CN218648812U - 2-wire mode transceiving communication circuit without independent working power supply - Google Patents

Abstract

The utility model discloses a 2 line mode receiving and dispatching communication circuit that need not independent power supply relates to the communication field, and this 2 line mode receiving and dispatching communication circuit that need not independent power supply includes: the host is used for carrying out information transmission with the extension; the extension sets are used for establishing communication with the host, and the number of the extension sets is multiple; the host computer includes: the constant current source module is used for supplying constant current sources to the extension sets; the pulse detection comparator module is used for receiving the information that the extension set changes the constant current source and sending the information to the sending and control module; the sending and controlling module is used for sending information to the extension set by changing the size of the constant current source; compared with the prior art, the beneficial effects of the utility model are that: the receiving and transmitting part of the extension of the utility model does not need a special chip and an independent working power supply, and only uses a photoelectric coupler to complete the receiving and transmitting task; when the extension set and the host machine receive and send out, the voltage provided by the host machine and 2 photoelectric couplers are utilized to complete the receiving and sending out, so that the isolation characteristic is achieved, the circuit is simple, and the cost is low.

Description

A 2-wire mode transceiver communication circuit without independent working power supply

technical field

The utility model relates to the communication field, in particular to a 2-wire mode transceiver communication circuit without an independent working power supply.

Background technique

RS485, the existing 2-wire mode for communication, is the standard of serial data interface. It was created to make up for the shortcomings of RS232 such as short communication distance and low speed. It is a standard formulated on the basis of RS422, adding multi-point and two-way communication. The ability to allow multiple transmitters to be connected to the same bus, it uses a pair of twisted pairs, is isolated by 3 photocouplers, and needs to provide an independent working power supply. In order to carry out RS485 communication in 2-wire mode, special chips such as MAX485E, MAX487E, MAX1487E, and SN75LBC184 are usually used for sending and receiving.

Using the RS485 standard, a relatively economical communication platform with high noise suppression and high transmission rate can be established, but when building a system with one host and N extensions for two-way communication, there is a need to use a dedicated chip in each extension to provide an independent working power supply , and three photocouplers are required for isolation, so the cost is high and the circuit is complicated, which needs to be improved.

Utility model content

The purpose of this utility model is to provide a 2-wire mode transceiver communication circuit that does not need an independent working power supply, so as to solve the problems raised in the above-mentioned background technology.

In order to achieve the above object, the utility model provides the following technical solutions:

A 2-wire mode transceiver communication circuit that does not require an independent working power supply, including:

The host is used for information transmission with the extension;

The extension is used to establish communication with the host, and there are multiple extensions;

Hosts include:

The constant current source module is used to supply the constant current source for the extension;

The pulse detection comparator module is used to receive the information that the extension changes the constant current source and send it to the sending and control module;

The sending and control module is used to send information to the extension by changing the size of the constant current source; and receive extension information;

The constant current source module is connected to the extension, the extension is connected to the pulse detection comparator module, the sending and control module, and the pulse detection comparator module is connected to the sending and control module.

As a further solution of the utility model: the constant current source module includes a resistor R1, a resistor R3, a transistor Q1, and a transistor Q2. One end of the resistor R1 is connected to a voltage of 15V and the emitter of the transistor Q1, and the other end of the resistor R1 is connected to the base of the transistor Q1. pole, the emitter of the transistor Q3, the collector of the transistor Q1 is connected to the base of the transistor Q3, one end of the resistor R3, the other end of the resistor R3 is grounded, and the collector of the transistor Q3 is connected to the extension.

As a further solution of the utility model: the pulse detection comparator module includes a resistor R2, a transistor Q2, and a resistor R4, the emitter of the transistor Q2 is connected to a 5V voltage, the base of the transistor Q2 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to In the extension, the collector of the triode Q2 is connected to one end of the resistor R4, the sending and control module, and the other end of the resistor R4 is grounded.

As a further solution of the utility model: the sending and control module includes single-chip microcomputer U1, MOS tube Q4, MOS tube Q6, triode Q5, resistor R5, resistor R6, resistor R7, and resistor R8. The S pole is connected to one end of the resistor R5, 15V voltage, the other end of the resistor R5 is connected to the G pole of the MOS transistor Q4, the collector of the triode Q5, the D pole of the MOS transistor Q4 is connected to the extension, the D pole of the MOS transistor Q6, and the collector of the MOS transistor Q6 The S pole is grounded through the resistor R8, the G pole of the MOS transistor Q6 is connected to the emitter of the transistor Q5, and the No. 2 pin of the microcontroller U1, and the base of the transistor Q5 is connected to one end of the resistor R6 and one end of the resistor R7, and the other end of the resistor R7 is grounded , the other end of the resistor R6 is connected to the No. 1 pin of the food grade U1, and the No. 3 pin of the single-chip microcomputer U1 is connected to the pulse detection comparator module.

