Near-infrared communication circuit based on 5V system

Abstract

The utility model relates to a near-infrared communication circuit based on a 5V system. The near-infrared communication circuit comprises an infrared transmitting tube DI1, an infrared receiving tube DI2, triodes QI1 and QI3, a triode QI2, and resistors RI1, RI2, RI3, RI4, RI5, RI6 and RI7. One end of the resistor RI5 is connected with a signal end of the InfraredTXD chip, and the other end of the resistor RI5 is connected with a base electrode of the PNP triode QI2; the emitter electrode of the triode QI2 is connected with the LDO33, the collector electrode of the triode QI2 is connected with one end of the resistor RI3, one end of the resistor RI3 is grounded GND, the collector electrode of the triode QI2 is further connected with one end of the resistor RI6, and the other end of the resistor RI6 is connected with the base electrode of the triode QI3. The device is reasonable in design, compact in structure and convenient to use.

Description

Technical Field

[0001] The utility model relates to a near infrared communication circuit based on a 5V system. Background Art

[0002] In the process of developing and designing smart meters, the near-infrared communication function has been widely used in various markets overseas and domestically. The currently widely used near-infrared system power supply is 3.3V, which cannot meet the situation where the system power supply is 5V. Therefore, in order to meet the near-infrared communication of the 5V system power supply, it is necessary to improve and innovate the currently widely used near-infrared circuit to meet the needs of smart meters in overseas markets.

[0003] Near infrared communication circuit before improvement (attached Figure 1 ) is introduced as follows: The circuit consists of an infrared transmitting part and an infrared receiving part. When the control signal Infrared_TXD at the transmitting end is high, the transistor QI3 is not conducting, and the infrared transmitting tube will not send infrared signals. When the Infrared_TXD control signal is low, the transistor QI3 is turned on, the infrared transmitting tube sends infrared signals, and the infrared receiving tube DI4 receives infrared signals. The base of the transistor QI4 is low, and the transistor QI4 is turned on to output a high level, so Infrared_RXD is a high level signal. At this time, the near-infrared communication result is successful.

[0004] However, the current common near-infrared communication circuit has the following disadvantages: 1. It cannot meet the infrared communication requirements when the system power supply is 5V; 2. The communication rate is relatively low, and the communication will be interrupted when encountering obstacles; 3. Applying the current infrared communication circuit with a 3V system power supply to a 5V system power supply may cause interference to the MCU system and damage the chip. Utility Model Content

[0005] The technical problem to be solved by the utility model is generally to provide a near-infrared communication circuit based on a 5V system.

[0006] In order to solve the above problems, the technical solution adopted by the utility model is:

[0007] In the design of smart meters, the near-infrared communication circuit is suitable for a 5V power supply system, which can ensure the power consumption during power outages and the normal operation of the single-chip microcomputer. The system power supply for smart meters is 5V near-infrared communication, which has strong anti-interference ability, fast communication rate, and can be used for a variety of baud rates, 300-9600bps; it is safe and reliable, easy to use; the circuit is simple, the cost is low, the sensitivity is high, and it has strong adaptability and practicality.

[0008] The utility model has the advantages of reasonable design, low cost, firmness and durability, safety and reliability, simple operation, time-saving, labor-saving, money-saving, compact structure and convenient use. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram before improvement of the utility model.

[0010] Figure 2 It is a schematic diagram after improvement of the utility model.

[0011] Figure 3 It is a schematic diagram of a near-infrared 5V power supply system of the utility model.

[0012] Figure 4 It is a communication flow chart of the utility model.

[0013] Figure 5 This is a near infrared communication principle diagram of the utility model.

[0014] Among them: Figure 2 Among them, DI1 is an infrared transmitting tube with a forward conduction voltage of 1.4V; DI2 is an infrared receiving tube with a forward conduction voltage of 1.2V; QI1 and QI3 are NPN transistors; QI2 is a PNP transistor; RI1 and RI4 are chip resistors with a resistance of 100Ω; RI2, RI3, and RI7 are chip resistors with a resistance of 10KΩ; RI5 is a chip resistor with a resistance of 1KΩ; RI6 is a chip resistor with a resistance of 5.1KΩ;

[0015] exist Figure 3 Among them, CN4 and CN5 are chip ceramic resistors with a capacitance of 4.7uF and a voltage of 25V; UV1 is an LDO power chip with an output voltage of 5.3V; DN10 and DN11 are rectifier diodes with a forward conduction voltage of 1.1V. DETAILED DESCRIPTION

