An infrared transceiver system based on a single infrared diode

Abstract

The invention discloses an infrared transceiver system based on a single infrared diode. The invention comprises an infrared transmitting circuit, an infrared receiving circuit and a digital controller. The infrared transmitting circuit comprises a data buffer with an enable function, an NMOS tube and an infrared light emitting diode. The infrared receiving circuit comprises a current detection circuit, a detection circuit, a hysteresis comparator and an auxiliary circuit. The current detection circuit comprises two amplifiers and a feedback circuit. The detection circuit comprises a shaping circuit, a delay circuit, a switching circuit, a current source and a filter capacitor. The input end of the digital controller comprises a command input end, a clock input end and a signal receiving end, and the output end comprises a signal output end, a transmitting enable end and a receiving enable end. The invention adopts a single infrared tube to realize transceiver, the receiving circuit has a simple structure and a low input impedance, and the ability to receive current is enhanced, and the output impedance RD can be configured according to the size of the current signal received by the infrared diode, so that the circuit has a larger working range.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated circuits, in particular to the field of infrared remote control communication, and relates to an infrared transceiver system based on a single infrared diode. Background Art

[0002] Infra-Red (IR) optical communication is a wireless data communication technology that uses infrared light and is widely used in the fields of home appliance remote control, audio communication, and industrial production testing. This technology uses a typical Universal Asynchronous Receiver / Transmitter (UART) to exchange bidirectional data at a rate of 9.6k-115.2kbit / s, and some high-speed expansion ports can reach a speed of 1Mb / s to 4Mb / s.

[0003] Infrared light is an electromagnetic wave with a wavelength between 750nm and 1mm. The common wavelengths are 850nm, 880nm and 940nm. In terms of power: 850nm>880nm>940nm; in terms of price: 850nm>880nm>940nm. 850nm and 940nm are more commonly used in the market. 850nm has high emission power and a long irradiation distance, so it is mainly used in infrared monitoring equipment; while 940nm is mainly used in infrared remote controls for home appliances.

[0004] The infrared remote control system includes a transmitting circuit and a receiving circuit. Figure 1 , the infrared light-emitting diode D1 of the transmitting circuit works in the forward conduction area, that is, the positive terminal voltage of the diode PN junction is greater than the negative terminal voltage. The 38kHz pulse width modulation voltage signal is amplified by the power amplifier Q1 to generate a corresponding 38kHz current signal, driving D1 to emit 38kHz infrared light. Figure 2 , the infrared photodiode D2 in the receiving circuit works in the reverse bias region, that is, the positive voltage of the diode PN junction is less than the negative voltage. Within a certain distance range, when D2 senses the infrared light signal emitted by D1, it will generate a corresponding current signal. The transimpedance amplifier A in the receiving circuit can amplify the signal and output a voltage signal. After amplification, filtering and voltage comparison, the signal emitted by D1 can be restored, realizing infrared light communication.

[0005] With the development of technology, people need to control multiple appliances such as TVs, air conditioners, smart speakers, etc. with one remote control. However, different appliance manufacturers use different "passwords" for infrared remote control. Remote controls with reconfigurable and infrared learning functions have emerged. This infrared learning remote control can be used as a universal remote control. It can also actively receive the "passwords" emitted by other infrared transmitters, store the "passwords" in the circuit after decoding, learning, etc., and then load the "passwords" to the transmitter of the remote control to control the appliance.

[0006] There are several infrared learning remote control solutions in the prior art: first, a dedicated integrated infrared receiving tube is used, which is simple, convenient and easy to develop, but the cost is high and the power consumption is difficult to control; second, a single infrared diode is used to realize the transmitting and receiving functions, the transmitting circuit chip is connected to an external power tube, and the receiving circuit uses an off-chip discrete transistor to realize the amplification, detection and voltage comparison of the current signal; third, two or more general input and output interfaces (Input, Output, I / O) and discrete components are used.

[0007] The invention patent with the patent number of 201510145361.X discloses a CMOS infrared detector readout circuit with pixel-by-pixel dark current suppression, which includes three parts: input circuit, integration circuit, and output circuit. The input circuit adopts a structure combining a current storage unit and a current mirror. Among them, the current storage unit is distributed in each pixel of the linear circuit, and is composed of a transmission gate, a virtual switch pair, and a capacitive coupling loop, which can realize customized modulation of dark current; the current mirror is arranged at the left and right ends of the linear circuit, which can realize overall suppression of dark current.

