CN101834520A - Scanning type backlight driving device and liquid crystal display device using same - Google Patents
Scanning type backlight driving device and liquid crystal display device using same Download PDFInfo
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- CN101834520A CN101834520A CN200910047557A CN200910047557A CN101834520A CN 101834520 A CN101834520 A CN 101834520A CN 200910047557 A CN200910047557 A CN 200910047557A CN 200910047557 A CN200910047557 A CN 200910047557A CN 101834520 A CN101834520 A CN 101834520A
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Abstract
The invention relates to a scanning type backlight driving device and a liquid crystal display device using the same. The scanning type backlight driving device comprises a direct current (DC) / alternating current (AC) voltage converter, N transformers, N switches and a control circuit, wherein N is a natural number; the DC/AC voltage converter is provided with a first output end and a second output end which are used for outputting an AC voltage; each transformer is provided with a primary winding; each switch can electrically connect the first output end with the second output end through one of the primary windings; and the control circuit can control the switches to switch off or on temporarily and periodically according to a predetermined sequence.
Description
Technical field
The invention relates to the field of liquid crystal indicator, and particularly use the scanning type backlight driving device of an AC/DC voltage changer and use its liquid crystal indicator relevant for a kind of need.
Background technology
For now, (liquid crystal display LCD) is still and adopts the cold cathode fluorescent lamp pipe widely (cold cathode fluorescent lamp CCFL) is used as backlight liquid crystal indicator.Owing to when showing dynamic menu,, will make that ghost appears in picture, drive these fluorescent tubes so more novel liquid crystal indicator just changes with the scan-type point method of going out, to improve the quality of dynamic menu if every cold cathode fluorescent lamp pipe all is in complete bright state.In other words, these fluorescent tubes are to light in the mode of taking turns.Thus, but just the emulation cathode ray tube (cathode ray tube, CRT) pulsed of display (impulse type) principle of luminosity does not have the ghost that liquid crystal indicator is covered in luminous dark state zone territory with fluorescent tube.
Fig. 1 has promptly illustrated known scanning type backlight driving device, this scanning type backlight driving device be by No. 006778415, U.S. Pat propose.As shown in Figure 1, this scanning type backlight driving device adopts a plurality of AC/DC voltage changer (DC/AC inverter, as indicate shown in 10～16), and adopt a plurality of transformers (transformer, as indicate shown in 110) of corresponding AC/DC voltage changer quantity.In addition, this scanning type backlight driving device has also adopted control circuit 40 to control the operation of above-mentioned AC/DC voltage changer, and this control circuit 40 includes pulse generator 46 and phase selector 44.Elementary winding (the primary winding of each transformer, be called winding again one time, as indicate shown in 112) be used for receiving the alternating voltage that the AC/DC voltage changer is exported, and each Secondary winding of transformer (secondary winding, be called secondary winding again, as indicate shown in 114) then be used for connecting load, just connect the cold cathode fluorescent lamp pipe.As long as allow these AC/DC voltage changers take turns output AC voltage, just can see through transformer and light the cold cathode fluorescent lamp pipe in turn.
Even if this scanning type backlight driving device can drive the cold cathode fluorescent lamp pipe with the scan-type point method of going out, reach the effect of improving ghost, yet but can know by its circuit framework and to know, each transformer AC/DC voltage changer of all need arranging in pairs or groups.So, not only make the volume of circuit very big, circuit cost also can be very high.
Summary of the invention
The invention provides a kind of scanning type backlight driving device, its need use an AC/DC voltage changer, significantly reduce the volume and the cost of circuit.
The present invention provides a kind of liquid crystal indicator in addition, and it adopts above-mentioned scanning type backlight driving device, so its need use an AC/DC voltage changer, makes the cost of liquid crystal indicator be minimized.
