the embodiment of the invention solves the technical problems that the actual low level is higher than 0.8V and the chip cannot identify the low level to cause communication failure under the condition of the transmission bias limit or the ambient temperature bias limit of the optical coupler in the prior art.

In some embodiments of the present invention, as shown in fig. 2 and 3, the optocoupler output conversion circuit may further include a first resistor R1, a second resistor R2, and a third resistor R3, wherein:

the first resistor R1 is arranged in series between the emitter of the phototransistor U12 and the base of the triode relay Q3. The first resistor R1 is used to turn on the driving transistor Q3 or energize the relay coil when the phototransistor is turned on.

One end of the second resistor R2 is connected with a power supply, and the other end of the second resistor R2 is connected with the output end of the relay Q3 (namely, the collector electrode of the triode relay Q3). The second resistor R2 is used for ensuring that the voltage of the output terminal of the relay is low level under the condition that the triode Q3 is conducted or the relay contact is conducted.

One end of the third resistor R3 is connected to a power supply, and the positive electrode of the light emitting diode U11 at the other end of the third resistor R3 is connected.

In some embodiments of the present invention, R1 and R2 are generally equal to each other for resistor selection. For example: in the embodiments of fig. 2 and 3, the resistance values of R1 and R2 may be selected to be 1K ohms.

In other embodiments of the present invention, R2 may also be slightly larger than R1, making it easier to bring transistor Q3 into saturation.

In the above embodiment of the present invention, the first resistor R1, the second resistor R2, and the third resistor R3 are pull-up resistors.

In some embodiments of the present invention, the third resistor R3 may have a resistance of 680 ohms.

In some embodiments of the present invention, when the slave sends a high level signal (1 signal), the primary side of the photo coupler U1 is not conductive, the secondary side has no current signal, the transistor Q3 is not operated, the collector of the transistor outputs a high level signal (1 signal), and the host receives a high level signal.

The embodiments of fig. 2 and 3 of the present invention adopt a mode of adding a triode at the second output end (for example, the emitter of a phototriode) of the output photoelectric coupler, so that the influence of low level overhigh caused by the limiting temperature characteristic and the limiting current transmission ratio characteristic of the photoelectric coupler element can be removed. The host side chip of the embodiment of the invention can identify high and low levels under various conditions, and is safe and reliable.

In some embodiments of the present invention, as shown in fig. 2, the slave communication circuit 20 may further include an optocoupler input conversion circuit, wherein:

the input end of the optocoupler input conversion circuit is connected with the host signal transmitting end TX through the slave communication interface 21 to receive the host signal.

The output end of the optocoupler input conversion circuit is connected with the slave signal receiving end RXS.

Therefore, the slave communication circuit of the embodiment of the invention can also conveniently receive the host signal issued by the host.

In some embodiments of the present invention, as shown in fig. 2, the optocoupler input conversion circuit includes an input optocoupler U2, the input optocoupler U2 including a primary side light emitting diode U21 and a secondary side photodiode U22, wherein:

the positive electrode of the light emitting diode U21 is connected to a power source, and the negative electrode of the light emitting diode U21 is connected to the master signal transmitting terminal TX through the slave communication interface 21.

The collector of the photodiode U22 is connected to the slave signal receiving end RXS, and the emitter of the photodiode U22 is grounded.

In some embodiments of the present invention, as shown in fig. 2, the optocoupler input conversion circuit may further include a fourth resistor R4, wherein:

one end of the fourth resistor R4 is connected to a power source, and the other end of the fourth resistor R4 is connected to the collector of the photodiode U22.

In some embodiments of the present invention, the resistance of the fourth resistor R4 may be 1k ohms.

In some embodiments of the present invention, as shown in fig. 2, the host communication circuit 10 may further include a fifth resistor R5, wherein:

one end of the fifth resistor R5 is connected to the host signal transmitting end TX, and the other end of the fifth resistor R5 is connected to the host signal transmitting interface of the host communication interface 11.