[0008] The invention patent application with application number 201910616760.8 discloses a new type of CMOS infrared transceiver. The CMOS infrared transceiver includes an IR transmitter circuit, an IR receiver circuit and an IR diode configured to transmit or receive IR signals. CMOS elements used in CMOS infrared transceivers, such as PMOS current mirrors, PMOS switches, NMOS switches, NMOS current mirrors and receiver-enabled PMOSFET switches. The main circuit includes a current detection circuit composed of an operational amplifier, a resistor and a switch, a proportional amplifier circuit formed by an operational amplifier and resistor feedback, and a voltage comparator circuit. The advantage of this circuit is that, except for the use of an external infrared diode, all devices can be integrated on a CMOS process. The disadvantage is that the output of the comparator is at the same frequency as the carrier signal, and the circuit has a weak anti-interference ability.

[0009] US Patent [US 6,330,091 B1], IR RECEIVER USING IR TRANSMITTING DIODE discloses an infrared remote control receiving circuit using an infrared emitting diode as a receiving diode. The circuit uses transistors PNP and NPN to process the signal. This circuit is not suitable for integrated circuits using CMOS technology. Summary of the invention

[0010] The purpose of the present invention is to provide an infrared transceiver system based on a single infrared diode.

[0011] The invention comprises an infrared transmitting circuit, an infrared receiving circuit and a digital controller.

[0012] The infrared transmitting circuit comprises a data buffer BUFFER with an enable function, an NMOS tube and an infrared light-emitting diode; the signal input terminal IN of the data buffer BUFFER is connected to the signal output terminal TX_SIG of the digital controller, the enable terminal EN is connected to the transmission enable terminal TX_EN of the digital controller, and the output terminal is connected to the gate of the first NMOS tube NM1; the source of the first NMOS tube NM1 is grounded, and the drain is connected to the cathode of the infrared light-emitting diode D as the output terminal PAD of the infrared transmitting circuit, and the anode of the infrared light-emitting diode D is connected to the external power supply VDD.

[0013] The infrared receiving circuit comprises a current detection circuit, a detection circuit, a hysteresis comparator and an auxiliary circuit; the auxiliary circuit comprises a reference voltage circuit and a current generating circuit.

[0014] The current detection circuit includes two amplifiers and a feedback circuit.

[0015] The first amplifier A1 includes two current sources and a PMOS tube; the positive end of the first current source I1 is connected to the power supply end, and the negative end is connected to the source of the first PMOS tube PM1, serving as the input end Iin of the first amplifier A1, that is, the input end of the current detection circuit, connected to the output end PAD of the infrared emission circuit; the positive end of the second current source I2 is connected to the drain of the first PMOS tube PM1, and the negative end is grounded, and the gate of PM1 is connected to the DC bias voltage Vb.

[0016] The feedback circuit F includes an NMOS tube; the gate of the second NMOS tube NM2 is connected to the drain of the first PMOS tube PM1, the drain of the second NMOS tube NM2 is connected to the source of the first PMOS tube PM1, serving as the output terminal Vin1 of the feedback circuit F, and the source of the second NMOS tube NM2 is grounded.

[0017] The second amplifier A2 includes a resistor network R DThe gate of the third NMOS tube NM3 is connected to the drain of the first PMOS tube PM1, the source is grounded, and the drain is connected to the resistor network R D One end of the current detection circuit is used as the output terminal Vo1, and the resistor network R D The other end of the resistor network R D The control end is connected to the control signal output end of the digital controller, and the resistor network R is adjusted by changing the configuration D resistance value.

[0018] The detection circuit comprises a shaping circuit, a delay circuit, a switch circuit, a current source and a filter capacitor.

[0019] The shaping circuit comprises a comparator Comp1, an input terminal Vin2 of the comparator Comp1 is connected to an output terminal Vo1 of the current detection circuit, and an output terminal of the comparator Comp1 is connected to an input terminal of the delay circuit.

[0020] The delay circuit includes one or more delay circuit units, and the multiple delay circuit units are connected in series in sequence. The output end of the first delay circuit unit is connected to the input end of the second delay circuit unit, and the output end of the second delay circuit unit is connected to the input end of the third delay circuit unit, and so on, wherein the input end of the first delay circuit unit serves as the input end of the delay circuit.

[0021] The switch circuit includes one or more switch units, and the multiple switch units are connected in parallel, and the number of the switch units is one more than the delay circuit unit. Furthermore, each switch unit is composed of an NMOS switch tube M and a current limiting resistor R limit Switch resistors in series; current limiting resistor R limit One end is connected to the drain of the NMOS switch tube M, the other end serves as the positive end P of the switch unit, the source of the NMOS switch tube M serves as the negative end N of the switch unit, and the gate of the NMOS switch tube M serves as the control end Sw of the switch unit.

[0022] The input end of the delay circuit and the output end of each delay circuit unit are respectively connected to the control end Sw of the corresponding switch unit; the positive ends of all switch units are connected and connected to the power supply VDD2; the negative ends of all switch units are connected and connected to the positive end of the third current source I3 and one end of the filter capacitor Cs as the output end Vout of the detection circuit, the negative end of the third current source I3 and the other end of the filter capacitor Cs are connected and grounded; the total delay of the delay circuit of the detection circuit is less than or equal to one carrier cycle.

[0023] The output terminal Vout of the detection circuit is connected to the positive input terminal of the hysteresis comparator Comp, the negative input terminal of the hysteresis comparator Comp is connected to the reference voltage Vref terminal, and the output terminal OUT of the hysteresis comparator Comp serves as the output terminal of the infrared receiving circuit and is connected to the signal receiving terminal RX_SIG of the digital controller.

[0024] The input end of the digital controller includes a command input end, a clock input end, and a signal receiving end RX_SIG, and the output end includes a signal output end TX_SIG, a transmission enable end TX_EN, and a reception enable end RX_EN. The circuit functions of the digital controller include: generating a pulse width modulation waveform and an enable control signal that meet the requirements of the infrared communication protocol and outputting them to the infrared transmitting circuit to transmit the information; receiving an infrared signal received by the infrared receiving circuit and learning the signal to realize an infrared learning remote control function; generating an enable signal according to system requirements to control the infrared transmitting circuit and the infrared receiving circuit.

[0025] Except for the infrared light-emitting diode, all circuits in the system of the present invention can be integrated on the CMOS process. The present invention adopts a single infrared tube to realize transmission and reception, and the receiving circuit structure is simple. Because of the addition of the feedback circuit, the input impedance is low, and the ability to receive current is enhanced. The output impedance RD of the current detection circuit of the present invention can be configured according to the size of the current signal received by the infrared diode, so that the circuit has a larger working range, and RD is a real impedance, which has little to do with the process realization of the MOS tube. The present invention adds a detection circuit to enhance the anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the transmitting circuit of the existing infrared remote control system;

[0027] Figure 2 It is a schematic diagram of a receiving circuit of an existing infrared remote control system;

[0028] Figure 3 is an overall circuit diagram of the circuit of the present invention;

[0029] Figure 4 for Figure 3 Schematic diagram of the medium current detection circuit;

[0030] Figure 5 for Figure 3 Schematic diagram of the detection circuit;

[0031] Figure 6 for Figure 5 Schematic diagram of the switch unit;

[0032] Figure 7 A schematic diagram of simulation results of the detection circuit. DETAILED DESCRIPTION

[0033] like Figure 3 As shown, an infrared transceiver system based on a single infrared diode includes an infrared transmitting circuit, an infrared receiving circuit and a digital controller.

[0034] The infrared transmitting circuit includes a data buffer BUFFER with an enabling function, an NMOS tube and an infrared light emitting diode. The signal input terminal IN of the data buffer BUFFER is connected to the signal output terminal TX_SIG of the digital controller, the enable terminal EN is connected to the transmitting enable terminal TX_EN of the digital controller, and the output terminal is connected to the gate of the first NMOS tube NM1; the source of the first NMOS tube NM1 is grounded, and the drain is connected to the cathode of the infrared light emitting diode D as the output terminal PAD of the infrared transmitting circuit, and the anode of the infrared light emitting diode D is connected to the external power supply VDD.

[0035] When the transmit enable terminal TX_EN of the digital controller outputs a high level, the data buffer BUFFER delays the output of the received 38kHz pulse width modulation voltage signal PWM, and drives the first NMOS tube NM1 to turn on or off: when the PWM signal is high, the first NMOS tube NM1 is turned on; when the PWM signal is low, the first NMOS tube NM1 is turned off;

[0036] When the transmit enable terminal TX_EN of the digital controller outputs a low level, the data buffer BUFFER outputs a zero level, the first NMOS tube NM1 is turned off, and the infrared light emitting diode D has no current flowing.

