High-voltage multi-section constant-current LED emergency lighting driving system and control method

Abstract

The invention discloses a high-voltage multi-section constant-current LED emergency lighting driving system and a control method. Relates to the technical field of power supply. Comprising LED lamp beads, an alternating current power supply part, an EPS power supply part and a driving IC. The alternating current power supply part and the EPS power supply part supply power to the same LED lamp bead through the same driving IC; according to the scheme, a traditional circuit structure is improved, the alternating current power supply part and the EPS power supply part supply power to the same LED lamp bead through the same driving IC, and the purposes of reducing cost and simplifying a circuit are achieved; wherein the alternating current power supply part accords with high-low voltage power grid input and meets sub-harmonic requirements; meanwhile, the EPS power supply part outputs constant voltage, the output power of the voltage changes along with the combination of the LED lamp beads, linear driving is shared to realize single-section constant current, and the purposes of reducing the cost and simplifying the circuit are realized on the premise of flexibly realizing EPS illumination application of different powers.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, specifically to a high-voltage multi-segment constant current LED emergency lighting drive system and control method. Background Technology

[0002] Emergency lighting systems are critical facilities for ensuring the safe evacuation of personnel in emergencies such as fires. According to strict fire safety regulations, emergency lighting systems typically employ a dual power supply mode of "normal power + emergency power supply." Specifically, the system includes a normal lighting section powered by mains electricity (grid power) and an emergency lighting section powered by a centralized emergency power supply (EPS). To ensure that the emergency lighting can operate independently and reliably in the event of a mains power failure, these two lighting sections are usually completely independent in terms of physical layout and circuit design.

[0003] In current mainstream emergency lighting fixture designs, especially LED-based lighting solutions, the driving methods for the mains lighting section are mainly divided into two types: switching power supply driving and high-voltage linear driving. Switching power supply driving solutions provide a stable and efficient constant current source to drive LED strings through complex AC-DC conversion circuits. Their advantages include stable performance, high efficiency, and good dimming compatibility, but they are relatively expensive and require significant space for magnetic component placement. High-voltage linear driving solutions, on the other hand, use a simplified circuit structure to directly rectify and segmentedly control the AC mains power to drive the LED strings. Their advantages include low cost, fewer components, and no need for inductors or transformers, but their performance is typically significantly affected by mains voltage fluctuations.

[0004] For reasons of system reliability, cost control, and meeting the needs of different lighting scenarios, many designs choose to integrate both of the above-mentioned driving schemes and their corresponding LED strings on the same luminaire PCB (printed circuit board). For example, a switching power supply is used to drive a set of high-brightness, dimmable LED strings as the main lighting, while a high-voltage linear drive is used to drive another set of LED strings for basic lighting as an auxiliary or backup.

[0005] However, this architecture, which combines mains lighting (containing two independent drive schemes) and EPS emergency lighting in parallel, presents significant difficulties and challenges for the layout design of a single PCB:

[0006] The three types of driver circuits (switching power supply, high-voltage linear drive, and EPS emergency drive) and their corresponding multi-channel LED strings all need to be laid out on a limited PCB area, resulting in an extremely crowded component layout and severely insufficient trace space. High-frequency switching devices (such as MOSFETs) in the switching power supply circuit are strong interference sources; the high-order harmonics they generate can easily interfere with the noise-sensitive high-voltage linear drive circuit and EPS control circuit through spatial radiation or PCB trace coupling, affecting their operational stability. Therefore, strict isolation areas and grounding strategies must be planned for different circuit modules during layout, further exacerbating the complexity of the board layout. The concentrated operation of multiple driver circuits generates a large amount of heat, especially the high-voltage linear drive circuit, which has a high power consumption due to its operating principle. In a confined space, the concentrated accumulation of heat not only reduces the luminous efficacy and lifespan of the LEDs but may also affect the reliability of the driver chip, placing extremely high demands on the layout of heat dissipation channels and hot-swappable components. The wiring needs to be planned to be non-intersecting and have reasonable paths for multiple inputs (mains live and neutral wires, EPS inputs), multiple outputs (multiple LED + / - groups), and various control signals. At the same time, it is also necessary to meet the safety clearance requirements (such as creepage distance and clearance between primary high voltage and secondary low voltage). This makes the wiring work extremely complicated and often requires increasing the number of PCB layers, which leads to increased costs.

[0007] In summary, while the existing "three-in-one" layout achieves integration and redundancy in system functionality, its inherent multi-circuit independent parallel architecture is the root cause of the high difficulty, cost, and reliability challenges in PCB layout. Therefore, there is an urgent need in this field for an innovative circuit architecture that can effectively simplify PCB design, save space and cost, and improve the overall reliability of the system while ensuring all functions and safety specifications are met. Summary of the Invention

[0008] The technical problem this invention aims to solve is that in emergency lighting design, mains lighting and EPS lighting are usually laid out separately; mains-powered lighting is further divided into switching power supplies and high-voltage linear drives, with the LED strings of the two drive schemes operating independently. This layout increases the difficulty of PCB layout. The purpose of this invention is to provide a high-voltage multi-segment constant current LED emergency lighting drive system and control method, which improves upon the traditional circuit architecture. The AC power supply section and the EPS power supply section supply power to the same LED beads through the same driver IC, achieving cost reduction and simplified circuitry. The AC power supply section meets both high and low voltage mains input requirements and satisfies harmonic requirements. At the same time, the EPS power supply section outputs a constant voltage, the output of which changes in power according to the combination of LED beads, and shares a linear drive to achieve single-segment constant current, flexibly realizing EPS lighting applications with different power levels.