In some embodiments of the present invention, the fifth resistor R5 may have a resistance of 680 ohms.

In some embodiments of the invention, the supply voltage VCC may be 3.3V.

In some embodiments of the present invention, as shown in fig. 2, the master communication circuit 10 may further include a first capacitor C1 and a second capacitor C2, and the slave communication circuit 20 may further include a third capacitor C3, wherein:

on the host side, one end of a first capacitor C1 is connected with a host signal transmitting end TX, and the other end of the first capacitor C1 is grounded; one end of the second capacitor C2 is connected to the host signal receiving terminal RX, and the other end of the second capacitor C2 is grounded. The first capacitor C1 and the second capacitor C2 are used for filtering to reduce system interference.

On the slave side, one end of the third capacitor C3 is connected with the slave signal receiving interface, and the other end of the third capacitor C3 is connected with a power supply.

In some embodiments of the present invention, the first capacitor C1, the second capacitor C2 and the third capacitor C3 may be filter capacitors.

In some embodiments of the present invention, the first capacitor C1, the second capacitor C2 and the third capacitor C3 may each have a capacity of 1nF.

In some embodiments of the present invention, in the case where the host signal transmitting terminal TX outputs a high level, the light emitting diode U21 is not turned on, the photo diode U22 is not turned on, and the collector of the photo diode U22 outputs a high level. Therefore, the slave signal receiving terminal RXS receives a high level signal.

In the case where the host signal transmitting terminal TX outputs a low level, the light emitting diode U21 is turned on, the photodiode U22 is turned on, and the collector of the photodiode U22 outputs a low level. Therefore, the slave signal receiving terminal RXS receives a low level signal.

Fig. 4 is a schematic diagram of an optocoupler output conversion circuit according to another embodiment of the invention. In contrast to the embodiment of fig. 2 and 3, in the embodiment of fig. 4, the relay Q3 may be a conventional relay.

As shown in fig. 4, the relay Q3 includes a relay coil 41, a relay movable contact 42, and a relay stationary contact 43, wherein:

the relay coil 41 is an input end of the relay Q3, the relay movable contact 42 is an output end of the relay Q3, and the relay fixed contact 43 is grounded.

When the low-level signal (0) is output from the slave signal transmitting terminal, the primary side (light emitting diode U11) of the output photocoupler U1 is turned on; in the case where the light emitting diode U11 is turned on, the secondary side (phototransistor U12) of the photocoupler U1 is turned on; the emitter current of the phototransistor U12 flows through the relay coil 41, so that the relay coil 41 is energized.

When the relay coil 41 is energized, the relay movable contact 42 is closed, the relay movable contact 42 communicates with the relay stationary contact 43, and the relay movable contact 42 outputs a low level to the host receiving side.

In some embodiments of the present invention, when the slave sends a high level signal (1 signal), the primary side of the photo coupler U1 is not conductive, the secondary side has no current signal, the relay coil 41 is not powered, the relay movable contact 42 is a high level signal (1 signal), and the host receives a high level signal.

In the embodiment of the invention, the relay is arranged at the second output end of the output photoelectric coupler to form the high-low level conversion circuit, so that the influence of low level overhigh caused by the limiting temperature characteristic and the limiting current transmission ratio characteristic of the photoelectric coupler element can be removed. The host side chip of the embodiment of the invention can identify high and low levels under various conditions, and is safe and reliable.

Fig. 5 is a schematic diagram of an optocoupler output conversion circuit according to still another embodiment of the invention. In comparison with fig. 4, in the embodiment of fig. 5, the relay Q3 comprises a relay coil 41, a relay movable contact 42 and a relay stationary contact 43, wherein:

the relay coil 41 is an input end of the relay Q3, the relay fixed contact 43 is an output end of the relay Q3, and the relay movable contact 42 is grounded.

When the relay coil 41 is energized, the relay movable contact 42 is closed, the relay movable contact 42 communicates with the relay stationary contact 43, and the relay stationary contact 43 outputs a low level to the host receiving side.