[0037] When the infrared transmitting circuit is working, the infrared receiving circuit is not working. At this time, the infrared light emitting diode D is forward biased, and the infrared light emitting diode D is used as a transmitting diode; when the infrared receiving circuit is working, the infrared transmitting circuit is not working, the first NMOS tube NM1 is disconnected, and the infrared light emitting diode D is used as a receiving diode.

[0038] The infrared receiving circuit includes a current detection circuit, a detection circuit, a hysteresis comparator and an auxiliary circuit. The auxiliary circuit includes a reference voltage circuit and a current generating circuit.

[0039] The current detection circuit includes a first amplifier A1, a feedback circuit F and a second amplifier A2. Figure 4 shown.

[0040] The first amplifier A1 includes two current sources and a PMOS tube. The positive end of the first current source I1 is connected to the power supply end, and the negative end is connected to the source of the first PMOS tube PM1, which serves as the input end Iin of the first amplifier A1, that is, the input end of the current detection circuit, and is connected to the output end PAD of the infrared emission circuit; the positive end of the second current source I2 is connected to the drain of the first PMOS tube PM1, and the negative end is grounded, and the gate of PM1 is connected to the DC bias voltage Vb.

[0041] The feedback circuit F includes an NMOS transistor. The gate of the second NMOS transistor NM2 is connected to the drain of the first PMOS transistor PM1, the drain of the second NMOS transistor NM2 is connected to the source of the first PMOS transistor PM1, serving as the output terminal Vin1 of the feedback circuit F, and the source of the second NMOS transistor NM2 is grounded.

[0042] The second amplifier A2 includes a resistor network R D The gate of the third NMOS tube NM3 is connected to the drain of the first PMOS tube PM1, the source is grounded, and the drain is connected to the resistor network R D One end of the current detection circuit is used as the output terminal Vo1, and the resistor network R D The other end of the resistor network R D The control end is connected to the control signal output end of the digital controller, and the resistor network R is adjusted by changing the configuration D resistance value.

[0043] Input impedance of current sensing circuit V in is the input voltage, I in is the input current, g m1 is the transconductance of the first PMOS tube PM1, g m2 is the transconductance of the second NMOS tube NM2, r 01 is the intrinsic input impedance of the first PMOS transistor PM1.

[0044] Output transresistance of the current sensing circuit V 01 is the output voltage of the current detection circuit, g m3 is the transconductance of the third NMOS tube NM3, R D is the resistance of the resistor network.

[0045] From formula (1), we can see that in this design, the input impedance Z of the current detection circuit is in The input impedance can be designed to be higher than that of conventional common-gate Little G m2 ·r 01 Times, those skilled in the art will understand that g m2 ·r 01 The value of is about 10 to 30. Low input impedance can enhance the ability of the current detection circuit to detect current.

[0046] Because the gate inputs of the second NMOS tube NM2 and the third NMOS tube NM3 are connected together, it can be deduced that Where (W / L)3 represents the width-to-length ratio of the third NMOS transistor NM3, and (W / L)2 represents the width-to-length ratio of the second NMOS transistor NM2. Combining formula (1), it can be seen that the output transresistance of the current detection circuit proposed in the present invention is mainly related to R D Therefore, different R D To enhance the detection range of the current detection circuit. Those skilled in the art can easily complete the specific design of the circuit diagram based on the resistor network circuit diagram of the present application, which will not be described in detail here.

[0047] The detection circuit includes a shaping circuit, a delay circuit, a switching circuit, a current source and a filter capacitor, as shown in FIG. Figure 5 shown.

[0048] The shaping circuit comprises a comparator Comp1, an input terminal Vin2 of the comparator Comp1 is connected to an output terminal Vo1 of the current detection circuit, and an output terminal of the comparator Comp1 is connected to an input terminal of the delay circuit.

[0049] The delay circuit includes one or more delay circuit units, and the multiple delay circuit units are connected in series in sequence. The output end of the first delay circuit unit is connected to the input end of the second delay circuit unit, and the output end of the second delay circuit unit is connected to the input end of the third delay circuit unit, and so on, wherein the input end of the first delay circuit unit serves as the input end of the delay circuit.

[0050] The switch circuit comprises one or more switch units, and the multiple switch units are connected in parallel, and the number of the switch units is one more than the delay circuit unit.

[0051] like Figure 6 As shown, each switch unit consists of an NMOS switch tube M and a current limiting resistor R limit The switch resistors are connected in series. The current limiting resistor R limit One end is connected to the drain of the NMOS switch tube M, the other end serves as the positive end P of the switch unit, the source of the NMOS switch tube M serves as the negative end N of the switch unit, and the gate of the NMOS switch tube M serves as the control end Sw of the switch unit.

