CN201063926Y - Back light source driving circuit and LCD device - Google Patents
Back light source driving circuit and LCD device Download PDFInfo
- Publication number
- CN201063926Y CN201063926Y CNU2007201212332U CN200720121233U CN201063926Y CN 201063926 Y CN201063926 Y CN 201063926Y CN U2007201212332 U CNU2007201212332 U CN U2007201212332U CN 200720121233 U CN200720121233 U CN 200720121233U CN 201063926 Y CN201063926 Y CN 201063926Y
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- resistance
- driving voltage
- diode
- output unit
- current balance
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
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Abstract
The utility model provides a backlight drive circuit which is suitable for the liquid-crystal display field. The utility model comprises a driving voltage output unit and a plurality of lighting tube connecting ends and also comprises an inverter, a plurality of current balance testing circuits and a busbar, wherein, an input stage of the inverter is connected with an output end of the driving voltage output unit; an output stage of the inverter is simultaneously connected with input ports of a plurality of lighting tube connecting ends; the inverter outputs alternating voltage for a plurality of lighting tube connecting ends; input ends of a plurality of current balance testing circuits are connected with output ports of a plurality of lighting tube connecting ends one by one; output ends of a plurality of lighting tube connecting ends are connected with current testing feet of the driving voltage output unit; the current balance testing circuits detects current variance of lighting tubes and triggers the driving voltage output unit to adjust outputted driving voltage; the busbar is connected with each current balance testing circuit and adjusts testing voltage of each current balance testing circuit to be equal. In the utility model, because the inverter simultaneously supplies the alternating voltage for a plurality of lighting tube connecting ends, the cost is reduced.
Description
Technical field
The utility model belongs to field of liquid crystal display, relates in particular to a kind of backlight source driving circuit and liquid crystal indicator.
Background technology
At present, advantage such as LCD is fast because of its reaction speed, display quality is preferable, radiationless is widely used in television set, computer, industry monitoring device, GPS (Global Position System) and some other mancarried devices.Backlight is as the important component part in the LCD, and can it will directly have influence on the display effect of LCD for liquid crystal panel provides the even and stable light source of brightness.
For cold-cathode fluorescence lamp (Cold Cathode Fluorescent Lamps, CCFL) backlight, current balance type in each fluorescent tube is to keep one of even brightness key factor, existing drive circuit generally adopts transformer and the man-to-man supply power mode of fluorescent tube, perhaps come balanced balanced current with inductance behind transformer, cost is too high.
The utility model content
The purpose of the utility model embodiment is to provide a kind of backlight source driving circuit, is intended to solve existing drive circuit and is the too high problem of control lamp tube current balance cost.
The utility model embodiment is achieved in that a kind of backlight source driving circuit, comprises driving voltage output unit and a plurality of fluorescent tube link, and described drive circuit also comprises:
Inverter, its input stage is connected with the output of described driving voltage output unit, and output stage connects the input port of described a plurality of fluorescent tube links simultaneously, to described a plurality of fluorescent tube link output AC voltages;
A plurality of current balance type testing circuits, the output port of its input and described a plurality of fluorescent tube links connects one to one, its output is connected with the current detecting pin of described driving voltage output unit, detects the variation of lamp current and triggers the driving voltage that described driving voltage output unit adjustment is exported;
Bus connects each current balance type testing circuit, and the detection voltage adjustment of each current balance type testing circuit is equal.
Another purpose of the utility model embodiment is to provide a kind of liquid crystal indicator, comprises backlight source driving circuit, and described drive circuit comprises driving voltage output unit and a plurality of fluorescent tube link, and described drive circuit also comprises:
Inverter, its input stage is connected with the output of described driving voltage output unit, and output stage connects the input port of described a plurality of fluorescent tube links simultaneously, to described a plurality of fluorescent tube link output AC voltages;
A plurality of current balance type testing circuits, the output port of its input and described a plurality of fluorescent tube links connects one to one, its output is connected with the current detecting pin of described driving voltage output unit, detects the variation of lamp current and triggers the driving voltage that described driving voltage output unit adjustment is exported;
Bus connects each current balance type testing circuit, and the detection voltage adjustment of each current balance type testing circuit is equal.
