CN104684180A - LED (light emitting diode) lighting circuit and LED drive method - Google Patents
LED (light emitting diode) lighting circuit and LED drive method Download PDFInfo
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- CN104684180A CN104684180A CN201310641846.9A CN201310641846A CN104684180A CN 104684180 A CN104684180 A CN 104684180A CN 201310641846 A CN201310641846 A CN 201310641846A CN 104684180 A CN104684180 A CN 104684180A
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Abstract
The invention discloses an LED (light emitting diode) lighting circuit and an LED drive method. The LED lighting circuit comprises at least one LED string and a constant-current control unit, wherein each LED string comprises at least one LED, the constant-current control unit comprises a reference current input end and a drive current output end, the reference current input end is used for receiving a reference current, the reference current is adjustable, the constant-current control unit is used for obtaining a drive current according to the reference current, a current value of the drive circuit and the current value of the reference current are in a linear relation, and the drive current is outputted from an output end of the drive current and used for driving the LED string. By implementing the LED lighting circuit, the luminescent property of the LED can be improved, and the service life of the LED can be prolonged.
Description
Technical field
The present invention relates to electronic circuit technology field, especially relate to a kind of light-emitting diode (light emitting diode, LED) lighting circuit and LED driving method.
Background technology
At present, LED due to its life-span long, the advantage such as high and good reliability of switching speed and being widely used.Such as, LED is typically used as indicator light, the backlight of display, exterior decoration etc.LED is a kind of current driven light-emitting element, and existing LED illumination circuit and LED driving method usually adopt and directly adopt constant-current source to drive, and the current value of constant-current source is non-adjustable, under therefore making LED usually can not be operated in suitable operating current for various reasons.If under LED is operated in inappropriate operating current, its performance and useful life can be affected, and also there will be some faults.Such as, excessive electric current easily makes LED burn out, and too small electric current then makes the luminescent properties of LED not good.
Summary of the invention
Therefore, be necessary to provide a kind of LED luminescent properties better and be not easy LED illumination circuit that LED is burnt out.
Further, be necessary to provide a kind of LED luminescent properties better and be not easy LED driving method that LED is burnt out.
A kind of LED illumination circuit, described LED illumination circuit comprises at least one LED strip row and constant-current control unit, each described LED strip row comprise at least one LED, described constant-current control unit comprises a reference current input and a drive current output, described reference current input is for receiving a reference current, the size of described reference current is adjustable, described constant-current control unit is used for obtaining a drive current according to described reference current, the current value of described drive current and the current value of described reference current are linear relationship, described drive current exports from described drive current output, arrange for driving described LED strip.
Preferably, described LED illumination circuit also comprises voltage generating unit and reference resistance, and described voltage generating unit is for exporting a reference voltage, and described voltage generating unit connects described reference resistance to described reference current input, to obtain described reference current.
Preferably, described LED illumination circuit also comprises the first filter capacitor, and described first filter capacitor one end connects described voltage generating unit, other end ground connection, and described first filter capacitor is used for the clutter in reference voltage described in filtering.
Preferably, described constant-current control unit also comprises an Enable Pin, described LED illumination circuit also comprises a signal generation unit, described signal generation unit is for generation of a pulse width modulating signal, described Enable Pin receives described pulse width modulating signal, described constant-current control unit is used under the control of described pulse width modulating signal, regulates the size of described drive current.
Preferably, described LED illumination circuit also comprises the second filter capacitor and a resistance, and described signal generation unit connects described resistance and described second filter capacitor successively to ground.
Preferably, described constant-current control unit is DD311 integrated chip.
A kind of LED driving method, for driving at least one LED strip to arrange, described LED strip row comprise at least one LED, and described LED driving method comprises:
There is provided a constant-current control unit, described constant-current control unit comprises a reference current input and a drive current output;
There is provided a reference current to described reference current input, the size of described reference current is adjustable;
Described constant-current control unit obtains a drive current according to described reference current, and described drive current is exported via described drive current output, to drive described LED strip to arrange, wherein, the current value of described drive current and the current value of described reference current are linear relationship.
Preferably, described LED driving method also comprises: the driving voltage providing a magnitude of voltage adjustable and a reference resistance, described driving voltage obtains described reference current via described reference resistance.
Preferably, described constant-current control unit also comprises an Enable Pin, and described LED driving method also comprises: provide a pulse width modulating signal to the Enable Pin of described constant-current control unit, to regulate the size of described drive current.
Preferably, when the duty ratio of described pulse width modulating signal increases, the increase of described drive current, when the duty ratio of described pulse width modulating signal reduces, described drive current reduces.
Compare with prior art, LED illumination circuit of the present invention and LED driving method, obtain described drive current by constant-current control unit by reference to electric current, the size of described reference current can be arranged as required, and then, the size of described drive current can regulate as required, therefore, under making LED can be operated in suitable operating current, the luminescent properties of LED is improved, LED is not easy to burn out, and further increases the life-span of LED.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the electrical block diagram of the LED illumination circuit of a preferred embodiment of the present invention.
Fig. 2 is the flow chart of the LED driving method of a preferred embodiment of the present invention.
Main element symbol description
LED illumination circuit 100
Voltage generating unit 110
LED strip row 120
Constant-current control unit 130
Signal generation unit 140
First filter capacitor C1
Second filter capacitor C2
Divider resistance R1
Resistance R2
One LED D1
2nd LED D2
3rd LED D3
Reference current input 131
Drive current output 132
First earth terminal 133
Second earth terminal 134
Enable Pin 135
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Refer to Fig. 1, it is the electrical block diagram of the LED illumination circuit 100 of a preferred embodiment of the present invention.Described LED illumination circuit 100 comprises a voltage generating unit 110, LED strip row 120, constant-current control unit 130, signal generation unit 140, first filter capacitor C1, divider resistance R1, resistance R2 and the second filter capacitor C2.
Described constant-current control unit 130 comprises reference current input 131 and a drive current output 132.Described reference current input 131 is for receiving a reference current, and the size of described reference current is adjustable, and described constant-current control unit 130 is for obtaining a drive current according to described reference current.Described drive current exports from described drive current output 132, for driving described LED strip row 120.
Wherein, the current value of described drive current and the current value of described reference current are linear relationship.For example, the current value of described drive current is y, and the current value of described reference current is x, then, y=ax+b, wherein, a, b are real number.Therefore, if the current value of drive current changes, then the current value of described drive current can change, by adjusting the size of described drive current, the adjustment to described drive current can be realized, and then under making the LED in described LED strip row 120 be operated in suitable electric current, the luminescent properties of LED is improved.
Particularly, the operation principle of described LED illumination circuit is described in detail as follows.
Described reference voltage for generation of a reference voltage, and exports by described voltage generating unit 110.In the present embodiment, the range of voltage values of described reference voltage is 5 ~ 36V.When the resistance of described reference resistance R1 is certain, can regulate by regulating the current value of magnitude of voltage to described reference current of described reference voltage, and then the LED in described LED strip row 120 size of described drive current can be regulated, under can be made to be operated in suitable drive current.
Described reference resistance R1 is connected between described voltage generating unit 110 and described reference current input 131.In other words, described voltage generating unit 110 contacts described reference resistance R1 to described reference current input 131, to produce described reference current.Understandably, namely the voltage drop on described reference resistance R1 of the voltage that produces of described voltage generating unit 110 obtains described reference current divided by the resistance of described reference resistance R1.Understandably, the resistance of described reference resistance R1 can adjust as required, to regulate the current value of described reference current better.
Described LED strip row 120 comprise 3 LED connected successively, for convenience of description, and described 3 LED called after the one LED D1, the 2nd LED D2 and the 3rd LED D3 respectively.After LED described in 3 connects successively, be connected between described voltage generating unit 110 and described drive current output 132.That is, the positive pole of a described LED D1 connects described voltage generating unit 110, and the negative pole of a described LED D2 connects the positive pole of described 2nd LED D2.The negative pole of described 2nd LED D2 connects the positive pole of described 3rd LED D3, and the negative pole of the 3rd LED D3 connects described drive current output 132.Understandably, in other embodiments, the number of included in described LED strip row 120 LED is not limited only to 3.
Described constant-current control unit 130 also comprises two earth terminals and an Enable Pin 135, for convenience of describing, and described two earth terminals called after first earth terminal 133 and the second earth terminal 134 respectively.Described first earth terminal 133 and described second earth terminal 134 ground connection.Described Enable Pin 135 for receiving external control signal, to control work and the closedown of described constant-current control unit 130.
Described first filter capacitor C1 one end connects described voltage generating unit 110, other end ground connection.Described first filter capacitor C1 is used for the clutter in reference voltage described in filtering.
