CN104968070B - A kind of LED drive circuit - Google Patents

A kind of LED drive circuit Download PDF

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Publication number
CN104968070B
CN104968070B CN201510116713.9A CN201510116713A CN104968070B CN 104968070 B CN104968070 B CN 104968070B CN 201510116713 A CN201510116713 A CN 201510116713A CN 104968070 B CN104968070 B CN 104968070B
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China
Prior art keywords
resistance
diode
power supply
negative pole
operational amplifier
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Expired - Fee Related
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CN201510116713.9A
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Chinese (zh)
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CN104968070A (en
Inventor
夏菽兰
王吉林
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Yangcheng Institute of Technology
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Yangcheng Institute of Technology
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Abstract

The invention discloses a kind of LED drive circuit, including current foldback circuit(1), EMI protection circuit(2), rectification circuit(3), constant-current control circuit(4), LED light group(5).When supply voltage is fluctuated, remain to keep the electric current of LED drive circuit to fluctuate in less scope, autoregulation is played when system is disturbed by constant-current control circuit, make output voltage and electric current stable, on the premise of constant-current characteristics is kept, electromagnetic interference is greatly reduced.

Description

A kind of LED drive circuit
Technical field
The present invention relates to lighting field, more particularly to a kind of LED drive circuit.
Background technology
With the development of science and technology, LED is as new type light source, and with small volume, power consumption is low, light efficiency is high, the life-span Long, environmentally friendly the advantages of, it is widely used in lighting field, miscellaneous LED drive circuit is consequently also occurred in that, in practical application In, the driving current of LED/light source all has a direct impact to luminous efficiency and life-span.
In the place of low-voltage be all at present that LED is driven using DC-DC wave chopping technologies, it have small power consumption, efficiency high, Reliable and stable the advantages of, but its cost is high, circuit is complicated, fragile, has the defects such as stronger High-frequency Interference, is brought to user Inconvenience.In the application, LED drive circuit needs to keep constant-current characteristics as far as possible, i.e., when supply voltage is fluctuated, remain to The electric current of LED drive circuit is kept to be fluctuated in less scope, on the premise of constant-current characteristics is kept, defencive function is also very heavy Will, such as overvoltage protection, electromagnetism interference etc..
The content of the invention
Present invention is primarily aimed at solve the above problems that there is provided one kind burning voltage, stabling current, anti-electromagnetism can be provided The LED drive circuit of interference.
In order to realize foregoing invention purpose, the present invention provides a kind of LED drive circuit, it is characterised in that including overcurrent protection Circuit(1), EMI protection circuit(2), rectification circuit(3), constant-current control circuit(4), LED light group(5), current foldback circuit(1) Input termination AC alternating currents, output termination EMI protection circuit(2), EMI protection circuit(2)Output termination rectification circuit (3), the output termination constant-current control circuit of rectification circuit(4), constant-current control circuit(4)Connect LED light group(5), wherein constant current control Circuit processed(4)Stable input voltage and electric current is provided for LED light group.
Further, current foldback circuit include fuse, EMI protection circuit include electric capacity C1, electric capacity C2, inductance L1, Inductance L2, rectification circuit uses bridge rectifier.
Further, bridge rectifier(3)1 end, 2 ends be rectifier power source input, 3 ends, 4 ends be rectification circuit Output end, constant-current control circuit(4)Including power supply chip U1, transformer T, metal-oxide-semiconductor Q1, optocoupler OC, operational amplifier OPA1 With operational amplifier OPA2, bridge rectifier(3)2 ends power supply chip U1 HV pin are connect through diode D1, resistance R3 simultaneously connects At diode D1 two ends, 3 ends of bridge rectifier are grounded after inductance L4, and 4 ends of bridge rectifier are after inductance L3 Connect one end of transformer T armature windings, another termination metal-oxide-semiconductor Q1 of transformer T armature windings drain electrode, metal-oxide-semiconductor Q1 source electrode It is grounded after resistance R6, power supply chip U1 Adj pin are grounded after resistance R4, power supply chip U1 Gnd pin ground connection, power supply chip U1 FB pin connect the phototriode input in optocoupler OC, the output head grounding of phototriode, power supply chip U1 CS pin Metal-oxide-semiconductor Q1 source electrode is connect, power supply chip U1 NC pin are empty, be grounded after power supply chip U1 VCC foot meridian capacitors C6, power supply chip U1 Drv pin connect metal-oxide-semiconductor Q1 grid, and electric capacity C5, resistance R5, diode D2 constitute clamp circuit and be connected across transformer T primary The two ends of winding, one end of transformer T secondary windings is connected to the positive pole of LED light group 5, T level of transformer after diode D3 Winding the other end ground connection, the negative pole connecting resistance R15 of LED light group 5 one end, resistance R15 the other end ground connection, electric capacity C12 with Diode D3 two ends are connected to after resistance R7 series connection, electric capacity C8, C9 are connected between diode D3 negative pole and ground, electricity R8 terminating diode D3 negative pole is hindered, the other end connects voltage-regulator diode ZD1 negative pole and resistance R10 one end respectively, surely Pressure diode ZD1 positive pole connects optocoupler OC light emitting diode positive pole and ground respectively, and electric capacity C10 and resistance R11 are in parallel respectively Be connected to voltage-regulator diode ZD1 two ends, the resistance R10 other end connect respectively operational amplifier OPA1 positive input and Resistance R13 one end, resistance R13 another termination operational amplifier OPA2 positive input, operational amplifier OPA2 is just It is grounded to input after resistance R14, voltage-regulator diode ZD2 plus earth, negative pole connects the positive defeated of operational amplifier OPA1 Enter to hold, the positive pole of a divider resistance R9 termination LED light group 5, another termination divider resistance R12 one end, divider resistance R12's The other end is grounded, and divider resistance R9 and divider resistance R12 tie point connect operational amplifier OPA1 reverse input end, and computing is put Big device OPA1 output terminating diode D4 negative pole, diode D4 positive pole connects the negative pole of light emitting diode in optocoupler OC, LED The negative pole of lamp group 5 is followed by operational amplifier OPA2 reverse input end, operational amplifier OPA2 reverse input end through resistance R16 Resistance R17, electric capacity C11 through concatenation are followed by diode D5 negative pole, and diode D5 positive pole connects light emitting diode in optocoupler OC Negative pole, operational amplifier OPA2 output terminating diode D5 negative pole.
Further, power supply chip U1 uses NCP1203 power supply control chips.
The present invention when supply voltage is fluctuated, remain to holding LED drive circuit electric current in less scope ripple It is dynamic, autoregulation is played when system is disturbed by constant-current control circuit, makes output voltage and electric current stable, is being protected On the premise of holding constant-current characteristics, electromagnetic interference is greatly reduced.
Brief description of the drawings
Fig. 1 is the LED drive circuit functional schematic of the present invention.
Fig. 2 is the LED drive circuit physical circuit connection figure of the present invention.
Embodiment
The present invention is described in further detail and described with reference to the accompanying drawings and examples.
Embodiment:The present embodiment provides a kind of LED drive circuit, as shown in figure 1, preventing including current foldback circuit 1, EMI Protection circuit 2, rectification circuit 3, constant-current control circuit 4, LED light group 5.
As shown in Fig. 2 current foldback circuit 1 includes fuse, EMI protection circuit 2 includes electric capacity C1, electric capacity C2, inductance L1, inductance L2, electric capacity C1 are serially connected in inductance L1 and inductance L2 one end, and electric capacity C2 is serially connected in the another of inductance L1 and inductance L2 End, rectification circuit 3 uses bridge rectifier, wherein 1 end of bridge rectifier, the input that 2 ends are rectifier power source, 3 ends, 4 ends are the output end of rectification circuit, and constant-current control circuit 4 includes power supply chip U1, transformer T, metal-oxide-semiconductor Q1, optocoupler OC, computing Amplifier OPA1 and operational amplifier OPA2,2 ends of bridge rectifier connect power supply chip U1 HV pin, resistance through diode D1 R3 is attempted by diode D1 two ends, and 3 ends of bridge rectifier are grounded after inductance L4, and 4 ends of bridge rectifier are through electricity Sense L3 is followed by one end of transformer T armature windings, another termination metal-oxide-semiconductor Q1 of transformer T armature windings drain electrode, metal-oxide-semiconductor Q1 Source electrode be grounded after resistance R6, power supply chip U1 Adj pin are grounded after resistance R4, power supply chip U1 Gnd pin ground connection, electricity Source chip U1 FB pin meet the phototriode input in optocoupler OC, the output head grounding of phototriode, power supply chip U1 CS pin connect metal-oxide-semiconductor Q1 source electrode, power supply chip U1 NC pin are empty, and are grounded after power supply chip U1 VCC foot meridian capacitors C6, electricity Source chip U1 Drv pin connect metal-oxide-semiconductor Q1 grid, and electric capacity C5, resistance R5, diode D2 constitute clamp circuit and be connected across transformer The two ends of T armature windings, one end of transformer T secondary windings is connected to the positive pole of LED light group 5, transformer T after diode D3 The other end ground connection of secondary windings, the negative pole connecting resistance R15 of LED light group 5 one end, resistance R15 other end ground connection, electric capacity C12 is connected to diode D3 two ends after being connected with resistance R7, electric capacity C8, C9 are connected to diode D3 negative pole and ground Between, resistance R8 terminating diode D3 negative pole, the other end connect respectively voltage-regulator diode ZD1 negative pole and resistance R10 one End, voltage-regulator diode ZD1 positive pole connects optocoupler OC light emitting diode positive pole and ground, electric capacity C10 and resistance R11 difference respectively Voltage-regulator diode ZD1 two ends are connected in parallel in, the resistance R10 other end connects operational amplifier OPA1 positive input respectively And resistance R13 one end, resistance R13 another termination operational amplifier OPA2 positive input, operational amplifier OPA2 Positive input be grounded after resistance R14, voltage-regulator diode ZD2 plus earth, negative pole is meeting operational amplifier OPA1 just To input, the positive pole of a divider resistance R9 termination LED light group 5, another termination divider resistance R12 one end, divider resistance R12 other end ground connection, divider resistance R9 and divider resistance R12 tie point connect operational amplifier OPA1 reverse input end, Operational amplifier OPA1 output terminating diode D4 negative pole, diode D4 positive pole connects the negative of light emitting diode in optocoupler OC Pole, the negative pole of LED light group 5 is followed by operational amplifier OPA2 reverse input end through resistance R16, and operational amplifier OPA2's is reverse Resistance R17 of the input through concatenation, electric capacity C11 are followed by diode D5 negative pole, and diode D5 positive pole, which is connect in optocoupler OC, to light The negative pole of diode, operational amplifier OPA2 output terminating diode D5 negative pole.
Power supply chip U1 wherein in present embodiment uses NCP1203 power supply control chips.
When output voltage exceedes default voltage, operational amplifier OPA1 outputs are dragged down in signal, current direction OC Light emitting diode, so that the electric current of phototriode in OC is pulled down, when electric current exceedes power supply chip U1 feedback pin threshold current During value, power supply chip U1 output control signals close metal-oxide-semiconductor Q1, when output voltage is less than default voltage, then power supply chip U1 output control signals conducting metal-oxide-semiconductor Q1;When the electric current for flowing through LED light group is more than default current value, operational amplifier OPA2 outputs drag down the light emitting diode in signal, current direction OC, so as to pull down the electric current of phototriode in OC, work as electric current During feedback pin threshold current value more than power supply chip U1, power supply chip U1 output control signals close metal-oxide-semiconductor Q1, when output electricity Force down when default voltage, then power supply chip U1 output control signals conducting metal-oxide-semiconductor Q1, by above-mentioned regulation, can cause Voltage, the electric current substantially constant of output.
The present invention when supply voltage is fluctuated, remain to holding LED drive circuit electric current in less scope ripple It is dynamic, autoregulation is played when system is disturbed by constant-current control circuit, makes output voltage and electric current stable, is being protected On the premise of holding constant-current characteristics, electromagnetic interference is greatly reduced.
The preferred embodiment of simply invention described in this specification, above example is merely to illustrate the present invention's Technical scheme, rather than the limitation to invention.All those skilled in the art by logic analysis, reasoning or have under this invention's idea The available technical scheme of experiment of limit, all should be within the scope of the present invention.

