CN102510614A - LED (light-emitting diode) multi-lamp distributed group drive system - Google Patents

Abstract

Translated fromChinese

本发明涉及一种LED多灯集散式群驱动系统。该系统由一个前端的大功率隔离恒压源与多个后端的小功率非隔离恒流源组成。前端的大功率隔离恒压源包括：输入整流滤波电路，电源管理芯片，变压器初级钳位电路，高频变压器，输出整流滤波电路，输出电压采样、比较、反馈电路。后端的小功率非隔离恒流源输入端接前端的大功率隔离恒压源输出端，通过恒流电路将前端输出的稳定直流电压转化为要求的直流电流，实现小型LED灯具的单灯恒流驱动。本发明具有结构简单、体积小、高恒流精度、高可靠性、高功率因数、及高效率等优点。

The invention relates to an LED multi-lamp collecting and distributing group driving system. The system consists of a front-end high-power isolated constant voltage source and multiple back-end low-power non-isolated constant current sources. The front-end high-power isolated constant voltage source includes: input rectification and filter circuit, power management chip, transformer primary clamp circuit, high-frequency transformer, output rectification and filter circuit, output voltage sampling, comparison, and feedback circuit. The input terminal of the low-power non-isolated constant current source at the rear end is connected to the output terminal of the high-power isolated constant voltage source at the front end, and the stable DC voltage output by the front end is converted into the required DC current through the constant current circuit to realize the single-lamp constant current of small LED lamps drive. The invention has the advantages of simple structure, small volume, high constant current precision, high reliability, high power factor, high efficiency and the like.

Description

Many lamps of LED collecting and distributing type crowd drive system

Technical field

The present invention relates to a kind of many lamps of LED efficiently collecting and distributing type crowd drive system, be used for simultaneously a plurality of compact LED light fixtures that disperse being carried out centralized driving, belong to the LED lighting technical field.

Background technology

LED has advantages such as luminous efficiency height, long service life, good stability, is widely used in lighting field.Yet led drive circuit hampers the reduction of LED illuminator cost in the deficiency of aspects such as efficient, reliability and stability always, and is restricting the useful life and the scope of popularizing of LED illuminator.

At present, led drive circuit roughly can be divided into: resistance step-down type of drive, linear voltage stabilization/constant-current supply type of drive, charge pump type of drive and DC-DC conversion driving mode, wherein the first-selection of LED constant-current drive circuit is a DC-DC conversion driving mode.

DC-DC conversion driving mode can be divided into: switching mode LED constant current chip drives mode, non-isolated Switching Power Supply type of drive, isolation type switching power supply type of drive.Switching mode LED constant current chip drives mode is used for portable set mostly to be used, as as backlights such as mobile phone, notebook, MP3, or as the automobile headlamp illumination etc.; The driving force of these chip for driving is limited; Output current is limited, and it is direct current that input voltage requires, and price comparison is expensive.Non-isolated Switching Power Supply type of drive like Buck and Boost circuit etc., utilizes switching technique can obtain the higher efficient and the voltage range of broad, and the isolation type switching power supply volume is littler relatively, and output performance is also better usually.Yet these type of DC-DC converter input and output can not realize good electrical isolation altogether, thereby and are not suitable for the occasion that exchanges input.The isolation type switching power supply type of drive; Like forward conversion mode and inverse-excitation converting mode etc.; The isolation that utilizes transformer to import and export; Can adopt industrial-frequency alternating current power supply, have advantages such as efficient height, applicability are good, safe, reliable, become the first-selection of present stage commercial LED constant-current drive circuit.