Among the utility model embodiment, each lamp tube current balance detection circuit is connected by bus, the detection voltage of each current balance type testing circuit is influenced each other finally reach current balance type, and because an inverter provides alternating voltage for simultaneously a plurality of fluorescent tube links, thereby reduced cost.
Description of drawings
Fig. 1 is the schematic diagram of the drive circuit of the backlight lighting tube that provides of the utility model embodiment;
Fig. 2 is the enlarged diagram of the circuit balancing testing circuit in the circuit shown in Figure 1.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearer,, the utility model is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the utility model, and be not used in qualification the utility model.
The utility model embodiment adopts control integrated operational amplifier circuit in-phase input end to equate with the input voltage of inverting input, and the mode that the in-phase input end of each integrated operational amplifier circuit or inverting input are connected is controlled each lamp tube current balance, thereby the brightness of control CCFL backlight is evenly with stable.
As shown in Figure 1, IC is the chip for driving of CCFL backlight, formed the driving voltage output unit of CCFL backlight with driving voltage processing module 1, the input of driving voltage processing module 1 is connected with the output of chip for driving IC, output is connected to the input stage of inverter T1 and T2 respectively through capacitor C 1 and C3, inverter T1 and T2 are respectively A lamp, B lamp, C lamp and D lamp, E lamp, the F lamp provides alternating voltage.The equal ground connection of output stage one end of inverter T1 and T2, the other end are lighted fluorescent tube by impedance capacitor C 2 and C4 with the High AC voltage that produces respectively.A among Fig. 1, b, c, d, e, f represent the current balance type testing circuit of A lamp, B lamp, C lamp, D lamp, E lamp, F lamp respectively, each lamp tube current balance detection circuit principle is identical and parameter each respective devices is identical, and all having two outputs to be connected to the current detecting pin Is pin of chip for driving IC respectively by resistance R 01 and R02, each circuit balancing testing circuit links together by bus Va.
Fig. 2 shows the concrete structure of the current balance type testing circuit of A lamp among Fig. 1, A lamp input is connected with impedance capacitor C 2, output connects the positive pole of diode D1 and the negative pole of diode D3 simultaneously, the plus earth of diode D3, and two ends are parallel with detection resistance R 3.Diode D1 negative pole is connected with diode D2 is anodal, and diode D2 is connected to the current detecting pin Is pin of chip for driving IC by resistance R 02.Diode D1 negative pole also is connected with two component piezoresistances, as shown in Figure 2, resistance R 1 and R4 series connection, series connection place connects the inverting input of integrated operational amplifier circuit, and the other end of resistance R 1 and R4 connects negative pole and the ground connection of diode D1 respectively; Resistance R 2 and R5 series connection, series connection place connects the in-phase input end of integrated operational amplifier U1A, and the other end of resistance R 2 and R5 connects negative pole and the ground connection of diode D1 respectively.As an example of the present utility model, the inverting input of integrated operational amplifier U1A also meets bus Va simultaneously, and the inverting input by the integrated operational amplifier in bus Va and other current balance type testing circuits is connected.The output of integrated operational amplifier U1A connects the negative pole of diode D4, and diode D4 positive pole is connected to the current detecting pin Is pin of chip for driving IC by resistance R 01.