Described signal generation unit 140 is for generation of a pulse width modulation (pulse width modulation, PWM) signal.Described signal generation unit 140 connects the described Enable Pin 135 of described constant-current control unit 130.Described Enable Pin 135 receives institute's pwm signal, and described constant-current control unit 130, under the control of described pwm signal, regulates the size of described drive current.Particularly, described signal generation unit 140 is by modulating the duty ratio of described pwm signal to modulate the size of described drive current.When the duty ratio of described pwm signal increases, described drive current increases, and now, the electric current that described LED strip row 120 flow through increases, then the brightness of LED improves.When the duty ratio of described pwm signal reduces, described drive current reduces, and now, the electric current that described LED strip row 120 flow through reduces, then the brightness of LED reduces.As can be seen here, the size of the drive current that described constant-current control unit 120 can be regulated to export by the duty ratio adjusting pwm signal, and then the brightness of described LED strip row 120 can be regulated.
Understandably, described pwm signal also can be used as the control signal of the open and close of described constant-current control unit 130.When the magnitude of voltage that described pwm signal is carried in described Enable Pin 135 is 0V, described constant-current control unit 130 is closed, that is, now described constant-current control unit 130 quits work, and described drive current output 132 no current exports; The magnitude of voltage being carried in described Enable Pin 135 when described pwm signal is higher, and such as during 3.3V ~ 18V, described constant-current control unit 130 is opened, and now, described constant-current control unit 130 works, and described drive current output 132 exports described drive current.
In addition, described signal generation unit 140 successively resistance R2 described in tandem and described second filter capacitor C2 to ground.Described resistance R2 and described second filter capacitor C2 is used for the clutter in pwm signal described in filtering.
In the present embodiment, described constant-current control unit 130 is DD311 integrated chip, now, described reference current input 131 is the REXT pin of DD311, described drive current output 132 is the OUT pin of described DD311, described first earth terminal 133 is the GND pin of described DD311, and described second earth terminal 134 is the VSS pin of described DD311, and described Enable Pin 135 is the EN pin of described DD311.The size of the drive current that the described drive current output 132 in described DD311 produces is 100 times of the reference current size of described reference current input 131 input.
Be introduced LED driving method of the present invention below in conjunction with Fig. 1, refer to Fig. 2, it is the flow chart of the LED driving method of a preferred embodiment of the present invention.Described driving method comprises the following steps.
Step S201, provides a constant-current control unit 130, and described constant-current control unit 130 comprises reference current input 131 and a drive current output 132.
Step S202, provide a reference current to described reference current input 131, the size of described reference current is adjustable.In the present embodiment, the method that described step S202 obtains described reference current can be, driving voltage to the reference resistance R1 providing a magnitude of voltage adjustable, described driving voltage obtains described reference current through described reference resistance.
Step S203, described constant-current control unit 130 obtains a drive current according to described reference current, and described drive current is exported via described drive current output, to drive described LED strip row 120, wherein, the current value of described drive current and the current value of described reference current are linear relationship.
Step S204, provides a pulse width modulating signal to the described Enable Pin 135 of described constant-current control unit 130, to adjust the size of described drive current.When the duty ratio of described pwm signal increases, described drive current increases, and now, the electric current that described LED strip row 120 flow through increases, then the brightness of LED improves.When the duty ratio of described pwm signal reduces, described drive current reduces, and now, the electric current that described LED strip row 120 flow through reduces, then the brightness of LED reduces.As can be seen here, the size of the drive current that described constant-current control unit 120 can be regulated to export by the duty ratio adjusting pwm signal, and then the brightness of described LED strip row 120 can be regulated.
Compare with prior art, LED illumination circuit of the present invention and LED driving method, constant-current control unit obtains described drive current by reference to electric current, and described drive current is greatly little can be arranged as required, and then, the size of described drive current can regulate as required, therefore, under making LED can be operated in suitable operating current, the luminescent properties of LED is improved, LED is not easy to burn out, and further increases the life-span of LED.
Above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although with reference to preferred embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that, can modify to technical scheme of the present invention or equivalent replacement, and not depart from the spirit and scope of technical solution of the present invention.
Claims (10)
1. a LED illumination circuit, it is characterized in that, described LED illumination circuit comprises at least one LED strip row and constant-current control unit, each described LED strip row comprise at least one LED, described constant-current control unit comprises a reference current input and a drive current output, described reference current input is for receiving a reference current, the size of described reference current is adjustable, described constant-current control unit is used for obtaining a drive current according to described reference current, the current value of described drive current and the current value of described reference current are linear relationship, described drive current exports from described drive current output, arrange for driving described LED strip.
