CN102411903A - Light emitting diode (LED) driving device - Google Patents
Light emitting diode (LED) driving device Download PDFInfo
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- CN102411903A CN102411903A CN2010102942860A CN201010294286A CN102411903A CN 102411903 A CN102411903 A CN 102411903A CN 2010102942860 A CN2010102942860 A CN 2010102942860A CN 201010294286 A CN201010294286 A CN 201010294286A CN 102411903 A CN102411903 A CN 102411903A
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- light emitting
- emitting diode
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- drive device
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Abstract
The invention provides a light emitting diode (LED) driving device. The device comprises: a power switching circuit, which is used to receive and switch an input power supply so as to produce a direct current (DC) voltage which can simultaneously drive multiple groups of parallel LED strings; a plurality of current adjusting chips possessing a single regulation channel, wherein the current adjusting chips correspond with the LED strings, the ist current adjusting chip is only used to adjust a current flowed through the ist group of the LED string and the i is a positive integer.
Description
Technical field
The present invention relates to a kind of light emitting diode drive device, relate in particular to a kind of light emitting diode drive device with extendible (expandable) and current balance type (current balance)/currents match (current matching) characteristic.
Background technology
In recent years, along with semiconductor science and technology is flourish, portable electronic product and flat-panel screens product also rise thereupon.And in the middle of the type of numerous flat-panel screens, (Liquid Crystal Display LCD) based on advantage such as its low voltage operating, radiationless line scattering, in light weight and volume be little, has become the main flow of each display product to LCD immediately.Generally speaking, because display panels itself does not have self luminous characteristic, therefore must below display panels, place module backlight, to provide display panels required (back of the body) light source.
Traditional module backlight roughly can be divided into two types; The first is by cold-cathode tube (cold cathode fluorescent lamp; CCFL) module of being formed backlight, another is then by light emitting diode (light emitting diode, the module of LED) being formed backlight.Wherein, because the LED backlight module can promote the colour gamut (color gamut) of LCD, so each tame panel dealer replaces cold-cathode tube module backlight with the LED backlight module mostly now.
The LED backlight module has the light emitting diode string that many groups are in juxtaposition, and each light emitting diode string is made up of many light emitting diodes that are serially connected.On the practice, adopt DC-to-dc converter (DC-DC converter) will import power source conversion mostly and become can drive the required DC voltage of each light emitting diode string simultaneously.Yet; Because the load characteristic (current-voltage curve (I-V Curve)) of each light emitting diode string all is not quite similar; So what can know by inference is; The electric current of each light emitting diode string of flowing through will (that is current imbalance) inequality, thereby not only can cause the light-source brightness of LED backlight display panels that module offers inhomogeneous, and can derive and reduce the problem of lifetime of LED.
In order to solve such problem; Can regulate the electric current of each light emitting diode string of flowing through through in the LED backlight module, adding a current balance type or currents match (Current Balance or Current Matching) operation circuit, can identical (that is current balance type/coupling) with the electric current that causes each light emitting diode string of flowing through.And common current balance type or currents match operation circuit can be made up of current mirror (current mirror) circuit or electric current back coupling compensation (current feedback compensation) circuit that a plurality of active members (for example MOSFET) institute pocket becomes.In addition, current balance type or currents match operation circuit also can be made up of ready-made Current Regulation chip (for example current sink IC).
Yet; (for example often be 4 or 6 and regulate port number) that the adjusting port number of ready-made Current Regulation chip is normally fixing; And because one regulated passage in order to the flow through electric current of one group of light emitting diode string of adjusting; So when the LED backlight module for example has 10 groups of light emitting diode string (its number be based on the size of different panels and determine), then must select for use 3 to have 4 Current Regulation chips of regulating port numbers, or select for use 2 to have 6 Current Regulation chips of regulating port numbers; But select any situation generation that 2 untapped adjusting passages all can be arranged for use, this can cause unnecessary cost waste undoubtedly.
Summary of the invention
In view of this; The present invention proposes a kind of have extendible and light emitting diode drive device current balance type/currents match characteristic; It is able to solve the problem that prior art is addressed; And it includes: a power-switching circuit, in order to receive and to change an input power supply, come driving multiple sets light emitting diode string arranged side by side simultaneously to produce a direct current voltage; And a plurality of Current Regulation chips with single adjusting passage, corresponding said light emitting diode string, and i Current Regulation chip respectively is only in order to the responsible electric current of regulating the i group light emitting diode string of flowing through, and wherein i is a positive integer.
