CN2640196Y - Multi-tube single-coil inverter sampling circuit - Google Patents
Multi-tube single-coil inverter sampling circuit Download PDFInfo
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- CN2640196Y CN2640196Y CN 03258802 CN03258802U CN2640196Y CN 2640196 Y CN2640196 Y CN 2640196Y CN 03258802 CN03258802 CN 03258802 CN 03258802 U CN03258802 U CN 03258802U CN 2640196 Y CN2640196 Y CN 2640196Y
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Abstract
The utility model relates to a mongline system inverter sampling circuit with a plurality of lamps. The utility model is characterized in that: the drive circuit corresponding with each lamp arranges an additional inductance sampling coil winding, wherein, a port of the coil winding is connected with terra and the other port is the sampling feedback. The utility model utilizes the existent circuit frame that single transformer drives a single lamp and gets the transformation power by the inductance sampling coil, makes each high frequency transformer of each lamp have the same output power Po, and ensures the brightness uniformity of the whole screen of the backlit panels. The technical proposal adopted by the utility model has the advantages of simple circuit, low cost, compared with the backlit panels of existent LCD monitor, the style of which is multi-lamp and dual lane system. The technical proposal has the advantages of high anti-jamming capability, more reliable while compared with the multi-lamp mongline system sampling circuit, which is under research at present.
Description
Technical field
The utility model relates to the sample circuit of the luminous uniformity of each cold cathode fluorescent tube of relevant controlling (CCFT) in many fluorescent tubes transmission type lcd device backlight (LCD), is specifically related to a kind of cold cathode fluorescent tube (CCFT) driving sample circuit that many fluorescent tubes one wire system is arranged that is suitable for.
Background technology
At present, LCD (LCD) has entered large-screen (22 "～42 ") product development stage, back lighting part for this class LCD (LCD) has also entered many fluorescent tubes pattern, wherein, the high brightness more than six fluorescent tubes and six fluorescent tubes, the lcd products of high definition enjoy people to pay close attention to.Yet, under many lamp works pattern, how to guarantee that the uniformity of whole image light is still the critical problem that the LCD backlight lighting technology need solve.
In the past in the known technology, the back side of transmission type lcd device (LCD) is provided with the backlight structure, this backlight mainly with cold cathode fluorescent tube (CCFT) as light source, adopt inverter (INVERTER) electric power system of high-frequency and high-voltage to drive, thereby realize back lighting.At present, for large scale, many fluorescent tubes backlight panel, comparatively mature technique is to adopt the double wire system mode of connection between fluorescent tube and the inverter, see Fig. 1 and shown in Figure 5, promptly even for the brightness that makes each fluorescent tube, from the low-pressure end sampling feedback of each fluorescent tube, handle the output current of control inverter then respectively through comparison circuit and IC controller.Because every group of this sample circuit is independent of fluorescent tube sampling feedback, therefore each street lamp pipe is had current balance type ability preferably, thereby has guaranteed the uniformity of whole image light.But also there is following shortcoming in the design of many fluorescent tubes double wire system: 1, owing to have n root wiring circuit arrangement complexity between fluorescent tube and the inverter power supply system; 2, backlight mechanism becomes complicated; 3, cost height.For this reason, a kind of many fluorescent tubes one wire system connection plan is being tested by the relevant producer of Korea S, Japan and TaiWan, China at present, sees shown in Figure 2.This scheme is fed back the low-pressure end ground connection of all fluorescent tubes and directly take out lamp current from the transformer secondary output high-voltage line bag that drives fluorescent tube, see Fig. 3 and shown in Figure 4.The characteristics of above-mentioned many fluorescent tubes one wire system wiring are that low-pressure end to the inverter power supply system of all fluorescent tubes supplies to have simplified circuit structure with a loop, have reduced cost.From the sample circuit possible in theory, but in fact because the difference of fluorescent tube, feedback under the difference of transformer, especially the one wire system situation is because of the effect of high-frequency and high-voltage, there is bigger interference mutually in the secondary district of transformer, therefore used sampling feedback circuit can't more accurately reflect the actual lamp tube current size that outputs to, and makes the pulse-width modulation (PWM) of control circuit lose efficacy, and the result causes the output current deviation of each inverter bigger, and the fluorescent tube number is many more, and deviation is big more.Experiment shows that when 16 fluorescent tubes, the size of normal current is 6mA, and maximum deviation can reach 1.5mA, and the degree of deviation is 25%.