The present invention proposes a kind of scanning type backlight driving device.This scanning type backlight driving device includes one direct current/AC voltage convertor, a N transformer, a N switch and a control circuit, and wherein N is a natural number.The AC/DC voltage changer has first output and second output, and first output and second output the two in order to export an alternating voltage.Each transformer all has an elementary winding, and one of them is electrically connected to second output and each switch all sees through first output those elementary windings.As for control circuit, it is periodically controlled with a predefined procedure, and those switches are of short duration closes.
The present invention proposes a kind of scanning type backlight driving device again.This scanning type backlight driving device includes one direct current/AC voltage convertor, a N transformer, a N switch and a control circuit, and wherein N is a natural number.The AC/DC voltage changer has first output and second output, and first output and second output the two in order to export an alternating voltage.Each transformer all has an elementary winding, and one of them is electrically connected to second output and whether each switch all sees through first output those elementary windings in order to decision.As for control circuit, it periodically controls the of short duration conducting of those switches with a predefined procedure.
The present invention proposes a kind of liquid crystal indicator in addition, and it also adopts the wherein a kind of of above-mentioned two kinds of scanning type backlight driving devices except including a display floater.
In one embodiment of this invention, those above-mentioned switches all comprise with an electronic switch assembly or a mechanical switch assembly realizes the electronic switch assembly comprises it being a two-way switch, and the mechanical switch assembly comprises it being a relay.
The present invention adopts one direct current/AC voltage convertor, a N transformer, a N switch and a control circuit to form scanning type backlight driving device, and utilizes the conducting state of above-mentioned each switch to determine whether the alternating voltage that the AC/DC voltage changer is exported is sent to elementary winding in the corresponding transformer.See through control circuit and come the conducting state of switch is controlled, just can drive backlight, and entire circuit also only needs an AC/DC voltage changer, significantly reduce the volume and the cost of circuit with the scan-type point method of going out.In addition, if a liquid crystal indicator adopts above-mentioned scanning type backlight driving device, just the cost of this liquid crystal indicator is significantly reduced so.
Description of drawings
Fig. 1 illustrates and is known scanning type backlight driving device;
Fig. 2 illustrates the scanning type backlight driving device according to one embodiment of the invention;
Fig. 3 illustrates wherein a kind of sequential of controlling signal C1～C4 of Fig. 2;
Fig. 4 is the wherein another kind of sequential of controlling signal C1～C4 of illustrating Fig. 2;
Fig. 5 illustrates the scanning type backlight driving device according to another embodiment of the present invention.
For above-mentioned feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and cooperate appended graphicly, be described in detail below.
Embodiment
Fig. 2 illustrates the scanning type backlight driving device according to one embodiment of the invention.This scanning type backlight driving device includes AC/DC voltage changer 210, control circuit 220, switches set 230, also has transformer 240,250,260 and 270, and wherein switches set 230 includes switch 232,234,236,238 again.AC/DC voltage changer 210 also has output 216 and 218 except having input 212 and 214.In addition, each transformer all has an elementary winding and a level winding.With transformer 240 is example, and it just has elementary winding 242 and secondary winding 244.Each secondary winding all is used for connecting load, for example is to connect cold cathode fluorescent lamp pipe (as indicating shown in 282～288).
Should be noted that, in this example, switch 232,234,236,238 is all operated in the mode of normality conducting (on), so with the switch connected mode among this figure as can be known, each switch among the figure all is that one of them is electrically connected to output 218 with output 216 sees through those elementary windings.With switch 232 is example, and it sees through elementary winding 242 with output 216 exactly and is electrically connected to output 218.As for control circuit 220, it is in order to produce controlling signal C1～C4, and export these controlling signal the control end of switch 232,234,236 and 238 to respectively, control periodically with a predefined procedure so that utilize these controlling signal that these switches are of short duration closes (off).In addition, in this example, control circuit 220 more in order to output controlling signal CS to AC/DC voltage changer 210 so that the startup of control AC/DC voltage changer 210 with close.
