CN217216612U

CN217216612U - Two-wire system direct current carrier communication circuit

Info

Publication number: CN217216612U
Application number: CN202221243301.3U
Authority: CN
Inventors: 刘兵; 肖郭璇
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-05-23
Filing date: 2022-05-23
Publication date: 2022-08-16
Anticipated expiration: 2032-05-23

Abstract

The utility model discloses a two-wire system direct current carrier communication circuit, which comprises a plurality of nodes, wherein all the nodes are connected to a two-wire system communication bus; the two-wire system communication bus is connected with an external power supply and takes electricity; each node comprises a power supply circuit, a control circuit, a driving circuit, a modulation coupling circuit, a demodulation output circuit and a comparison circuit; the power supply circuit supplies power; when the signal is modulated and transmitted, the control circuit receives a signal to be modulated, and the signal is modulated and outputs a PWM signal to be output to the two-wire system communication bus through the driving circuit and the modulation coupling circuit by adopting the prior art; when the signal is received and demodulated, the demodulation output circuit receives the signal and compares the signal through the comparison circuit, the comparison signal is uploaded to the control circuit, and the control circuit adopts the existing demodulation circuit to demodulate and output the signal to the outside. The utility model discloses a circuit design of innovation makes the utility model discloses a communication circuit not only can realize two-wire system direct current carrier communication's function, and the reliability is high moreover, stability is good and low cost.

Description

Two-wire system direct current carrier communication circuit

Technical Field

The utility model belongs to the technical field of communication, concretely relates to two-wire system direct current carrier communication circuit.

Background

With the development of economic technology, the industry has largely used the form of a bus for communication. The bus communication has the advantages of simple and reliable communication hardware, strong anti-interference capability and the like, and is widely applied to various industrial occasions.

In current bus applications, two-wire buses occupy a large proportion. The two-bus communication mode has been widely applied in the fields of lighting, building automation, factory automation and control, HVAC systems, electrical appliances, power grid infrastructure, power transmission and the like. The two-wire bus has the greatest advantage that the master-slave device communication can be completed only by two wires without an additional power line.

However, when the existing two-wire bus is applied, one type of bus needs a master station to modulate and is limited by master-slave communication, once the master station is abnormal, the whole system cannot work, and the system stability is poor; and when the number of nodes is small, the cost is high because the master station is still needed. The other type of communication is performed by using a power carrier mode, modules such as a band-pass filter module, a phase-locked loop module and the like are required to be used for waveform decoding, the requirement on the waveform distortion degree of the communication carrier is strict, and the requirement on the central frequency offset is also strict, so that a peripheral circuit of the communication mode is extremely complex, the cost is high, and the anti-interference capability is poor.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a reliability is high, stability is good and low cost's two-wire system direct current carrier communication circuit.

The utility model provides a two-wire system direct current carrier communication circuit, which comprises a plurality of nodes, wherein all the nodes are connected to a two-wire system communication bus; the two-wire system communication bus is connected with an external power supply and used for getting electricity; each node comprises a power supply circuit, a control circuit, a driving circuit, a modulation coupling circuit, a demodulation output circuit and a comparison circuit; the output end of the drive circuit is connected with the input end of the modulation coupling circuit, and the output end of the modulation coupling circuit is connected with the two-wire system communication bus; the input end of the demodulation output circuit is connected with the two-wire system communication bus, and the output end of the demodulation output circuit is connected with the input end of the comparison circuit; the input end of the driving circuit and the output end of the comparison circuit are both connected with the control circuit; the power supply circuit is used for getting electricity from the two-wire system communication bus and supplying power to the nodes; when the modulation of the signal is sent, the control circuit receives the signal to be modulated, and after the modulation is carried out by adopting the prior art, the modulated PWM signal is output to the two-wire system communication bus through the driving circuit and the modulation coupling circuit; when receiving and demodulating signals, the demodulation output circuit receives the signals on the two-wire system communication bus, the signals are compared by the comparison circuit, the comparison signals are uploaded to the control circuit, the control circuit demodulates by adopting the existing demodulation technology, and the demodulated signals are output to the outside.

The power supply circuit comprises a power-taking electronic circuit and a voltage-stabilizing electronic circuit; the power taking electronic circuit is connected with the voltage stabilizing electronic circuit; the power taking electronic circuit is used for taking power from the two-wire system communication bus; the voltage stabilizing sub-circuit is used for obtaining electric energy from the electronic taking circuit, stabilizing the voltage and then outputting the electric energy.

The power-taking electronic circuit comprises a power-taking first filter capacitor, a power-taking second filter capacitor, a power-taking protection TVS tube, a power-taking first isolation inductor, a power-taking second isolation inductor, a power-taking rectifier bridge and a power-taking output filter capacitor; a power-taking protection TVS tube is connected between the first input end of the power-taking electronic circuit and the second input end of the power-taking electronic circuit and is used for protecting bus surge voltage; a first input end of the power taking electronic circuit is grounded through a power taking first filter capacitor and is used for filtering; a second input end of the electronic taking circuit is grounded through a second filter capacitor for taking electricity and filtering; the first input end of the power-taking electronic circuit is also connected with the first input end of the power-taking rectifier bridge after being connected with the power-taking first isolation inductor in series; the second input end of the power taking electronic circuit is also connected with the second input end of the power taking rectifier bridge after being connected with the power taking second isolation inductor in series; the power-taking first isolation inductor and the power-taking second isolation inductor are used for isolating carrier signals on the two-wire system communication bus; the output positive pole of the power-taking rectifier bridge outputs a final power-taking power supply and is connected with the voltage-stabilizing sub-circuit; the output cathode of the power-taking rectifier bridge is grounded; the output anode of the power-taking rectifier bridge is grounded through a power-taking output filter capacitor and is filtered.

The power-taking electronic circuit comprises a power-taking first filter capacitor, a power-taking second filter capacitor, a power-taking protection TVS tube, a power-taking first isolation inductor, a power-taking second isolation inductor, a power-taking output device and a power-taking output filter capacitor; a power-taking protection TVS tube is connected between the first input end of the power-taking electronic circuit and the second input end of the power-taking electronic circuit and is used for protecting bus surge voltage; a first input end of the power taking electronic circuit is grounded through a power taking first filter capacitor and is used for filtering; a second input end of the electronic taking circuit is grounded through a second filter capacitor for taking electricity and filtering; the first input end of the power-taking electronic circuit is also connected in series with a power-taking first isolation inductor and a power-taking output device, and then directly outputs a power-taking power supply and is connected with the voltage-stabilizing electronic circuit; the second input end of the electronic fetching circuit is also connected in series with a second isolating inductor for fetching electricity and then is directly grounded; the power-taking first isolation inductor and the power-taking second isolation inductor are used for isolating carrier signals on the two-wire system communication bus; the power supply is grounded through a power supply output filter capacitor and filters; the electricity-taking output device is a diode or a short-circuit wire.