Light emitting diode drive device proposed by the invention mainly is that the Current Regulation chip design is become only to have single adjusting passage, with the flow through electric current of single light emitting diode string of adjusting.Therefore, the adjusting passage in each Current Regulation chip can be considered an accurate current source.In addition, each independently the Current Regulation chip can connect together again to reach open-ended purpose.Thus; No matter have how much organize light emitting diode string arranged side by side (its number is based on the size of different panels and determines) in the LED backlight module; As long as the Current Regulation chip that the present invention designed of quantity such as collocation; Just can cause the electric current of each light emitting diode string of flowing through can identical (that is current balance type/coupling), nor the problem that has a unnecessary cost waste produce.
For letting the above-mentioned feature and advantage of the present invention can be more obviously understandable, hereinafter is special lifts embodiment, and conjunction with figs. elaborates.
Description of drawings
Fig. 1 is the synoptic diagram of the light emitting diode drive device 10 of one embodiment of the invention.
Fig. 2 is the light emitting diode string LLBi (synoptic diagram of i=1～m) of one embodiment of the invention.
Fig. 3 is i the Current Regulation chip 103_i (synoptic diagram of i=1～m) of one embodiment of the invention.
Main description of reference numerals:
10: light emitting diode drive device; 20: the LED backlight module;
101: power-switching circuit; 103_i (i=1～m): the Current Regulation chip;
301: controllable current source; 303: the detecting control module;
305: protected location; 307: the working bias voltage unit;
LLBi (i=1～m): light emitting diode string; Li1～LiN (i=1～m): light emitting diode;
P
VCC, P
GND, P
LED, P
CTR, P
DIM: pin; Vin: input power supply;
Vbus: DC voltage; VCC: outside supply voltage;
GND: earthing potential; Vbias: bias voltage;
Vref: reference voltage; V
CTR: control voltage;
DS: dim signal; N: node.
Embodiment
Existing with detailed reference example embodiment of the present invention, the instance of said example embodiment will be described in the accompanying drawings.In addition, all possibility parts use element/member of same numeral to represent identical or similar portions in graphic and embodiment.
Fig. 1 is the synoptic diagram of the light emitting diode drive device 10 of one embodiment of the invention.Please with reference to Fig. 1; The light emitting diode drive device 10 of present embodiment is suitable for driving liquid crystal device (liquid crystal display at least; LCD) LED backlight module (light emitting diode (LED) backlight module) 20, but be not restricted to this.Wherein, Light emitting diode string (LED string) LLBi that group is in juxtaposition more than having in the LED backlight module 20 (i=1～m); And each light emitting diode string LLBi (i=1～m) by many light emitting diode Li1～LiN that are serially connected (i=1～m) form, as shown in Figure 2.
In addition, light emitting diode drive device 10 includes Current Regulation chip (the current regulation chip) 103_i that power-switching circuit (power conversion circuit) 101 and a plurality of have single adjusting passage (single regulation channel) (i=1～m).Wherein, power-switching circuit 101 is in order to receiving and conversion input power supply Vin, comes the light emitting diode string LLBi arranged side by side of many groups in the driven for emitting lights diode backlight module 20 simultaneously (i=1～m) to produce DC voltage (DC voltage) Vbus.
What deserves to be mentioned is at this; Power-switching circuit 101 is according to the type (for example direct current or AC-input voltage) of input voltage vin and can be DC-to-dc converter (DC-DC converter) (when input voltage vin is DC input voitage) or AC-DC converter (AC-DC converter) (when input voltage vin is AC-input voltage), but the invention is not restricted to this.
On the other hand; Current Regulation chip 103_i (i=1～m) respectively respective leds string LLBi (i=1～m), and i Current Regulation chip 103_i (i=1～m) only organizes the light emitting diode string LLBi (electric current of i=1～m) in order to be responsible for regulating the i that flows through.For instance, Current Regulation chip 103_1 respective leds string LLB1; Current Regulation chip 103_2 respective leds string LLB2; Please the rest may be inferred.In addition, the 1st Current Regulation chip 103_1 is only in order to be responsible for regulating the electric current of the 1st group of light emitting diode string LLB1 that flow through; The 2nd Current Regulation chip 103_2 is only in order to be responsible for regulating the electric current of the 2nd group of light emitting diode string LLB2 that flow through; Please the rest may be inferred.