The utility model is at above-mentioned technical background, a kind of many fluorescent tubes one wire system inverter sample circuit has been proposed, this sample circuit had both kept the wiring characteristics of many fluorescent tubes one wire system, can overcome the deficiencies in the prior art in the past again, thereby preferably resolve the mutual current balance type problem of many fluorescent tubes one wire system, guaranteed the uniformity of whole image light.
Summary of the invention
For achieving the above object, the technical solution adopted in the utility model is: a kind of many fluorescent tubes one wire system inverter sample circuit, its technical scheme is: set up an inductance sample coil winding in the every pairing driving transformer of fluorescent tube, this coil windings one end ground connection, other end sampling feedback.
Related content and change interpretation in the technique scheme are as follows:
1, in the such scheme, described fluorescent tube is meant cold cathode fluorescent tube (CCFT), and cold cathode fluorescent tube is generally driven by inverter, and inverter is a kind of high-frequency and high-voltage electric power system, wherein contain transformer, the secondary cold cathode fluorescent tube that connects of this transformer, promptly single transformer drives single fluorescent tube.
2, in the such scheme, the other end of described inductance coil winding sampling feedback is meant generally from this end and compares by resistance or the sampling of other form and by comparison circuit that the IC controller adopts the output current size of negative feedback type control inverter according to comparative result then.
3, in the such scheme, described inductance coil winding is arranged in driving transformer and can be adopted following two kinds of forms:
(1), with the inductance coil winding as an elementary winding of driving transformer be arranged in elementary on, see shown in Figure 6.
(2), with the inductance coil winding as a secondary winding of driving transformer be arranged in secondary on, see shown in Figure 7.
The utility model operation principle is: utilize existing single transformer to drive the circuit structure of single fluorescent tube, obtain the transfer power of transformer with the inductance sample coil, make that the power output Po of each high frequency transformer of driving each fluorescent tube is identical.Thereby, keep the power P o of each fluorescent tube gained identical.Though fluorescent tube is variant, but differ and not quite, and cold cathode fluorescent tube (CCFT) is under hot machine state, consistency (this is guaranteed by fluorescent tube manufacturer) is preferably arranged, guarantee the voltage regulation result (Vrms) under hot machine state, according to Po=Vrms*Irms, thereby reach the consistency of output current Irms.
This programme inverter output current control procedure: IC → elementary → secondary → feedback → IC, circulate with this.
This programme inverter output current control principle: referring to shown in Figure 6,
If: winding coil number of turn electric current and voltage
Elementary n
1V
1I
1
Secondary n
2V
2I
2
Feedback n
3V
3I
3
Get according to transformer principle:
n
2/ n
1=V
2/ V
1=m formula (1)
n
3/ n
1=V
3/ V
1=n formula (2)
Get by formula (1)/formula (2):
n
2/n
3＝V
2/V
3＝m/n
V
2=(m/n) * V
3Formula (3)
Because V
2=I
2* R
2V
3=I
3* R
3Substitution formula (3):
I
2＝(m/n)×(R
3/R
2)×I
3
I
2=K * I
3Formula (4)
K is a constant in the formula
Find out by feedback current I by formula (4)
3Can effectively control the transformer secondary output I that outputs to fluorescent tube
2
Because the technique scheme utilization, the utility model compared with prior art has following advantage:
1, the utility model is compared with the wiring of many fluorescent tubes of available liquid crystal display backlight plate double wire system, because the low-pressure end of every fluorescent tube supplies with a grounded circuit to the loop in the inverter power supply system, therefore the wiring of circuit becomes simply, thereby has further reduced cost.