Claims (2)

1. a kind of LED drive circuit, including current foldback circuit(1), EMI protection circuit(2), bridge rectifier(3), constant current Control circuit(4), LED light group(5), current foldback circuit(1)Input termination AC alternating currents, output termination EMI protection circuit (2), EMI protection circuit(2)Output termination bridge rectifier, bridge rectifier output termination constant-current control circuit (4), constant-current control circuit(4)Connect LED light group(5), wherein constant-current control circuit(4)Stable input electricity is provided for LED light group Pressure and electric current, current foldback circuit include fuse, and EMI protection circuit includes electric capacity C1, electric capacity C2, inductance L1, inductance L2, its It is characterised by, bridge rectifier(3)1 end, 2 ends be rectifier power source input, 3 ends, 4 ends be rectification circuit output End, constant-current control circuit(4)Including power supply chip U1, transformer T, metal-oxide-semiconductor Q1, optocoupler OC, operational amplifier OPA1 and computing Amplifier OPA2, bridge rectifier(3)2 ends power supply chip U1 HV pin are connect through diode D1, resistance R3 is attempted by two poles Pipe D1 two ends, 3 ends of bridge rectifier are grounded after inductance L4, and 4 ends of bridge rectifier are followed by transformation through inductance L3 One end of device T armature windings, another termination metal-oxide-semiconductor Q1 of transformer T armature windings drain electrode, metal-oxide-semiconductor Q1 source electrode is through resistance It is grounded after R6, power supply chip U1 Adj pin are grounded after resistance R4, power supply chip U1 Gnd pin ground connection, power supply chip U1 FB Pin connects the phototriode input in optocoupler OC, and the output head grounding of phototriode, power supply chip U1 CS pin connect metal-oxide-semiconductor Q1 source electrode, power supply chip U1 NC pin are empty, and are grounded after power supply chip U1 VCC foot meridian capacitors C6, power supply chip U1 Drv Pin connects metal-oxide-semiconductor Q1 grid, and electric capacity C5, resistance R5, diode D2 constitute clamp circuit and be connected across the two of transformer T armature windings End, one end of transformer T secondary windings is connected to the positive pole of LED light group 5 after diode D3, transformer T secondary windings it is another One end is grounded, the negative pole connecting resistance R15 of LED light group 5 one end, and resistance R15 other end ground connection, electric capacity C12 and resistance R7 goes here and there Diode D3 two ends are connected to after connection, electric capacity C8, C9 are connected between diode D3 negative pole and ground, the one of resistance R8 Terminating diode D3 negative pole, the other end connects voltage-regulator diode ZD1 negative pole and resistance R10 one end, voltage-regulator diode respectively ZD1 positive pole connects optocoupler OC light emitting diode positive pole and ground respectively, and electric capacity C10 and resistance R11 are connected in parallel in surely respectively Diode ZD1 two ends are pressed, the resistance R10 other end connects operational amplifier OPA1 positive input and resistance R13 respectively One end, resistance R13 another termination operational amplifier OPA2 positive input, operational amplifier OPA2 positive input It is grounded after resistance R14, voltage-regulator diode ZD2 plus earth, negative pole connects operational amplifier OPA1 positive input, partial pressure The positive pole of a resistance R9 termination LED light group 5, another termination divider resistance R12 one end, divider resistance R12 another termination Ground, divider resistance R9 and divider resistance R12 tie point connect operational amplifier OPA1 reverse input end, operational amplifier OPA1 Output terminating diode D4 negative pole, diode D4 positive pole connects the negative pole of light emitting diode in optocoupler OC, LED light group 5 Negative pole is followed by operational amplifier OPA2 reverse input end through resistance R16, and operational amplifier OPA2 reverse input end is through concatenation Resistance R17, electric capacity C11 be followed by diode D5 negative pole, diode D5 positive pole connects the negative pole of light emitting diode in optocoupler OC, Operational amplifier OPA2 output terminating diode D5 negative pole.
2. a kind of LED drive circuit as claimed in claim 1, it is characterised in that power supply chip U1 uses NCP1203 power supply controls Coremaking piece.
CN201510116713.9A 2015-03-18 2015-03-18 A kind of LED drive circuit Expired - Fee Related CN104968070B (en)

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Publication number Priority date Publication date Assignee Title
CN106612578A (en) * 2015-10-21 2017-05-03 香港商酷异有限公司 Driving circuit capable of preventing electromagnetic interference
CN105873278B (en) * 2016-05-23 2017-08-18 东莞市领冠半导体照明有限公司 A kind of multi-mode dimming power source circuit
CN107120550A (en) * 2017-06-22 2017-09-01 佛山市南海亮明电器有限公司 The general low-voltage LED bulb of one kind exchange
CN112564471B (en) * 2020-11-27 2022-06-07 国创移动能源创新中心(江苏)有限公司 Working sequence control circuit in two-stage conversion circuit and method thereof

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CN202206605U (en) * 2011-08-01 2012-04-25 深圳市昂发电子科技有限公司 Light emitting diode (LED) energy-saving constant-current power supply
CN202750273U (en) * 2012-05-23 2013-02-20 张小科 LED (Light Emitting Diode) constant-current power supply circuit

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KR100948098B1 (en) * 2009-09-29 2010-03-16 선광에이앤씨 주식회사 Lighting circuit and protection device of led lighting apparatus and method for the same
CN202103892U (en) * 2011-03-16 2012-01-04 上海致达智利达系统控制有限责任公司 Driving power supply for LED street lamp

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Publication number Priority date Publication date Assignee Title
CN202206605U (en) * 2011-08-01 2012-04-25 深圳市昂发电子科技有限公司 Light emitting diode (LED) energy-saving constant-current power supply
CN202750273U (en) * 2012-05-23 2013-02-20 张小科 LED (Light Emitting Diode) constant-current power supply circuit

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