In case AC/DC voltage changer 210 starts, AC/DC voltage changer 210 will be converted to alternating voltage (AC) with its input 212 and 214 direct voltages that received (DC), and then sees through its output 216 and 218 output AC voltages.So, just can see through the conducting state of each switch of control, determine whether the alternating voltage that AC/DC voltage changer 210 is exported is sent to elementary winding in the corresponding transformer, and then whether decision lights corresponding cold cathode fluorescent lamp pipe.So, just can reach the purpose that drives backlight with the scan-type point method of going out, and entire circuit also only needs an AC/DC voltage changer, significantly reduce the volume and the cost of circuit.
Fig. 3 is wherein a kind of sequential of controlling signal C1～C4 of illustrating Fig. 2.Please be simultaneously with reference to Fig. 3 and Fig. 2.Simple and clear, when controlling signal was electronegative potential, corresponding switch just presented conducting state; Otherwise when controlling signal was high potential, corresponding switch just presented closed condition.And by sequential shown in Figure 3 as can be known, switch 232,234,236 and 238 is to present closed condition in turn according to the order of mentioning, and at one time, only has a switch and be closed.In other words, cold cathode fluorescent lamp pipe 282,284,286 and 288 is that closing sequence according to switch 232,234,236 and 238 extinguishes in turn.So, promptly can the scan-type point method of going out drive cold cathode fluorescent lamp pipe 282～288.
Certainly, control circuit 220 also can be to control in the mode of each two switches that those switches are of short duration closes, and illustrates with Fig. 4.Fig. 4 is the wherein another kind of sequential of controlling signal C1～C4 of illustrating Fig. 2.Please be simultaneously with reference to Fig. 4 and Fig. 2.Simple and clear, when controlling signal was electronegative potential, corresponding switch just presented conducting state; Otherwise when controlling signal was high potential, corresponding switch just presented closed condition.And by sequential shown in Figure 4 as can be known, switch 232,234,236 and 238 is to be divided into two groups to present closed condition in turn, just at one time in, have two switches and be closed.In other words, cold cathode fluorescent lamp pipe 282,284,286 and 288 is to extinguish in turn according to the group of switch.So, just, the scan-type point method of going out that can another kind of kenel drives cold cathode fluorescent lamp pipe 282,284,286 and 288.
Though in Fig. 2, only adopt four transformers and four switches to come for example, yet promote, device shown in Figure 2 is when adopting N transformer and N switch to operate, wherein N is a natural number.In addition, the Fig. 4 that arranges in pairs or groups with Fig. 2 for example in, control circuit 220 is to control in the mode of each two switches that those switches are of short duration closes, yet promote, when scanning type backlight driving device has N switch, control circuit 220 also can be to control in the mode of each K switch that those switches are of short duration closes, and wherein K also is a natural number, and N/K is an integer.
Although in Fig. 2, switch 232,234,236 and 238 is all operated in the mode of normality conducting, yet knows that usually the knowledgeable should be known in that these switches all operate in the mode that normality is closed even if this field has, and also can implement the present invention, illustrates with Fig. 5.Fig. 5 illustrates the scanning type backlight driving device according to another embodiment of the present invention.In Fig. 5, each switch in the switches set 510 is all normality and cuts out, and all whether output 216 is seen through those elementary windings in order to decision one of them be electrically connected to output 218.As for control circuit 220, it is to utilize controlling signal C1～C4 and periodically control the of short duration conducting of these switches with a predefined procedure.
The controlling signal C1 of Fig. 5～C4 also can sequential shown in Figure 3 describe.Please be simultaneously with reference to Fig. 5 and Fig. 3, simple and clear, when controlling signal was electronegative potential, corresponding switch just presented closed condition; Otherwise when controlling signal was high potential, corresponding switch just presented conducting state.And by sequential shown in Figure 3 as can be known, switch 512,514,516 and 518 is to present conducting state in turn according to the order of mentioning, and at one time, only has a switch conduction.In other words, cold cathode fluorescent lamp pipe 282,284,286 and 288 is that conducting according to switch 512,514,516 and 518 comes to light in turn in proper order.So, just, can be again drive cold cathode fluorescent lamp pipe 282,284,286 and 288 with the scan-type point method of going out of another kind of kenel again.
