CN221125242U

CN221125242U - Circuit for realizing high-speed communication by two optocouplers

Info

Publication number: CN221125242U
Application number: CN202322594413.4U
Authority: CN
Inventors: 胡新强; 张君杰
Original assignee: Zhejiang Donghong Electronics Co ltd
Current assignee: Zhejiang Donghong Electronics Co ltd
Priority date: 2023-09-22
Filing date: 2023-09-22
Publication date: 2024-06-11
Anticipated expiration: 2033-09-22

Abstract

The utility model discloses a circuit for realizing high-speed communication by two optocouplers, which comprises a communication module, a first optocoupler module and a second optocoupler module, wherein the first optocoupler module and the second optocoupler module are respectively and electrically connected with the communication module, the communication module comprises a communication chip U5, the first optocoupler module comprises an optocoupler E5, the second optocoupler module comprises an optocoupler E6, a pin 1 of the communication chip U5 is electrically connected with a base electrode of a triode Q1 through a resistor RX2, a resistor RX1 is connected between an emitter and the base electrode of the triode Q1, and an emitter of the triode Q1 is electrically connected with a pin 3 of the optocoupler E5. The utility model discloses a circuit for realizing high-speed communication by two optical couplers, which realizes high-speed communication by isolating TTL signals by 2 high-speed optical couplers; and the volume occupation is small, the method is suitable for small-volume ammeter, the signal waveform is stable, and the frame loss rate is low.

Description

Circuit for realizing high-speed communication by two optocouplers

Technical Field

The utility model belongs to the technical field of ammeter communication, and particularly relates to a circuit for realizing high-speed communication by two optocouplers.

Background

In the RS485 communication circuit of the intelligent ammeter, a two-optocoupler scheme and a three-optocoupler scheme are used for isolating an RS485 chip from an MCU. The three optocouplers are 2 optocouplers 817 and 1 optocoupler 816 or three 816 optocouplers, the upper limit of the RS485 communication baud rate is 19200bps, the communication waveform of the higher baud rate becomes unstable, and the frame loss frequency is increased.

Most communication circuits of two optocouplers are simple in circuit, and although communication can be realized, the baud rate is generally limited below 9600bps, but the signal waveform is not stable enough, long-distance communication is easy to be interfered, and long-distance communication with a 1km communication line length cannot be met.

The NPN transistor in the optical coupler shortens the time of entering the saturation region along with the increase of the baud rate, so that the signal waveform is distorted, and then the communication is interrupted. In addition, the NPN transistor is affected by high temperature, the current from the collector to the emitter in the high temperature environment is reduced compared with the current at normal temperature, and the signal cannot reach the due level, so that the communication is interrupted.

Accordingly, the above problems are further improved.

Disclosure of utility model

The utility model mainly aims to provide a circuit for realizing high-speed communication by two optical couplers, which realizes high-speed communication by isolating TTL signals by 2 high-speed optical couplers; and the volume occupation is small, the method is suitable for small-volume ammeter, the signal waveform is stable, and the frame loss rate is low.

In order to achieve the above objective, the present utility model provides a circuit for implementing high-speed communication by two optocouplers, which includes a communication module, a first optocoupler module and a second optocoupler module, wherein the first optocoupler module and the second optocoupler module are electrically connected with the communication module respectively, and the circuit comprises:

The communication module comprises a communication chip U5, the first optical coupler module comprises an optical coupler E5, and the second optical coupler module comprises an optical coupler E6, wherein:

The communication chip U5 is characterized in that a 1 pin is electrically connected with a base electrode of a triode Q1 through a resistor RX2, a resistor RX1 is connected between an emitter electrode and the base electrode of the triode Q1, the emitter electrode of the triode Q1 is electrically connected with a 3 pin of an optocoupler E5, a6 pin of the optocoupler E5 is connected with a first power supply end (3.3V), a capacitor CU5 is connected between a6 pin and a 4 pin of the optocoupler E5, two ends of the capacitor CU5 are connected with a resistor RU6 and a capacitor CU6 in series in parallel, and a 5 pin of the optocoupler E5 is connected with a common connection end of the resistor RU6 and the capacitor 6 and is also connected with a connection end RXD;

The base of the triode Q2 is electrically connected with the emitter of the triode Q3, the base of the triode Q2 is electrically connected with the collector of the triode Q4, the base of the triode Q4 is electrically connected with the emitter of the triode Q4, a resistor RS10 is connected between the base of the triode Q4 and the emitter of the triode Q4, the base of the triode Q4 is electrically connected with the 4 pin of the optocoupler E6 through a resistor RS8, the 1 pin of the optocoupler E6 is connected with a first power supply end through a resistor RU7, the 3 pin of the optocoupler E6 is electrically connected with the emitter of the triode Q3, a resistor RX4 is connected between the base of the triode Q3 and the emitter of the triode Q3, and the base of the triode Q3 is connected with a connecting end TXD through a resistor RX 3.

As a further preferable technical solution of the foregoing technical solution, a diode T4 is connected between the 6 pin and the 7 pin of the communication chip U5, a first end of the diode T4 is grounded through the diode T5, and a second end of the diode T4 is grounded through the diode T6, and the first end of the diode T4 is electrically connected with the 3 pin of the common-mode inductor T3 and the second end of the diode T4 is electrically connected with the 2 pin of the common-mode inductor T3.

As a further preferable technical solution of the above technical solution, the 6 pin and the 8 pin of the communication chip U5 are connected with a resistor RSA and the 7 pin and the 5 pin of the communication chip U5 are connected with a resistor RSB.

As a further preferable technical solution of the foregoing technical solution, the 1 pin of the optocoupler E5 is connected to the second power supply terminal (t+5) through a resistor RU5 and the 6 pin of the optocoupler E6 is connected to the second power supply terminal (t+5).

As a further preferable embodiment of the foregoing embodiment, the collector of the transistor Q2 is grounded through a resistor R112.

Drawings

Fig. 1 is a circuit diagram of a circuit for implementing high-speed communication by two optocouplers according to the present utility model.

Detailed Description

The following description is presented to enable one of ordinary skill in the art to make and use the utility model. The preferred embodiments in the following description are by way of example only and other obvious variations will occur to those skilled in the art. The basic principles of the utility model defined in the following description may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the utility model.

The utility model discloses a circuit for realizing high-speed communication by two optocouplers, and the specific embodiments of the utility model are further described below with reference to the preferred embodiments.

In the embodiments of the present utility model, it is noted by those skilled in the art that the electricity meter and the like to which the present utility model relates can be regarded as the prior art.

Preferred embodiments.

The utility model discloses a circuit for realizing high-speed communication by two optocouplers, which comprises a communication module, a first optocoupler module and a second optocoupler module, wherein the first optocoupler module and the second optocoupler module are respectively and electrically connected with the communication module, and the circuit comprises:

Specifically, a diode T4 is connected between the 6 pin and the 7 pin of the communication chip U5, a first end of the diode T4 is grounded through the diode T5, a second end of the diode T4 is grounded through the diode T6, the first end of the diode T4 is electrically connected with the 3 pin of the common-mode inductor T3, and a second end of the diode T4 is electrically connected with the 2 pin of the common-mode inductor T3.

More specifically, the resistor RSA is connected between the 6 pin and the 8 pin of the communication chip U5 and the resistor RSB is connected between the 7 pin and the 5 pin of the communication chip U5.

Further, the 1 pin of the optocoupler E5 is connected to the second power supply terminal (t+5) through a resistor RU5, and the 6 pin of the optocoupler E6 is connected to the second power supply terminal (t+5).

Further, the collector of the triode Q2 is grounded through a resistor R112.

For the present utility model:

The utility model uses QXW511 high-speed optocoupler to replace conventional optocoupler, the RS485 chip uses BL3085, and 3 TVS tubes are output from the AB port of the chip for protecting the chip, so that abnormal high-voltage channeling is prevented. Common mode inductance at the output end filters common mode electromagnetic interference.

The receiving and transmitting control pin of the BL3085 chip is pulled down by default, and the chip is always in a receiving state. The chip receives the information and outputs the waveform by 1 foot. The IO port driving capability of the chip is weak, the on-off of the optocoupler is affected, and the PNP triode Q1 is added here to improve the current of the transmitting end. The optocoupler output RXD has a resistor pull-up, defaulting to a high level. When the output of the pin 1 of the chip is low level, the Q1 triode is conducted, the light coupler LED is lighted, the photodiode in the light coupler works under the reverse bias condition, after receiving illumination, current flows from the anode to the cathode, the NPN transistor is conducted, and RXD becomes low level. When the pin 1 of the chip outputs high level, the Q1 triode is closed, the optocoupler does not work, and RXD outputs high level due to the pull-up resistor. The level of RXD and chip 1 pins are kept consistent.

The transmitting end, the receiving end circuit and the optical coupler E5 of the optical coupler E6 are the same, so that the 5-pin output level of the optical coupler E6 is consistent with the TXD level of the MCU.

When TXD is high level, the NPN transistor in the optocoupler is not conducted, the NPN triode Q4 is not conducted, and the chip 4 is high level. PNP transistor Q2 is not on and chip 2 and 3 are low. By looking up the BL3085 chip driver truth table, the chip AB output is in a high-resistance state, and the A output is high level and the B output is low level because the A has a pull-up resistor and the B has a pull-down resistor.