[0052] The input end of the delay circuit and the output end of each delay circuit unit are respectively connected to the control end Sw of the corresponding switch unit; the positive ends of all switch units are connected and connected to the power supply VDD2; the negative ends of all switch units are connected and connected to the positive end of the third current source I3 and one end of the filter capacitor Cs as the output end Vout of the detection circuit, and the negative end of the third current source I3 and the other end of the filter capacitor Cs are connected and grounded. The total delay of the delay circuit of the detection circuit is less than or equal to one carrier cycle.

[0053] Figure 7This is a schematic diagram of a simulation result of the detection circuit of the present invention. carrier The system recovers the 38kHz carrier signal with a 1 / 3 duty cycle and carries information. Figure 7 There is a missing code in the middle oval frame, and the middle V out1 This is the output waveform of the detection circuit with delay function. The output ripple is small, and the peak voltage generated at the leakage point is relatively small. out2 This is the output waveform of the detection circuit without delay function. The output ripple is large, and the spike voltage generated at the leakage point is relatively large. The large spike voltage will cause the subsequent comparator output to flip incorrectly, increasing the bit error rate.

[0054] The output terminal Vout of the detection circuit is connected to the positive input terminal of the hysteresis comparator Comp, the negative input terminal of the hysteresis comparator Comp is connected to the reference voltage Vref terminal, and the output terminal OUT of the hysteresis comparator Comp serves as the output terminal of the infrared receiving circuit and is connected to the signal receiving terminal RX_SIG of the digital controller.

[0055] The input end of the digital controller includes a command input end, a clock input end, and a signal receiving end RX_SIG; the output end of the digital controller includes a signal output end TX_SIG, a transmission enable end TX_EN, and a reception enable end RX_EN. The circuit functions of the digital controller include two aspects. First, a pulse width modulation (PWM) waveform and an enable control signal that meet the requirements of the infrared communication protocol are generated and output to the infrared transmitting circuit to transmit the information; second, an infrared signal received by the infrared receiving circuit is received and the signal is learned, thereby realizing an infrared learning remote control function. In addition, the digital control circuit can generate an enable signal to control the infrared transmitting circuit and the infrared receiving circuit according to system requirements. In the present invention, infrared reception and transmission are performed separately.

[0056] When the command received by the digital controller is "transmit", it generates a pulse width modulation waveform and a transmission enable control signal TX_EN that meet the requirements of the infrared communication protocol and outputs them to the infrared transmission circuit, so that the infrared transmission circuit works and transmits the information. When the command received by the digital controller is "receive", it generates a receive enable signal RX_EN and outputs it to the enable end of the receiving circuit. The receiving circuit starts working and outputs the received infrared signal to the digital controller. The digital controller learns and records these infrared signals, thereby realizing the infrared learning remote control function.

Claims

1. An infrared transceiver system based on a single infrared diode, comprising an infrared transmitting circuit, an infrared receiving circuit and a digital controller; characterized in that: The infrared transmitting circuit comprises a data buffer BUFFER with an enable function, a first NMOS tube and an infrared light emitting diode; the signal input terminal IN of the data buffer BUFFER is connected to the signal output terminal TX_SIG of the digital controller, the enable terminal EN is connected to the transmission enable terminal TX_EN of the digital controller, and the output terminal is connected to the gate of the first NMOS tube NM1; the source of the first NMOS tube NM1 is grounded, the drain is connected to the cathode of the infrared light emitting diode D, serving as the output terminal PAD of the infrared transmitting circuit, and the anode of the infrared light emitting diode D is connected to the external power supply VDD; The infrared receiving circuit includes a current detection circuit, a detection circuit, a hysteresis comparator Comp and an auxiliary circuit; the auxiliary circuit includes a reference voltage circuit and a current generating circuit; The current detection circuit includes two amplifiers and a feedback circuit; The first amplifier A1 includes two current sources and a PMOS tube; the positive end of the first current source I1 is connected to the power supply end, and the negative end is connected to the source of the first PMOS tube PM1, serving as the input end Iin of the first amplifier A1, that is, the input end of the current detection circuit, and connected to the output end PAD of the infrared emission circuit; the positive end of the second current source I2 is connected to the drain of the first PMOS tube PM1, and the negative end is grounded, and the gate of PM1 is connected to the DC bias voltage Vb; The feedback circuit F includes a second NMOS transistor; the gate of the second NMOS transistor NM2 is connected to the drain of the first PMOS transistor PM1, the drain of the second NMOS transistor NM2 is connected to the source of the first PMOS transistor PM1, serving as the output terminal Vin1 of the feedback circuit F, and the source of the second NMOS transistor NM2 is grounded; The second amplifier A2 includes a resistor network R D and the third NMOS tube; The gate of the third NMOS transistor NM3 is connected to the drain of the first PMOS transistor PM1, the source is grounded, and the drain is connected to the resistor network R D One end of the current detection circuit is used as the output terminal Vo1, and the resistor network R D The other end of the resistor network R D The control end is connected to the control signal output end of the digital controller, and the resistor network R is adjusted by changing the configuration D The resistance value; The detection circuit includes a shaping circuit, a delay circuit, a switching circuit, a current source and a filter capacitor; The shaping circuit comprises a comparator Comp1, an input terminal Vin2 of the comparator Comp1 is connected to an output terminal Vo1 of the current detection circuit, and an output terminal of the comparator Comp1 is connected to an input terminal of the delay circuit; The delay circuit comprises one or more delay circuit units, wherein the multiple delay circuit units are connected in series, the output end of the first delay circuit unit is connected to the input end of the second delay circuit unit, the output end of the second delay circuit unit is connected to the input end of the third delay circuit unit, and so on, wherein the input end of the first delay circuit unit serves as the input end of the delay circuit; The switch circuit comprises a plurality of switch units, which are connected in parallel, and the number of the switch units is one more than the delay circuit unit; The input end of the delay circuit and the output end of each delay circuit unit are respectively connected to the control end Sw of the corresponding switch unit; the positive ends of all switch units are connected and connected to the power supply VDD2; the negative ends of all switch units are connected and connected to the positive end of the third current source I3 and one end of the filter capacitor Cs as the output end Vout of the detection circuit, and the negative end of the third current source I3 and the other end of the filter capacitor Cs are connected and grounded; the total delay of the delay circuit of the detection circuit is less than or equal to one carrier cycle; The output terminal Vout of the detection circuit is connected to the positive input terminal of the hysteresis comparator Comp, the negative input terminal of the hysteresis comparator Comp is connected to the reference voltage Vref terminal, and the output terminal OUT of the hysteresis comparator Comp is used as the output terminal of the infrared receiving circuit and is connected to the signal receiving terminal RX_SIG of the digital controller; The input end of the digital controller includes a command input end, a clock input end, and a signal receiving end RX_SIG, and the output end includes a signal output end TX_SIG, a transmission enable end TX_EN, and a reception enable end RX_EN.

2. An infrared transceiver system based on a single infrared diode as claimed in claim 1, characterized in that: When the transmitting enable terminal TX_EN of the digital controller outputs a high level, the data buffer BUFFER delays the output of the received pulse width modulation voltage signal PWM, and drives the first NMOS tube NM1 to turn on or off: when the PWM signal is high level, the first NMOS tube NM1 is turned on; when the PWM signal is low level, the first NMOS tube NM1 is turned off; When the transmit enable terminal TX_EN of the digital controller outputs a low level, the data buffer BUFFER outputs a zero level, the first NMOS tube NM1 is turned off, and no current flows through the infrared light emitting diode D; When the infrared transmitting circuit is working, the infrared receiving circuit is not working. At this time, the infrared light emitting diode D is forward biased, and the infrared light emitting diode D is used as a transmitting diode; when the infrared receiving circuit is working, the infrared transmitting circuit is not working, the first NMOS tube NM1 is disconnected, and the infrared light emitting diode D is used as a receiving diode.

3. The infrared transceiver system based on a single infrared diode as claimed in claim 1, characterized in that: Each switch unit consists of an NMOS switch tube M and a current limiting resistor R limit Switch resistors in series; current limiting resistor R limit One end is connected to the drain of the NMOS switch tube M, the other end serves as the positive end P of the switch unit, the source of the NMOS switch tube M serves as the negative end N of the switch unit, and the gate of the NMOS switch tube M serves as the control end Sw of the switch unit.

4. The infrared transceiver system based on a single infrared diode as claimed in claim 1, characterized in that: The circuit functions of the digital controller include: generating a pulse width modulation waveform and an enable control signal that meet the requirements of the infrared communication protocol and outputting them to the infrared transmitting circuit to transmit the information; receiving an infrared signal received by the infrared receiving circuit and learning the signal to realize an infrared learning remote control function; generating an enable signal according to system requirements to control the infrared transmitting circuit and the infrared receiving circuit.

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