[0009] This invention is achieved through the following technical solution:

[0010] This solution provides a high-voltage multi-segment constant current LED emergency lighting drive system, including:

[0011] LED beads are used for emergency lighting;

[0012] The AC power supply section is used to provide the main power supply; the AC power supply section is electrically connected to the LED lamp beads.

[0013] The EPS power supply section is used to provide backup power; the EPS power supply section is electrically connected to the LED beads.

[0014] The driver IC is used to drive the AC power supply section to provide constant current power to the LED beads, or to drive the EPS power supply section to provide constant voltage power to the LED beads; the driver IC is also used to adjust the power supply power of the EPS power supply section based on the change in the LED bead string ratio.

[0015] The AC power supply section and the EPS power supply section supply power to the same LED bead through the same driver IC, and the driver IC is electrically connected to both the AC power supply section and the EPS power supply section.

[0016] A further optimized solution is that the AC power supply section includes: an AC input terminal, a varistor, a rectifier bridge, resistors R1 and R2, and an isolation diode D1;

[0017] The first port of the AC input terminal is connected to the first port of the rectifier bridge. The second port of the AC input terminal is connected to the third port of the rectifier bridge after being connected in series with a fuse. One end of the varistor is connected to the first port of the rectifier bridge, and the other end is connected between the fuse and the rectifier bridge. The second port of the rectifier bridge is connected to the positive terminal of the isolation diode D1, and the negative terminal of the isolation diode D1 is connected to the LED bead. The fourth port of the rectifier bridge is grounded.

[0018] One end of resistor R1 is connected to the second port of the rectifier bridge, and the other end is connected to the fourth port of the rectifier bridge after being connected in series with resistor R2.

[0019] The driver IC is connected between resistors R1 and R2.

[0020] A further optimization is that the driver IC is the PT1918 chip;

[0021] The VDD and TPC terminals of the PT1918 chip are connected together and then connected in series with capacitor C1 to the fourth port of the rectifier bridge.

[0022] The GND terminal of the PT1918 chip is connected to the fourth port of the rectifier bridge;

[0023] The CS terminal of the PT1918 chip is connected to the fourth port of the rectifier bridge after being connected in series with resistor R3.

[0024] The DR terminal of the PT1918 chip is connected to the LED beads.

[0025] A further optimized solution is that the EPS power supply section includes: a battery, a boost circuit, a charging circuit, an isolation diode D2, and an inverter output circuit;

[0026] The charging circuit is connected to the fourth port of the rectifier bridge at one end and to the input terminal of the battery at the other end.

[0027] The battery output terminal is connected to a boost circuit, the boost circuit output terminal is connected to an inverter output circuit, the inverter output circuit is connected to the positive terminal of isolation diode D2, and the negative terminal of isolation diode D2 is connected to an LED bead.

[0028] A further optimized solution includes a detection circuit; the detection circuit includes: resistors R4, R5, R6, and R7, transistor Q1, Zener diode D4, and isolation diode D3;

[0029] One end of resistor R4 is connected to the positive terminal of isolation diode D2, and the other end is connected to the collector of transistor Q1. The emitter of transistor Q1 is connected to ground in series with resistors R5 and R6.

[0030] One end of resistor R7 is connected to the base of transistor Q1, and the other end is connected to the collector of transistor Q1; the positive terminal of Zener diode D4 is grounded, and the negative terminal is connected to the base of transistor Q1.

[0031] The positive terminal of the isolation diode D3 is connected between resistors R5 and R6, and the other terminal is connected between resistors R1 and R2.

[0032] A further optimized solution is that the charging circuit and boost circuit include: boost inductor L7, diode D5, control chip, field-effect transistor M0, and output capacitor C2;

[0033] One end of the boost inductor L7 is connected to the positive terminal of the battery, and the other end is connected to the positive terminal of the diode D5. The negative terminal of the diode D5 is connected to the output terminal. One end of the output capacitor C2 is connected to the output terminal, and the other end is grounded. The negative terminal of the battery is grounded.

[0034] One end of the control chip is grounded, and the other end is connected to the gate of the field-effect transistor M0. The source of the field-effect transistor is grounded, and the drain of the field-effect transistor is connected between the boost inductor L7 and the diode D5.

