CN212381436U

CN212381436U - Light circuit

Info

Publication number: CN212381436U
Application number: CN202021372058.6U
Authority: CN
Inventors: 王火炎; 李渝贵; 刘凯
Original assignee: Shenzhen Dart Illumination Co ltd
Current assignee: Shenzhen Date Culture Technology Co.,Ltd.
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2021-01-19
Anticipated expiration: 2030-07-10

Abstract

The utility model discloses a lighting circuit, which comprises a sending unit and a receiving unit, wherein the sending unit comprises a direct current power supply circuit, a signal modulation circuit and a lamp controller, and the receiving unit comprises a power supply restoration circuit and at least one lighting unit; the utility model discloses during the communication, the sending unit is at first in the DC power supply with digital signal modulation to the power, sends again toward the receiving element after generating carrier wave power supply signal, thereby receiving element demodulation carrier wave power supply signal obtains digital communication signal and DC power supply, finally realizes power supply and communication, in addition because light unit is parallelly connected, light unit realizes writing the order that address code distinguished light unit in order through the address line, so, the utility model discloses can satisfy the conveying of power supply, information, address code simultaneously on the basis of three lines, the utility model discloses the line is few, and communication quality is reliable, and is with low costs, and hardware overhead is few, is particularly suitable for large-scale light control system.

Description

Light circuit

Technical Field

The utility model relates to a DMX lamps and lanterns control field especially relates to a lighting circuit.

Background

DMX is an abbreviation for Digital MulTIpleX, meaning multiplexed Digital transmission. The DMX512 control protocol is an industry standard for transmitting data between a lighting controller and a luminaire device, published by the american society for stage lighting (usITT) in 1990, and is collectively referred to as the usITT DMX512(1990), and includes contents of electrical characteristics, data protocols, data formats, and the like. Compared with the traditional analog dimming system, the digital lighting system based on the DMX512 control protocol brings the change of the coverage of the sky to the lighting effects of large and medium-sized landscape brightening and film and television studios and comprehensive art stages by the powerful control function, and can be matched with the LED DMX drive to form a complete DMX control system due to the fact that a plurality of wound DMX lamps can be cascaded. In large-scale LED outdoor landscape brightening and decorating engineering, a control system consisting of a DMX512 controller and a DMX driver is widely applied. With the rise of the outdoor landscape decoration field in recent years, especially the connection mode of parallel transmission signals, the DMX512 protocol is greatly and heteroloudly applied to outdoor landscape decoration. On the large-scale landscape brightening project, in order to ensure that the subsequent manual maintenance cost is low, or the maintenance is not needed at all due to single-point faults, and the faults of any lamp point do not influence the work of other lamps, a parallel connection mode is basically adopted.

Although the light control system is developed to a networked control system, the DMX512 signal system is still the most widely applied system at present, and even if the networked light control system is large, the control end still adopts a DMX512 signal control mode in a large quantity. However, the DMX512 light control standard has some disadvantages, and the wiring and initial setting become too complicated as the system scale becomes larger.

Referring to fig. 1, in the conventional lighting DMX512 host, power supply and data transmission between peripherals (LED lamps) are mainly performed in a five-wire manner (one power line, two differential signal output data lines, one ground line, and one serial address code line), so that power supply and communication are performed respectively, as shown in the figure, U1 to Un represent a lamp chip, VIN and GND nodes are connected to the power line and the ground line respectively, A, B nodes are connected to the two differential signal output data lines, as shown by a dashed box in the figure, data can be written in any position on the data lines, and the ADRI node is connected to the address code line. The communication and power supply scheme inevitably causes more communication lines and difficult wiring, which not only causes the waste of connection resources, but also increases the connection complexity of the system.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in, to the above-mentioned defect of prior art, provide a lighting circuit.