The constant-current driving of compact LED light fixture often faces the contradiction of circuit volume and performance, and the drive circuit of this light fixture generally need be integrated in lamp interior, so want for drive circuit that cube is little, heating is few; Drive circuit satisfies requirements such as constant current accuracy, isolation, electromagnetic compatibility, power factor correction again simultaneously, and the balance that realize the two is the main challenge that the compact LED light fixture drives.Fig. 1 is the simplification circuit theory diagrams of modal free-standing compact LED light fixture constant-current driving on the market; Wherein current rectifying and wave filtering circuit is to output to switching circuit behind the direct current with the commercial power rectification; Through high frequency transformer Conversion of energy is arrived output in order to driving LED again; Survey output through the auxiliary frontier inspection of transformer and produce feedback signal, the duty ratio of control switch to be realizing the output constant current, employing be that former limit feedback anti-swashs structure.The circuit of reversed excitation volume of common secondary feedback is bigger, can't meet the demands, so under this specific operational environment, use former limit feedback system to carry out constant current control usually.The main deficiency of sort circuit is: (1) because this circuit adopts former limit feedback arrangement, its output constant current accuracy is not very desirable relatively; (2) though adopted former limit feedback to make the volume of circuit of reversed excitation obtain reducing to a certain degree; But because it has comprised high frequency transformer; Add that circuit itself has more relatively element to make its volume still bigger, just design has proposed very high requirement to circuit layout within the light fixture if place; (3) the general power of compact LED light fixture is less, and within 10W, so drive circuit seems that for this power grade more complicated and cost are higher; (4) based on the consideration of volume and cost, this circuit does not have the link of EMI filtering and power factor correction usually, influences its Electro Magnetic Compatibility and power factor; (5) input voltage is bigger to the drop of output voltage, must make that like this conversion efficiency of circuit is not ideal.Though constantly in improvement, above shortcoming is owing to the reason of circuit structure and applied environment still is difficult to solve for sort circuit and derived structure thereof.

Summary of the invention

Problem such as the objective of the invention is to solve that existing free-standing compact LED light fixture swashs instead that the constant-current drive circuit number of elements is many, volume is big, cost is high, power factor is low, the EMI performance is not good, poor stability, efficient are low; A kind of many lamps of LED efficiently collecting and distributing type crowd drive system is provided; Reduce the average element quantity of each compact LED lamp driving circuit; The volume of circuit is significantly reduced, improve reliability, constant current accuracy, power factor and the EMI performance of system, reduced the driving power cost of single compact LED light fixture simultaneously again.

The technical problem that the present invention will solve is:Occasion towards great quantity of small LED light fixture pooled applications; A kind of collecting and distributing type LED crowd Driving technique is proposed; Provide a kind of simple in structure, volume is little, cost is low, high constant current accuracy, high reliability, High Power Factor, and crowd's drive system of high efficiency multichannel compact LED light fixture; Swash the constant-current source type of drive so that the stand alone type that substitutes existing compact LED light fixture is anti-, problem such as overcome that its number of elements is many, volume is big, cost is high, power factor is low, the EMI performance is not good, poor stability, efficient are low.

In order to achieve the above object, design of the present invention is:The LED constant-current driving that the present invention realizes is through public demands such as the isolation of a large amount of LED light fixtures, transformation, filtering, correction are separated with constant current, small size, few individual demand that generates heat of single led light fixture; The former is realized that by the high-power isolation constant pressure source of the front end of grid side the latter is realized by the non-isolation constant-current source of the rear end small-power of light fixture side.High-power isolation constant pressure source is responsible for civil power is reduced to a lower direct voltage, in addition also is responsible for the electrical isolation of whole system, EMI filtering, system protection and power factor correction.The non-isolation constant-current source of the small-power of rear end is responsible for converting the output of constant pressure source into galvanic current stream driving LED.That said system has is simple in structure, volume is little, high constant current accuracy, high reliability, High Power Factor, and plurality of advantages such as high efficiency, can replace under many occasions that stand alone type is anti-to swash constant-current source, is easy to realize commercialization.

According to the foregoing invention design, the technical scheme that the present invention adopts is:

A kind of many lamps of LED efficiently collecting and distributing type crowd drive system is made up of the high-power isolation constant pressure source of a front end and the non-isolation constant-current source of small-power of a plurality of rear ends.High-power isolation constant pressure source is responsible for electric main is converted into the direct voltage (like 12V or 24V) of setting, in addition also is responsible for the electrical isolation of whole system, EMI filtering, system protection and power factor correction.The non-isolation constant-current source of a plurality of small-powers of rear end is responsible for converting the direct current output of constant pressure source into galvanic current stream to drive single led light fixture.