As a further solution of the utility model: the extension includes resistor R9, diode D1, optocoupler PH1, optocoupler PH2, resistor R10, resistor R11, and one end of resistor R9 is connected to the constant current source module, pulse detection comparator module, sending and control Module, the third end of optocoupler PH1, the fourth end of optocoupler PH1, the second end of optocoupler PH2, the other end of resistor R9 is connected to the cathode of diode D1, the anode of diode D1 is connected to the first end of optocoupler PH1, The first end of the optocoupler PH2, the third end of the optocoupler PH2, the second end of the optocoupler PH1 are connected to the sending signal through the resistor R10, the fourth end of the optocoupler PH2 is connected to the receiving signal, one end of the resistor R11, and the other end of the resistor R11 One end is grounded.

Compared with the prior art, the utility model has the beneficial effects that: the transceiver part of the extension of the utility model does not need a dedicated chip and an independent working power supply, and only uses a photoelectric coupler to complete the task of sending and receiving; Voltage and 2 photocouplers are completed, so it has isolation characteristics, simple circuit and low cost.

Description of drawings

Figure 1 is a circuit diagram of a 2-wire mode transceiver communication circuit that does not require an independent power supply.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. For example, based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

Please refer to Figure 1, a 2-wire mode transceiver communication circuit that does not require an independent power supply, including:

The host is used for information transmission with the extension;

The extension is used to establish communication with the host, and there are multiple extensions;

Hosts include:

The constant current source module is used to supply the constant current source for the extension;

The pulse detection comparator module is used to receive the information that the extension changes the constant current source and send it to the sending and control module;

The sending and control module is used to send information to the extension by changing the size of the constant current source; and receive extension information;

The constant current source module is connected to the extension, the extension is connected to the pulse detection comparator module, the sending and control module, and the pulse detection comparator module is connected to the sending and control module.

In this embodiment: please refer to Figure 1, the constant current source module includes resistor R1, resistor R3, transistor Q1, and transistor Q2, one end of resistor R1 is connected to 15V voltage and the emitter of transistor Q1, and the other end of resistor R1 is connected to transistor Q1 The base of the transistor Q3, the emitter of the transistor Q3, the collector of the transistor Q1 is connected to the base of the transistor Q3, one end of the resistor R3, the other end of the resistor R3 is grounded, and the collector of the transistor Q3 is connected to the extension.

这个电流通过Q3的集电极提供给SL线供分机使用。Transistor Q3 is turned on to provide emitter current I ₃ , when the voltage drop generated by I ₃ on R1 U _R3 = I ₃ R ₃ ≥ 0.5V (0.5V is the conduction voltage of Q1), Q1 starts to conduct and limit Q3 BE junction voltage, therefore

This current is supplied to the SL line through the collector of Q3 for use by the extension.

In this embodiment: please refer to FIG. 1, the pulse detection comparator module includes a resistor R2, a transistor Q2, and a resistor R4, the emitter of the transistor Q2 is connected to a 5V voltage, the base of the transistor Q2 is connected to one end of the resistor R2, and the other end of the resistor R2 One end is connected to the extension, the collector of the transistor Q2 is connected to one end of the resistor R4, the sending and control module, and the other end of the resistor R4 is grounded.

When the extension sends a signal, the voltage of the SL line is controlled. When the voltage of the SL line is lower than 4.5V, the base of the transistor Q2 is supplied with current through the resistor R2, so the transistor Q2 is saturated and turned on, and a high level of 5V is generated at both ends of the resistor R4 to provide When the voltage of the SL line is higher than 4.5V, the triode Q2 is cut off, and a low level of 0V is generated at both ends of the resistor R4, which is supplied to the pin 3 of the microcontroller U1. The microcontroller U1 analyzes a series of high and low voltages. Get the information sent by the extension after Ping. The pulse detection comparator module outputs the information sent by the extension to the sending and control module.