[0035] A further optimized solution is that the driver IC includes a multiplier digital integrator circuit and a driver circuit;

[0036] The multiplier digital integrator circuit includes amplifiers G1, G2, G3, G4, and G5; field-effect transistors M1, M2, M3, M4, M5, M6, M7, M8, M9, and M10; resistors R8, R9, R10, R11, and R12; a digital integrating capacitor; and a multiplier.

[0037] The EPS power supply section is connected to the input terminal of the multiplier digital integrator circuit. One end of resistor R8 is connected to the input terminal of the multiplier digital integrator circuit, and the other end is connected to point A after being connected in series with resistor R9. The negative input terminal of amplifier G1 is connected to point A after being connected in series with resistor R10. The output terminal of amplifier G1 is connected to the gate of field-effect transistor M5. The drain of field-effect transistor M5 is connected to the drain of field-effect transistor M1. The source of field-effect transistor M5 is connected to point A after being connected in series with resistor R10.

[0038] The source of field-effect transistor M1 is connected to the source of field-effect transistor M2, and the gates of field-effect transistor M1 and M2 are connected to the drain of field-effect transistor M5.

[0039] The drain of field-effect transistor M2, the drain of field-effect transistor M3, and the gate of field-effect transistor M3 are all connected to the drain of field-effect transistor M6; the source of field-effect transistor M6 is connected to point A after being connected in series with resistor R11; the gate of field-effect transistor M6 is connected to the output terminal of amplifier G2, and the negative input terminal of amplifier G2 is connected to point A after being connected in series with resistor R11.

[0040] The source of field-effect transistor M2 is connected to the source of field-effect transistor M3; the source of field-effect transistor M3 is connected to the source of field-effect transistor M4; the source of field-effect transistor M4 is connected to the source of field-effect transistor M9; and the source of field-effect transistor M9 is connected to the source of field-effect transistor M10.

[0041] The drain of the field-effect transistor M4 is connected to the negative input terminal of the amplifier G3. One end of the resistor R12 is connected to the negative input terminal of the amplifier G3, and the other end is connected to the output terminal of the amplifier G3.

[0042] The output of amplifier G3 is connected to point A via resistors R13 and R14 in series; the positive input of amplifier G4 is connected between resistors R13 and R14, and the negative input of amplifier G4 is connected to point A via resistor R15 in series.

[0043] The gate of field-effect transistor M9, the drain of field-effect transistor M9, and the gate of field-effect transistor M10 are all connected to the drain of field-effect transistor M7; the source of field-effect transistor M7 is connected to point A after being connected in series with resistor R15.

[0044] The drain of MOSFET M10 is connected to the drain of MOSFET M8, and the source of MOSFET M8 is connected to point A via a series resistor R16; the gate of MOSFET M8 is connected to the output of amplifier G5; the negative input of amplifier G5 is connected to point A via a series resistor R16.

[0045] The drains of MOSFET M10 and MOSFET M8 are both connected to the input of the digital integrating capacitor, and the output of the digital integrating capacitor is connected to the multiplier; the multiplier is connected between resistors R8 and R9.

[0046] A further optimized solution is that the driver circuit includes: resistor R17, resistor R18, field-effect transistor M11, field-effect transistor M12, field-effect transistor M13, field-effect transistor M14, amplifier G6, amplifier G7, amplifier G8, and amplifier G9.

[0047] One end of resistor R17 is connected to the positive input terminal of amplifier G9, and the other end is connected to the positive input terminal of amplifier G8. One end of resistor R18 is connected to the positive input terminal of amplifier G8, and the other end is connected to the positive input terminal of amplifier G7. The positive input terminal of amplifier G6 is connected to the positive input terminal of amplifier G7. The output terminal of amplifier G6 is connected to the gate of field-effect transistor M11, and the drain of field-effect transistor M11 is connected to the positive input terminal of amplifier G7.

[0048] The output of amplifier G7 is connected to the gate of field-effect transistor M12, and the drain of field-effect transistor M12 is connected to the first DR port.

[0049] The negative input terminal of amplifier G7, the source of field-effect transistor M12, the negative input terminal of amplifier G8, the source of field-effect transistor M13, the negative input terminal of amplifier G9, and the source of field-effect transistor M14 are connected together; the source and drain of field-effect transistor M13 are connected to the second DR port, and the source and drain of field-effect transistor M14 are connected to the third DR port.

[0050] This solution also provides a control method for controlling the aforementioned high-voltage multi-segment constant current LED emergency lighting drive system; the method includes:

[0051] When the AC power supply section provides the main power supply, the driver IC operates in a multi-segment driving mode and simultaneously provides charging current to the EPS power supply section.

[0052] After the detection circuit detects that the AC power supply is cut off, the EPS power supply outputs a DC voltage to provide current to the LED beads and simultaneously supplies power to the driver IC, which operates in a single-segment driving mode.

[0053] A further optimized solution is that, when the AC power supply section provides the main power, the multi-segment drive method meets the IEC requirements for harmonic ordering.

[0054] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0055] 1. This invention provides a high-voltage multi-segment constant current LED emergency lighting drive system and control method; it improves upon the traditional circuit architecture by using the same driver IC to power the same LED beads for both the AC power supply section and the EPS power supply section, thereby reducing costs and simplifying the circuit; the AC power supply section conforms to both high and low voltage grid inputs and meets harmonic requirements; simultaneously, the EPS power supply section outputs a constant voltage, the power output of which changes with the combination of LED beads, and uses a shared linear drive to achieve single-segment constant current, flexibly realizing EPS lighting applications with different power levels.

[0056] 2. The present invention provides a high-voltage multi-segment constant current LED emergency lighting driving system and control method; the driver IC can be used as a multi-segment linear drive in the AC power supply section to meet the current harmonic standard, and can also be used as a single-segment constant current source for the output of the EPS power supply section to achieve the purpose of cost reduction and circuit simplification.

[0057] 3. The present invention provides a high-voltage multi-segment constant current LED emergency lighting driving system and control method. When the driving IC drives the EPS power supply section, the lighting power can be adjusted as the ratio of LED light strings changes. Attached Figure Description

[0058] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0059] Figure 1 This is a structural outline diagram of a high-voltage multi-segment constant current LED emergency lighting drive system;

[0060] Figure 2 This is a circuit diagram of a high-voltage multi-segment constant current LED emergency lighting drive system.

[0061] Figure 3 This is a schematic diagram of a boost circuit;

[0062] Figure 4 This is a schematic diagram of the charging circuit;

[0063] Figure 5 The specific circuit structure diagrams for the charging circuit and the boost circuit are shown below.

[0064] Figure 6This is a schematic diagram of the driver section of the PT1918 chip;

[0065] Figure 7 This is a schematic diagram of a digital integrator circuit for a multiplier.

[0066] Figure 8 Simulation waveform diagram A when power is supplied to the AC power supply section;

[0067] Figure 9 Simulation waveform diagram B when powering the EPS power supply section. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0069] While the existing "three-in-one" layout achieves integration and redundancy in system functionality, its inherent multi-circuit independent parallel architecture is the root cause of the high difficulty, cost, and reliability challenges in PCB layout. Therefore, this solution provides the following embodiments to address the aforementioned technical problems:

[0070] Example 1

[0071] This embodiment provides a high-voltage multi-segment constant current LED emergency lighting drive system, such as... Figure 1 and Figure 2 As shown, it includes:

[0072] LED beads are used for emergency lighting;

[0073] The AC power supply section is used to provide the main power supply; the AC power supply section is electrically connected to the LED lamp beads.

[0074] The EPS power supply section is used to provide backup power; the EPS power supply section is electrically connected to the LED beads.

[0075] The driver IC is used to drive the AC power supply section to provide constant current power to the LED beads, or to drive the EPS power supply section to provide constant voltage power to the LED beads; the driver IC is also used to adjust the power supply power of the EPS power supply section based on the change in the LED bead string ratio.

[0076] The AC power supply section and the EPS power supply section supply power to the same LED bead through the same driver IC, and the driver IC is electrically connected to both the AC power supply section and the EPS power supply section.

[0077] The AC power supply section includes: AC input terminal, varistor SD, rectifier bridge, resistor R1, resistor R2 and isolation diode D1;

[0078] The first port of the AC input terminal is connected to the first port 1 of the rectifier bridge. The second port 2 of the AC input terminal is connected to port 3 of the rectifier bridge after being connected in series with fuse RR1. One end of the varistor is connected to the first port 1 of the rectifier bridge, and the other end is connected between the fuse and the rectifier bridge. The second port 2 of the rectifier bridge is connected to the positive terminal of isolation diode D1, and the negative terminal of isolation diode D1 is connected to the LED. The fourth port 4 of the rectifier bridge is grounded.

[0079] One end of resistor R1 is connected to the second port 2 of the rectifier bridge, and the other end is connected to the fourth port of the rectifier bridge after being connected in series with resistor R2.

[0080] The driver IC is connected between resistors R1 and R2.

[0081] The driver IC is the PT1918 chip;

[0082] The VDD and TPC terminals of the PT1918 chip are connected together and connected in series with capacitor C1, and then connected to the fourth port 4 of the rectifier bridge.

[0083] The GND terminal of the PT1918 chip is connected to the fourth port 4 of the rectifier bridge;

[0084] The CS terminal of the PT1918 chip is connected to the fourth port 4 of the rectifier bridge after being connected in series with resistor R3.

[0085] The DR terminal of the PT1918 chip is connected to the LED beads.

[0086] The EPS power supply section includes: battery, boost circuit, charging circuit, isolation diode D2, and inverter output circuit;

[0087] One end of the charging circuit is connected to port 4 of the rectifier bridge, and the other end is connected to the input terminal of the battery; for example... Figure 3 and Figure 4 As shown,

[0088] The battery output terminal is connected to a boost circuit, the boost circuit output terminal is connected to an inverter output circuit, the inverter output circuit is connected to the positive terminal of isolation diode D2, and the negative terminal of isolation diode D2 is connected to an LED bead.