The high-power isolation constant pressure source of above-mentioned front end comprises input rectifying filter circuit, Switching Power Supply managing chip, isolated switch transformer, primary clamp circuit, output rectifier and filter, output voltage sampling and comparison circuit, electro-optical feedback circuit.Said input rectifying filter circuit input connects with electric main, and input connects with primary clamp circuit, the elementary winding of high frequency transformer through power management chip successively; Said output rectifier and filter input is parallelly connected with the high frequency transformer secondary winding, the non-isolation constant-current source of the output said a plurality of small-powers of termination; The voltage acquisition end of said output voltage sampling and comparison circuit is parallelly connected with the output of output constant current filter circuit, and the comparison circuit output connects with power management chip through the electro-optical feedback circuit.Described input rectifying filter circuit is supplied with isolated switch transformer after industrial-frequency alternating current being rectified into the high direct voltage of pulsation; Be integrated with high-power MOSFET in the described Switching Power Supply managing chip; In MOSFET conduction period, isolated switch transformer with power storage in elementary winding; At the MOSFET blocking interval; The electric energy that is stored in the elementary winding of isolated switch transformer is sent to the transformer secondary output winding; The peak voltage that primary winding two ends produced when but described primary clamp circuit absorbed power MOSFET turn-offed; With the protection power MOSFET, output rectifier and filter is converted into level and smooth direct current output with isolated switch transformer secondary winding voltage, and described output voltage sampling and comparison circuit detect output voltage; Current sampling data and reference value are compared; Produce control signal, described electro-optical feedback circuit transfers to the electrical isolation between Switching Power Supply managing chip and realization input and the output with control signal, and the Switching Power Supply managing chip is regulated conducting, the turn-off time of its internal power MOSFET according to control signal; To control the NE BY ENERGY TRANSFER of isolated transformer, finally make output voltage keep constant.

The non-isolation constant-current source of the small-power of above-mentioned rear end is made up of power management chip (9), constant current main circuit (10) and sampling feedback circuit (11); Said power management chip (9) connects the DC output of the high-power isolation constant pressure source of front end; It exports the said constant current main circuit of termination (10); The output of constant current main circuit (10) connects sampling feedback circuit (11) and load LED light fixture, and power management chip (9) is received in the output of sampling feedback circuit (11).The output that the non-isolation constant-current source of the small-power of above-mentioned rear end will be isolated constant voltage circuit through the size that the switch of the integrated MOSFET of chip internal is regulated output current, forms galvanic current stream driving LED lamp group as its input voltage after the output filtering.Electric current flows through a current sense resistor after flowing to load, on this resistance, forms pressure drop, and is constant to regulate output current as the duty ratio of feedback signal control MOSFET with this voltage.

The present invention has following conspicuous outstanding substantive distinguishing features and remarkable advantage compared with prior art:

(1) the high-power isolation constant pressure source of the present invention partly adopts the reverse exciting topological structure, can design transformer secondary output winding quantity as required, and is to realize multichannel output or the output of multiple direct voltage, simple and convenient.Input adopts isolated switch transformer and photoelectricity coupling circuit to carry out electrical isolation, and the driving output of LED and high pressure civil power do not have directly and be electrically connected, and disturbs little, reliability to improve the fail safe when also having strengthened system works like this.Circuit input end uses the transformer peak voltage to absorb circuit, but the peak voltage that absorbed power MOSFET shutdown moment primary winding two ends produce, and ability better protect power MOSFET has improved circuit reliability.Whole system is operated in the volume that has reduced devices such as transformer and inductance under the high frequency state.

(2) the non-isolation constant-current source of the present invention partly adopts the BUCK topological structure, and simple in structure, volume is very little.The compact LED light fixture requires to reduce as far as possible the volume of light fixture as a rule, thereby relatively stricter for the volume requirement of driving power.The anti-sharp constant-current source circuit structure of conventional stand alone type must have the relatively large device of this volume of high frequency transformer, so the requirement difficulty that will satisfy on the volume is bigger.Within the light fixture only is non-isolation constant-current source part and place in the native system, and transless, volume are significantly less than the single anti-constant-current source that swashs.

(3) generally single anti-sharp constant-current source saves power factor correction and EMC filtering link usually because volume and cost are limit; Though single compact LED light fixture is little to power factor and EMC influence, however under the occasion that great quantity of small LED light fixture is arranged necessary power factor correction and the EMC filtering link of adding.All add power factor correction and EMC filtering link if instead swash on the constant-current source at each on the other hand, can increase the volume and the cost of circuit again greatly, also can influence driving efficient.The present invention places isolation constant pressure source part with power factor correction and EMC filter circuit, has no influence for the volume that places the non-isolation constant-current source in the light fixture, and the average unit cost that drives for single compact LED light fixture does not influence basically yet.

(4) rear end of system of the present invention is the constant-current source that adopts non-isolation structure, and it is that output current changes with input voltage hardly on the 160-270VAC at the electrical network input voltage.And the former limit feedback that usually adopts anti-swashs constant-current source output current in same input voltage range and has comparatively significantly fluctuation along with the variation of input voltage.So this system instead swashs constant-current source with respect to stand alone type has much higher current stability.

(5) system of the present invention is on cost, and n compact LED light fixture of every driving only used a high frequency transformer, a power-factor correcting network, EMC filter circuit and set of circuits protection; If stand alone type is anti-to swash constant-current source and will reach all these functions and use, drives n compact LED light fixture and just need use n high frequency transformer, n power-factor correcting network, n EMC filter circuit and n organize circuit protection.So this system has remarkable advantages on cost.

In sum; LED collecting and distributing type crowd drive system of the present invention; Front end adopts a high-power isolation constant pressure source to concentrate constant voltage driving; The non-isolation constant-current source of a plurality of small-powers constant-current driving is respectively adopted in the rear end, have simple in structure, volume is little, cost is low, high constant current accuracy, high reliability, High Power Factor, and plurality of advantages such as high efficiency.Under the occasion that a plurality of compact LED light fixture pooled applications are arranged, this system can replace the anti-sharp constant-current source of traditional stand alone type fully, is fit to produce in batches.

Description of drawings

The common compact LED light fixture of Fig. 1 instead swashs the circuit theory diagrams of constant-current driving;

Fig. 2 fundamental system block diagram of the present invention;

The circuit block diagram of Fig. 3 isolation constant pressure source of the present invention;

The circuit block diagram of the non-isolation constant-current source of Fig. 4 small-power of the present invention;

The circuit theory diagrams of Fig. 5 isolation constant pressure source of the present invention;

The circuit theory diagrams of Fig. 6 non-isolation constant-current source of the present invention.

Embodiment

Below, through preferred case study on implementation of the present invention and combine accompanying drawing to describe the present invention in detail.

Embodiment one: referring to Fig. 2, originally many lamps of LED collecting and distributing type crowd drive system is made up of the high-power isolation constant pressure source of a front end and the non-isolation constant-current source of small-power of a plurality of rear ends efficiently.The high-power isolation constant pressure source input of front end connects with electric main; Be responsible for electric main is converted into the direct voltage of setting and realizes constant voltage output through power management chip, in addition also be responsible for concentrated electrical isolation, EMI filtering, system protection and the power factor correction of whole system.The high-power isolation constant pressure source output of the non-isolation constant-current source of the small-power of rear end input termination front end is converted into the direct current of requirement through constant-current circuit with the stable DC voltage of front end output, realizes single lamp constant-current driving of compact LED light fixture.

Shown in accompanying drawing 3; Above-mentioned high-power isolation constant voltage circuit comprises: input EMC filtering, rectifying and wave-filtering, power factor adjustment circuit 1, power management chip 2, primary clamp circuit 3; High frequency transformer 4; Output rectifier and filter 5, output voltage sampling and comparison circuit 6, electro-optical feedback circuit 7.