2, the utility model with just compare at present at many fluorescent tubes one wire system sample circuit of experimental stage, have antijamming capability strongly, it is more reliable to work.Its reason is: owing to used the inductance coil winding in the transformer as sampling feedback, the mutual interference volume in transformer secondary output district can be embodied, therefore the effective size of control inverter output current.And many fluorescent tubes of above-mentioned experimental stage one wire system sample circuit, owing to directly take out lamp current feedback (seeing Fig. 3 and Fig. 4) over the ground from transformer high-voltage line bag, therefore can't reflect the phase mutual interference in transformer secondary output district, the effective current deviation exported of control inverter.
3, the degree of deviation of the utility model lamp current can be accomplished 5～6% (size of normal current is 6mA), and TaiWan, China and Korean and Japanese can only accomplish 6.7% at present, and it is 10% that industry can be accepted as the degree of deviation at most.
Description of drawings
Accompanying drawing 1 is many fluorescent tubes double wire system wiring schematic diagram of LCD screen backlight plate;
Accompanying drawing 2 is many fluorescent tubes one wire system wiring schematic diagram of LCD screen backlight plate;
Accompanying drawing 3 is many fluorescent tubes one wire system lamp current sampling feedback circuit block diagram;
Accompanying drawing 4 is many fluorescent tubes one wire system lamp current sampling feedback circuit schematic diagram;
Accompanying drawing 5 is many fluorescent tubes double wire system lamp current sampling feedback circuit schematic diagram;
Accompanying drawing 6 is many fluorescent tubes of the utility model one wire system lamp current sampling feedback circuit schematic diagram ();
Accompanying drawing 7 is many fluorescent tubes of the utility model one wire system lamp current sampling feedback circuit schematic diagram (two).
Embodiment
Below in conjunction with drawings and Examples the utility model is further described:
Embodiment one: shown in accompanying drawing 6, a kind of many fluorescent tubes one wire system inverter sample circuit, its scheme is: set up an inductance sample coil winding in the every pairing driving transformer of fluorescent tube, this coil windings is as an elementary winding of driving transformer, one end ground connection, other end sampling feedback.
Embodiment two: shown in accompanying drawing 7, a kind of many fluorescent tubes one wire system inverter sample circuit is with the difference of embodiment one: with the inductance coil winding as a secondary winding of driving transformer be arranged in secondary on.Other is identical with embodiment one.
The foregoing description only is explanation technical conceive of the present utility model and characteristics, and its purpose is to allow the personage who is familiar with this technology can understand content of the present utility model and enforcement according to this, can not limit protection range of the present utility model with this.All equivalences of being done according to the utility model spirit change or modify, and all should be encompassed within the protection range of the present utility model.
Claims (3)
1, a kind of many fluorescent tubes one wire system inverter sample circuit is characterized in that: set up an inductance sample coil winding in the every pairing driving transformer of fluorescent tube, this coil windings one end ground connection, other end sampling feedback.
2, sample circuit according to claim 1 is characterized in that: described inductance coil winding is as an elementary winding of driving transformer.
3, sample circuit according to claim 1 is characterized in that: described inductance coil winding is as a secondary winding of driving transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03258802 CN2640196Y (en) | 2003-06-12 | 2003-06-12 | Multi-tube single-coil inverter sampling circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03258802 CN2640196Y (en) | 2003-06-12 | 2003-06-12 | Multi-tube single-coil inverter sampling circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2640196Y true CN2640196Y (en) | 2004-09-08 |
Family
ID=34295854
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03258802 Expired - Fee Related CN2640196Y (en) | 2003-06-12 | 2003-06-12 | Multi-tube single-coil inverter sampling circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2640196Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101098578B (en) * | 2006-06-28 | 2011-02-09 | 台达电子工业股份有限公司 | Lamp tube driving circuit |
| CN101188896B (en) * | 2006-09-08 | 2012-08-29 | 三星电子株式会社 | Inverter circuit and backlight assembly having the same |
-
2003
- 2003-06-12 CN CN 03258802 patent/CN2640196Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101098578B (en) * | 2006-06-28 | 2011-02-09 | 台达电子工业股份有限公司 | Lamp tube driving circuit |
| CN101188896B (en) * | 2006-09-08 | 2012-08-29 | 三星电子株式会社 | Inverter circuit and backlight assembly having the same |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |