CN201700048U

CN201700048U - High power drive circuit capable of controlling LED load current

Info

Publication number: CN201700048U
Application number: CN2010201810709U
Authority: CN
Inventors: 俞才龙; 王水平
Original assignee: NINGBO YINZHOU LONGYUAN ILLUMINATED APPLIANCE CO Ltd
Current assignee: Ningbo Longyuan Lighting Electric Appliance Co., Ltd.
Priority date: 2010-05-06
Filing date: 2010-05-06
Publication date: 2011-01-05
Anticipated expiration: 2020-05-06

Abstract

The utility model belongs to a power supply of an illumination light source, in particular to a high power drive circuit capable of controlling the LED load current. The high power drive circuit at least comprises an EMC and surge current control circuit, a primary rectifying and filtering circuit, a single-end flyback DC/DC power converter, a secondary rectifying and filtering circuit and a constant current and constant voltage output circuit, wherein the constant current and constant voltage output circuit is electrically connected with two electrodes of an LED array. The high power drive circuit is characterized in that an over-current, over-voltage, overheat and under-voltage signal sampling circuit and a photoelectric coupling isolation circuit are connected between the constant current and constant voltage output circuit and the single-end flyback DC/DC power converter; and the output of the photoelectric coupling isolation circuit is electrically connected with the control end of the single-end flyback DC/DC power converter. The high power drive circuit capable of controlling the LED load current has the advantages of high power, high reliability and small change along the input voltage, the temperature and other factors.

Description

A kind of high-power drive circuit of controllable LED load current

Technical field

The utility model belongs to the high-power drive circuit of the power supply of lighting source, particularly a kind of controllable LED load current.

Background technology

LE DBe a kind of solid light source, when its two ends adds forward voltage, minority carrier in the semiconductor and majority carrier take place compound, and the excess energy of emitting will cause photo emissions.Adopt different materials, can be made into the light-emitting diode of different colours.As a kind of new light source, each major company and research institution are in the ascendant to the research of LED in recent years, and its light efficiency is greatly improved, and Lumiled company has researched and developed and produced the White LED that light efficiency reaches 90Lm/W at present, have reached the level of incandescent lamp.

With comparing of incandescent lamp, LED has lot of advantages on performance:

See the following form:

The performance of table 1 incandescent lamp and White LED relatively

New light source is called new high-power LED drive circuit, and different with the electric ballast of fluorescent lamp, the major function of led drive circuit is that alternating voltage is converted to constant-current supply, and finishes the coupling with the voltage and current of LED simultaneously.

In practice, connection in series-parallel LED forming array is often adopted in load, this can make output current more remarkable with the variation that factors such as input voltage and ambient temperature take place, and array format or LED number change, current-limiting resistance is also answered respective change, so it is fixing to adopt the led drive circuit of this simple structure generally only to be suitable for driving array format, and lamp number less LED display.

The mathematical model of LED voltage-current characteristic can be represented by the formula

VF=Vturn-on+RsIF+（ΔVF/ΔT）（T-25℃）

Wherein, Vturn-on is the starting resistor of LED.

Rs represents the slope of volt-ampere curve.The T ambient temperature, Δ VF/ Δ T is the temperature coefficient of LED forward voltage, representative value is-2V/ ℃ for most LED.

From volt-ampere curve and the mathematical model of LED, the great changes of the LED tiny change of its forward voltage behind forward conduction will causing LED electric current, and, ambient temperature, factors such as LED ageing time also will change the electric property that influences LED.And the output of the light of LED is directly relevant with the LED electric current, so led drive circuit is under the situation of factor changes such as input voltage and ambient temperature, the light output of LED will change with factors vary such as input voltage and temperature, and, if the LED electric current is out of control, the LED long-term work will influence reliability and the life-span of LED under big electric current, and might lose efficacy.

Summary of the invention

The purpose of this utility model provides that a kind of power is big, reliability is high, with the high-power drive circuit of the little controllable LED load current of factors vary such as input voltage and temperature.

The purpose of this utility model realizes like this; a kind of high-power drive circuit of controllable LED load current; at least comprise: EMC and surge current control circuit; a rectification and filter circuit; single-ended flyback DC/DC power inverter; secondary rectification and filter circuit and constant current; constant voltage outputting circuit; constant current; constant voltage outputting circuit is electrically connected with two electrodes of LED battle array example; it is characterized in that: constant current; be electrically connected in series signal sample circuit between constant voltage outputting circuit and the single-ended flyback DC/DC power inverter; photoelectricity coupling buffer circuit and protective circuit; signal sample circuit is with overcurrent; overvoltage; overheated and under-voltage signal through processing and amplifying after photoelectricity coupling buffer circuit isolated controlling overcurrent; overvoltage; overheated and under-voltage protecting circuit; pass through overcurrent; overvoltage; overheated and under-voltage protecting circuit is adjusted the output of single-ended flyback DC/DC power inverter, makes constant current; the voltage and current that constant voltage outputting circuit output is stable.

Described single-ended flyback DC/DC power inverter is the wide dynamic range isolated form, it comprises the voltage stabilizing circuit that voltage-stabiliser tube P6KE200A and diode IN4007 constitute, transformer T2 and TOP245 and peripheral circuit, convert the low pressure high frequency to by transformer T2 and TOP245 and the peripheral circuit high pressure low frequency that transformer T2 is elementary, the secondary of transformer T2 comprises two groups, one group offers the load led array through secondary rectification and filter circuit rectification and filtering, another group is voltage sample output, voltage sample output and IN4148/ES1D, ZMM5243B-7 and capacitor C 9 constitute overcurrent, overvoltage, overheated and under-voltage signal sample circuit.

Described voltage sample output one end arrives negative supply through IN4148/ES1D and capacitor C 9, and the other end directly arrives negative supply.

The output end of pressure-stabilizing of described IN4148/ES1D is connected with the positive terminal of electrochemical capacitor C9, its link is input to the control end C of TOP245 behind ZMM5243B-7 and resistance, feed back to the control end C of TOP245 by the output of voltage sample coil, regulate the frequency of oscillation of transformer T2 by TOP245.

Have less than the resistance of 10 Ω and the electrochemical capacitor that is connected in series between the control end C of described TOP245 and the negative supply.

The in-phase end of first group of coil of a described rectification and filter circuit output and transformer T2 is connected with capacitor C 4, and C4 selects 2.2nF/1kV for use.

The utility model has the advantages that: because the utility model has been introduced voltage or Current Feedback Control link.The user can change load led array form and LED number as required, obtains different power outputs.This drive circuit has also overcome the drawbacks such as the easy change of color that make LED light because of factors such as input voltage, ambient temperatures simultaneously; power factor reaches more than 0.9; THD can accomplish below 20%; life-span can reach more than 50000 hours; also can finish from 100% to 1% dimming function simultaneously, and these series of products also possess overvoltage and overcurrent protection function.

Description of drawings

The utility model is described in further detail below in conjunction with the embodiment accompanying drawing:

Fig. 1 is the utility model embodiment schematic block circuit diagram;

Fig. 2 is the utility model embodiment circuit diagram;

Fig. 3 is EMC and surge current control circuit figure.

Among the figure: 1, AC220V input; 2, EMC and surge current control circuit; 3, a rectification and filter circuit; 4, single-ended flyback DC/DC power inverter; 5, secondary rectification and filter circuit; 6, constant current, constant voltage outputting circuit; 7, led array; 8, sample circuit; 9, photoelectricity coupling buffer circuit; 10, protective circuit.

Embodiment

As shown in Figure 1; a kind of drive circuit of load current of high-power controllable LED; at least comprise: EMC and surge current control circuit 2; a rectification and filter circuit 3; single-ended flyback DC/DC power inverter 4; secondary rectification and filter circuit 5 and constant current; constant voltage outputting circuit 6; constant current; constant voltage outputting circuit 6 is electrically connected with two electrodes of led array 7; it is characterized in that: constant current; be connected with overcurrent between constant voltage outputting circuit 6 and the single-ended flyback DC/DC power inverter 4; overvoltage; overheated and under-voltage signal sample circuit 8; photoelectricity coupling buffer circuit 9 and overcurrent; overvoltage; overheated and under-voltage protecting circuit 10; overcurrent; overvoltage; overheated and under-voltage signal sample circuit 8 is with overcurrent; overvoltage; overheated and under-voltage signal through processing and amplifying after photoelectricity coupling buffer circuit 9 isolated controlling overcurrents; overvoltage; overheated and under-voltage protecting circuit 10; pass through overcurrent; overvoltage; overheated and under-voltage protecting circuit 10 is adjusted 4 outputs of single-ended flyback DC/DC power inverter, makes constant current; the stable voltage and current of constant voltage outputting circuit 6 outputs.

As shown in Figure 2, single-ended flyback DC/DC power inverter 4 is wide dynamic range isolated forms, it comprises the voltage stabilizing circuit that voltage-stabiliser tube P6KE200A and diode FR103, BYV29-400, current-limiting resistance R5 constitute, and the high-frequency coupling circuit, the output of voltage stabilizing circuit is carried in the input of transformer T1.The high-frequency coupling circuit is made of transformer T1 and TOP245 and peripheral circuit, transformer T1 and TOP245 and peripheral circuit convert the high pressure low frequency of transformer T1 prime to the low pressure high frequency, the secondary of transformer T1 comprises two groups, one group offers constant current, constant voltage outputting circuit 6 through secondary rectification and filter circuit 5 rectifications and filtering, and constant current, constant voltage outputting circuit 6 resupply load led array 7.Another is organized end of the same name and arrives negative supply through IN4148/ES1D and capacitor C 10, and the different name end is to negative supply.The output end of pressure-stabilizing of IN4148/ES1D is connected with the positive terminal of electrochemical capacitor C10, and its link and photoelectricity coupling buffer circuit 9 outputs are connected, through photoelectricity buffer circuit 9 and the IN4148 control end C to TOP245 that is coupled.The control end C change in voltage of TOP245 directly influences the D end frequency of oscillation of TOP243.Therefore, the electric current that electric current, change in voltage or the environment that is caused by load causes, change in voltage feed back to the control end C of TOP245 by the output of voltage sample coil, the stabilized input voltage of control end C, and then D end frequency of oscillation is stable.Therefore, the input terminal voltage of photoelectricity coupling buffer circuit 9 also affects the output of D end frequency of oscillation simultaneously.

Overcurrent, overvoltage, overheated and under-voltage signal sample circuit 8 comprises: (PNP) triode 2N3906V2, diode RF107 and resistance capacitance, the end of the same name that transformer T1 offers one group of secondary output of load LED divides two-way through diode RF107, one the tunnel is electrically connected with the emitter of triode 2N3906V2, another road is through resistance R 12, R13 is to the base stage of triode 2N3906V2, resistance R 12, the R13 electric connection point through the electrochemical capacitor of 47 μ F to negative supply, the collector electrode of triode 2N3906V2 is by the input anode of current-limiting resistance R14 to photoelectricity coupling buffer circuit 9, simultaneously through the input negative terminal of a resistance R 24 to photoelectricity coupling buffer circuit 9.

In the utility model, the output of transformer T1 offers constant current, constant voltage outputting circuit 6, constant current, constant voltage outputting circuit 6 direct supply load led array through secondary rectification and filter circuit 5 rectifications and filtering.And the load variations of led array can influence constant current, constant voltage outputting circuit 6 equally, therefore, after constant current, constant voltage outputting circuit 6 pass through overcurrent, overvoltage, overheated and under-voltage signal sample circuit 8, its signal with load variations is input to the input of photoelectricity coupling buffer circuit 9, and the control end C that feeds back to TOP245 through photoelectricity coupling buffer circuit 9 realizes transformer T1 FREQUENCY CONTROL then.Finally reach the burning voltage and the electric current that offer load LED.

Constant current, constant voltage outputting circuit 6 comprises two (NPN) triode 2N3904, (PNP) triode 2N3906V3 and resistance capacitance, by a triode 2N3904 and resistance R 15, R16 constitutes the collector electrode output circuit, resistance R 15, R16 is connected in series as the collector load resistor of collector electrode output circuit, collector electrode output circuit anode and negative terminal connect secondary rectification and filter circuit 5 anodes and negative terminal output respectively, resistance R 15, R16 is connected in series a little and triode 2N3906(PNP) base stage of V5 is electrically connected, 2N3906(PNP) emitter of V5 connects secondary rectification and filter circuit 5 anodes by resistance R 20, collector electrode 2N3906(PNP) divides three the tunnel, wherein leading up to resistance and a voltage-stabiliser tube connects secondary rectification and filter circuit 5 anodes, and another road is electrically connected with the input anode of photoelectricity coupling buffer circuit 9.Collector electrode Third Road 2N3906(PNP) is by 22 fens two-way of resistance R, the resistance R 23 of leading up to is electrically connected with the base stage of collector electrode output circuit, another road and another triode 2N3904(NPN) base stage of V4 is electrically connected, the collector electrode of V4 is electrically connected with the base stage of V3, and the emission of V4 is hit the utmost point and connect negative supply by three resistance that are connected in parallel.

Resistance R 17, R18, the R19 that is connected in parallel is the resistance of 0.13/3W.

Photoelectricity coupling circuit in the utility model in the photoelectricity coupling buffer circuit 9 adopts LTV817A, the emitter and collector of LTV817A output stage triode is electrically connected with triode 2N390 base stage and collector electrode respectively, and the emitter of triode 2N390 is by the control end C of diode to TOP245.A rectification and filter circuit 3 exchange the 220V of AC220V input 1 and become direct current, for EMC and the surge current that prevents that AC220V input 1 from producing, and adding EMC and surge current control circuit 2 before a rectification and filter circuit 3.

Because TOP245 is an integrated circuit, and reliable performance is arranged.Therefore, can guarantee effectively that the electric current of supply load led array and voltage are stabilized on the set point that needs.

Its output current voltage of the circuit that provides among Fig. 2 is: 24V/3A.Power supply indicator is by LM358 rear drive indicator light.

Fig. 3 has provided the physical circuit of AC220V input 1, EMC and surge current control circuit 2, and the output of surge current control circuit 2 is electrically connected with the input of single-ended flyback DC/DC power inverter 4 through a rectification and filter circuit 3.Because a surge current control circuit 2 and a rectification and filter circuit 3 belong to the technology that most genus circuit adopts, therefore, the refinement explanation is not done in too much explanation.

Claims

1. the high-power drive circuit of a controllable LED load current, at least comprise: EMC and surge current control circuit (2), a rectification and filter circuit (3), single-ended flyback DC/DC power inverter (4), secondary rectification and filter circuit (5) and constant current, constant voltage outputting circuit (6), constant current, constant voltage outputting circuit (6) is electrically connected with two electrodes of LED battle array example (7), it is characterized in that: constant current, be connected with overcurrent between constant voltage outputting circuit (6) and the single-ended flyback DC/DC power inverter (4), overvoltage, overheated and under-voltage signal sample circuit (8) and photoelectricity coupling buffer circuit (9), photoelectricity coupling buffer circuit (9) output is electrically connected with single-ended flyback DC/DC power inverter (4) control end.

2. the high-power drive circuit of a kind of controllable LED load current according to claim 1, it is characterized in that: described single-ended flyback DC/DC power inverter (4) is the wide dynamic range isolated form, it comprises voltage-stabiliser tube P6KE200A and diode FR103, BYV29-400, the voltage stabilizing circuit that current-limiting resistance R5 constitutes, and high-frequency coupling circuit, the output of voltage stabilizing circuit is carried in the input of transformer T1, the high-frequency coupling circuit is made of transformer T1 and TOP245 and peripheral circuit, transformer T1 and TOP245 and peripheral circuit convert the high pressure low frequency of transformer T1 prime to the low pressure high frequency, the secondary of transformer T1 comprises two groups, one group offers constant current through secondary rectification and filter circuit (5) rectification and filtering, constant voltage outputting circuit (6), constant current, constant voltage outputting circuit (6) resupplies load led array (7), another is organized end of the same name and arrives negative supply through IN4148/ES1D and capacitor C 10, the different name end is to negative supply, the output end of pressure-stabilizing of IN4148/ES1D is connected with the positive terminal of electrochemical capacitor C10, its link and photoelectricity coupling buffer circuit (9) output is connected, through photoelectricity buffer circuit (9) and the IN4148 control end C to TOP245 that is coupled.

3. the high-power drive circuit of a kind of controllable LED load current according to claim 1, it is characterized in that: described overcurrent, overvoltage, overheated and under-voltage signal sample circuit (8) comprising: a PNP triode 2N3906V2, diode RF107 and resistance capacitance, the end of the same name that transformer T1 offers one group of secondary output of load LED divides two-way through diode RF107, one the tunnel is electrically connected with the emitter of triode 2N3906V2, another road is through resistance R 12, R13 is to the base stage of triode 2N3906V2, resistance R 12, the R13 electric connection point through the electrochemical capacitor of 47 μ F to negative supply, the collector electrode of triode 2N3906V2 is by the input anode of current-limiting resistance R14 to photoelectricity coupling buffer circuit (9), simultaneously through the input negative terminal of a resistance R 24 to photoelectricity coupling buffer circuit (9).

4. the high-power drive circuit of a kind of controllable LED load current according to claim 1, it is characterized in that: described constant current, constant voltage outputting circuit (6) comprises two NPN triode 2N3904, PNP triode 2N3906V3 and resistance capacitance, by a triode 2N3904 and resistance R 15, R16 constitutes the collector electrode output circuit, resistance R 15, R16 is connected in series as the collector load resistor of collector electrode output circuit, collector electrode output circuit anode and negative terminal connect secondary rectification and filter circuit 5 anodes and negative terminal output respectively, resistance R 15, R16 is connected in series and a little is electrically connected with the base stage of PNP triode 2N3906 V5, the emitter of PNP triode 2N3906 V5 connects secondary rectification and filter circuit (5) anode by resistance R 20, the collector electrode of PNP triode 2N3906 divides three the tunnel, wherein leading up to resistance and a voltage-stabiliser tube connects secondary rectification and filter circuit (5) anode, and another road is electrically connected with the input anode of photoelectricity coupling buffer circuit (9); The collector electrode Third Road of PNP triode 2N3906 is by 22 fens two-way of resistance R, the resistance R 23 of leading up to is electrically connected with the base stage of collector electrode output circuit, another road is electrically connected with the base stage of another NPN triode 2N3904 V4, the collector electrode of V4 is electrically connected with the base stage of V3, and the emission of V4 is hit the utmost point and connect negative supply by three resistance that are connected in parallel.

5. the high-power drive circuit of a kind of controllable LED load current according to claim 1, it is characterized in that: the photoelectricity coupling circuit in the described photoelectricity coupling buffer circuit (9) adopts LTV817A, the emitter and collector of LTV817A output stage triode is electrically connected with triode 2N390 base stage and collector electrode respectively, and the emitter of triode 2N390 is by the control end C of diode to TOP245.