The voltage stabilizing sub-circuit is an LDO linear voltage stabilizing circuit or a DC/DC direct current conversion voltage stabilizing circuit.

The control circuit is a singlechip.

The driving circuit comprises a first push-pull circuit and a second push-pull circuit; two paths of PWM signals output by the control circuit, wherein the first path of PWM signal outputs a first driving PWM signal through a first push-pull circuit connected in series, and the second path of PWM signal outputs a second driving PWM signal through a second push-pull circuit connected in series; the first push-pull circuit and the second push-pull circuit are used for enhancing the driving capability of the PWM signal.

The driving circuit is a first short connecting wire and a second short connecting wire; and the second path of PWM signals outputs a second driving PWM signal through a second short connecting wire connected in series.

The modulation coupling circuit comprises a modulation coupling first capacitor and a modulation coupling second capacitor; and the second path of driving PWM signals are coupled to a second bus of the two-wire system communication bus through a modulation coupling second capacitor connected in series.

The demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor, a demodulation output matching resistor and a demodulation output lifting voltage source; any one path of communication bus of the two-wire system communication bus outputs a final single-phase demodulation output signal through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is also connected with a demodulation output lifting voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit.

The demodulation output boost voltage source is obtained by a power supply signal output by the power supply circuit through a voltage division circuit, or by a voltage stabilization of a voltage stabilization diode, or by a LDO linear voltage stabilization circuit.

The demodulation output circuit also comprises a first voltage-dividing resistor and a second voltage-dividing resistor, wherein the first voltage-dividing resistor and the second voltage-dividing resistor are connected between the demodulation output lifting voltage source and the ground in series; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs comparison threshold voltage and is connected with a comparison circuit; the first voltage dividing resistor and the second voltage dividing resistor are used for outputting comparison threshold voltage in a resistor voltage dividing mode.

The demodulation output circuit also comprises a second demodulation output coupling capacitor; the other communication bus of the two-wire system communication bus is connected with a demodulation output lifting voltage source through a second demodulation output coupling capacitor connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

The demodulation output circuit also comprises a first voltage-dividing resistor, a second voltage-dividing resistor and a second demodulation output coupling capacitor; the first voltage-dividing resistor and the second voltage-dividing resistor are connected between the demodulation output lifting voltage source and the ground in series; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs comparison threshold voltage and is connected with a comparison circuit; the first voltage dividing resistor and the second voltage dividing resistor are used for outputting comparison threshold voltage in a resistor voltage dividing mode; the other communication bus of the two-wire system communication bus is connected with a demodulation output lifting voltage source through a second demodulation output coupling capacitor connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

The demodulation output lifting voltage source is grounded through a lifting voltage source filter capacitor; the power supply signal output by the power supply circuit is grounded through the demodulation output first voltage-dividing resistor, the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source; the connection end of the first voltage-dividing resistor for demodulation output and the second voltage-dividing resistor for demodulation output outputs a comparison threshold voltage and is connected with a comparison circuit; the demodulation output voltage stabilizer is a voltage stabilizing resistor or a voltage stabilizing diode.

The demodulation output circuit also comprises a second demodulation output coupling capacitor; the other communication bus of the two-wire system communication bus is connected with a comparison threshold voltage through a second demodulation output coupling capacitor which is connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

The demodulation output circuit is a differential demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor, a second demodulation output coupling capacitor, a demodulation output lifting voltage source, a demodulation output first matching resistor, a demodulation output second matching resistor and a demodulation output third matching resistor; any one path of communication bus of the two-wire system communication bus outputs a final demodulation output first signal through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the demodulation output first signal is grounded through a demodulation output first matching resistor, a demodulation output second matching resistor and a demodulation output third matching resistor which are sequentially connected in series; the connection end of the first demodulation output matching resistor and the second demodulation output matching resistor is connected with a demodulation output lifting voltage source; the other communication bus of the two-wire system communication bus outputs a final demodulation output second signal through a second demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the connection end of the demodulation output second matching resistor and the demodulation output third matching resistor is directly connected with the demodulation output second signal; the demodulation output lifting voltage source, the demodulation output first matching resistor, the demodulation output second matching resistor and the demodulation output third matching resistor are used for lifting the voltage level of the demodulation output first signal and the demodulation output second signal to the working voltage range of the comparison circuit; the first demodulation output coupling capacitor and the second demodulation output coupling capacitor are used for coupling the carrier signal on the two-wire system communication bus into the demodulation output circuit; the demodulation output boost voltage source is obtained by a power supply signal output by the power supply circuit through a voltage division circuit, or by a voltage stabilization of a voltage stabilization diode, or by a LDO linear voltage stabilization circuit.

The demodulation output circuit is a differential demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor, a second demodulation output coupling capacitor, a demodulation output uplift voltage source and a demodulation output first matching resistor; any one path of communication bus of the two-wire system communication bus outputs a final demodulation output first signal through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the demodulation output first signal is also connected with a demodulation output lifting voltage source through a demodulation output first matching resistor which is connected in series; the other communication bus of the two-wire system communication bus outputs a final demodulation output second signal through a second demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the demodulation output lifting voltage source and the demodulation output first matching resistor are used for lifting the voltage level of the demodulation output first signal to be within the working voltage range of the comparison circuit; the first demodulation output coupling capacitor and the second demodulation output coupling capacitor are used for coupling the carrier signal on the two-wire system communication bus into the demodulation output circuit; the demodulation output uplift voltage source is grounded through an uplift voltage source filter capacitor; the power supply signal output by the power supply circuit is grounded through the demodulation output first voltage-dividing resistor, the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs a second signal and is connected with a comparison circuit; the demodulation output voltage stabilizer is a voltage stabilizing resistor or a voltage stabilizing diode.

The comparison circuit is a special comparator chip; or a singlechip integrated with a comparator.

The utility model provides a two-wire system direct current carrier communication circuit, through the circuit design of innovation, make the utility model discloses a communication circuit not only can realize two-wire system direct current carrier communication's function, and the reliability is high moreover, stability is good and low cost.

Drawings

Fig. 1 is a schematic diagram of functional modules of the communication circuit of the present invention.

Fig. 2 is a schematic diagram of the circuit principle of the first embodiment of the power supply circuit of the present invention.