Clearer, Fig. 3 is i the Current Regulation chip 103_i (synoptic diagram of i=1～m) of one embodiment of the invention.Please merge with reference to Fig. 1～Fig. 3; In present embodiment; (i=1～m) includes controllable current source (controllable current source) 301, detecting control module (detection-control unit) 303, protected location (protection unit) 305 and working bias voltage unit (operation bias unit) 307 for i Current Regulation chip 103_i.
What deserves to be mentioned is earlier at this; In present embodiment, (controllable current source 301 in the i=1～m), detecting control module 303, protected location 305 and working bias voltage unit 307 can packed (package) become to have 5 pins (pin) (P for example to each Current Regulation chip 103_i
VCC, P
GND, P
LED, P
CTRAnd P
DIM) integrated circuit (integrated circuit IC), but is not restricted to this.
At this, be that example describes with the 1st Current Regulation chip 103_1 (i=1) earlier, (i=2～m) then the rest may be inferred for all the other Current Regulation chip 103_2～103_m.
In the 1st Current Regulation chip 103_1, controllable current source 301 can be through pin P
LEDWith P
GNDAnd be connected between the 1st group of light emitting diode LLB1 and earthing potential (ground) GND, and constant current source (constant current source) is provided according to dim signal DS.In present embodiment, controllable current source 301 is able to through pin P
DIMAnd be controlled by dim signal (dimming signal) DS, and this dim signal DS is in order to adjusting the brightness (brightness) that the 1st group of light emitting diode string LLB1 appeared, that is the size of the constant current source that provided of adjustment controllable current source 301.Wherein, the mode of the size of the constant current source that provided of adjustment controllable current source 301 can be the voltage quasi position (voltage level) that changes dim signal DS, or changes the responsibility cycle (duty cycle) of dim signal DS, but neitherly is limited to this.
In addition, detecting control module 303 can be connected to node (node) N between controllable current source 301 and the 1st group of light emitting diode LLB1, in order to the pressure drop (voltage drop/headroom) of detecting controllable current source 301, and passes through pin P according to this
CTRAnd output control voltage V
CTR(can be linear signal or numerical digit signal) controlled the size of the DC voltage Vbus that power-switching circuit 101 produced, thereby regulates the pressure drop of controllable current source 301, reduces the power attenuation that controllable current source 301 is produced thus.In addition; Protected location 305 can be connected to node N equally; In order to avoid the 1st Current Regulation chip 103_1 because of overvoltage (over voltage), overpower (over power), excess temperature (over temperature), perhaps other factors and cause damaging (damage).
Moreover working bias voltage unit 307 can be connected to controllable current source 301, detecting control module 303 and protected location 305, in order to pass through pin P
VCCSupply voltage (extemal supply voltage) VCC and receive the outside; And required bias voltage (bias voltage) Vbias when controllable current source 301 running is provided according to this, and required reference voltage (reference voltage) Vref when detecting control module 303 is provided with protected location 305 runnings.
In present embodiment, all Current Regulation chip 103_i (pin P of i=1～m)
DIMCan directly link together.Thus, (controllable current source 301 in the i=1～m) can be controlled by identical dim signal DS to each Current Regulation chip 103_i, adjusts each group light emitting diode string LLBi (brightness of i=1～m) appeared with synchronously (synchronously).Certainly; In other embodiments of the invention; (controllable current source 301 in the i=1～m) also can be controlled by different dim signal DS to each Current Regulation chip 103_i, adjusts each group light emitting diode string LLBi (brightness (this mode can realize the purposes of region-type light modulation (1ocal Dimming)) of i=1～m) appeared with (independently)/severally (respectively) independently.All are looked closely the actual design demand and decide.
On the other hand, all Current Regulation chip 103_i (pin P of i=1～m)
CTRCan also directly link together.Thus, each Current Regulation chip 103_i (control voltage V that the detecting control module 303 in the i=1～m) is exported
CTRPromptly can intercouple together, so that the control voltage V of minimum (minimum)
CTRCan control the size of the DC voltage Vbus that power-switching circuit 101 produced, that is: minimum control voltage V
CTRCan obtain control to power-switching circuit 101.