In this embodiment: please refer to Fig. 1, the transmission and control module includes single-chip microcomputer U1, MOS tube Q4, MOS tube Q6, triode Q5, resistor R5, resistor R6, resistor R7, resistor R8, single-chip microcomputer U1 model is MK6A12P, MOS tube The S pole of Q4 is connected to one end of the resistor R5 and 15V voltage, the other end of the resistor R5 is connected to the G pole of the MOS transistor Q4, the collector of the triode Q5, the D pole of the MOS transistor Q4 is connected to the extension, the D pole of the MOS transistor Q6, and the MOS transistor The S pole of Q6 is grounded through the resistor R8, the G pole of the MOS transistor Q6 is connected to the emitter of the triode Q5, the No. One end is grounded, the other end of the resistor R6 is connected to the No. 1 pin of the food grade U1, and the No. 3 pin of the single-chip microcomputer U1 is connected to the pulse detection comparator module.

When the host sends information, the pin 1 of the single-chip microcomputer U1 outputs a high level of 5V, and after the voltage is divided by the resistor R6 and the resistor R7, a 2.5V voltage is provided at the base of the transistor Q5. The host sends a signal through the pin 2 of the single-chip microcomputer U1. When the high level is high, the transistor Q6 is turned on and the transistor Q5 is cut off. There is no voltage at both ends of the resistor R5, so the transistor Q4 is cut off, and the voltage of the SL line is low level 0V. There is a voltage of 5V at both ends of R5, so the triode Q4 is saturated and turned on, and the voltage of the SL line is high level 15V. After the host sends the information, in order to receive the information of the extension, the 1 pin and 2 pin of the single chip microcomputer U1 output low level, so the triode Q6, Q5, and Q4 are all cut off, the SL line is pulled up to 15V by a constant current source, and the function of the resistor R8 is to absorb the narrow pulse generated when the transistors Q4 and Q6 are turned on in turn.

In this embodiment: please refer to Figure 1, the extension includes resistor R9, diode D1, optocoupler PH1, optocoupler PH2, resistor R10, resistor R11, one end of resistor R9 is connected to the constant current source module, the pulse detection comparator module, the sending And the control module, the third end of optocoupler PH1, the fourth end of optocoupler PH1, the second end of optocoupler PH2, the other end of resistor R9 is connected to the cathode of diode D1, and the anode of diode D1 is connected to the first end of optocoupler PH1 end, the first end of optocoupler PH2, the third end of optocoupler PH2, the second end of optocoupler PH1 is connected to send signal through resistor R10, the fourth end of optocoupler PH2 is connected to receive signal, one end of resistor R11, resistor R11 The other end of the ground.

The SL line is pulled up to 15V by a constant current source. The receiving part of each extension is composed of a diode D1, a resistor R9, a resistor R11, and an optocoupler PH2 (the optocoupler includes a light-emitting diode and a phototransistor). The constant current source provides After the current I ₃ is shunted by the receiving part of the N extensions, U _SL1 = R ₉ I ₃ /N+U _D1 + _UD > 11V voltage drop (U _D = 1V is the diode voltage drop at the input of PH2, U _D1 = 10V is the voltage regulation value of the voltage regulator D1), because of the existence of D1, no matter how many extensions are connected in parallel, it always meets the condition of U _SL1 >11V , the sending part of the extension uses this voltage to send the information of the extension, so the extension does not need an independent power supply.

When the host sends information, the high-level voltage is 15V, which is much higher than 11V, so the current generated by the current-limiting resistor R9 makes the output terminal of the optocoupler PH2 saturated and turned on, and a high level is generated at both ends of the resistor R11 to provide the receiving terminal of the extension. , when the host sends a low voltage of 0V, it is far less than 11V, so the diode D1 and the optocoupler PH2 are cut off to generate a low level of 0V at both ends of the resistor R11, which is provided to the receiving end of the extension; the sending part of each extension is controlled by the resistor R10 , optocoupler PH1, each time the host sends information, it actively disconnects the triode Q4, Q6, and gives up the SL line to provide a voltage of US _SL >11V for the extension. The flow resistance R10 generates current, so the output terminal of the optocoupler PH1 is saturated and turned on, bypassing the current _I3 of the constant current source, and providing a low level of 0.5V on the SL line. When the extension sends a high level of 5V, the optocoupler PH1 The diode at the input end is cut off, so the output end of the optocoupler PH1 is also cut off, and a high level greater than 11V is provided on the SL line for the host to receive information.