The utility model provides a technical scheme that its technical problem adopted is: constructing a lighting circuit, which comprises a sending unit and a receiving unit, wherein the sending unit comprises a direct-current power supply circuit, a signal modulation circuit and a DMX512 lamp controller, and the receiving unit comprises a power supply restoration circuit and at least one DMX512 lighting unit;

the positive and negative output ends of the direct current power supply circuit are respectively connected with the two input ends of the signal modulation circuit, the two differential output ends of the signal modulation circuit are respectively connected with the differential input ends of the light units and the two input ends of the power supply restoration circuit through a first power supply line and a second power supply line, and all the light units are sequentially connected in series through address lines;

the signal modulation circuit is used for modulating a digital communication signal to a direct-current power supply output by the direct-current power supply circuit to form carrier power supply signal output; the light unit is used for receiving the carrier power supply signal and demodulating to obtain the digital communication signal; the power supply restoring circuit is used for receiving the carrier power supply signal and rectifying and restoring the direct-current power supply according to the original current direction to supply power to the whole receiving unit, and the lamp controller is used for writing in sequential address codes to each lamp unit through the address lines.

Preferably, the signal modulation circuit includes two sets of switches controlled by the lamp controller or the modulation controller, the lamp controller or the modulation controller is configured to control the state switching of the two sets of switches according to the digital communication signal, the states of the two sets of switches are opposite at any time, and only one set of switches is turned on;

the group of switches comprises a first switch connected between the positive output end of the direct-current power supply circuit and a first power supply line and a second switch connected between the negative output end of the direct-current power supply circuit and a second power supply line; the other set of switches includes a third switch connected between the positive output terminal of the dc power supply circuit and the second power supply line and a fourth switch connected between the negative output terminal of the dc power supply circuit and the first power supply line.

Preferably, the first switch and the third switch are both PMOS transistors, the second switch and the fourth switch are both NMOS transistors, the sources of the first switch and the third switch are connected in common and connected to the positive output terminal of the dc power supply circuit, the sources of the second switch and the fourth switch are connected in common and connected to the negative output terminal of the dc power supply circuit, the drains of the first switch and the fourth switch are connected in common and connected to the first power line via an inductor, the drains of the second switch and the third switch are connected in common and connected to the second power line via another inductor, the first switch and the third switch are connected to a resistor between their respective sources and gates, the gate of the first switch is connected in common to the gate of the second switch via a signal flip circuit and connected to the first control pin of the lamp controller or the modulation controller, and the gate of the third switch is connected in common to the gate of the fourth switch via another signal flip circuit and connected to the lamp controller or the modulation controller The second control pin of the modulation controller, the signal turning circuit is used for turning the input signal and then outputting the signal, and the first control pin and the second control pin of the lamp controller or the modulation controller are used for outputting square wave signals which are turned over mutually.

Preferably, the signal inverting circuit includes an NPN triode, a filter capacitor and a filter resistor, a base of the NPN triode receives an input square wave signal, a resistor is connected between the base and an emitter of the NPN triode, the emitter of the NPN triode is grounded, a collector of the NPN triode is connected to first ends of the filter capacitor and the filter resistor, and second ends of the filter capacitor and the filter resistor are used for outputting an inverted square wave signal.

Preferably, the sending unit further includes an output detection circuit, the output detection circuit includes an operational amplifier, a non-inverting input terminal of the operational amplifier is connected to the source of the second switch, an inverting input terminal of the operational amplifier is grounded via a resistor, a resistor is further connected between the inverting input terminal of the operational amplifier and an output terminal of the operational amplifier, and an output terminal of the operational amplifier is connected to one detection pin of the lamp controller or the modulation controller.

Preferably, each lamplight unit comprises a DXM decoding chip, an address signal input end of the DXM decoding chip is connected with an address signal output end of the DXM decoding chip of the previous lamplight unit through an address line, an address signal input end of the DXM decoding chip of the first lamplight unit is suspended, and two voltage detection pins of each DXM decoding chip are connected with the first power line and the second power line after being respectively subjected to optical coupling isolation and resistance voltage reduction.

Preferably, the power supply restoration circuit includes a bridge stack including a fifth switch, a sixth switch, a seventh switch, and an eighth switch, control ends of the seventh switch and the eighth switch are connected between the fifth switch and the sixth switch and connected to the first power line, control ends of the fifth switch and the sixth switch are connected between the seventh switch and the eighth switch and connected to the second power line, and a positive output end of the restored dc power supply between the fifth switch and the seventh switch and a negative output end of the restored dc power supply between the sixth switch and the eighth switch are used.

Preferably, the power supply reduction circuit further comprises a filter capacitor connected between the positive output terminal and the negative output terminal of the dc power supply.

Preferably, the fifth switch and the seventh switch are both PMOS transistors, and the sixth switch and the eighth switch are both NMOS transistors.

Preferably, the fifth switch and the eighth switch are each connected with a resistor between the source and the drain of each switch.

The utility model discloses a lighting circuit has following beneficial effect: the utility model discloses during the communication, the sending unit is at first in the DC power supply with digital signal modulation to the power, sends toward the receiving element again after generating carrier wave power supply signal, thereby receiving element demodulation carrier wave power supply signal obtains digital communication signal and DC power supply, finally realizes power supply and communication, in addition because light unit is parallelly connected, light unit realizes writing the order that address code distinguished light unit in order through the address line, so, the utility model discloses can satisfy the conveying of power supply, information, address code simultaneously on the basis of three lines, the utility model discloses the line is few, and communication quality is reliable, and is with low costs, and the hardware overhead is few, is convenient for expand and advantage such as maintenance, is particularly suitable for large-scale DMX512 light control system.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts:

fig. 1 is a schematic diagram of a conventional lighting DMX512 host and an LED lamp, which are powered and data-transmitted in a five-wire manner;

FIG. 2 is a schematic structural diagram of a lighting circuit according to the present invention;

FIG. 3 is a circuit schematic of a signal modulation circuit;

fig. 4 is a circuit schematic of the receiving unit.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. Exemplary embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. It should be understood that the embodiments and specific features in the embodiments of the present invention are described in detail in the present application, but not limited to the present application, and the technical features in the embodiments and specific features in the embodiments of the present invention can be combined with each other without conflict.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. It is noted that the term "coupled" or "connected" as used herein includes not only the direct coupling of two entities, but also the indirect coupling via other entities with beneficial and improved effects.

The terms including ordinal numbers such as "first", "second", and the like used in the present specification may be used to describe various components, but the components are not limited by the terms. These terms are used only for the purpose of distinguishing one constituent element from other constituent elements. For example, a first component may be named as a second component, and similarly, a second component may also be named as a first component, without departing from the scope of the present invention.

Referring to fig. 1, the power supply circuit based on two lines of direct current of the present invention has a communication circuit, which includes a transmitting unit 1 and a receiving unit 2, and the transmitting unit 1 and the receiving unit 2 are connected only by a first power line 100 and a second power line 200. The transmitting unit 1 includes a dc power circuit 11, a signal modulation circuit 12 and a DMX512 lamp controller 13, and the receiving unit 2 includes a power restoration circuit 21 and at least one DMX512 light unit 22.

The positive and negative output ends of the dc power circuit 11 are respectively connected to the two input ends of the signal modulation circuit 12, and the two differential output ends of the signal modulation circuit 12 are respectively connected to the differential input ends of the lighting units 22 and the two input ends of the power restoration circuit 21 via a first power line 100 and a second power line 200. In addition, because the power supply and communication modes of the light units 22 belong to parallel connection, in order to distinguish the sequence of the light units 22, all the light units 22 are sequentially connected in series through the address lines 300, and the light units 22 realize sequential address code writing through the address lines 300 to distinguish the sequence of the light units.

The signal modulation circuit 12 is configured to modulate a digital communication signal (such as a square wave signal) onto the dc power output by the dc power circuit 11 to form a carrier power signal output; the light unit 22 is configured to receive the carrier power signal and demodulate the carrier power signal to obtain the digital communication signal; the power source restoring circuit 21 is configured to receive the carrier power source signal, and rectify and restore the dc power source according to an original current direction to supply power to the whole receiving unit 1, that is, a current direction of the restored dc power source is stable, that is, an anode and a cathode of the restored dc power source are stable, so that an original output electrical parameter of the dc power source is not reduced due to the carrier.

Referring to fig. 3, the signal modulation circuit 12 includes a modulation controller U1(MCU, such as STC8G1K08-SOP8) and two sets of switches controlled by the modulation controller U1, and the modulation controller U1 is configured to control the state switching of the two sets of switches according to the digital communication signal, and the states of the two sets of switches are opposite at any time and only one set of switches is turned on. It will be appreciated that the modulator controller U1 could be omitted, with the lamp controller taking over its function directly.

Wherein, a set of switches comprises a first switch U3A connected between the positive output terminal of the DC power supply circuit 11 and the first power supply line 100 and a second switch U4B connected between the negative output terminal of the DC power supply circuit 11 and the second power supply line 200; the other set of switches comprises a third switch U3B connected between the positive output terminal of the dc power supply circuit 11 and the second power supply line 200 and a fourth switch U4A connected between the negative output terminal of the dc power supply circuit 11 and the first power supply line 100.

In this embodiment, the first switch U3A and the third switch U3B are PMOS transistors, the second switch U4B and the fourth switch U4A are NMOS transistors, the sources of the first switch U3A and the third switch U3B are connected in common and connected to the positive output terminal of the dc power circuit 11, the sources of the second switch U4B and the fourth switch U4A are connected in common and connected to the negative output terminal of the dc power circuit 11 via the parallel resistors R9 and R10, the drains of the first switch U3A and the fourth switch U4A are connected in common and connected to the first power line 100 via an inductor L1 (mainly filtering, which may be omitted), the drains of the second switch U4B and the third switch U3B are connected in common and connected to the second power line 200 via another inductor L2 (mainly filtering, which may be omitted), the first switch U4B and the third switch U3R 3527 are connected between the source of the resistor U3 and the gate B, the gate of the first switch U3A is connected to the gate of the second switch U4B through a signal inversion circuit and connected to the first control pin, i.e., pin 7, of the modulation controller U1, and the gate of the third switch U3B is connected to the gate of the fourth switch U4A through another signal inversion circuit and connected to the second control pin, i.e., pin 8, of the modulation controller U1.

The signal inverting circuit is configured to invert an input signal and output the inverted signal, and specifically, the signal inverting circuit connected to the gate of the first switch U3A includes an NPN transistor Q1, a filter capacitor C1, and a filter resistor R1, a base of the NPN transistor Q1 receives an input square wave signal PWM1 (a waveform of the square wave signal PWM1 is identical to a waveform of a digital communication signal) via a resistor R5, a resistor R6 is connected between the base and an emitter of the NPN transistor Q1, an emitter of the NPN transistor Q1 is grounded, a collector of the NPN transistor Q1 is connected to first ends of the filter capacitor C1 and the filter resistor R1, and second ends of the filter capacitor C1 and the filter resistor R1 are configured to output the inverted square wave signal to the U3A. Similarly, the signal inverting circuit connected to the gate of the third switch U3B includes an NPN transistor Q2, a filter capacitor C2, and a filter resistor R4, the base of the NPN transistor Q2 receives the input square wave signal PWM2 via a resistor R7, a resistor R8 is connected between the base and the emitter of the NPN transistor Q2, the emitter of the NPN transistor Q2 is grounded, the collector of the NPN transistor Q2 is connected to the first ends of the filter capacitor C2 and the filter resistor R4, and the second ends of the filter capacitor C2 and the filter resistor R4 are configured to output the inverted square wave signal to the U3B.

The first control pin (7 pins) and the second control pin (8 pins) of the modulation controller U1 are used for outputting square wave signals which are mutually reversed. As shown in the figure, the first control pin (pin 7) outputs a square wave signal PWM1, the second control pin (pin 8) outputs a square wave signal PWM2, the PWM1 and the PWM2 are inverted with respect to each other, and the resulting output PWM3 is a carrier power signal.

Preferably, the signal modulation circuit 12 further includes an output detection circuit 13, the output detection circuit 13 includes an operational amplifier U2A, a non-inverting input terminal of the operational amplifier U2A is connected to the source of the second switch U4B, an inverting input terminal of the operational amplifier U2A is connected to the ground via a resistor R12, a resistor R11 is further connected between the inverting input terminal of the operational amplifier U2A and the output terminal of the operational amplifier U2A, and the output terminal of the operational amplifier U2A is connected to one detection pin, i.e., pin 6, of the modulation controller U1.

Referring to fig. 4, the principle of each light unit 22 in terms of power supply and signal decoding is the same, and only one of the light units 22 is taken as an example for explanation. As shown, the first lighting unit 22 includes a DXM decoding chip DMX512-U1 such as UCS512, and R, G, B, W four light strings respectively connected to R, G, B, W pins of the DMX512-U1, each light string including at least one LED light bead. The two voltage detection pins (11 and 12 pins) of the DMX512-U1 are respectively connected to the first power line 100 and the second power line 200 through resistors R4 and R3 after being optically coupled and isolated. The resistors R3 and R4 mainly have the functions of voltage division and current limitation so as to protect the optical coupler and avoid burning out the optical coupler due to overcurrent.

Because the power supply and communication modes of the light units 22 belong to parallel connection, the sequence of the light units 22 cannot be determined, in order to distinguish the sequence of the light units 22, all the light units 22 are sequentially connected in series through the address lines 300, and the light units 22 realize sequential address code writing through the address lines 300 to distinguish the sequence of the light units. Specifically, the address signal input terminal (pin 10 in the figure) of each DXM decoding chip is connected to the address signal output terminal (pin P0 in the figure) of the previous DXM decoding chip through an address line, and the address signal input terminals of the DXM decoding chips DMX512-U1 of the first lighting unit are floating. The address writing process is that the first DXM decoding chip writes the address after decoding the signal, and informs the second DXM decoding chip connected with the first DXM decoding chip of the address writing process through the address line 300, and informs the third DXM decoding chip connected with the second DXM decoding chip of the address writing process through the address line 300, and so on, so that the sequence of the light units can be determined. For other DXM decoding chips except the first DXM decoding chip, since their input address signal outputs are connected to the DXM decoding chip, they all write addresses after being notified by the DXM decoding chip of the previous stage.

It should be noted that, in practice, to facilitate the replacement of the sequence of the light units 22 and also to facilitate the installation, the address signal input and the address signal output of each DXM decoding chip are connected to the address line 300, so that the address signal outputs of the DMX512-U1 shown in fig. 4 are actually connected to the address line 300.

The power supply restoration circuit 21 includes a bridge stack formed by a fifth switch U1A, a sixth switch U2A, a seventh switch U1B, and an eighth switch U2B, control ends of the seventh switch U1B and the eighth switch U2B are connected between the fifth switch U1A and the sixth switch U2A and connected to the first power line 100, control ends of the fifth switch U1A and the sixth switch U2A are connected between the seventh switch U1B and the eighth switch U2B and connected to the second power line 200, and a positive output end of the restored dc power supply is between the fifth switch U1A and the seventh switch U1B, and a negative output end of the restored dc power supply is between the sixth switch U2A and the eighth switch U2B. Preferably, the fifth switch U1A and the eighth switch U2B are connected with resistors R1 and R2 between the source and the drain of each switch.

In this embodiment, the fifth switch U1A and the seventh switch U1B are both PMOS transistors, and the sixth switch U2A and the eighth switch U2B are both NMOS transistors. Of course, in other embodiments, the MOS transistor may be replaced by a triode, which are simple variations of this embodiment and are all within the scope of the present invention. The power supply restoring circuit 21 of this embodiment can convert the carrier power supply signal into the stable dc power supply of current direction automatically (that is, the positive pole and the negative pole of dc power supply are all stable), no matter who is positive and negative in the first power cord 100, the second power cord 200, the positive pole and the negative pole of the dc power supply that final power supply restoring circuit 21 reduced are stable all the time, and this circuit voltage drop is very little moreover, and the voltage drop to the power is better than general rectifier bridge.

The utility model discloses a theory of operation is:

referring to fig. 3, when the 8 pin output of U1 is high, U3B and U4A are both turned on to form a complete loop, and dc power flows out through U3B and then flows back through U4A. When the output of pin 7 of U1 is high, U3A and U4B are turned on simultaneously, and dc power flows out through U3A and then flows back through U4B to form another complete loop. Because the current directions of the two loops are completely opposite, the pins 7 and 8 of the MCU only need to output a PWM square wave which is mutually reversed (namely complementary), and finally the output carrier power supply signal carries a square wave signal.