If the situation of the electric current of A lamp occur less than other lamp currents, this moment, the in-phase input end voltage of integrated operational amplifier U1A can reduce, and inverting input voltage is owing to be subjected to the restraining function of bus Va, it is littler than in-phase input end voltage to reduce amplitude, after integrated operational amplifier U1A amplifies computing to the difference of in-phase input end voltage and inverting input voltage, cause the current detecting pin Is pin change in voltage of chip for driving IC, chip for driving IC rises the A lamp current by the driving voltage of adjusting fluorescent tube.Because the shared driving voltage of each fluorescent tube, when the electric current in fluorescent tube of needs adjustment rises, may cause that other lamp tube current are excessive, other fluorescent tubes also will feed back to the current detecting pin Is pin of chip for driving IC this moment, for example the A lamp is by diode D2 and resistance R 02 feedback, and after adjusting repeatedly, the in-phase input end voltage of each integrated operational amplifier is close with inverting input voltage, the voltage that is in-phase input end voltage and bus Va is close, reaches current balance type.And as lamp current during less than other lamp currents, its adjustment process is identical with said process, repeats no more.
The utility model embodiment is connected by the inverting input with the integrated operational amplifier in the current balance type testing circuit, progressively realize current balance type between each fluorescent tube with the mode of amplifier comparison electric current, because an inverter provides alternating voltage for simultaneously a plurality of fluorescent tube links, thereby has reduced cost.
The above only is preferred embodiment of the present utility model; not in order to restriction the utility model; all any modifications of within spirit of the present utility model and principle, being done, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.
Claims (8)
1. a backlight source driving circuit comprises driving voltage output unit and a plurality of fluorescent tube link, it is characterized in that described drive circuit also comprises:
Inverter, its input stage is connected with the output of described driving voltage output unit, and output stage connects the input port of described a plurality of fluorescent tube links simultaneously, to described a plurality of fluorescent tube link output AC voltages;
A plurality of current balance type testing circuits, the output port of its input and described a plurality of fluorescent tube links connects one to one, its output is connected with the current detecting pin of described driving voltage output unit, detects the variation of lamp current and triggers the driving voltage that described driving voltage output unit adjustment is exported;
Bus connects each current balance type testing circuit, and the detection voltage adjustment of each current balance type testing circuit is equal.
2. backlight source driving circuit as claimed in claim 1 is characterized in that, described current balance type testing circuit comprises:
First diode, its anodal output port that connects described a plurality of fluorescent tube links;
Second diode, its positive pole is connected with the negative pole of described first diode, and negative pole is connected to the current detecting pin of described driving voltage output unit by resistance;
The 3rd diode, its negative pole connect an output port of described a plurality of fluorescent tube links, plus earth;
Detect resistance, in parallel with described the 3rd diode;
The first component piezoresistance comprises first resistance and the 4th resistance, first resistance and the series connection of the 4th resistance one end, and the other end connects described first diode cathode and ground connection respectively;
The second component piezoresistance comprises second resistance and the 5th resistance, second resistance and the series connection of the 5th resistance one end, and the other end connects described first diode cathode and ground connection respectively;
Integrated operational amplifier, its inverting input are connected to series connection place of described first resistance and the 4th resistance, and in-phase input end is connected to series connection place of described second resistance and the 5th resistance;
The 4th diode, its negative pole connects the output of described integrated operational amplifier, the anodal current detecting pin that is connected to described driving voltage output unit by resistance.
3. backlight source driving circuit as claimed in claim 2 is characterized in that the inverting input of the integrated operational amplifier of each current balance type testing circuit is connected by described bus.
4. backlight source driving circuit as claimed in claim 2 is characterized in that the in-phase input end of the integrated operational amplifier of each current balance type testing circuit is connected by described bus.
5. a liquid crystal indicator comprises backlight source driving circuit, and described drive circuit comprises driving voltage output unit and a plurality of fluorescent tube link, it is characterized in that described drive circuit also comprises:
Inverter, its input stage is connected with the output of described driving voltage output unit, and output stage connects the input port of described a plurality of fluorescent tube links simultaneously, to described a plurality of fluorescent tube link output AC voltages;
A plurality of current balance type testing circuits, the output port of its input and described a plurality of fluorescent tube links connects one to one, its output is connected with the current detecting pin of described driving voltage output unit, detects the variation of lamp current and triggers the driving voltage that described driving voltage output unit adjustment is exported;
Bus connects each current balance type testing circuit, and the detection voltage adjustment of each current balance type testing circuit is equal.