Fig. 3 is a schematic circuit diagram of a second embodiment of the power supply circuit of the present invention.

Fig. 4 is a schematic diagram of the circuit principle of the third embodiment of the power supply circuit of the present invention.

Fig. 5 is a schematic circuit diagram of a voltage regulator sub-circuit according to a first embodiment of the present invention.

Fig. 6 is a schematic circuit diagram of a voltage regulator sub-circuit according to a second embodiment of the present invention.

Fig. 7 is a schematic diagram of a circuit principle when the driving circuit of the present invention is a push-pull circuit.

Fig. 8 is a schematic circuit diagram of the modulation coupling circuit according to the present invention.

Fig. 9 is a schematic circuit diagram of a demodulation output circuit according to a first embodiment of the present invention.

Fig. 10 is a schematic circuit diagram of a demodulation output circuit according to a second embodiment of the present invention.

Fig. 11 is a schematic circuit diagram of a demodulation output circuit according to a third embodiment of the present invention.

Fig. 12 is a schematic circuit diagram of a fourth embodiment of the demodulation output circuit according to the present invention.

Fig. 13 is a schematic circuit diagram of the demodulation output boost voltage source in the first to fourth embodiments of the demodulation output circuit according to the present invention.

Fig. 14 is a schematic circuit diagram of a fifth embodiment of the demodulation output circuit according to the present invention.

Fig. 15 is a schematic circuit diagram of a sixth embodiment of the demodulation output circuit according to the present invention.

Fig. 16 is a schematic circuit diagram of the demodulation output boost voltage source in the fifth to sixth embodiments of the demodulation output circuit according to the present invention.

Fig. 17 is a schematic circuit diagram of a seventh embodiment of the demodulation output circuit of the present invention.

Fig. 18 is a schematic circuit diagram of an eighth embodiment of the demodulation output circuit of the present invention.

Fig. 19 is a circuit diagram of a comparison circuit and a control circuit according to a first embodiment of the present invention.

Fig. 20 is a circuit diagram of a comparison circuit and a control circuit according to a second embodiment of the present invention.

Fig. 21 is a circuit diagram of a comparison circuit and a control circuit according to a third embodiment of the present invention.

Detailed Description

Fig. 1 shows a schematic diagram of functional modules of the communication circuit of the present invention: the utility model provides a two-wire system direct current carrier communication circuit, which comprises a plurality of nodes, wherein all the nodes are connected to a two-wire system communication bus; the two-wire system communication bus is connected with an external power supply and used for getting electricity; each node comprises a power supply circuit, a control circuit, a driving circuit, a modulation coupling circuit, a demodulation output circuit and a comparison circuit; the output end of the drive circuit is connected with the input end of the modulation coupling circuit, and the output end of the modulation coupling circuit is connected with the two-wire system communication bus; the input end of the demodulation output circuit is connected with the two-wire system communication bus, and the output end of the demodulation output circuit is connected with the input end of the comparison circuit; the input end of the driving circuit and the output end of the comparison circuit are both connected with the control circuit; the power supply circuit is used for getting electricity from the two-wire system communication bus and supplying power to the nodes; when the modulation of the signal is sent, the control circuit receives the signal to be modulated, and after the modulation is carried out by adopting the prior art, the modulated PWM signal is output to the two-wire system communication bus through the driving circuit and the modulation coupling circuit; when receiving and demodulating signals, the demodulation output circuit receives the signals on the two-wire system communication bus, the signals are compared by the comparison circuit, the comparison signals are uploaded to the control circuit, the control circuit adopts the existing demodulation technology to demodulate, and the demodulated signals are output to the outside; the bus power supply "V _ power supply" and "GND _ power supply" are also supplied through two inductors Ls to isolate the carrier signal and reduce the attenuation of the carrier signal and the interference of the power supply to the bus. And simultaneously, the utility model discloses the during operation, there is not polarity in two buses: the bus is to the back of exchanging promptly, the utility model discloses still can normally work.

For the existing modulation technique, reference may be made to the modulation technique described in binary amplitude keying (OOK); as for the existing demodulation technique, a demodulation technique described in binary amplitude keying (OOK) may be referred to.

In specific implementation, the power supply circuit comprises a power-taking electronic circuit and a voltage-stabilizing electronic circuit; the power taking electronic circuit is connected with the voltage stabilizing electronic circuit; the power taking electronic circuit is used for taking power from the two-wire system communication bus; the voltage stabilizing sub-circuit is used for obtaining electric energy from the electronic taking circuit, stabilizing the voltage and then outputting the electric energy. The control circuit can be a singlechip, a DSP and other control devices.

Fig. 2 shows a schematic diagram of a circuit principle of a first embodiment of the power supply circuit for obtaining the electronic circuit of the present invention: in this embodiment, the power-taking electronic circuit includes a power-taking first filter capacitor C3, a power-taking second filter capacitor C4, a power-taking protection TVS tube D2, a power-taking first isolation inductor L1, a power-taking second isolation inductor L2, a power-taking rectifier bridge D3, and a power-taking output filter capacitor C1; j1 in the figure is connected with a bus and takes electricity; a power-taking protection TVS tube is connected between the first input end of the power-taking electronic circuit and the second input end of the power-taking electronic circuit and is used for protecting bus surge voltage; a first input end of the power taking electronic circuit is grounded through a power taking first filter capacitor and is used for filtering; a second input end of the electronic taking circuit is grounded through a second filter capacitor for taking electricity and filtering; the first input end of the power-taking electronic circuit is also connected with the first input end of the power-taking rectifier bridge after being connected with the power-taking first isolation inductor in series; the second input end of the power taking electronic circuit is also connected with the second input end of the power taking rectifier bridge after being connected in series with the power taking second isolation inductor; the power-taking first isolation inductor and the power-taking second isolation inductor are used for isolating carrier signals on the two-wire system communication bus; the output positive pole of the power-taking rectifier bridge outputs a final power-taking power supply and is connected with the voltage-stabilizing sub-circuit; the output cathode of the power-taking rectifier bridge is grounded; the output anode of the power-taking rectifier bridge is grounded through a power-taking output filter capacitor and is filtered.

Fig. 3 is a schematic diagram of a circuit principle of a second embodiment of the power supply circuit for obtaining the electronic circuit of the present invention: the power taking electronic circuit comprises a power taking first filter capacitor, a power taking second filter capacitor, a power taking protection TVS tube, a power taking first isolation inductor, a power taking second isolation inductor, a power taking output device and a power taking output filter capacitor; a power-taking protection TVS tube is connected between the first input end of the power-taking electronic circuit and the second input end of the power-taking electronic circuit and is used for protecting bus surge voltage; a first input end of the power taking electronic circuit is grounded through a power taking first filter capacitor and is used for filtering; a second input end of the electronic taking circuit is grounded through a second filter capacitor for taking electricity and filtering; the first input end of the power-taking electronic circuit is also connected in series with a power-taking first isolation inductor and a power-taking output device, and then directly outputs a power-taking power supply and is connected with the voltage-stabilizing electronic circuit; the second input end of the electronic fetching circuit is also connected in series with a second isolating inductor for fetching electricity and then is directly grounded; the power-taking first isolation inductor and the power-taking second isolation inductor are used for isolating carrier signals on the two-wire system communication bus; the power supply is grounded through a power supply output filter capacitor and filters; in this embodiment, the power take-off output device is a diode for preventing reverse connection.

Fig. 4 is a schematic circuit diagram of a third embodiment of the power supply circuit of the present invention, which gets the electronic circuit: the power taking electronic circuit comprises a power taking first filter capacitor, a power taking second filter capacitor, a power taking protection TVS tube, a power taking first isolation inductor, a power taking second isolation inductor, a power taking output device and a power taking output filter capacitor; a power-taking protection TVS tube is connected between the first input end of the power-taking electronic circuit and the second input end of the power-taking electronic circuit and is used for protecting bus surge voltage; a first input end of the power taking electronic circuit is grounded through a power taking first filter capacitor and is used for filtering; a second input end of the electronic taking circuit is grounded through a second filter capacitor for taking electricity and filtering; the first input end of the power-taking electronic circuit is also connected in series with a power-taking first isolation inductor and a power-taking output device, and then directly outputs a power-taking power supply and is connected with the voltage-stabilizing electronic circuit; the second input end of the electronic fetching circuit is also connected in series with a second isolating inductor for fetching electricity and then is directly grounded; the power-taking first isolation inductor and the power-taking second isolation inductor are used for isolating carrier signals on the two-wire system communication bus; the power supply is grounded through a power supply output filter capacitor and filters; in this embodiment, the power-taking output device is a short-circuit wire, and the circuit takes power with polarity at this time.

Fig. 5 is a schematic diagram of a first embodiment of the voltage regulator sub-circuit of the power circuit of the present invention: the voltage stabilizing sub-circuit is an LDO linear voltage stabilizing circuit; the LDO linear voltage regulation chip VR1 can be 78M05, ME6203A50M3G, AMS1117 and the like; the Vin pin of the chip is directly connected with the output end of the power-taking electronic circuit and takes power; meanwhile, the Vin pin of the chip is grounded through a filter capacitor C8 and is filtered; the GND pin of the chip is directly grounded; an output pin Vout of the chip directly outputs a stable power supply signal VCC _ n, and meanwhile, the power supply signal is grounded and filtered through C9; in this embodiment, the suffix _ n of the output stable power source VCC _ n indicates the power source VCC of the nth node on the bus.

Fig. 6 is a schematic diagram of a second embodiment of the voltage regulator sub-circuit of the power circuit of the present invention: the voltage stabilizing sub-circuit is a DC/DC direct current conversion voltage stabilizing circuit; the DC/DC direct current conversion voltage stabilizing circuit consists of a voltage stabilizing chip with the model number TD 1468; pin 1 of the chip is connected with pin 8 of the output pin through a capacitor C12; the pin 2 of the chip is a power supply pin, is directly connected with the output end of the electronic circuit and supplies power, and is grounded and filtered through a filter capacitor C13; the pin 3 of the chip is an enable terminal, and the enable terminal is directly connected with a power supply pin through a pull-up resistor R1, so that the enable terminal of the chip is ensured to be at a high level. The 7 pins of the chip are grounding pins and are directly grounded; the 8 pins of the chip are output pins, stable voltage signals are output by the pins, freewheeling is carried out through a diode D6, and then the voltage is reduced by BUCK after being filtered through an inductor L7 and a capacitor C14, and stable power supply signals VCC _ n are output; in the embodiment, the suffix _ n of the output stable power supply VCC _ n indicates the power supply VCC of the nth node on the bus; in addition, the output power supply signal VCC _ n is also sampled by sampling resistors R2 and R3, and the sampled voltage is fed back to pin 5 of the chip, thereby realizing stable control of the output voltage.

Fig. 7 is a schematic diagram of a circuit principle when the driving circuit of the present invention is a push-pull circuit: the drive circuit includes a first push-pull circuit (U1 in fig. 7 (a)) and a second push-pull circuit (U2 in fig. 7 (b)); the first PWM signal PWM _ P outputs a first driving PWM signal OUT _ P through a first push-pull circuit connected in series; the second path of PWM signal outputs a second driving PWM signal OUT _ N through a second push-pull circuit connected in series; the first push-pull circuit and the second push-pull circuit are used for enhancing the driving capability of the PWM signal; the push-pull circuit is a traditional push-pull circuit consisting of two switching tubes; the push-pull circuit may also employ conventional chips such as LMBT3946, 8050 and 8550 combinations, and the like.

In addition, a push-pull circuit is not needed, and the singlechip directly drives the modulation coupling circuit; at the moment, the driving circuit is a first short connecting wire and a second short connecting wire; and the second path of PWM signals outputs a second driving PWM signal through a second short connecting wire connected in series.

Fig. 8 is a schematic diagram of the circuit principle of the modulation coupling circuit of the present invention: the modulation coupling circuit comprises a modulation coupling first capacitor and a modulation coupling second capacitor; and the second path of driving PWM signals are coupled to a second bus of the two-wire system communication bus through a modulation coupling second capacitor connected in series.

Fig. 9 is a schematic circuit diagram of a first embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C6, a demodulation output matching resistor R4 and a demodulation output boost voltage source VREF; any one path of communication BUS (BUS _ P in the figure) of the two-wire system communication BUS outputs a final single-phase demodulation output signal CMP _ P through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is also connected with a demodulation output lifting voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit; in this embodiment, the output comparison threshold voltage is generated by the control circuit itself.

Fig. 10 is a schematic circuit diagram of a second embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C6, a demodulation output matching resistor R4, a demodulation output boosting voltage source VREF, a first voltage dividing resistor R1 and a second voltage dividing resistor R2; any one path of communication BUS (BUS _ P in the figure) of the two-wire system communication BUS outputs a final single-phase demodulation output signal CMP _ P through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is also connected with a demodulation output lifting voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit; the first voltage-dividing resistor and the second voltage-dividing resistor are connected between the demodulation output lifting voltage source and the ground in series; the connection end of the first divider resistor and the second divider resistor outputs a comparison threshold voltage CMP _ N and is connected with a comparison circuit; the first voltage dividing resistor and the second voltage dividing resistor are used for outputting comparison threshold voltage in a resistor voltage dividing mode.

Fig. 11 is a schematic circuit diagram of a third embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C6, a demodulation output matching resistor R4, a demodulation output boost voltage source VREF and a second demodulation output coupling capacitor C10; any one path of communication BUS (BUS _ P in the figure) of the two-wire system communication BUS outputs a final single-phase demodulation output signal CMP _ P through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is connected with a demodulation output boost voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit; the other communication BUS BUS _ N of the two-wire system communication BUS is connected with a demodulation output lifting voltage source through a second demodulation output coupling capacitor connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop; in this embodiment, the output comparison threshold voltage is generated by the control circuit itself.

Fig. 12 is a schematic circuit diagram of a fourth embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C6, a demodulation output matching resistor R4, a demodulation output boost voltage source VREF, a first voltage dividing resistor R1, a second voltage dividing resistor R2 and a second demodulation output coupling capacitor C10; any one path of communication BUS (BUS _ P in the figure) of the two-wire system communication BUS outputs a final single-phase demodulation output signal CMP _ P through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is connected with a demodulation output boost voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit; the first voltage-dividing resistor and the second voltage-dividing resistor are connected between the demodulation output lifting voltage source and the ground in series; the connection end of the first divider resistor and the second divider resistor outputs a comparison threshold voltage CMP _ N and is connected with a comparison circuit; the first voltage dividing resistor and the second voltage dividing resistor are used for outputting comparison threshold voltage in a resistor voltage dividing mode; the other communication BUS BUS _ N of the two-wire system communication BUS is connected with a demodulation output lifting voltage source through a second demodulation output coupling capacitor connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

Fig. 13 is a schematic diagram of the circuit principle of the demodulation output boost voltage source in the first to fourth embodiment circuits of the demodulation output circuit of the present invention: the power supply circuit is used for demodulating and outputting the lifting voltage source, and a power supply signal output by the power supply circuit is obtained through a voltage division circuit, or the power supply signal output by the power supply circuit is obtained through voltage stabilization of a voltage stabilizing diode, or the power supply signal output by the power supply circuit is obtained through an LDO linear voltage stabilizing circuit;

in fig. 13(a), the power supply signal VCC output by the power supply circuit passes through the resistor R5 for current limiting, and then the demodulated output boost voltage VREF is obtained through the zener diode D8; the demodulated output boost voltage VREF is also grounded and filtered through a filter capacitor C8;

in fig. 13(b), the power supply signal VCC output by the power supply circuit is divided by serially connecting resistors R5 and R9 to obtain the demodulated output boost voltage VREF; the demodulated output boost voltage VREF is also grounded and filtered through a filter capacitor C4.

The circuits of the first to fourth embodiments of the demodulation output circuit all satisfy the same condition, that is, the comparison threshold voltage CMP _ N is smaller than the demodulation output boost voltage source VREF.

Fig. 14 is a schematic circuit diagram of a fifth embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C17, a demodulation output matching resistor R19 and a demodulation output boost voltage source VREF _ CMPP; any one path of communication BUS (BUS _ P in the figure) of the two-wire system communication BUS outputs a final single-phase demodulation output signal CMP _ P through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is also connected with a demodulation output lifting voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit; the comparison threshold voltage VREF _ CMPN may be generated by the control circuit itself.

Fig. 15 is a schematic circuit diagram of a sixth embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C17, a demodulation output matching resistor R19, a demodulation output boost voltage source VREF _ CMPP and a second demodulation output coupling capacitor C18; any one path of communication BUS (BUS _ P in the figure) of the two-wire system communication BUS outputs a final single-phase demodulation output signal CMP _ P through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is also connected with a demodulation output lifting voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit; the other communication BUS BUS _ N of the two-wire system communication BUS is connected with a comparison threshold voltage VREF _ CMPN through a second demodulation output coupling capacitor which is connected in series, and simultaneously outputs the comparison threshold voltage CMP _ N to a comparator; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

Fig. 16 is a schematic circuit diagram of the demodulation output boost voltage source in the fifth to sixth embodiment circuits of the demodulation output circuit of the present invention: demodulating and outputting a lifting voltage source, and grounding through a filter capacitor of the lifting voltage source; the power supply signal output by the power supply circuit is grounded through the demodulation output first voltage-dividing resistor, the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source; the connection end of the first voltage-dividing resistor for demodulation output and the second voltage-dividing resistor for demodulation output outputs a comparison threshold voltage and is connected with a comparison circuit; the demodulation output voltage stabilizer is a voltage stabilizing resistor or a voltage stabilizing diode.

In specific implementation, fig. 16(a) shows that the demodulation output voltage regulator is a zener diode; at the moment, the boost voltage source is demodulated and output, and is grounded through a boost voltage source filter capacitor C11; a power supply signal VCC output by the power supply circuit is grounded through a demodulation output first voltage-dividing resistor R14, a demodulation output second voltage-dividing resistor R15 and a demodulation output voltage stabilizer (a voltage-stabilizing diode D1) which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source VREF _ CMPP; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs a comparison threshold voltage CREF _ CMPN and is connected with a comparison circuit;

FIG. 16(b) shows the demodulation output voltage regulator being a voltage stabilizing resistor; at the moment, the boost voltage source is demodulated and output, and is grounded through a boost voltage source filter capacitor C12; a power supply signal VCC output by the power supply circuit is grounded through a demodulation output first voltage-dividing resistor R13, a demodulation output second voltage-dividing resistor R16 and a demodulation output voltage stabilizer (voltage-stabilizing resistor R17) which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source VREF _ CMPP; the connection end of the first voltage-dividing resistor for demodulation output and the second voltage-dividing resistor for demodulation output outputs a comparison threshold voltage CREF _ CMPN and is connected with a comparison circuit.

The fifth to sixth embodiments of the demodulation output circuits all satisfy the same condition that the comparison threshold voltage VREF _ CMPN is greater than the demodulation output boost voltage source VREF _ CMPP.

Fig. 17 is a schematic circuit diagram of a seventh embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a differential demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C2, a second demodulation output coupling capacitor C3, a demodulation output boost voltage source VREF, a demodulation output first matching resistor R3, a demodulation output second matching resistor R6 and a demodulation output third matching resistor R7; any one path of communication BUS (BUS _ P in the figure) of the two-wire system communication BUS outputs a final demodulation output first signal CMP _ P through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the demodulation output first signal is grounded through a demodulation output first matching resistor, a demodulation output second matching resistor and a demodulation output third matching resistor which are sequentially connected in series; the connection end of the first demodulation output matching resistor and the second demodulation output matching resistor is connected with a demodulation output lifting voltage source VREF; the other communication BUS (marked as BUS _ N in the figure) of the two-wire system communication BUS outputs a final demodulation output second signal CMP _ N through a second demodulation output coupling capacitor which is connected in series and is connected with a comparison circuit; the connection end of the demodulation output second matching resistor and the demodulation output third matching resistor is directly connected with the demodulation output second signal; the demodulation output lifting voltage source, the demodulation output first matching resistor, the demodulation output second matching resistor and the demodulation output third matching resistor are used for lifting the voltage level of the demodulation output first signal and the demodulation output second signal to the working voltage range of the comparison circuit; the first demodulation output coupling capacitor and the second demodulation output coupling capacitor are used for coupling the carrier signal on the two-wire system communication bus into the demodulation output circuit.

In this embodiment, the boost voltage source is demodulated and output, and the power signal output by the power circuit is obtained through a voltage dividing circuit, or the power signal output by the power circuit is obtained through voltage stabilization of a voltage stabilizing diode, or the power signal output by the power circuit is obtained through an LDO linear voltage stabilizing circuit. The circuit diagram of the demodulation output boost voltage source VREF is the same as that in fig. 13, and the comparison threshold voltage CMP _ N is smaller than the demodulation output boost voltage source VREF.

Fig. 18 is a schematic circuit diagram of an eighth embodiment of the demodulation output circuit of the present invention: the demodulation output circuit is a differential demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor C2, a second demodulation output coupling capacitor C3, a demodulation output boost voltage source VREF _ CMPP and a demodulation output first matching resistor R3; any one path of communication BUS (marked BUS _ P in the figure) of the two-wire system communication BUS outputs a final demodulation output first signal CMP _ P through a first demodulation output coupling capacitor which is connected in series and is connected with a comparison circuit; the demodulation output first signal is also connected with a demodulation output lifting voltage source through a demodulation output first matching resistor which is connected in series; the other communication BUS (marked BUS _ N in the figure) of the two-wire system communication BUS outputs a final demodulation output second signal CMP _ N through a second demodulation output coupling capacitor which is connected in series and is connected with a comparison circuit; the demodulation output lifting voltage source and the demodulation output first matching resistor are used for lifting the voltage level of the demodulation output first signal to be within the working voltage range of the comparison circuit; the first demodulation output coupling capacitor and the second demodulation output coupling capacitor are used for coupling the carrier signal on the two-wire system communication bus into the demodulation output circuit.

In this embodiment, the demodulated output boost voltage source is grounded through a boost voltage source filter capacitor; the power supply signal output by the power supply circuit is grounded through the demodulation output first voltage-dividing resistor, the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs a second signal and is connected with a comparison circuit; the demodulation output voltage stabilizer is a voltage stabilizing resistor or a voltage stabilizing diode. The circuit diagram of the demodulation output boost voltage source is the same as that in fig. 16, and the comparison threshold voltage VREF _ CMPN is greater than the demodulation output boost voltage source VREF _ CMPP.

Fig. 19 is a circuit schematic diagram of a comparison circuit and a control circuit according to a first embodiment of the present invention: in this embodiment, the comparator uses a comparator provided in a control chip of the control circuit, and thus the control chip is the comparison circuit; at the moment, the control chip is composed of a control chip with the model number of NY8A 054E; pins 6 and 7 of the chip are connected with demodulation signals CMP _ N and CMP _ P output by the demodulation output circuit; a pin 1 of the chip is directly connected with a power supply signal VCC and gets electricity; the 8 pins of the chip are directly grounded; the 2 pins and 3 pins of the chip are connected with external equipment: DATA _ IN is a bus signal to be modulated acquired from the outside, and DATA _ OUT is a demodulated signal which has been demodulated and output to an external device; pins 4 and 5 of the chip are the PWM signals output to the driver circuit.

Fig. 20 is a circuit diagram of a comparison circuit and a control circuit according to a second embodiment of the present invention: in this embodiment, a separate external comparator is used, so the demodulation desired signals CMP _ N and CMP _ P output by the demodulation output circuit also need to be connected to an external comparator U3 (model may be TL 331); the comparison signal IN _ INT output by the comparator is connected with a pin 7 of a control chip U5 (model is NY8A 054E); pins 4 and 5 of the control chip are PWM signals output to the driving circuit; a pin 1 of the control chip is directly connected with a power supply signal VCC and gets electricity; the 8 pins of the control chip are directly grounded; the

pins

2 and 3 of the control chip are connected with external equipment: DATA _ IN is a bus signal to be modulated acquired from the outside, and DATA _ OUT is a demodulated signal that has been demodulated and output to an external device.

In the embodiments of fig. 19 and 20, the control circuit itself does not generate the output comparison threshold voltage; furthermore, the non-inverting input and inverting input of the CMP _ N and CMP _ P and comparator (or control chip) can be reversed.

Fig. 21 is a circuit diagram of a comparison circuit and a control circuit according to a third embodiment of the present invention: in the embodiment, the control circuit generates output comparison threshold voltage, and meanwhile, the comparator also uses a comparator carried by the control circuit; at this time, the control chip is composed of a chip with model number NY8A 054E; a pin 1 of the chip learns a power supply signal VCC and gets electricity, and is grounded and filtered through a filter capacitor C19; the 8 pins of the chip are directly grounded; the 2 pins and 3 pins of the chip are connected with external equipment: DATA _ IN is a bus signal to be modulated acquired from the outside, and DATA _ OUT is a demodulated signal which has been demodulated and output to an external device; pins 4 and 5 of the chip are PWM signals output to the driving circuit; the 7 pins of the chip are input pins of a self-contained comparator, are connected with a signal CMP _ P output by the demodulation output circuit, and simultaneously, the control circuit generates output comparison threshold voltage by itself.

The utility model discloses the control chip who uses is general singlechip, except satisfying essential IO mouth quantity, the singlechip peripheral hardware only need satisfy possess outside interrupt function or built-in comparator function, can satisfy the utility model discloses the controller circuit requirement.

The reference voltage VREF used by the circuits of FIGS. 9, 10, 11, 12 and 17 of the present invention is derived from the circuit of FIG. 13; the reference voltages VREF _ CMPN, VREF _ CMPP used by the circuits of FIGS. 14, 15, 18 are derived from the circuit of FIG. 16; the circuits in the remaining figures are general circuits.