Referring to fig. 4, assuming that the signal of the power line 100 is positive and the signal of the power line 200 is negative, the source and drain of U2B are turned on. Similarly, the source and the drain of the U1A are just conducted by the combined action of the negative voltage and the positive voltage, the output voltage is equal to the input voltage because the MOS tube is completely conducted and is connected by the approximate conducting wire, and the internal resistance is equal to the sum of the conducting resistances of the PMOS tube and the NMOS tube. When the input is opposite, the other loop is formed by just completely conducting the other group U2A and U1B. In this embodiment, in order to prevent the 4 MOS transistors from being unable to form 2 stable states of conducting 2 loads and consuming energy, 2 resistors R1 and R23 are added, and the resistance is selected to be 300K, so that the balance is intentionally broken and the MOS transistors are in a stable state. Because the on-resistance of the MOS transistor is much smaller than that of the silicon diode, substantially no energy is lost and no heat is generated.

Through the address lines in the serial form, a manner similar to a hand holding is formed between the light units 22, so that the lamp controller 13 can conveniently identify and detect the arrangement sequence of the light units 22, and the light units 22 closest to the ports of the lamp controller 13 are arranged in sequence by adding one to the first. The light units 22 actively enter the address code comparison mode, and the address codes are sequentially encoded on the corresponding light units 22, so that the sequential address codes can be automatically written in.

The utility model discloses do not receive the puzzlement of making a round trip to transmit signal data, not polarity division on two power lines in the wiring or the multi-thread puzzlement of bringing. The trouble caused by wiring between the sending unit and the receiving unit is well solved, and the communication method is particularly suitable for communication between the SELV voltage (the SELV voltage is commonly called safe ultra-low voltage and refers to the highest voltage which is not dangerous to people and exists between two conductive parts which can be touched at the same time under the most adverse condition) power supply equipment and the module. The problem of wired communication connection wiring many is greatly solved, a series of problems such as high cost, electromagnetic interference many, hardware complicacy that adopt wireless communication are avoided again. Meanwhile, signal transmission is carried out by adopting similar difference, signals are transmitted on the two wires by the differential transmission, the amplitudes of the two signals are the same, and the phases of the two signals are opposite. In addition, compared with the traditional method of routing one signal wire and one ground wire (namely, single-ended signals), the differential signal also solves the problem that routing one signal wire or one power wire and one ground wire does not have the following characteristics: 1) the anti-interference capability is strong: the interference noise is generally loaded on two lines equally and simultaneously, and the difference value is 0, namely, the noise does not influence the logic significance of the signal; 2) electromagnetic interference (EMI) can be effectively suppressed: since the two wires are close together and the signal amplitudes are equal, the coupling electromagnetic fields between the two wires and the ground are also equal in amplitude, and at the same time, their signal polarities are opposite, and their electromagnetic fields cancel each other out. Therefore, the electromagnetic interference to the outside is small; 3) the time sequence positioning is accurate: the receiving end of the differential signal is a point where the difference between the amplitudes of the signals on the two lines makes a positive or negative transition, and serves as a transition point of the judgment logic 0/1. The common single-ended signal uses the threshold voltage as the trip point of the signal logic 0/1, is greatly influenced by the ratio of the threshold voltage to the signal amplitude voltage, and is not suitable for low-amplitude signals.

In summary, the light circuit of the present invention has the following beneficial effects: the utility model discloses during the communication, the sending unit is at first in the DC power supply with digital signal modulation to the power, sends toward the receiving element again after generating carrier wave power supply signal, thereby receiving element demodulation carrier wave power supply signal obtains digital communication signal and DC power supply, finally realizes power supply and communication, in addition because light unit is parallelly connected, light unit realizes writing the order that address code distinguished light unit in order through the address line, so, the utility model discloses can satisfy the conveying of power supply, information, address code simultaneously on the basis of three lines, the utility model discloses the line is few, and communication quality is reliable, and is with low costs, and the hardware overhead is few, is convenient for expand and advantage such as maintenance, is particularly suitable for large-scale DMX512 light control system.