2. LED illumination circuit as claimed in claim 1, it is characterized in that, described LED illumination circuit also comprises voltage generating unit and reference resistance, described voltage generating unit is for exporting a reference voltage, described voltage generating unit connects described reference resistance to described reference current input, to obtain described reference current.
3. LED illumination circuit as claimed in claim 2, it is characterized in that, described LED illumination circuit also comprises the first filter capacitor, and described first filter capacitor one end connects described voltage generating unit, other end ground connection, described first filter capacitor is used for the clutter in reference voltage described in filtering.
4. LED illumination circuit as claimed in claim 1, it is characterized in that, described constant-current control unit also comprises an Enable Pin, described LED illumination circuit also comprises a signal generation unit, described signal generation unit is for generation of a pulse width modulating signal, described Enable Pin receives described pulse width modulating signal, and described constant-current control unit is used under the control of described pulse width modulating signal, regulates the size of described drive current.
5. LED illumination circuit as claimed in claim 4, it is characterized in that, described LED illumination circuit also comprises the second filter capacitor and a resistance, and described signal generation unit connects described resistance and described second filter capacitor successively to ground.
6. LED illumination circuit as claimed in any one of claims 1 to 5, wherein, it is characterized in that, described constant-current control unit is DD311 integrated chip.
7. a LED driving method, for driving at least one LED strip to arrange, described LED strip row comprise at least one LED, and it is characterized in that, described LED driving method comprises:
There is provided a constant-current control unit, described constant-current control unit comprises a reference current input and a drive current output;
There is provided a reference current to described reference current input, the size of described reference current is adjustable;
Described constant-current control unit obtains a drive current according to described reference current, and described drive current is exported via described drive current output, to drive described LED strip to arrange, wherein, the current value of described drive current and the current value of described reference current are linear relationship.
8. LED driving method as claimed in claim 7, it is characterized in that, described LED driving method also comprises:
The driving voltage providing a magnitude of voltage adjustable and a reference resistance, described driving voltage obtains described reference current via described reference resistance.
9. LED driving method as claimed in claim 7, it is characterized in that, described constant-current control unit also comprises an Enable Pin, and described LED driving method also comprises:
There is provided a pulse width modulating signal to the Enable Pin of described constant-current control unit, to regulate the size of described drive current.
10. LED driving method as claimed in claim 9, is characterized in that, when the duty ratio of described pulse width modulating signal increases, the increase of described drive current, when the duty ratio of described pulse width modulating signal reduces, described drive current reduces.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310641846.9A CN104684180A (en) | 2013-12-03 | 2013-12-03 | LED (light emitting diode) lighting circuit and LED drive method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310641846.9A CN104684180A (en) | 2013-12-03 | 2013-12-03 | LED (light emitting diode) lighting circuit and LED drive method |
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| CN104684180A true CN104684180A (en) | 2015-06-03 |
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| CN102088804A (en) * | 2009-12-07 | 2011-06-08 | 徐秋珍 | Energy conservation illumination driving device |
| CN201995176U (en) * | 2011-02-15 | 2011-09-28 | 成都中科唯实仪器有限责任公司 | LED lighting drive circuit |
| CN102523657A (en) * | 2011-12-22 | 2012-06-27 | 天津职业技术师范大学 | Projected-agricultural LED lamp for plant growth |
| US20120161781A1 (en) * | 2010-12-28 | 2012-06-28 | Hon Hai Precision Industry Co., Ltd. | Measurement circuit for capacitor |
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2013
- 2013-12-03 CN CN201310641846.9A patent/CN104684180A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102088804A (en) * | 2009-12-07 | 2011-06-08 | 徐秋珍 | Energy conservation illumination driving device |
| US20120161781A1 (en) * | 2010-12-28 | 2012-06-28 | Hon Hai Precision Industry Co., Ltd. | Measurement circuit for capacitor |
| CN201995176U (en) * | 2011-02-15 | 2011-09-28 | 成都中科唯实仪器有限责任公司 | LED lighting drive circuit |
| CN102523657A (en) * | 2011-12-22 | 2012-06-27 | 天津职业技术师范大学 | Projected-agricultural LED lamp for plant growth |
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Application publication date: 20150603 |