What deserves to be mentioned is at this, on controllable current source 301, must need enough pressure drops and just can keep each Current Regulation chip 103_i (controllable current source 301 in the i=1～m) becomes constant current source (constant current source).Yet (load characteristic of i=1～m) possibly all be not quite similar, so (pressure drop that i=1～m) is caused on pairing controllable current source 301 separately will be different for different light emitting diode string LLBi because each group light emitting diode string LLBi.Therefore, excessive pressure drop will cause controllable current source 301 to produce excessive power dissipation (power dissipation), thereby reduces the efficient (efficiency) of controllable current source 301.
In view of this, present embodiment utilizes minimum control voltage V especially
CTRThe reason of controlling power-switching circuit 101 is that (i=1～m) interior controllable current source 301 produces excessive power dissipation in order to avoid each Current Regulation chip 103_i.Therefore, (controllable current source 301 in the i=1～m) possesses and enough pressure drops are arranged and can be maintained in constant current source as long as DC voltage Vbus that power-switching circuit 101 produced is able to let each Current Regulation chip 103_i.Certainly, in other embodiments of the invention, also can utilize the control voltage V of maximum (maximum) according to different application
CTROr all control voltage V
CTRMean value (average) control power-switching circuit 101.All are looked closely the actual design demand and decide.
Similarly, all Current Regulation chip 103_i (pin P of i=1～m)
VCCCan directly link together, and all Current Regulation chip 103_i (pin P of i=1～m)
GNDAlso can directly link together.Thus, (the working bias voltage unit 307 in the i=1～m) promptly can receive identical outside supply voltage VCC to each Current Regulation chip 103_i, and (i=1～m) is that framework operates at identical operations voltage so that all Current Regulation chip 103_i.Hence one can see that, and each is Current Regulation chip 103_i (i=1～m) can pass through corresponding pin (P independently
VCC, P
GND, P
CTRAnd P
DIM) and connect together open-ended to realize (expandable) purpose (purpose)/mechanism (mechanism).
In addition, though the foregoing description is that (i=1～m) for the integrated circuit with 5 pins is that example describes, the present invention is not restricted to this with each Current Regulation chip 103_i.In other words, if LED backlight module 10 do not need dimming function (dimming function), each Current Regulation chip 103_i (pin P of i=1～m) then
DIMCan omit, thereby make that (i=1～m) becomes the integrated circuit with 4 pins to each Current Regulation chip 103_i.All are looked closely the actual design demand and decide.
In sum; Light emitting diode drive device proposed by the invention mainly is that the Current Regulation chip design is become only to have single adjusting passage (single regulation channel), with the flow through electric current of single light emitting diode string (single LED string) of adjusting.In addition, each independently the Current Regulation chip can connect together again to reach the purpose of extendible (expandable).Thus; No matter have how much organize light emitting diode string arranged side by side (its number is based on the size of different panels and determines) in the LED backlight module; As long as the Current Regulation chip that the present invention designed of quantity such as collocation; Just can cause the electric current of each light emitting diode string of flowing through can identical (that is current balance type (current balance)/coupling (current matching)), nor the problem that has a unnecessary cost waste produce.
Though the present invention discloses as above with embodiment; But it is not that any those skilled in the art are not breaking away from the spirit and scope of the present invention in order to qualification the present invention; Can change arbitrarily or be equal to replacement, so protection scope of the present invention should be as the criterion with the scope that the application's claim is defined.
Claims (10)
1. light emitting diode drive device comprises:
One power-switching circuit in order to receive and to change an input power supply, comes driving multiple sets light emitting diode string arranged side by side simultaneously to produce a direct current voltage; And
A plurality of Current Regulation chips with single adjusting passage, corresponding said light emitting diode string, and i Current Regulation chip respectively is only in order to the responsible electric current of regulating the i group light emitting diode string of flowing through, and wherein i is a positive integer.
2. light emitting diode drive device according to claim 1, wherein i Current Regulation chip comprises:
One controllable current source is connected between an i group light emitting diode and the earthing potential, and according to a dim signal certain electric current is provided;
One detecting control module; Connect the node between this controllable current source and the i group light emitting diode; In order to detecting the pressure drop of this controllable current source, and export a control voltage according to this and control this DC voltage size that this power-switching circuit produces, thereby regulate the pressure drop of this controllable current source;
One protected location connects this node, causes damaging because of overvoltage, overpower or overcurrent in order to avoid i Current Regulation chip; And
One working bias voltage unit; Connect this controllable current source, this detecting control module and this protected location; In order to receive an outside supply voltage; And required bias voltage when the running of this controllable current source is provided according to this, and required reference voltage when providing this detecting control module and this protected location to operate.