While the embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many modifications may be made by one skilled in the art without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A lighting circuit is characterized by comprising a sending unit and a receiving unit, wherein the sending unit comprises a direct-current power supply circuit, a signal modulation circuit and a lamp controller, and the receiving unit comprises a power supply restoration circuit and at least one lighting unit;

2. The light circuit of claim 1, wherein the signal modulation circuit comprises two sets of switches controlled by the light controller or the modulation controller, the two sets of switches being in opposite states at any time and only one set of switches being on;

3. The light circuit of claim 2, wherein the first switch and the third switch are both PMOS transistors, the second switch and the fourth switch are both NMOS transistors, the sources of the first switch and the third switch are connected in common and connected to the positive output terminal of the DC power supply circuit, the sources of the second switch and the fourth switch are connected in common and connected to the negative output terminal of the DC power supply circuit, the drains of the first switch and the fourth switch are connected in common and connected to a first power line via an inductor, the drains of the second switch and the third switch are connected in common and connected to a second power line via another inductor, the first switch and the third switch are connected with a resistor between the respective source and gate, the gate of the first switch is connected in common with the gate of the second switch via a signal flipping circuit and connected to the first control pin of the lamp controller or the modulation controller, the grid of the third switch is connected with the grid of the fourth switch through another signal turning circuit in a common mode and is connected with the second control pin of the lamp controller or the modulation controller, the signal turning circuit is used for turning input signals and then outputting the input signals, and the first control pin and the second control pin of the lamp controller or the modulation controller are used for outputting square wave signals which are turned over mutually.

4. The lamp circuit according to claim 3, wherein the signal flipping circuit comprises an NPN triode, a filter capacitor and a filter resistor, wherein a base of the NPN triode receives an input square wave signal, a resistor is connected between the base and an emitter of the NPN triode, the emitter of the NPN triode is grounded, a collector of the NPN triode is connected with first ends of the filter capacitor and the filter resistor, and second ends of the filter capacitor and the filter resistor are used for outputting the flipped square wave signal.

5. The lamp circuit of claim 3, wherein the sending unit further comprises an output detection circuit, the output detection circuit comprises an operational amplifier, a non-inverting input terminal of the operational amplifier is connected to the source of the second switch, a non-inverting input terminal of the operational amplifier is grounded via a resistor, a resistor is further connected between the non-inverting input terminal of the operational amplifier and an output terminal of the operational amplifier, and an output terminal of the operational amplifier is connected to a detection pin of the lamp controller or the modulation controller.

6. The lighting circuit according to claim 1, wherein each lighting unit comprises a DXM decoding chip, an address signal input terminal of the DXM decoding chip is connected to an address signal output terminal of the DXM decoding chip of a previous lighting unit via an address line, an address signal input terminal of the DXM decoding chip of a first lighting unit is floating, and two voltage detection pins of each DXM decoding chip are respectively connected to the first power line and the second power line after being stepped down via an optical coupler and a resistor.

7. The light circuit of claim 1, wherein the power supply recovery circuit comprises a bridge stack including a fifth switch, a sixth switch, a seventh switch, and an eighth switch, control terminals of the seventh switch and the eighth switch are connected between the fifth switch and the sixth switch and connected to the first power line, control terminals of the fifth switch and the sixth switch are connected between the seventh switch and the eighth switch and connected to the second power line, and a positive output terminal of the recovered dc power supply is connected between the fifth switch and the seventh switch, and a negative output terminal of the recovered dc power supply is connected between the sixth switch and the eighth switch.

8. A light circuit as claimed in claim 7, wherein the power supply restoration circuit further comprises a filter capacitor connected between the positive and negative output terminals of the DC power supply.

9. A light circuit as claimed in claim 7, wherein the fifth switch and the seventh switch are both PMOS transistors and the sixth switch and the eighth switch are both NMOS transistors.

10. A light circuit as claimed in claim 9, wherein the fifth and eighth switches each have a resistor connected between their respective sources and drains.