[0089] It also includes a detection circuit; the detection circuit includes: resistors R4, R5, R6, and R7, transistor Q1, Zener diode D4, and isolation diode D3;

[0090] One end of resistor R4 is connected to the positive terminal of isolation diode D2, and the other end is connected to the collector of transistor Q1. The emitter of transistor Q1 is connected to ground in series with resistor R5 and the sixth resistor R6.

[0091] One end of resistor R7 is connected to the base of transistor Q1, and the other end is connected to the collector of transistor Q1; the positive terminal of Zener diode D4 is grounded, and the negative terminal is connected to the base of transistor Q1.

[0092] The positive terminal of the isolation diode D3 is connected between resistors R5 and R6, and the other terminal is connected between resistors R1 and R2.

[0093] like Figure 5 As shown, the charging circuit and boost circuit include: boost inductor L7, diode D5, control chip, field-effect transistor M0 and output capacitor C2;

[0094] One end of the boost inductor L7 is connected to the positive terminal of the battery, and the other end is connected to the positive terminal of the diode D5. The negative terminal of the diode D5 is connected to the output terminal. One end of the output capacitor C2 is connected to the output terminal, and the other end is grounded. The negative terminal of the battery is grounded.

[0095] One end of the control chip is grounded, and the other end is connected to the gate of the field-effect transistor M0. The source of the field-effect transistor is grounded, and the drain of the field-effect transistor is connected between the boost inductor L7 and the diode D5.

[0096] The driver IC includes a multiplier digital integrator circuit and a driver circuit;

[0097] like Figure 7 As shown, the multiplier digital integrator circuit includes amplifiers G1, G2, G3, G4, and G5; field-effect transistors M1, M2, M3, M4, M5, M6, M7, M8, M9, and M10; resistors R8, R9, R10, R11, and R12; a digital integrating capacitor; and a multiplier.

[0098] The EPS power supply section is connected to the input terminal of the multiplier digital integrator circuit. One end of resistor R8 is connected to the input terminal of the multiplier digital integrator circuit, and the other end is connected to point A after being connected in series with resistor R9. The negative input terminal of amplifier G1 is connected to point A after being connected in series with resistor R10. The output terminal of amplifier G1 is connected to the gate of field-effect transistor M5. The drain of field-effect transistor M5 is connected to the drain of field-effect transistor M1. The source of field-effect transistor M5 is connected to point A after being connected in series with resistor R10.

[0099] The source of field-effect transistor M1 is connected to the source of field-effect transistor M2, and the gates of field-effect transistor M1 and M2 are connected to the drain of field-effect transistor M5.

[0100] The drain of field-effect transistor M2, the drain of field-effect transistor M3, and the gate of field-effect transistor M3 are all connected to the drain of field-effect transistor M6; the source of field-effect transistor M6 is connected to point A after being connected in series with resistor R11; the gate of field-effect transistor M6 is connected to the output terminal of amplifier G2, and the negative input terminal of amplifier G2 is connected to point A after being connected in series with resistor R11.

[0101] The source of field-effect transistor M2 is connected to the source of field-effect transistor M3; the source of field-effect transistor M3 is connected to the source of field-effect transistor M4; the source of field-effect transistor M4 is connected to the source of field-effect transistor M9; and the source of field-effect transistor M9 is connected to the source of field-effect transistor M10.

[0102] The drain of the field-effect transistor M4 is connected to the negative input terminal of the amplifier G3. One end of the resistor R12 is connected to the negative input terminal of the amplifier G3, and the other end is connected to the output terminal of the amplifier G3.

[0103] The output of amplifier G3 is connected to point A via resistors R13 and R14 in series; the positive input of amplifier G4 is connected between resistors R13 and R14, and the negative input of amplifier G4 is connected to point A via resistor R15 in series.

[0104] The gate of field-effect transistor M9, the drain of field-effect transistor M9, and the gate of field-effect transistor M10 are all connected to the drain of field-effect transistor M7; the source of field-effect transistor M7 is connected to point A after being connected in series with resistor R15.

[0105] The drain of MOSFET M10 is connected to the drain of MOSFET M8, and the source of MOSFET M8 is connected to point A via a series resistor R16; the gate of MOSFET M8 is connected to the output of amplifier G5; the negative input of amplifier G5 is connected to point A via a series resistor R16.

[0106] The drains of MOSFET M10 and MOSFET M8 are both connected to the input of the digital integrating capacitor, and the output of the digital integrating capacitor is connected to the multiplier; the multiplier is connected between resistors R8 and R9.

[0107] like Figure 8 As shown, the driver circuit includes: resistor R17, resistor R18, field-effect transistor M11, field-effect transistor M12, field-effect transistor M13, field-effect transistor M14, amplifier G6, amplifier G7, amplifier G8 and amplifier G9.