In the case where the relay movable contact 42 communicates with the relay fixed contact 43, the voltage difference between the relay movable contact 42 and the relay fixed contact 43 is less than 0.7V, at a normal low level.

In some embodiments of the present invention, when the slave sends a high level signal (1 signal), the primary side of the photo coupler U1 is not conductive, the secondary side has no current signal, the relay coil 41 is not powered, the relay stationary contact 43 is a high level signal (1 signal), and the host receives a high level signal.

The master-slave communication circuit provided by the embodiment of fig. 4 or 5 of the present invention may be specifically a slave communication circuit, and the low-level signal of the slave may be accurately identified under the condition of the optical coupler transmission bias limit or the ambient temperature bias limit by adding a conventional relay at the second output end (for example, the emitter of the phototransistor) of the output photocoupler. Therefore, the embodiment of the invention solves the technical problems that the actual low level is higher than 0.8V and the chip cannot identify the low level to cause communication failure under the condition of the transmission bias limit or the ambient temperature bias limit of the optical coupler in the prior art.

FIG. 6 is a schematic diagram of another embodiment of a master-slave communication circuit according to the present invention. As shown in fig. 6, the master-slave communication circuit may include a master communication circuit 10 and at least two slave communication circuits 20, wherein:

the master-slave communication circuit of the embodiment of fig. 6 may be provided in an electrical device comprising a master and at least two slaves to enable communication between the master and the slaves. Specifically, the master communication circuit 10 may be provided on the master side, and at least two slave communication circuits 20 may be provided on different slave sides, respectively.

For example: the master-slave communication circuit of the embodiment of fig. 6 may be disposed in an air conditioner including a master control board and at least two compressors, wherein a master of the air conditioner is the master control board, and a slave of the air conditioner is the compressor. The master communication circuit 10 may be disposed on an air conditioner main control board, and the slave communication circuit 20 may be disposed on a compressor driving board.

The at least two slave communication circuits 20 are identical in structure.

As shown in fig. 6, the master communication circuit 10 may be connected to at least one slave communication circuit 20 by parallel lines.

As shown in fig. 6, the parallel lines 30 sequentially include a power line, a host signal transmission line, a host signal reception line, and a ground line from top to bottom.

As shown in fig. 6, the host communication circuit 10 includes a host universal asynchronous receiver transmitter 12 and a power amplification circuit 13, in which:

the host universal asynchronous receiver transmitter 12 includes a host signal transmitting terminal TX and a host signal receiving terminal RX.

The input terminal of the power amplification circuit 13 is connected to the host signal transmitting terminal TX, and amplifies the host signal.

The output of the power amplifying circuit 13 is connected to at least one slave in order to transmit a master signal to the at least one slave.

As shown in fig. 6, the host communication circuit 10 may further include a sixth resistor R6 and a seventh resistor R7, wherein:

one end of the sixth resistor R6 is connected with the host signal receiving end RX, and the other end of the sixth resistor R6 is connected with at least one slave machine through a host receiving line.

One end of the seventh resistor R7 is connected to the power supply, and the other end is connected to the sixth resistor R6.

In some embodiments of the present invention, the resistance of the sixth resistor R6 and the seventh resistor R7 may be 1k ohms.

As shown in fig. 6, the slave communication circuit 20 may include a slave universal asynchronous receiver transmitter 22, an optocoupler output conversion circuit, and an optocoupler input conversion circuit, wherein:

The optocoupler output conversion circuit may include an output optocoupler U1 and a third resistor R3, wherein the output optocoupler U1 includes a light emitting diode U11 in the primary loop and a phototransistor U12 in the secondary loop.

The anode of the light-emitting diode U11 is connected with a power supply through a third resistor R3; the negative electrode of the light-emitting diode U11 is connected with the signal transmitting end of the slave; the collector of the phototriode U12 is connected with a host signal receiving end RX, and the emitter of the phototriode U12 is grounded.