For example, the circuit is composed of a power circuit input (any one of fig. 2, fig. 3 and fig. 4), a power circuit voltage stabilization (any one of fig. 5 and fig. 6), a driving circuit fig. 7 including U1 and U2 or fig. 7 not including U1 and U2 input/output short circuits, a modulation coupling circuit fig. 8, a demodulation output circuit (any one of fig. 9 and fig. 11) and a corresponding control circuit fig. 21 or a demodulation output circuit (any one of fig. 10, fig. 11 and fig. 12) and a corresponding control circuit (any one of fig. 19 and fig. 20) and a reference voltage circuit fig. 13 of the demodulation output circuit.

Or a two-wire system direct current carrier communication circuit, the circuit is composed of a power circuit input (any one of figures 2, 3 and 4), a power circuit voltage stabilization (any one of figures 5 and 6), a driving circuit figure 7 containing U1 and U2 or figure 7 not containing U1 and U2 input-output short circuit, a modulation coupling circuit figure 8, a demodulation output circuit figure 14 and a corresponding control circuit figure 21 or a demodulation output circuit (any one of figures 15 and 18) and a corresponding control circuit (any one of figures 19 and 20), and a reference voltage circuit figure 16 of the demodulation output circuit.

Claims

1. A two-wire system direct current carrier communication circuit is characterized by comprising a plurality of nodes, wherein all the nodes are connected to a two-wire system communication bus; the two-wire system communication bus is connected with an external power supply and used for getting electricity; each node comprises a power supply circuit, a control circuit, a driving circuit, a modulation coupling circuit, a demodulation output circuit and a comparison circuit; the output end of the drive circuit is connected with the input end of the modulation coupling circuit, and the output end of the modulation coupling circuit is connected with the two-wire system communication bus; the input end of the demodulation output circuit is connected with the two-wire system communication bus, and the output end of the demodulation output circuit is connected with the input end of the comparison circuit; the input end of the driving circuit and the output end of the comparison circuit are both connected with the control circuit; the power supply circuit is used for getting electricity from the two-wire system communication bus and supplying power to the nodes; when the modulation and transmission of signals are carried out, the control circuit receives the signals to be modulated, and after the modulation is carried out by adopting the prior art, the modulated PWM signals are output to the two-wire system communication bus through the driving circuit and the modulation coupling circuit; when receiving and demodulating signals, the demodulation output circuit receives the signals on the two-wire system communication bus, the signals are compared by the comparison circuit, the comparison signals are uploaded to the control circuit, the control circuit demodulates by adopting the existing demodulation technology, and the demodulated signals are output to the outside.

2. The two-wire system dc carrier communication circuit according to claim 1, wherein the power supply circuit includes a power supply sub-circuit and a voltage regulator sub-circuit; the power taking electronic circuit is connected with the voltage stabilizing electronic circuit; the power taking electronic circuit is used for taking power from the two-wire system communication bus; the voltage stabilizing sub-circuit is used for obtaining electric energy from the electronic taking circuit, stabilizing the voltage and then outputting the electric energy.

3. The two-wire system direct current carrier communication circuit according to claim 2, wherein the power taking electronic circuit comprises a power taking first filter capacitor, a power taking second filter capacitor, a power taking protection TVS tube, a power taking first isolation inductor, a power taking second isolation inductor, a power taking rectifier bridge and a power taking output filter capacitor; a power-taking protection TVS tube is connected between the first input end of the power-taking electronic circuit and the second input end of the power-taking electronic circuit and used for protecting bus surge voltage; a first input end of the power taking electronic circuit is grounded through a power taking first filter capacitor and is used for filtering; a second input end of the electronic taking circuit is grounded through a second filter capacitor for taking electricity and filtering; the first input end of the power-taking electronic circuit is also connected with the first input end of the power-taking rectifier bridge after being connected with the first power-taking isolation inductor in series; the second input end of the power taking electronic circuit is also connected with the second input end of the power taking rectifier bridge after being connected with the power taking second isolation inductor in series; the power-taking first isolation inductor and the power-taking second isolation inductor are used for isolating carrier signals on the two-wire system communication bus; the output positive pole of the power-taking rectifier bridge outputs a final power-taking power supply and is connected with the voltage-stabilizing sub-circuit; the output cathode of the power-taking rectifier bridge is grounded; the output anode of the power-taking rectifier bridge is grounded through a power-taking output filter capacitor and is filtered.

4. The two-wire system direct current carrier communication circuit according to claim 2, wherein the power taking electronic circuit comprises a power taking first filter capacitor, a power taking second filter capacitor, a power taking protection TVS tube, a power taking first isolation inductor, a power taking second isolation inductor, a power taking output device, and a power taking output filter capacitor; a power-taking protection TVS tube is connected between the first input end of the power-taking electronic circuit and the second input end of the power-taking electronic circuit and is used for protecting bus surge voltage; a first input end of the power taking electronic circuit is grounded through a power taking first filter capacitor and is used for filtering; a second input end of the electronic taking circuit is grounded through a second filter capacitor for taking electricity and filtering; the first input end of the power-taking electronic circuit is also connected in series with a power-taking first isolation inductor and a power-taking output device, and then directly outputs a power-taking power supply and is connected with the voltage-stabilizing electronic circuit; the second input end of the electronic fetching circuit is also connected in series with a second isolating inductor for fetching electricity and then is directly grounded; the power-taking first isolation inductor and the power-taking second isolation inductor are used for isolating carrier signals on the two-wire system communication bus; the power supply is grounded and filtered through a power supply output filter capacitor; the electricity-taking output device is a diode or a short-circuit wire.

5. The two-wire system DC carrier communication circuit according to claim 2, wherein the regulator circuit is an LDO linear regulator circuit or a DC/DC converter regulator circuit.

6. The two-wire system direct current carrier communication circuit according to claim 1, wherein the control circuit is a single chip microcomputer.

7. The two-wire system dc carrier communication circuit according to claim 1, wherein the driving circuit includes a first push-pull circuit and a second push-pull circuit; two paths of PWM signals output by the control circuit, wherein the first path of PWM signals outputs first driving PWM signals through a first push-pull circuit connected in series, and the second path of PWM signals outputs second driving PWM signals through a second push-pull circuit connected in series; the first push-pull circuit and the second push-pull circuit are used for enhancing the driving capability of the PWM signal.

8. The two-wire system dc carrier communication circuit according to claim 1, wherein the driving circuit is a first shorting wire and a second shorting wire; and the second path of PWM signals outputs a second driving PWM signal through a second short connecting wire connected in series.

9. The two-wire system dc carrier communication circuit according to claim 1, wherein the modulation coupling circuit comprises a modulation coupling first capacitor and a modulation coupling second capacitor; and the second path of driving PWM signals are coupled to a second bus of the two-wire system communication bus through a modulation coupling second capacitor connected in series.

10. The two-wire system dc carrier communication circuit according to claim 1, wherein the demodulation output circuit is a single-phase demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor, a demodulation output matching resistor and a demodulation output lifting voltage source; any one path of communication bus of the two-wire system communication bus outputs a final single-phase demodulation output signal through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; meanwhile, the single-phase demodulation output signal is also connected with a demodulation output lifting voltage source through a demodulation output matching resistor which is connected in series; the demodulation output coupling capacitor is used for coupling signals on the communication bus; the demodulation output matching resistor and the demodulation output lifting voltage source are used for lifting the voltage level of the single-phase demodulation output signal to be within the working voltage range of the comparison circuit.

11. The two-wire system dc carrier communication circuit according to claim 10, wherein the demodulation output boosts the voltage source, the power signal outputted by the power circuit is obtained by a voltage divider circuit, or the power signal outputted by the power circuit is obtained by a voltage regulator diode, or the power signal outputted by the power circuit is obtained by an LDO linear voltage regulator circuit.

12. The two-wire dc carrier communication circuit according to claim 11, wherein the demodulation output circuit further comprises a first voltage dividing resistor and a second voltage dividing resistor, the first voltage dividing resistor and the second voltage dividing resistor being connected in series between the demodulation output boost voltage source and the ground; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs comparison threshold voltage and is connected with a comparison circuit; the first voltage dividing resistor and the second voltage dividing resistor are used for outputting comparison threshold voltage in a resistor voltage dividing mode.

13. The two-wire dc carrier communication circuit according to claim 11, wherein the demodulation output circuit further comprises a second demodulation output coupling capacitor; the other communication bus of the two-wire system communication bus is connected with a demodulation output lifting voltage source through a second demodulation output coupling capacitor connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

14. The two-wire dc carrier communication circuit according to claim 11, wherein the demodulation output circuit further comprises a first voltage dividing resistor, a second voltage dividing resistor, and a second demodulation output coupling capacitor; the first voltage-dividing resistor and the second voltage-dividing resistor are connected between the demodulation output lifting voltage source and the ground in series; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs comparison threshold voltage and is connected with a comparison circuit; the first voltage dividing resistor and the second voltage dividing resistor are used for outputting comparison threshold voltage in a resistor voltage dividing mode; the other communication bus of the two-wire system communication bus is connected with a demodulation output lifting voltage source through a second demodulation output coupling capacitor connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

15. The two-wire system dc carrier communication circuit of claim 10, wherein the demodulation output boost voltage source is grounded through a boost voltage source filter capacitor; the power supply signal output by the power supply circuit is grounded through the demodulation output first voltage-dividing resistor, the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source; the connection end of the first voltage-dividing resistor for demodulation output and the second voltage-dividing resistor for demodulation output outputs a comparison threshold voltage and is connected with a comparison circuit; the demodulation output voltage stabilizer is a voltage stabilizing resistor or a voltage stabilizing diode.

16. The two-wire system dc carrier communication circuit according to claim 15, wherein the demodulation output circuit further comprises a second demodulation output coupling capacitor; the other communication bus of the two-wire system communication bus is connected with a comparison threshold voltage through a second demodulation output coupling capacitor which is connected in series; the second demodulation output coupling capacitor is used for coupling the signal on the other communication bus to the demodulation output circuit so that the carrier signal has a complete loop.

17. The two-wire system dc carrier communication circuit according to claim 1, wherein the demodulation output circuit is a differential demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor, a second demodulation output coupling capacitor, a demodulation output lifting voltage source, a demodulation output first matching resistor, a demodulation output second matching resistor and a demodulation output third matching resistor; any one path of communication bus of the two-wire system communication bus outputs a final demodulation output first signal through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the demodulation output first signal is grounded through a demodulation output first matching resistor, a demodulation output second matching resistor and a demodulation output third matching resistor which are sequentially connected in series; the connection end of the first demodulation output matching resistor and the second demodulation output matching resistor is connected with a demodulation output lifting voltage source; the other communication bus of the two-wire system communication bus outputs a final demodulation output second signal through a second demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the connection end of the demodulation output second matching resistor and the demodulation output third matching resistor is directly connected with the demodulation output second signal; the demodulation output lifting voltage source, the demodulation output first matching resistor, the demodulation output second matching resistor and the demodulation output third matching resistor are used for lifting the voltage level of the demodulation output first signal and the demodulation output second signal to the working voltage range of the comparison circuit; the first demodulation output coupling capacitor and the second demodulation output coupling capacitor are used for coupling the carrier signal on the two-wire system communication bus into the demodulation output circuit; the demodulation output boost voltage source is obtained by a power supply signal output by the power supply circuit through a voltage division circuit, or by a voltage stabilization of a voltage stabilization diode, or by a LDO linear voltage stabilization circuit.

18. The two-wire system dc carrier communication circuit according to claim 1, wherein the demodulation output circuit is a differential demodulation output circuit; the demodulation output circuit comprises a first demodulation output coupling capacitor, a second demodulation output coupling capacitor, a demodulation output uplift voltage source and a demodulation output first matching resistor; any one path of communication bus of the two-wire system communication bus outputs a final demodulation output first signal through a first demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the demodulation output first signal is also connected with a demodulation output lifting voltage source through a demodulation output first matching resistor which is connected in series; the other communication bus of the two-wire system communication bus outputs a final demodulation output second signal through a second demodulation output coupling capacitor connected in series and is connected with a comparison circuit; the demodulation output lifting voltage source and the demodulation output first matching resistor are used for lifting the voltage level of the demodulation output first signal to be within the working voltage range of the comparison circuit; the first demodulation output coupling capacitor and the second demodulation output coupling capacitor are used for coupling the carrier signal on the two-wire system communication bus into the demodulation output circuit; the demodulation output lifting voltage source is grounded through a lifting voltage source filter capacitor; the power supply signal output by the power supply circuit is grounded through the demodulation output first voltage-dividing resistor, the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer which are connected in series; the connection end of the demodulation output second voltage-dividing resistor and the demodulation output voltage stabilizer is directly connected with a demodulation output lifting voltage source; the connection end of the first voltage-dividing resistor and the second voltage-dividing resistor outputs a second signal and is connected with a comparison circuit; the demodulation output voltage stabilizer is a voltage stabilizing resistor or a voltage stabilizing diode.

19. The two-wire system dc carrier communication circuit according to claim 1, wherein the comparator circuit is a dedicated comparator chip; or a singlechip integrated with a comparator.