The input rectifying filter circuit converts electric main to high-voltage dc signal comparatively stably, from its high-voltage dc signal output output, as the energy supply of entire circuit, takes into account the function of power factor correction at this filter circuit; The Switching Power Supply managing chip carries out giving high frequency transformer with NE BY ENERGY TRANSFER after the pulse-width modulation to the high direct voltage signal through HF switch; Simultaneously, the Switching Power Supply managing chip is according to conducting and the turn-off time of its internal power of the control signal control MOSFET that is come by the optical coupler transmission; High frequency transformer has elementary winding a and secondary winding b, is parallel with elementary clamp circuit at elementary winding two ends, the peak voltage that the primary winding produces when being used for absorbed power MOSFET shutoff, the inner integrated MOS FET of protection power management chip; Secondary winding of transformer b exports the high-frequency alternating voltage of sensing to output rectification secondary filter circuit, and the output from output rectifier and filter after rectifying and wave-filtering is direct voltage is exported, in order to drive a plurality of non-isolation small-power constant-current source of rear end; Output voltage sampling and comparison circuit testing circuit output voltage compare with set point, and comparative result is also realized the electrical isolation between input and the output as feedback signal through electro-optical feedback circuit transmission to power management chip; Power management chip with the NE BY ENERGY TRANSFER of control high frequency transformer, finally makes output voltage keep constant according to the make-and-break time of its internal power of feedback signal adjusting MOSFET.

Shown in accompanying drawing 5, described input rectifying filter circuit 1 comprises rectifier bridge Br, capacitor C 1, C2, C3, triode D1, D2, D3 and common mode inductance L1.Described Switching Power Supply managing chip 2 is TOP254EN (U1) that PI company produces, TOP254EN is inner integrated high-power MOSFET.The S of TOP254EN end is that drain electrode, the A end of internal power MOSFET is " enabling/under voltage " difunctional end for the source electrode of internal power MOSFET, D; Enable chip operation and pressure limiting function; Connect with the rectifier bridge dc high-voltage output end through R4, R5 series connection, the X end is set end for outside current limliting, connects input ground; The F end is used to select working frequency of chip, and linking to each other frequency setting at this with the S end is 132KHz.Described primary clamp circuit 3 comprises diode D4, resistance R 1, R2, R3 and capacitor C 4.Described output rectifier and filter 5 comprises diode D5, capacitor C 8, C9, C10, C11, inductance L 2, resistance R 7.Described output current sampling comprisesresistance R 10, R11, capacitor C 13 and three terminal regulator TL431 (U3) with comparison circuit 6, and R10, R11 are parallel to circuit output two ends.Described electro-optical feedback circuit 7 comprises optocoupler U2, resistance R 8, R9, R6, capacitor C 12, C6, C5, the auxiliary winding c of diode D6 and isolated switch transformer T1.Optocoupler U2 comprises a light-emitting diode and a phototransistor.

Shown in accompanying drawing 4, the non-isolation constant-current source of above-mentioned small-power comprises:power management chip 9, constant currentmain circuit 10, sampling feedback circuit 11.Power management chip 9 connects the DC output of the high-power isolation constant pressure source of front end, its output termination constant currentmain circuit 10, and the output of constant currentmain circuit 10 connectssampling feedback circuit 11 and load LED light fixture, andpower management chip 9 is received in the output ofsampling feedback circuit 11.

Shown in accompanying drawing 6; The output voltage that is input as high-power isolation constant voltage circuit of the non-isolation constant-current circuit of above-mentioned small-power; Describedpower management chip 9 adopts LM3404, and its inside is integrated with MOSFET, and this MOSFET carries out the conducting and shutoff operation of high frequency under pulse-width signal control.Described constant currentmain circuit 10 comprises L1, C4, D1, and 9 inner MOSFET constitute the Buck reduction voltage circuit with power management chip, and output current is carried out filtering.Sampling feedback circuit 11 comprises that electric current adopts resistance R 2; Flow through R2 and form voltage at the R2 two ends of output current; CS pin throughpower management chip 9 detects the duty ratio of this voltage with the inner MOSFET of control chip; To realize that constant current output drives load, diode D1 plays the effect of afterflow in this process.

The concrete course of work: many lamps of LED collecting and distributing type crowd drive system is as long as the incoming transport civil power gets final product operate as normal efficiently.At first convert the 50Hz alternating voltage in the 160V-270V scope into lower direct voltage, convert stable DC current drives compact LED light fixture into by the non-isolation constant-current source of the multichannel small-power of the output direct voltage that this is lower again by high-power isolation constant pressure source.

Be that a front end isolation constant voltage circuit adds 12 the non-isolation constant-current circuits in rear end below, each non-isolation constant-current circuit drives the system example of a 3W LED light fixture respectively.Civil power is at first isolated constant pressure source through excessive power, and like accompanying drawing 3, shown in 5, because the input voltage that Switching Power Supply managing chip 2 requires is a direct current, so must earlier electric main be carried out rectifying and wave-filtering, this function is realized by input rectifying filter circuit 1.Electric main is through the EMC filtering link of cartridge fuse F1 and capacitor C 1 and inductance L 1 composition; Again through full-wave rectification bridge; Become high direct voltage after the filtering link that constitutes through filter capacitor C2, C3 and diode D1, D2, D3 again, the effective value of this high direct voltage be input AC civil power effective value

doubly.The common relatively capacitor filter network of this network has significantly improved the power factor of whole system, having only under the situation of capacitor filtering, the power factor of this system about 54%, replace single electric capacity with this network after the system power factor be increased to 92%.Common mode inductance L1 is mainly used in the inhibition common mode disturbances, and capacitor C 1 is mainly used in the inhibition series mode interference.

Be integrated with high-power MOSFET in the Switching Power Supply managing chip U1 (TOP254); This MOSFET carries out the conducting and shutoff operation of high frequency under pulse-width signal control; High direct voltage modulation is become the high-frequency alternating voltage on the isolated switch transformer 4 elementary winding a, utilize galvanomagnetic effect with power transfer to isolated switch transformer secondary winding b.In power MOSFET conduction period, high direct voltage--elementary winding a--power MOSFET--input ground constitutes the loop, and electric current flows through elementary winding a, this moment elementary winding a the different name end for just, end of the same name is the drain voltage of power MOSFET, near 0V.According to the character of transformer, this moment secondary winding b end of the same name also for negative, the different name end is for just, diode D5 oppositely ends.When power MOSFET turn-offed, elementary winding a produced induced electromotive force, and end of the same name is for just; The different name end is for negative, and this moment, the end of the same name of secondary winding b just became, and the different name end becomes negative; Diode D5 forward conduction, energy is passed to secondary winding b from elementary winding a, and this moment, secondary winding b was an electric.High frequency noise components in the output rectifier and filter filtering output voltage.

Because when power MOSFET turn-offs; Elementary winding a goes up and produces induced electromotive force; So the voltage in its drain electrode of power MOSFET shutdown moment is that high direct voltage adds induced electromotive force; If consider factors such as winding leakage inductance spike, above-mentioned high direct voltage add induced electromotive force may surpass power MOSFET withstand voltage and with its damage.The elementary winding absorbing clamp circuit of forming by diode D4, capacitor C 4 and resistance R 1, R2, R3, but the peak voltage that primary winding a produces when absorbed power MOSFET turn-offs, the protection power MOSFET.

R10 and R11 are the output sample resistances, and both control the shunting of this device from the negative electrode to the anode to the dividing potential drop of output through the REF pin of TL431.This electric current is again the diode section that directly drives optocoupler U2.So when output voltage has the main trend of change; The REF terminal voltage increases thereupon causes the electric current that flows through TL431 and optocoupler light-emitting diode to increase; So lumination of light emitting diode is strengthened, it is also just big more to flow through the transistorized electric current of sensitization, and the electric current of the C end of U1 is also just big more; Be that feedback signal increases, otherwise then reduce.The auxiliary limit that Transformer Winding c, diode D6 and capacitor C 12 are formed is responsible for feedback provides electric current.When feedback signal increases, mean that output voltage is excessive, the corresponding PWM duty ratio of turning down of chip U1; When feedback signal reduces, mean that output voltage is too small, the corresponding PWM duty ratio of heightening of chip U1.

Civil power converts the direct voltage of 12V into after the conversion of excessive power constant voltage circuit, be input with this voltage, and the non-isolation constant-current source of multichannel small-power is the 3W LED load separately of 350mA stable DC current drives with this voltage transitions.Like accompanying drawing 4, shown in 6; The output voltage that is input as high-power isolation constant voltage circuit of the non-isolation constant-current circuit of the small-power of system of the present invention; Be integrated with MOSFET in the Switching Power Supply managing chip 9 (LM3404), this MOSFET carries out the conducting and shutoff operation of high frequency under pulse-width signal control.

In the accompanying drawing 6, capacitor C 1 plays the effect of energy storage at the input two ends, and R1 is connected between the RON pin of input voltage anode and U1, plays the effect of setting chip operating frequency.Electric current flows into the VIN pin of U1, and the MOSFET that the chip internal of flowing through is integrated flows out from the SW pin; Through the rectification of L1 and C4, electric current flows through load (the 1W great power LEDs of three series connection), then flows through current sense resistor R2; On R2, form a pressure drop; This voltage is detected by the CS pin of U1, as the duty ratio of the inner MOSFET of feedback signal control chip, thus the output current of control circuit.Afterflow effect when diode D1 plays the MOSFET shutoff.

In sum; Many lamps of LED collecting and distributing type crowd drive system of the present invention; Front end adopts a high-power isolation constant pressure source to concentrate functions such as realizing constant voltage, isolation, filtering, correction; The rear end adopts the non-isolation constant-current source of a plurality of small-powers to realize constant-current driving respectively, have simple in structure, volume is little, cost is low, high constant current accuracy, high reliability, High Power Factor, and plurality of advantages such as high efficiency.Under the occasion that a plurality of compact LED light fixture pooled applications are arranged, this system can replace the anti-sharp constant-current source of traditional stand alone type fully, is fit to produce in batches.

Claims (3)

Translated fromChinese

1.一种LED多灯集散式群驱动系统，其特征在于：系统由一个前端的大功率隔离恒压源与多个后端的小功率非隔离恒流源组成；前端的大功率隔离恒压源输入端与交流市电联接，负责将交流市电转换为设定的直流电压并通过电源管理芯片实现恒压输出，除此之外还负责整个系统的集中电气隔离、EMI滤波、系统保护与功率因数校正；后端的小功率非隔离恒流源输入端接前端的大功率隔离恒压源输出端，通过恒流电路将前端输出的稳定直流电压转化为要求的直流电流，实现小型LED灯具的单灯恒流驱动。1. A LED multi-lamp distributed group drive system, characterized in that: the system consists of a front-end high-power isolated constant voltage source and multiple back-end low-power non-isolated constant current sources; the front-end high-power isolated constant voltage source The input terminal is connected to the AC mains, which is responsible for converting the AC mains into a set DC voltage and realizing constant voltage output through the power management chip. In addition, it is also responsible for the centralized electrical isolation, EMI filtering, system protection and power of the entire system. Factor correction; the input terminal of the low-power non-isolated constant current source at the rear end is connected to the output terminal of the high-power isolated constant voltage source at the front end, and the stable DC voltage output by the front end is converted into the required DC current through the constant current circuit, so as to realize the single operation of small LED lamps. Lamp constant current drive.2.根据权利要求1所述的LED多灯集散式群驱动系统，其特性在于所述大功率隔离恒压源，包括输入整流滤波电路（1）、电源管理芯片（2）、变压器初级钳位电路（3）、高频变压器（4）、输出整流滤波电路（5）、输出电压采样及比较电路（6）和光电反馈电路（7），所述输入整流滤波电路（1）输入端与交流市电联接，输出端经电源管理芯片（2）依次与变压器初级钳位电路（3）、高频变压器（4）初级绕组联接；所述输出整流滤波电路（5）输入端与高频变压器（4）次级绕组并联，输出端接所述多个小功率非隔离恒流源（8）；所述的输出电压采样及比较电路（6）的电压采集端与输出整流滤波电路（5）的输出端并联，比较电路输出端通过光电反馈电路（7）与电源管理芯片（2）联接；2. The LED multi-lamp distributed group drive system according to claim 1, characterized in that the high-power isolated constant voltage source includes an input rectification filter circuit (1), a power management chip (2), and a transformer primary clamp circuit (3), high-frequency transformer (4), output rectification and filter circuit (5), output voltage sampling and comparison circuit (6) and photoelectric feedback circuit (7), the input terminal of the input rectification and filter circuit (1) is connected to the AC Mains connection, the output terminal is connected to the primary clamping circuit of the transformer (3) and the primary winding of the high-frequency transformer (4) through the power management chip (2); the input terminal of the output rectification and filtering circuit (5) is connected to the high-frequency transformer ( 4) The secondary windings are connected in parallel, and the output terminals are connected to the multiple low-power non-isolated constant current sources (8); the voltage acquisition terminal of the output voltage sampling and comparison circuit (6) is connected to the output rectification filter circuit (5) The output ends are connected in parallel, and the output end of the comparison circuit is connected with the power management chip (2) through the photoelectric feedback circuit (7);所述的输入整流滤波电路（1）将工频交流电转换成较为平稳的直流高压后作为整个电路的能量供应，同时兼顾输入EMC滤波与功率因数校正的功能；所述的电源管理芯片（2）内集成了高压大功率MOSFET，可进行高频导通或关断；所述的高频变压器（4）用于输入-输出间的能量传递；所述的变压器初级钳位电路（3）用于吸收功率MOSFET关断时高频变压器（4）初级绕组两端产生的尖峰电压，以保护功率MOSFET；所述的输出整流滤波电路（5）将高频变压器（4）次级绕组的电压平滑成无纹波直流输出；所述的输出电压采样及比较电路（6）检测电路输出电压，与设定值进行比较，比较结果作为反馈信号通过光电反馈电路（7）传输至电源管理芯片（2）并实现输入与输出之间的电气隔离；所述的电源管理芯片（2）根据反馈信号调节其内部功率MOSFET的通断时间，以控制高频变压器（4）的能量传递，最终使输出电压保持恒定。The input rectification filter circuit (1) converts the power frequency alternating current into a relatively stable DC high voltage as the energy supply of the entire circuit, and at the same time takes into account the functions of input EMC filtering and power factor correction; the power management chip (2) A high-voltage and high-power MOSFET is integrated inside, which can be turned on or off at high frequency; the high-frequency transformer (4) is used for energy transfer between input and output; the transformer primary clamp circuit (3) is used for The peak voltage generated at both ends of the primary winding of the high-frequency transformer (4) is absorbed when the power MOSFET is turned off to protect the power MOSFET; the output rectification and filtering circuit (5) smoothes the voltage of the secondary winding of the high-frequency transformer (4) into Ripple-free DC output; the output voltage sampling and comparison circuit (6) detects the output voltage of the circuit and compares it with the set value, and the comparison result is transmitted as a feedback signal to the power management chip (2) through the photoelectric feedback circuit (7) And realize electrical isolation between input and output; the power management chip (2) adjusts the on-off time of its internal power MOSFET according to the feedback signal to control the energy transfer of the high-frequency transformer (4), and finally keeps the output voltage constant.3.根据权利要求1所述的一种LED多灯集散式群驱动系统，其特性在于所述小功率非隔离恒流源由电源管理芯片（9）、恒流主电路（10）和采样反馈电路（11）组成，所述电源管理芯片（9）接前端的大功率隔离恒压源的DC输出，其输出端接所述恒流主电路（10），恒流主电路（10）的输出接采样反馈电路（11）和负载LED灯具，采样反馈电路（11）的输出接到电源管理芯片（9）；3. A LED multi-lamp distributed group drive system according to claim 1, characterized in that the low-power non-isolated constant current source is composed of a power management chip (9), a constant current main circuit (10) and sampling feedback circuit (11), the power management chip (9) is connected to the DC output of the front-end high-power isolated constant voltage source, and its output terminal is connected to the constant-current main circuit (10), and the output of the constant-current main circuit (10) connected to the sampling feedback circuit (11) and the load LED lamp, and the output of the sampling feedback circuit (11) is connected to the power management chip (9);所述的电源管理芯片（9）内集成有功率MOSFET，与恒流主电路（10）一起实现电流稳定输出，为LED灯组供电；采样反馈电路（11）采样恒流主电路（10）的输出电流，并反馈给电源管理芯片（9）；电源管理芯片（9）将反馈电流与电流设定值进行比较，根据比较结果调整功率MOSFET的通断占空比，从而控制输出电流稳定在设定值，实现小型LED灯具的单灯恒流驱动。The power management chip (9) is integrated with a power MOSFET, which together with the constant current main circuit (10) realizes a stable current output and supplies power to the LED lamp group; the sampling feedback circuit (11) samples the constant current main circuit (10) output current, and feed it back to the power management chip (9); the power management chip (9) compares the feedback current with the current setting value, and adjusts the on-off duty ratio of the power MOSFET according to the comparison result, thereby controlling the output current to stabilize at the set value Fixed value, realize single lamp constant current drive of small LED lamps.

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