The optocoupler input conversion circuit may include an input optocoupler U2, a third capacitor C3, a fourth resistor R4, and an eighth resistor R8, where

The input photo-coupler U2 may include a primary side light emitting diode U21 and a secondary side photodiode U22,

The positive pole of the light emitting diode U21 is connected to the power supply through the eighth resistor R8, and the negative pole of the light emitting diode U21 is connected to the host signal transmitting terminal TX.

In some embodiments of the present invention, the eighth resistor R8 may have a resistance of 680 ohms.

One end of the third capacitor C3 is connected with the positive electrode of the light emitting diode U21, and the other end of the third capacitor C3 is connected with the negative electrode of the light emitting diode U21.

In some embodiments of the present invention, in the case where the master signal transmitting terminal TX outputs a high level, the light emitting diode U21 is not turned on, the photo diode U22 is not turned on, and the collector of the photo diode U22 outputs a high level in each slave communication circuit. Therefore, the slave signal receiving terminal RXS receives a high level signal.

In the case where the master signal transmitting terminal TX outputs a low level, the light emitting diode U21 is turned on, the photodiode U22 is turned on, and the collector of the photodiode U22 outputs a low level in the respective slave communication circuits. Therefore, the slave signal receiving terminal RXS receives a low level signal.

In some embodiments of the present invention, as shown in fig. 6, the host signal receiving terminal RX of the host communication circuit 10 may be further connected to at least one slave for receiving a slave signal sent by the at least one slave.

When any slave of the electrical equipment sends a low-level signal (0), the light emitting diode U11 of the output photoelectric coupler U1 is driven to emit light through the third resistor R3, the phototriode U12 of the output photoelectric coupler U1 is driven to be conducted, and after the emitter of the phototriode U12 is grounded, the level of the collector of the phototriode U12 is pulled to a low level after the phototriode U12 is conducted, and at the moment, the host receives the low-level signal 0.

When each slave of the electrical equipment transmits the high level signal 1, the light emitting diode U11 does not emit light, and at this time, the master receives the high level signal 1.

The master-slave communication circuit comprises a master communication circuit and a plurality of slave communication circuits, wherein the master communication circuit is arranged on a master control board of a master side of the electrical equipment, and the slave communication circuits are arranged on a driving board of a slave side of the electrical equipment.

The applicant found that: in the current UART technology, a master-to-slave technology is designed, the current provided by a master chip is limited, and when a plurality of slaves are used, the master cannot provide enough current to cause communication failure.

Therefore, the applicant sets a power amplifying circuit at the transmitting end of the UART of the host communication circuit, and performs current amplifying processing on the signal output by the UART through the power amplifying circuit, so that the amplified current signal can drive the photoelectric coupler in each driving board, thereby realizing the communication between the host and the plurality of slaves in the electrical equipment.

In some embodiments of the present invention, the power amplifying circuit 13 of the embodiment of fig. 6 may be a secondary power amplifying circuit, a tertiary power amplifying circuit, or a higher level power amplifying circuit.

The number of stages of the power amplification circuit 13 can be determined according to the number of slaves. And determining the current magnitude according to the requirements of the number of the slaves, and further determining the current amplification factor and the corresponding power amplification circuit grade. And amplifying according to the circuit, wherein for the secondary power amplifying circuit, the maximum amplification factor of the current is the amplification factor product of two triodes.

FIG. 7 is a schematic diagram of a master-slave communication circuit according to still another embodiment of the present invention. In comparison with the embodiment of fig. 6, a specific structure of the two-stage power amplifying circuit is given in the embodiment of fig. 7.

As shown in fig. 7, the master communication circuit 10 may be connected to at least one slave communication circuit 20 by parallel lines 30.

As shown in fig. 7, the parallel lines 30 sequentially include a power line, a host signal transmission line (tx_bus), a host signal reception line, and a ground line from top to bottom.

The host signal transmitting interface is connected with the slave signal receiving interfaces of at least two slaves through the host signal transmitting wires in the parallel lines 30, and the host signal receiving interface is connected with the slave signal transmitting interfaces of at least two slaves through the host signal receiving wires in the parallel lines 30.

In some embodiments of the present invention, as shown in fig. 7, the secondary power amplifying circuit may include a first transistor Q1 and a second transistor Q2, wherein the first transistor Q1 is a PNP transistor and the second transistor Q2 is an NPN transistor.

Specific:

the emitter of the first triode Q1 is connected to the direct current power supply VCC, the base of the first triode Q1 is connected to the transmitting end TX of the UART of the main control board 1 through a thirteenth resistor R13, and meanwhile, the base of the first triode Q1 is connected to the direct current power supply VCC through an eleventh resistor R11.

The base of the second triode Q2 is connected to the collector of the first triode Q1 through a twelfth resistor R12, meanwhile, the base of the second triode Q2 is grounded through a ninth resistor R9, the emitter of the second triode Q2 is grounded, the collector of the second triode Q2 is connected to a direct current power supply VCC through a tenth resistor R10, meanwhile, the collector of the second triode Q2 is connected with the cathode of a voltage stabilizing diode ZD1, the anode of the voltage stabilizing diode ZD1 is grounded, and the collector of the second triode Q2 is the output end of the power amplifying circuit.

When the host of the electrical equipment sends a low-level signal 0, the output end TX of the UART of the main control board 1 drives the first triode Q1 to be conducted through the thirteenth resistor R13, at the moment, the current at the collector side of the first triode Q1 is amplified by alpha times, the amplified current drives the second triode Q2 to be conducted through the twelfth resistor R12, the current is secondarily amplified by the second triode Q2, the current flowing through the collector of the second triode Q2 is amplified by beta times, and the current flowing through the light emitter of the input photoelectric coupler U2 of each driving board is the amplified current. Thereafter, the light emitter in the input photo coupler U2 of each driving board emits light, and the light receiver of the input photo coupler U2 is driven to be turned on, so that the level of the first output terminal (collector of the photodiode U22) of the input photo coupler U2 is pulled to the low level, and at this time, the slave receives 0.

When the master of the electrical apparatus transmits 1, the power amplifying circuit 11 does not operate, and the light emitter of the input photocoupler U2 in the driving board of each slave does not emit light, and at this time, the slave receives 1.

In some embodiments of the present invention, the thirteenth resistor R13 and the twelfth resistor R12 may have a resistance of 5.1k ohms. The fifth resistor R5 at the transmitting end of the host drives the first triode Q1, at the moment, the current at the collector side is amplified by alpha times, the amplified current drives the common emitter second triode Q2 to carry out second-stage amplification through another 5.1K resistor (twelfth resistor R12), the current is amplified by beta times, and 485 communication effects can be equivalent when the amplified current is communicated within 8 meters, so that the multi-stage node communication requirement can be met.

In some embodiments of the present invention, the ninth resistor R9 may have a resistance of 5.1k ohms; the 10 th resistor R10 may have a resistance of 1k ohms.

In some embodiments of the present invention, the host communication circuit may further include a first capacitor C1, a second capacitor C2, and a fourth capacitor C4, which are configured as shown in fig. 7. Specific: the collector of the second triode Q2 is grounded through a first capacitor C1, the base of the second triode Q2 is grounded through a fourth capacitor C4, and the common end of the first resistor R1 and the second resistor R2 is grounded through a second capacitor C2. By further providing the first capacitor C1, the second capacitor C2, and the fourth capacitor C4 in the host communication circuit, system interference can be reduced.

In some embodiments of the present invention, the capacity of the fourth capacitor C4 may be 1nF.

In some embodiments of the present invention, as shown in fig. 7, the master communication circuit 10 may include a master communication interface 11 and the slave communication circuit 20 includes a slave communication interface 21. The master communication interface 11 is connected to the slave communication interfaces 21 of at least two slave communication circuits 20 via parallel lines 30.

According to the embodiment of the invention, the number of the slave communication circuits in the master-slave communication circuits can be conveniently expanded through the master communication interface and the slave communication interface.

The slave communication interface 21 and the host communication interface 11 may be implemented as a hub, the host communication circuit 10 and each slave communication circuit 20 may be connected by using the hub, and when a node needs to be added, for example, when a master control board is connected with more driving boards, the hub may be used to quickly implement expansion.

In some embodiments of the present invention, the host communication interface 11 comprises a host signal transmitting interface and a host signal receiving interface, and the slave communication interface 21 comprises a slave signal transmitting interface and a slave signal receiving interface, wherein the host signal transmitting interface is connected to the slave signal receiving interfaces of at least two slaves through the host signal transmitting lines in parallel lines 30, and the host signal receiving interface is connected to the slave signal transmitting interfaces of at least two slaves through the host signal receiving lines in parallel lines 30.

FIG. 8 is a schematic diagram of another embodiment of a master-slave communication circuit according to the present invention. The embodiment of fig. 8 differs from the embodiment of fig. 7 only in that: the optocoupler output conversion circuit of the slave side of the embodiment of fig. 7 is replaced by the optocoupler output conversion circuit of any of the embodiments of fig. 3-5.

As shown in fig. 7, the optocoupler output conversion circuit of the slave side may include an output photo-coupler U1 and a relay Q3, wherein the output photo-coupler U1 includes a light emitting diode U11 located in the primary loop and a phototransistor U12 located in the secondary loop.

The anode of the light-emitting diode U11 is connected with a power supply through a third resistor R3; the negative electrode of the light-emitting diode U11 is connected with the signal transmitting end of the slave; the collector of the phototransistor U12 is connected to a power supply, the emitter of the phototransistor U12 is connected to an input terminal of the relay Q3 (e.g., a base of the triode Q3) through a first resistor R1, and an output terminal of the relay Q3 (e.g., the collector of the triode Q3) is connected to the host signal receiving terminal RX through a slave communication interface 21.

In an actual circuit, as shown in fig. 8, a secondary side second resistor R2 similar to any of the embodiments of fig. 2-5 can be moved to a receiving end of a host side to prevent the resistor R2 from being connected in parallel when the circuit has a plurality of nodes, so as to change the overall slave sending resistance in the circuit.

The embodiment of fig. 8 combines any of the embodiments of fig. 2-5 with the embodiment of fig. 6 or 7, so that the embodiment of fig. 8 not only can realize multi-node UART communication as in the embodiment of fig. 6 or 7, but also can reduce the communication cost in the air conditioning industry; and the influence of the excessively high low level caused by the extreme temperature characteristic and the extreme current transmission ratio characteristic of the optocoupler element can be removed as in any one of the embodiments shown in fig. 2-5, and the host side chip can identify the high and low level under various conditions, so that the optocoupler is safe and reliable.

The embodiment of the invention provides a multi-node UART optocoupler isolation communication circuit, which is a multi-node UART communication circuit automatically adapting to optocouplers and can eliminate the influence of low level and high transmission ratio of the optocouplers. The embodiment of the invention can reduce the communication cost in the air conditioner industry. The embodiment of the invention can also improve the communication reliability, so that the high and low levels are at the normal level which can be identified by the chip, and the host side chip can identify the high and low levels under various conditions.

Fig. 9 is a schematic diagram of some embodiments of the electrical device of the present invention. As shown in fig. 9, the electrical device may include a master 1 and at least one slave 2, wherein:

the electrical equipment may be an air conditioner including a main control board and at least one compressor. The host 1 is a main control board, and the slave 2 can be a compressor.

The host 1 may include host communication circuitry 10 as described in any of the embodiments described above (e.g., any of the embodiments of fig. 2-8).

The slave 2 may comprise a slave communication circuit 20 as described in any of the embodiments described above (e.g. any of the embodiments of figures 2-8).