[0016] like Figure 1-5 As shown, the near-infrared communication circuit based on the 5V system of this embodiment, the 5V system near-infrared communication circuit (attached Figure 2) includes an infrared transmitting tube DI1, an infrared receiving tube DI2, NPN transistors QI1, QI3, PNP transistor QI2, and resistors RI1, RI2, RI3, RI4, RI5, RI6, and RI7. The signal end of the Infrared_TXD chip is connected to one end of the resistor RI5, and the other end of the resistor RI5 is connected to the base of the PNP transistor QI2. The emitter of the transistor QI2 is connected to LDO33, and the collector of the transistor QI2 is connected to one end of the resistor RI3. One end of the resistor RI3 is grounded GND, and the collector of the transistor QI2 is also connected to one end of the resistor RI6. The other end of the resistor RI6 is connected to the base of the transistor QI3. The emitter of the transistor QI3 contacts GND, and the collector is connected to one end of the resistor RI4. The other end of the resistor RI4 is connected to the negative electrode of the infrared transmitting tube DI1, and the positive electrode of the infrared transmitting tube is connected to VCC_5V. The cathode of the infrared receiving tube DI2 is connected to LDO33, the anode of the infrared transmitting tube is connected to one end of the resistor RI1, the other end of the resistor RI1 is connected to the base of the transistor QI1, one end of the resistor RI2 is also connected to the base of the transistor QI1, the other end of the resistor RI2 is grounded DND, the emitter of the transistor QI1 is connected to GND, the collector of the transistor QI1 is connected to one end of the resistor RI7, the other end of the resistor RI7 is connected to LDO33, and the control signal terminal Infrared_RXD is connected to the collector of the transistor QI1.

[0017] Near infrared 5V power supply system (attached Figure 3 ) includes capacitors CN4, CN5, LDO power chip UV1, rectifier diodes DN10, DN11. The MHVDD power supply passes through the filter capacitor CN4 and then enters the input end of the LDO power chip UV1. Then the LDO power chip UV1 outputs a voltage value of 5.3V. The output voltage value of 5.3V passes through the filter capacitor CN5, and then the 5.3V power supply is supplied through the diode DN10.

[0018] When in static state, the infrared receiving tube DI2 has no infrared signal (or only a very weak infrared signal), the infrared receiving tube is in reverse cut-off state, the base of the transistor QI1 is low level, the transistor is cut off, and the infrared receiving port Infrared_RXD is pulled up to high level by the resistor RI7. When the host computer issues an instruction, the infrared tube of the host computer sends an infrared signal, the receiving tube DI2 ends the optical signal to the transmitting tube of the host computer and converts it into an electrical signal, at this time the light emitting tube is no longer in reverse cut-off state, the base-emitter voltage difference of the transistor QI1 is greater than 0.7V, the transistor is turned on, the turned-on Infrared RXD is grounded to a low level, and the data transmission is completed. After the information is processed by the MCU, the MCU's sending pin Infrared TXD sends a square wave signal composed of high and low levels of the baud rate set by the program. The square wave signal controls the transistor QI2 to switch on and off continuously. When TXD sends a low level, QI2 is turned on, and the resistor RI6 and the collector potential point of QI2 are high. The transistor QI3 on ​​the other side is turned on, and the infrared transmitting tube is turned on to generate an infrared signal that changes with the current. When TXD sends a high level, the PNP transistor QI2 is turned off, both ends of the resistor RI6 are low, the transistor QI3 is turned off, there is no voltage drop on the infrared transmitting tube, no current flows (or a very small current signal), and no infrared signal is generated. Communication with the host computer can be completed by using the receiving circuit and the transmitting circuit in conjunction.

[0019] The present invention is fully described for a clearer disclosure, and the prior art will not be listed one by one.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it; although the utility model is described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein with equivalents; it is obvious for those skilled in the art to combine multiple technical solutions of the utility model. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

Claims

1. A near infrared communication circuit based on a 5V system, characterized in that: Including infrared transmitting tube DI1, infrared receiving tube DI2, transistors QI1, QI3, transistor QI2, resistors RI1, RI2, RI3, RI4, RI5, RI6, RI7; One end of the resistor RI5 is connected to the Infrared_TXD chip signal end, and the other end of the resistor RI5 is connected to the base of the PNP transistor QI2; the emitter of the transistor QI2 is connected to LDO33, the collector of the transistor QI2 is connected to one end of the resistor RI3, one end of the resistor RI3 is grounded GND, the collector of the transistor QI2 is also connected to one end of the resistor RI6, and the other end of the resistor RI6 is connected to the base of the transistor QI3; The emitter contact GND and collector of the transistor QI3 are connected to one end of the resistor RI4, the other end of the resistor RI4 is connected to the negative electrode of the infrared emitting tube DI1, and the positive electrode of the infrared emitting tube DI1 is connected to VCC_5V; The cathode of the infrared receiving tube DI2 is connected to LDO33, the anode of the infrared receiving tube DI2 is connected to one end of the resistor RI1, the other end of the resistor RI1 is connected to the base of the triode QI1, one end of the resistor RI2 is connected to the base of the triode QI1, and the other end of the resistor RI2 is grounded DND; The emitter of the transistor QI1 is connected to GND, the collector of the transistor QI1 is connected to one end of the resistor RI7, the other end of the resistor RI7 is connected to LDO33, and the control signal terminal Infrared_RXD is connected to the collector of the transistor QI1.

2. A near infrared communication system based on a 5V system, characterized in that: Includes the near-infrared communication circuit described in claim 1.

3. The near infrared communication system based on the 5V system according to claim 2, characterized in that: The near infrared communication circuit is electrically connected to a 5V power supply system.

4. The near-infrared communication circuit based on the 5V system according to claim 3, characterized in that: The 5V power supply system includes filter capacitors CN4 and CN5, LDO power chip UV1, and rectifier diodes DN10 and DN11; The MHVDD power supply is electrically connected to the input end of the LDO power chip UV1 through one end of the filter capacitor CN4; the output end of the LDO power chip UV1 is supplied to the communication circuit after passing through the filter capacitor CN5 and the diode DN10.

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