The sending and receiving part of the extension does not need a special chip and an independent working power supply (powered by SL line), and only uses two optocouplers to complete the sending and receiving task, the circuit is simple and the cost is low.

The working principle of the utility model is: the host and the extension carry out information transmission, the extension and the host establish communication, there are multiple extensions, the host includes: a constant current source module supplies a constant current source for the extension; The information of the flow source is sent to the sending and control module; the sending and control module sends information to the extension by changing the size of the constant current source; and receives the information of the extension.

It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from all points of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, so it is intended to fall within the scope of the claims All changes within the meaning and range of equivalents of the required elements are included in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (5)

1. A2-wire mode transceiving communication circuit without an independent working power supply is characterized in that:

this 2 line mode receiving and dispatching communication circuit that need not independent operating power supply includes:

the host is used for carrying out information transmission with the extension;

the extension sets are used for establishing communication with the host, and the number of the extension sets is multiple;

the host computer includes:

the constant current source module is used for supplying constant current sources to the extension sets;

the pulse detection comparator module is used for receiving the information of the extension set changing the constant current source and sending the information to the sending and control module;

the sending and controlling module is used for sending information to the extension set by changing the size of the constant current source; and receiving extension information;

the constant current source module is connected with the extension, the extension is connected with the pulse detection comparator module and the sending and control module, and the pulse detection comparator module is connected with the sending and control module.

2. The 2-wire mode transceiving communication circuit without an independent operating power supply according to claim 1, wherein the constant current source module comprises a resistor R1, a resistor R3, a transistor Q1 and a transistor Q2, wherein one end of the resistor R1 is connected with a 15V voltage and an emitter of the transistor Q1, the other end of the resistor R1 is connected with a base of the transistor Q1 and an emitter of the transistor Q3, a collector of the transistor Q1 is connected with a base of the transistor Q3 and one end of the resistor R3, the other end of the resistor R3 is grounded, and the collector of the transistor Q3 is connected with an extension set.

3. The 2-wire mode transceiving communication circuit without an independent operating power supply of claim 1, wherein the pulse detection comparator module comprises a resistor R2, a transistor Q2 and a resistor R4, wherein an emitter of the transistor Q2 is connected with a voltage of 5V, a base of the transistor Q2 is connected with one end of the resistor R2, the other end of the resistor R2 is connected with the extension, a collector of the transistor Q2 is connected with one end of the resistor R4 and the transmission and control module, and the other end of the resistor R4 is grounded.

4. The 2-wire mode transceiving communication circuit without an independent operating power supply according to claim 1, wherein the transmitting and controlling module comprises a single chip microcomputer U1, an MOS transistor Q4, an MOS transistor Q6, a triode Q5, a resistor R6, a resistor R7 and a resistor R8, the model of the single chip microcomputer U1 is MK6A12P, the S pole of the MOS transistor Q4 is connected with one end of the resistor R5 and 15V voltage, the other end of the resistor R5 is connected with the G pole of the MOS transistor Q4 and the collector of the triode Q5, the D pole of the MOS transistor Q4 is connected with the extension and the D pole of the MOS transistor Q6, the S pole of the MOS transistor Q6 is grounded through the resistor R8, the G pole of the MOS transistor Q6 is connected with the emitter of the triode Q5 and the No. 2 pin of the single chip microcomputer U1, the base of the triode Q5 is connected with one end of the resistor R6 and one end of the resistor R7, the other end of the resistor R7 is grounded, the other end of the resistor R6 is connected with the No. 1 pin of the food-grade U1, and the No. 3 pin of the single chip microcomputer U1 is connected with the pulse detection comparator module.

5. The 2-wire mode transceiving communication circuit without an independent working power supply according to any one of claims 1 to 4, wherein the extension comprises a resistor R9, a diode D1, an optical coupler PH2, a resistor R10 and a resistor R11, a constant current source module is connected to one end of the resistor R9, a pulse detection comparator module, a sending and control module, a third end of the optical coupler PH1, a fourth end of the optical coupler PH1 and a second end of the optical coupler PH2, the other end of the resistor R9 is connected with a negative electrode of the diode D1, a first end of the optical coupler PH1 is connected to a positive electrode of the diode D1, a first end of the optical coupler PH2 and a third end of the optical coupler PH2, the second end of the optical coupler PH1 is connected with a sending signal through the resistor R10, a fourth end of the optical coupler PH2 is connected with a receiving signal, one end of the resistor R11, and the other end of the resistor R11 is grounded.

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