6. device as claimed in claim 5 is characterized in that, described current balance type testing circuit comprises:
First diode, its anodal output port that connects described a plurality of fluorescent tube links;
Second diode, its positive pole is connected with the negative pole of described first diode, and negative pole is connected to the current detecting pin of described driving voltage output unit by resistance;
The 3rd diode, its negative pole connect an output port of described a plurality of fluorescent tube links, plus earth;
Detect resistance, in parallel with described the 3rd diode;
The first component piezoresistance comprises first resistance and the 4th resistance, first resistance and the series connection of the 4th resistance one end, and the other end connects described first diode cathode and ground connection respectively;
The second component piezoresistance comprises second resistance and the 5th resistance, second resistance and the series connection of the 5th resistance one end, and the other end connects described first diode cathode and ground connection respectively;
Integrated operational amplifier, its inverting input are connected to series connection place of described first resistance and the 4th resistance, and in-phase input end is connected to series connection place of described second resistance and the 5th resistance;
The 4th diode, its negative pole connects the output of described integrated operational amplifier, the anodal current detecting pin that is connected to described driving voltage output unit by resistance.
7. device as claimed in claim 5 is characterized in that the inverting input of the integrated operational amplifier of each current balance type testing circuit is connected by described bus.
8. device as claimed in claim 5 is characterized in that the in-phase input end of the integrated operational amplifier of each current balance type testing circuit is connected by described bus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201212332U CN201063926Y (en) | 2007-07-02 | 2007-07-02 | Back light source driving circuit and LCD device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201212332U CN201063926Y (en) | 2007-07-02 | 2007-07-02 | Back light source driving circuit and LCD device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201063926Y true CN201063926Y (en) | 2008-05-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007201212332U Expired - Fee Related CN201063926Y (en) | 2007-07-02 | 2007-07-02 | Back light source driving circuit and LCD device |
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| Country | Link |
|---|---|
| CN (1) | CN201063926Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101340762B (en) * | 2008-08-18 | 2012-11-21 | 友达光电股份有限公司 | Lamp tube detection driving system and related detection driving method |
-
2007
- 2007-07-02 CN CNU2007201212332U patent/CN201063926Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101340762B (en) * | 2008-08-18 | 2012-11-21 | 友达光电股份有限公司 | Lamp tube detection driving system and related detection driving method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: LCD SKYWORTH (SHENZHEN) CO., LTD. Free format text: FORMER OWNER: SHENZHEN SKYWORTH-RGB ELECTRONIC CO., LTD. Effective date: 20090327 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20090327 Address after: Floor 518000, SKYWORTH science and technology industrial complex, Shiyan Industrial Street, Shiyan district, Shenzhen, Guangdong Province, 1, Baoan District Patentee after: Skyworth LCD Modules (Shenzhen) Co., Ltd. Address before: Guangdong city of Shenzhen province Nanshan District Gao Xin Road SKYWORTH building A13-16, zip code: 518057 Patentee before: Shenzhen Skyworth-RGB Electronics Co., Ltd. |
|
| CU03 | Correction of utility model patent gazette |
Correction item: Patentee Correct: Skyworth LCD Modules (Shenzhen) Co., Ltd. False: Skyworth Liquid Crystal Devices (Shenzhen) Co., Ltd. Number: 18 Page: 1014 Volume: 25 |
|
| ERR | Gazette correction |
Free format text: CORRECT: PATENTEE; FROM: SKYWORTH LIQUID CRYSTAL DEVICES(SHENZHEN) CO., LTD. TO: LCD SKYWORTH (SHENZHEN) CO., LTD. |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080521 Termination date: 20100702 |