Based on the host, the slave and the electrical equipment provided by the embodiment of the invention, the multi-node UART communication can be realized, so that the communication cost of the electrical appliance industries such as air conditioner and the like is reduced. The embodiment of the invention can also eliminate the influence of high low level caused by the transmission bit property of the optical coupler, thereby improving the communication reliability, leading the high level and the low level to be at the normal level which can be identified by the chip, and leading the chip at the host side to be able to identify the high level and the low level under various conditions.

Fig. 10 is a schematic diagram of some embodiments of the electrical device of the present invention. As shown in fig. 10, the electrical device may include a master 1, at least one slave 2, and a master-slave communication circuit 3, wherein:

The master-slave communication circuit 3 may be a master-slave communication circuit as described in any of the embodiments described above (e.g. any of the embodiments of fig. 2-8).

Based on the electrical equipment provided by the embodiment of the invention, multi-node UART communication can be realized, so that the communication cost of the electrical equipment industries such as air conditioner and the like is reduced. The embodiment of the invention can also eliminate the influence of high low level caused by the transmission bit property of the optical coupler, thereby improving the communication reliability, leading the high level and the low level to be at the normal level which can be identified by the chip, and leading the chip at the host side to be able to identify the high level and the low level under various conditions.

FIG. 11 is a schematic diagram of a master-slave communication method according to some embodiments of the present invention. Preferably, the present embodiment may be implemented by the master-slave communication circuit according to any one of the embodiments of fig. 2-5 and 8. The method may include:

in step 111, in the slave communication circuit 20 according to any of the above embodiments (e.g., any of fig. 2-5 and 8), when the slave signal transmitting terminal outputs the low level signal, the second output terminal of the output optocoupler U1 has a current output.

In some embodiments of the present invention, where the output photo-coupler U1 includes a light emitting diode U11 and a phototransistor U12, the emitter of the phototransistor U12 is the second output of the output photo-coupler U1. When a low-level signal is output from the signal transmitting end of the slave machine, the phototriode U12 is conducted under the condition that the light emitting diode U11 is conducted, and the emitter of the phototriode U12 is provided with current output.

Step 112, outputting the current output from the second output terminal of the photo coupler U1 causes the input terminal of the relay Q3 to be powered.

In step 113, when the input terminal of the relay Q3 is powered on, the output terminal of the relay Q3 outputs a low level.

Based on the master-slave communication method provided by the embodiment of the invention, the low-level signal of the slave can be accurately identified under the condition of the optical coupler transmission bias limit or the environment temperature bias limit. Therefore, the embodiment of the invention solves the technical problems that the actual low level is higher than 0.8V and the chip cannot identify the low level to cause communication failure under the condition of the transmission bias limit or the ambient temperature bias limit of the optical coupler in the prior art.

In some embodiments of the present invention, the master-slave communication method may further include: in the host communication circuit 10 according to any one of the embodiments described above (for example, the embodiment of fig. 8), the host signal transmitting terminal TX transmits the host signal to the power amplifying circuit 13; the power amplifying circuit 13 performs current amplification on the host signal; the master communication interface 11 transmits the amplified master signal to the at least one slave 2.

Based on the master-slave communication method provided by the embodiment of the invention, the multi-node UART communication can be realized, so that the communication cost of the electric appliance industry such as an air conditioner and the like is reduced. The embodiment of the invention can also eliminate the influence of high low level caused by the transmission bit property of the optical coupler, thereby improving the communication reliability, leading the high level and the low level to be at the normal level which can be identified by the chip, and leading the chip at the host side to be able to identify the high level and the low level under various conditions.

FIG. 12 is a schematic diagram of another embodiment of a master-slave communication method according to the present invention. Preferably, this embodiment may be implemented by the master-slave communication circuit according to any of the embodiments of the present invention shown in fig. 6-8. The method may include:

step 121, in the host communication circuit 10 according to any of the above embodiments (e.g. any of fig. 6-8), the host signal transmitting terminal TX transmits the host signal to the power amplifying circuit 13;

step 122, the power amplifying circuit 13 performs current amplification on the host signal;

the master communication interface 11 transmits the amplified master signal to the at least one slave 2, step 123.

Based on the master-slave communication method provided by the embodiment of the invention, the influence of low level high caused by the transmission ratio characteristic of the optical coupler can be eliminated. The embodiment of the invention can reduce the communication cost in the air conditioner industry. The embodiment of the invention can also improve the communication reliability, so that the high and low levels are at the normal level which can be identified by the chip, and the host side chip can identify the high and low levels under various conditions.

The present invention has been described in detail so far. In order to avoid obscuring the concepts of the invention, some details known in the art have not been described. How to implement the solutions disclosed herein will be fully apparent to those skilled in the art from the above description.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and the storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. The slave communication circuit is characterized by comprising a slave universal asynchronous receiving and transmitting transmitter and an optical coupling output conversion circuit, wherein:

the optical coupler output conversion circuit comprises an output photoelectric coupler and a relay, wherein a first input end of the output photoelectric coupler is connected with a power supply, and a second input end of the output photoelectric coupler is connected with a slave signal transmitting end; the first output end of the output photoelectric coupler is connected with a power supply, the second output end of the output photoelectric coupler is connected with the input end of the relay, and the output end of the relay is connected with the host signal receiving end of the host communication circuit; the output photoelectric coupler comprises a light emitting diode positioned in a primary loop and a phototriode positioned in a secondary loop; the positive electrode of the light-emitting diode is a first input end of the output photoelectric coupler, and the negative electrode of the light-emitting diode is a second input end of the output photoelectric coupler; the collector electrode of the phototriode is a first output end of the output photoelectric coupler, and the emitter electrode of the phototriode is a second output end of the output photoelectric coupler;

the optocoupler output conversion circuit further comprises a first resistor and a second resistor, wherein the first resistor is arranged between the second output end of the output optocoupler and the input end of the relay in series, one end of the second resistor is connected with a power supply, and the other end of the second resistor is connected with the output end of the relay;

And under the condition that the transmission signal of the slave signal transmission end is in a low level, the output voltage of the relay output end is smaller than a preset value.

2. The slave communication circuit of claim 1, wherein the relay is a triode, the base of the triode is a relay input, the collector of the triode is a relay output, and the emitter of the triode is grounded.

3. The slave communication circuit of claim 1, wherein the relay comprises a relay coil, a relay movable contact, and a relay stationary contact, wherein:

or,

4. A master-slave communication circuit is characterized by comprising a master communication circuit and at least one slave communication circuit, wherein,

the slave communication circuit is a slave communication circuit according to any one of claims 1-3.

5. The master-slave communication circuit of claim 4, wherein,

the host communication circuit comprises a host communication interface which is connected with the slave communication interface of at least one slave communication circuit through parallel lines;

The host communication interface comprises a host signal transmitting interface and a host signal receiving interface, wherein the host signal transmitting interface is connected with the host signal transmitting end, and the host signal receiving interface is connected with the host signal receiving end;

6. The master-slave communication circuit of claim 4 or 5, wherein the host communication circuit comprises a host universal asynchronous receiver-transmitter and a power amplifier circuit, wherein:

7. A slave comprising a slave communication circuit as claimed in any one of claims 1 to 4.

8. An electrical device comprising a master and at least one slave, wherein the slave is a slave according to claim 7.

9. An electrical device comprising a master, at least one slave, and a master-slave communication circuit as claimed in any one of claims 4 to 6.

10. A master-slave communication method, comprising:

in the master-slave communication circuit according to any one of claims 4 to 6, in the case where the slave signal transmitting terminal outputs a low level signal, the second output terminal of the output photo coupler has a current output;

11. The master-slave communication method of claim 10, further comprising:

the host signal transmitting end transmits host signals to the power amplifying circuit;

the power amplifying circuit amplifies the current of the host signal;