[0108] One end of resistor R17 is connected to the positive input terminal of amplifier G9, and the other end is connected to the positive input terminal of amplifier G8. One end of resistor R18 is connected to the positive input terminal of amplifier G8, and the other end is connected to the positive input terminal of amplifier G7. The positive input terminal of amplifier G6 is connected to the positive input terminal of amplifier G7. The output terminal of amplifier G6 is connected to the gate of field-effect transistor M11, and the drain of field-effect transistor M11 is connected to the positive input terminal of amplifier G7.

[0109] The output of amplifier G7 is connected to the gate of field-effect transistor M12, and the drain of field-effect transistor M12 is connected to the first DR port (DR1 in this embodiment).

[0110] The negative input terminal of amplifier G7, the source of field-effect transistor M12, the negative input terminal of amplifier G8, the source of field-effect transistor M13, the negative input terminal of amplifier G9, and the source of field-effect transistor M14 are connected together; the drain of the source of field-effect transistor M13 is connected to the second DR port (DR2 in this embodiment), and the drain of the source of field-effect transistor M14 is connected to the third DR port (DR3 in this embodiment).

[0111] In this embodiment, the LED beads are three 90V LEDs connected in series. The negative terminals of isolation diodes D1 and D2 are connected to the LED string. The VIN terminal of the PT1918 chip is connected to the input terminal of the LED string. The output terminal of each LED is connected to one DR terminal of the PT1918 chip.

[0112] like Figure 6 As shown, the AC power supply section, combined with the driver IC, forms a mains power supply (assuming a power of 25W). The LED bead voltage is 270V. When the AC power supply section receives AC input, the linear driver PT1918 forms a three-segment constant current drive through the LED beads. This drive complies with the IEC requirements for harmonics (IEC61000-3-2). When the detection circuit detects that the MULT pin voltage is greater than 0.3V, the MCU outputs a low level to turn off the EN enable terminal of the battery inverter section, causing the EPS power supply section to shut down and have no output.

[0113] When the AC power supply is interrupted, the detection circuit detects that the VD voltage is 0. After several milliseconds, it confirms that the AC power supply is interrupted. At this time, the MCU of the EPS power supply section outputs a high level, the boost circuit works, and outputs a stable DC voltage. The DC voltage is isolated by the isolation diode D2 and then selects any one of the XYZ LED beads (the DC voltage can be 90V, 180V and 270V, and the three specifications can achieve three power levels) to form a current loop with the PT1918 chip. The VIN of the PT1918 chip starts to work after being powered by DC, the VDD voltage reaches 5V, and provides a reference for the internal CS circuit to maintain constant current drive.

[0114] Another path of the DC voltage output is through a detection circuit consisting of resistors R4 to R7, transistor Q1, Zener diode D4, and isolation diode D3. After being divided to 1V, it is connected to the MULT terminal of the PT1918 chip. At this time, the internal multiplier of the system stops working, and the high-precision range of the reference is maintained by the 1V DC voltage.

[0115] When the AC power supply is restored, there will be a voltage MULT between resistor R1 and resistor R2. The MCU of chip PT1918 detects that the voltage MULT is greater than 0.3V, and immediately shuts off EN, so the EPS power supply section does not work.

[0116] Meanwhile, the rectified DCBUS is connected to the battery charging circuit. Figure 3 As shown, charging the battery ensures that it can provide emergency power to the LED lights during the next power outage.

[0117] When the voltage MULT is sampled by DCBUS and enters the multiplier in the digital integrator circuit, the signal has the same shape as DCBUS and a smaller amplitude.

[0118] The driver circuit includes the IC driver, power MOS, and current sampling signal CS. When current flows through the current sampling signal CS, the voltage MULT is compared with the voltage VREF = 400mV. When the voltage MULT is greater than the voltage VREF, a low pulse is given to the digital integrator, the comp voltage decreases, and the multiplier has no output.

[0119] When the voltage MULT is less than the voltage VREF, comp outputs a high level, and the multiplier outputs the voltage MULT.

[0120] Figure 7 The drivers for DR1, DR2, and DR3 are turned on sequentially by REF1, REF2, and REF3, and the current waveform is consistent with that of DCBUS, thus achieving a high power factor (PF).

[0121] like Figure 8 The simulated waveforms are, in order, the VBUS waveform, the voltage signal UL waveform, the CS waveform, and the waveforms when DR1, DR2, and DR3 are turned on.

[0122] When the AC power is off, the EPS power supply circuit operates. A stable DC voltage is provided to the MULT of the PT1918 chip via the detection circuit. At this time, the CS current increases and is compared with the VREF voltage, resulting in a low-level output. The digital integrator circuit shuts down, and the multiplier outputs a DC signal consistent with the MULT voltage. The CS current at this point is determined by L3. Because the reference voltage of L3 is greater than that of L2 and L1, the original sequential switching order of resistors R1, R2, and R3 under AC input is changed to the current setting order of resistor R3 under DC input. This achieves constant current under DC input, with the power determined by the CS resistor. Figure 9 The simulation waveforms are, in order, VBUS waveform, MULT waveform, CS waveform, and waveforms of DR1, DR2, and DR3 when they are turned on. It can be seen that when DC is input, the power is determined by the conduction current of DR3.