When TXD is low level, an NPN transistor in the optocoupler is conducted, an NPN triode Q4 is conducted, and a chip 4 pin is low level. PNP triode Q2 is on, chip 2 and 3 pin high level. By looking up the BL3085 chip driver truth table, A outputs a low level and B outputs a high level.

Compared with a three-optical coupling circuit, the process of receiving information is not different. When the more than 1 optocouplers work to send information, the pins 2 and 3 of the chip are pulled up all the time, so that the BL3085 chip is always in a sending state. By looking up the BL3085 chip driver truth table, pins 2 and 3 of the chip are always high, pin 4 is high when TXD is high, A outputs high, and B outputs low. When TXD is high, the 4 pin is high, A outputs low, and B outputs high.

In the circuit, the level relation between TXD and A and B is the same as that of a three-optical-coupler circuit, so that the same communication function is realized.

The utility model has the beneficial effects that:

1. The circuit uses a high-speed optocoupler to replace a conventional optocoupler, the switching time of the transistor is reduced from 4-18 us to 0.15-0.8 us, and 115200bps baud rate communication can be realized.

2. And a triode is added at the output end of the TXD optocoupler, the conduction voltage of the triode is low, and the phenomenon that the saturation time of an NPN transistor in the optocoupler is shortened to cause signal waveform distortion due to a high-temperature environment and a high baud rate can be relieved.

3. The signal waveform is stable, the environment of-40-85 ℃ can be satisfied through the test, 1200 bps-115200 bps is added, the communication test of a 1km communication line is added, and the frame loss rate is less than one ten thousandth.

It should be noted that technical features such as an ammeter related to the present application should be regarded as the prior art, and specific structures, working principles, and control modes and spatial arrangement modes possibly related to the technical features should be selected conventionally in the art, and should not be regarded as the utility model point of the present application, and the present application is not further specifically developed in detail.

Modifications of the embodiments described above, or equivalents of some of the features may be made by those skilled in the art, and any modifications, equivalents, improvements or etc. within the spirit and principles of the present utility model are intended to be included within the scope of the present utility model.

Claims

1. The circuit for realizing high-speed communication by two optocouplers is characterized by comprising a communication module, a first optocoupler module and a second optocoupler module, wherein the first optocoupler module and the second optocoupler module are respectively and electrically connected with the communication module, and the circuit comprises a first optocoupler and a second optocoupler, wherein the first optocoupler is electrically connected with the second optocoupler, the second optocoupler is electrically connected with the first optocoupler, the second optocoupler is electrically connected with the second optocoupler, and the first optocoupler is electrically connected with the second optocoupler, and the second optocoupler is electrically connected with the communication module.

The communication chip U5 is characterized in that a1 pin is electrically connected with a base electrode of a triode Q1 through a resistor RX2, a resistor RX1 is connected between an emitter electrode and the base electrode of the triode Q1, the emitter electrode of the triode Q1 is electrically connected with a 3 pin of an optocoupler E5, a6 pin of the optocoupler E5 is connected with a first power supply end, a capacitor CU5 is connected between the 6 pin and the 4 pin of the optocoupler E5, two ends of the capacitor CU5 are connected with a resistor RU6 and a capacitor CU6 in parallel in series, and a 5 pin of the optocoupler E5 is connected with a common connection end of the resistor RU6 and the capacitor CU6 and is also connected with a connection end RXD;

2. The circuit for implementing high-speed communication by two optocouplers according to claim 1, wherein a diode T4 is connected between the 6 pin and the 7 pin of the communication chip U5, a first end of the diode T4 is grounded by the diode T5 and a second end of the diode T4 is grounded by the diode T6, the first end of the diode T4 is electrically connected with the 3 pin of the common-mode inductor T3 and the second end of the diode T4 is electrically connected with the 2 pin of the common-mode inductor T3.

3. The circuit for realizing high-speed communication by using the two optocouplers according to claim 2, wherein the resistor RSA is connected between the 6 pin and the 8 pin of the communication chip U5 and the resistor RSB is connected between the 7 pin and the 5 pin of the communication chip U5.

4. A circuit for implementing high-speed communication by two optocouplers according to claim 3, wherein the 1 pin of the optocoupler E5 is connected to the second power supply terminal through a resistor RU5 and the 6 pin of the optocoupler E6 is connected to the second power supply terminal.

5. The circuit for implementing high-speed communication according to claim 4, wherein the collector of the triode Q2 is grounded through a resistor R112.