3. light emitting diode drive device according to claim 2, wherein this controllable current source in each Current Regulation chip is controlled by this identical dim signal, and this dim signal is in order to adjust the brightness that said light emitting diode string appears.
4. light emitting diode drive device according to claim 2; Wherein this control voltage of being exported of this detecting control module in each Current Regulation chip intercouples together, and is big or small so that this control voltage of minimum can be controlled this DC voltage that this power-switching circuit produces.
5. light emitting diode drive device according to claim 2, wherein this working bias voltage unit in each Current Regulation chip receives this identical outside supply voltage.
6. light emitting diode drive device according to claim 2, wherein this controllable current source, this detecting control module, this protected location and this working bias voltage unit in each Current Regulation chip can be packaged into one have many pins integrated circuit.
7. light emitting diode drive device according to claim 1, wherein this input power supply is an alternating current input power supplying or a direct-current input power supplying.
8. light emitting diode drive device according to claim 7, wherein when this input power supply was this alternating current input power supplying, then this power-switching circuit was an AC-DC converter.
9. light emitting diode drive device according to claim 7, wherein when this input power supply was this direct-current input power supplying, then this power-switching circuit was a DC-to-dc converter.
10. light emitting diode drive device according to claim 1, wherein this light emitting diode drive device is suitable for driving a LED backlight module of a LCD at least.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010294286.0A CN102411903B (en) | 2010-09-25 | 2010-09-25 | Light emitting diode (LED) driving device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010294286.0A CN102411903B (en) | 2010-09-25 | 2010-09-25 | Light emitting diode (LED) driving device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102411903A true CN102411903A (en) | 2012-04-11 |
| CN102411903B CN102411903B (en) | 2014-03-19 |
Family
ID=45913959
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010294286.0A Active CN102411903B (en) | 2010-09-25 | 2010-09-25 | Light emitting diode (LED) driving device |
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| CN (1) | CN102411903B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103118466A (en) * | 2013-02-18 | 2013-05-22 | 上海亚明照明有限公司 | Strobe-free alternating current drive LED light source dimming system and method thereof |
| CN109782565A (en) * | 2018-12-31 | 2019-05-21 | 珠海莱坦科技有限公司 | Current mirror laser projection circuit and laser projection clock |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW200728801A (en) * | 2006-01-17 | 2007-08-01 | Chi Mei Optoelectronics Corp | LED light source module and liquid crystal display thereof |
| US20080002102A1 (en) * | 2006-06-29 | 2008-01-03 | Samsung Electro-Mechanics Co., Ltd. | Liquid crystal display backlight driving system with light emitting diodes |
| US20080100561A1 (en) * | 2006-10-31 | 2008-05-01 | Price Erin L | System and Method for Managing LED Backlight Performance in a Display |
| CN101175346A (en) * | 2006-11-02 | 2008-05-07 | 立锜科技股份有限公司 | Backlight control circuit capable of automatically adjusting voltage and control method for luminous element |
-
2010
- 2010-09-25 CN CN201010294286.0A patent/CN102411903B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW200728801A (en) * | 2006-01-17 | 2007-08-01 | Chi Mei Optoelectronics Corp | LED light source module and liquid crystal display thereof |
| US20080002102A1 (en) * | 2006-06-29 | 2008-01-03 | Samsung Electro-Mechanics Co., Ltd. | Liquid crystal display backlight driving system with light emitting diodes |
| US20080100561A1 (en) * | 2006-10-31 | 2008-05-01 | Price Erin L | System and Method for Managing LED Backlight Performance in a Display |
| CN101175346A (en) * | 2006-11-02 | 2008-05-07 | 立锜科技股份有限公司 | Backlight control circuit capable of automatically adjusting voltage and control method for luminous element |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103118466A (en) * | 2013-02-18 | 2013-05-22 | 上海亚明照明有限公司 | Strobe-free alternating current drive LED light source dimming system and method thereof |
| CN109782565A (en) * | 2018-12-31 | 2019-05-21 | 珠海莱坦科技有限公司 | Current mirror laser projection circuit and laser projection clock |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102411903B (en) | 2014-03-19 |
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