[0123] Example 2

[0124] This embodiment provides a control method for controlling a high-voltage multi-segment constant current LED emergency lighting drive system described in Embodiment 1; the method includes:

[0125] When the AC power supply section provides the main power supply, the driver IC operates in a multi-segment driving mode and simultaneously provides charging current to the EPS power supply section.

[0126] After the detection circuit detects that the AC power supply is cut off, the EPS power supply outputs a DC voltage to provide current to the LED beads and simultaneously supplies power to the driver IC, which operates in a single-segment driving mode.

[0127] When the AC power supply section provides the main power supply, the multi-segment drive mode meets the IEC requirements for harmonic ordering.

[0128] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-voltage multi-segment constant current LED emergency lighting drive system, characterized in that, include: LED beads are used for emergency lighting; The AC power supply section is used to provide the main power supply. The AC power supply section is electrically connected to the LED beads; The EPS power supply section is used to provide backup power; the EPS power supply section is electrically connected to the LED beads. The driver IC is used to drive the AC power supply section to provide constant current power to the LED beads, or to drive the EPS power supply section to provide constant voltage power to the LED beads. The driver IC is also used to adjust the power supply of the EPS power supply section based on the change in the ratio of LED beads in the LED string; The AC power supply section and the EPS power supply section supply power to the same LED bead through the same driver IC, and the driver IC is electrically connected to both the AC power supply section and the EPS power supply section.

2. The high-voltage multi-segment constant current LED emergency lighting drive system according to claim 1, characterized in that, The AC power supply section includes: an AC input terminal, a varistor, a rectifier bridge, resistors R1 and R2, and an isolation diode D1; The first port of the AC input terminal is connected to the first port of the rectifier bridge. The second port of the AC input terminal is connected to the third port of the rectifier bridge after being connected in series with a fuse. One end of the varistor is connected to the first port of the rectifier bridge, and the other end is connected between the fuse and the rectifier bridge. The second port of the rectifier bridge is connected to the positive terminal of the isolation diode D1, and the negative terminal of the isolation diode D1 is connected to the LED bead. The fourth port of the rectifier bridge is grounded. One end of resistor R1 is connected to the second port of the rectifier bridge, and the other end is connected to the fourth port of the rectifier bridge after being connected in series with resistor R2. The driver IC is connected between resistors R1 and R2.

3. The high-voltage multi-segment constant current LED emergency lighting drive system according to claim 2, characterized in that, The driver IC is a PT1918 chip; The VDD and TPC terminals of the PT1918 chip are connected together and then connected in series with capacitor C1 to the fourth port of the rectifier bridge. The GND terminal of the PT1918 chip is connected to the fourth port of the rectifier bridge; The CS terminal of the PT1918 chip is connected to the fourth port of the rectifier bridge after being connected in series with resistor R3. The DR terminal of the PT1918 chip is connected to the LED beads.

4. The high-voltage multi-segment constant current LED emergency lighting drive system according to claim 2, characterized in that, The EPS power supply section includes: a battery, a boost circuit, a charging circuit, an isolation diode D2, and an inverter output circuit; The charging circuit is connected to the fourth port of the rectifier bridge at one end and to the input terminal of the battery at the other end. The battery output terminal is connected to a boost circuit, the boost circuit output terminal is connected to an inverter output circuit, the inverter output circuit is connected to the positive terminal of isolation diode D2, and the negative terminal of isolation diode D2 is connected to an LED bead.

5. A high-voltage multi-segment constant current LED emergency lighting drive system according to claim 2, characterized in that, It also includes a detection circuit; the detection circuit includes: resistors R4, R5, R6, and R7, transistor Q1, Zener diode D4, and isolation diode D3; One end of resistor R4 is connected to the positive terminal of isolation diode D2, and the other end is connected to the collector of transistor Q1. The emitter of transistor Q1 is connected to ground in series with resistors R5 and R6. One end of resistor R7 is connected to the base of transistor Q1, and the other end is connected to the collector of transistor Q1; the positive terminal of Zener diode D4 is grounded, and the negative terminal is connected to the base of transistor Q1. The positive terminal of the isolation diode D3 is connected between resistors R5 and R6, and the other terminal is connected between resistors R1 and R2.

6. A high-voltage multi-segment constant current LED emergency lighting drive system according to claim 4, characterized in that, The charging circuit and boost circuit include: boost inductor L7, diode D5, control chip, field-effect transistor M0 and output capacitor C2; One end of the boost inductor L7 is connected to the positive terminal of the battery, and the other end is connected to the positive terminal of the diode D5. The negative terminal of the diode D5 is connected to the output terminal. One end of the output capacitor C2 is connected to the output terminal, and the other end is grounded. The negative terminal of the battery is grounded. One end of the control chip is grounded, and the other end is connected to the gate of the field-effect transistor M0. The source of the field-effect transistor is grounded, and the drain of the field-effect transistor is connected between the boost inductor L7 and the diode D5.

7. A high-voltage multi-segment constant current LED emergency lighting drive system according to claim 5, characterized in that, The driver IC includes a multiplier digital integrator circuit and a driver circuit; The multiplier digital integrator circuit includes amplifiers G1, G2, G3, G4, and G5; field-effect transistors M1, M2, M3, M4, M5, M6, M7, M8, M9, and M10; resistors R8, R9, R10, R11, and R12; a digital integrating capacitor; and a multiplier. The EPS power supply section is connected to the input terminal of the multiplier digital integrator circuit. One end of resistor R8 is connected to the input terminal of the multiplier digital integrator circuit, and the other end is connected to point A after being connected in series with resistor R9. The negative input terminal of amplifier G1 is connected to point A after being connected in series with resistor R10. The output terminal of amplifier G1 is connected to the gate of field-effect transistor M5. The drain of field-effect transistor M5 is connected to the drain of field-effect transistor M1. The source of field-effect transistor M5 is connected to point A after being connected in series with resistor R10. The source of field-effect transistor M1 is connected to the source of field-effect transistor M2, and the gates of field-effect transistor M1 and M2 are connected to the drain of field-effect transistor M5. The drain of field-effect transistor M2, the drain of field-effect transistor M3, and the gate of field-effect transistor M3 are all connected to the drain of field-effect transistor M6; the source of field-effect transistor M6 is connected to point A after being connected in series with resistor R11; the gate of field-effect transistor M6 is connected to the output terminal of amplifier G2, and the negative input terminal of amplifier G2 is connected to point A after being connected in series with resistor R11. The source of field-effect transistor M2 is connected to the source of field-effect transistor M3; the source of field-effect transistor M3 is connected to the source of field-effect transistor M4. The source of field-effect transistor M4 is connected to the source of field-effect transistor M9, and the source of field-effect transistor M9 is connected to the source of field-effect transistor M10. The drain of the field-effect transistor M4 is connected to the negative input terminal of the amplifier G3. One end of the resistor R12 is connected to the negative input terminal of the amplifier G3, and the other end is connected to the output terminal of the amplifier G3. The output of amplifier G3 is connected to point A via resistors R13 and R14 in series; the positive input of amplifier G4 is connected between resistors R13 and R14, and the negative input of amplifier G4 is connected to point A via resistor R15 in series. The gate of field-effect transistor M9, the drain of field-effect transistor M9, and the gate of field-effect transistor M10 are all connected to the drain of field-effect transistor M7; the source of field-effect transistor M7 is connected to point A after being connected in series with resistor R15. The drain of MOSFET M10 is connected to the drain of MOSFET M8, and the source of MOSFET M8 is connected to point A via a series resistor R16; the gate of MOSFET M8 is connected to the output of amplifier G5; the negative input of amplifier G5 is connected to point A via a series resistor R16. The drains of both field-effect transistors M10 and M8 are connected to the input of the digital integrating capacitor, and the output of the digital integrating capacitor is connected to the multiplier. The multiplier is connected between resistors R8 and R9.

8. A high-voltage multi-segment constant current LED emergency lighting drive system according to claim 7, characterized in that, The driver circuit includes: resistor R17, resistor R18, field-effect transistor M11, field-effect transistor M12, field-effect transistor M13, field-effect transistor M14, amplifier G6, amplifier G7, amplifier G8 and amplifier G9. One end of resistor R17 is connected to the positive input terminal of amplifier G9, and the other end is connected to the positive input terminal of amplifier G8. One end of resistor R18 is connected to the positive input terminal of amplifier G8, and the other end is connected to the positive input terminal of amplifier G7. The positive input terminal of amplifier G6 is connected to the positive input terminal of amplifier G7. The output terminal of amplifier G6 is connected to the gate of field-effect transistor M11, and the drain of field-effect transistor M11 is connected to the positive input terminal of amplifier G7. The output of amplifier G7 is connected to the gate of field-effect transistor M12, and the drain of field-effect transistor M12 is connected to the first DR port. The negative input terminal of amplifier G7, the source of field-effect transistor M12, the negative input terminal of amplifier G8, the source of field-effect transistor M13, the negative input terminal of amplifier G9, and the source of field-effect transistor M14 are connected together; the source and drain of field-effect transistor M13 are connected to the second DR port, and the source and drain of field-effect transistor M14 are connected to the third DR port.

9. A control method, characterized in that, The method for controlling the high-voltage multi-segment constant current LED emergency lighting drive system as described in claim 5 includes: When the AC power supply section provides the main power supply, the driver IC operates in a multi-segment driving mode and simultaneously provides charging current to the EPS power supply section. After the detection circuit detects that the AC power supply is cut off, the EPS power supply outputs a DC voltage to provide current to the LED beads and simultaneously supplies power to the driver IC, which operates in a single-segment driving mode.

10. The control method according to claim 9, characterized in that, When the AC power supply section provides the main power supply, the multi-segment drive method meets the IEC requirements for harmonic ordering.

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