Certainly, the control circuit 220 of Fig. 5 also can be to control the of short duration conducting of those switches in the mode of each two switches, and its controlling signal C1～C4 also can sequential shown in Figure 4 describe.Please be simultaneously with reference to Fig. 5 and Fig. 4, simple and clear, when controlling signal was electronegative potential, corresponding switch just presented closed condition; Otherwise when controlling signal was high potential, corresponding switch just presented conducting state.And by sequential shown in Figure 4 as can be known, switch 512,514,516 and 518 is to be divided into two groups to present conducting state in turn, just at one time in, have two switch conductions.In other words, cold cathode fluorescent lamp pipe 282,284,286 and 288 is to light in turn according to the group of switch.So, just provide a kind of scan-type point method of going out of kenel to drive cold cathode fluorescent lamp pipe 282,284,286 and 288 again more.
Though in Fig. 5, only adopt four transformers and four switches to come for example, yet promote, device shown in Figure 5 is when adopting N transformer and N switch to operate, wherein N is a natural number.In addition, Fig. 5 arrange in pairs or groups Fig. 4 for example in, control circuit 220 is to control the of short duration conducting of those switches in the mode of each two switches, yet promote, when scanning type backlight driving device has N switch, control circuit 220 also can be to control the of short duration conducting of those switches in the mode of each K switch, and wherein K also is a natural number, and N/K is an integer.
What deserves to be mentioned is, each above-mentioned switch all can be to utilize an electronic switch assembly or a mechanical switch assembly to realize, wherein the electronic switch assembly comprises and shows bidirectional switch (bilateral switch), and the mechanical switch assembly comprises it being relay (relay).
In sum, the present invention adopts one direct current/AC voltage convertor, a N transformer, a N switch and a control circuit to form scanning type backlight driving device, and utilizes the conducting state of above-mentioned each switch to determine whether the alternating voltage that the AC/DC voltage changer is exported is sent to elementary winding in the corresponding transformer.See through control circuit and come the conducting state of switch is controlled, just can drive backlight, and entire circuit also only needs an AC/DC voltage changer, significantly reduce the volume and the cost of circuit with the scan-type point method of going out.
In addition, if changing, a liquid crystal indicator adopts scanning type backlight driving device of the present invention, that is to say, this liquid crystal indicator is except including a display floater, also adopt the wherein a kind of of Fig. 2 and the described scanning type backlight driving device of Fig. 5, the cost of this liquid crystal indicator is just significantly reduced so.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; have in the technical field under any and know the knowledgeable usually; without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is as the criterion when looking the claim person of defining.
Claims (8)
1. a scanning type backlight driving device is characterized in that, comprising:
One direct current/AC voltage convertor has one first output and one second output, this first output and this second output the two in order to export an alternating voltage;
N transformer, each transformer all have an elementary winding, and wherein N is a natural number;
N switch, each switch all this first output is seen through those elementary windings one of them be electrically connected to this second output; And
One control circuit controls periodically with a predefined procedure that those switches are of short duration to be closed or periodically control the of short duration startup of closing and control this AC/DC voltage changer of those switches and close with a predefined procedure.
2. scanning type backlight driving device as claimed in claim 1 is characterized in that, wherein this control circuit comprises and controls in the mode of each K switch that those switches are of short duration closes, and wherein K is a natural number, and N/K is an integer.
3. scanning type backlight driving device as claimed in claim 1 is characterized in that, wherein those switches all comprise with an electronic switch assembly or a mechanical switch assembly and realizing,
Wherein this electronic switch assembly comprises it being a two-way switch, and this mechanical switch assembly comprises it being a relay.
4. a scanning type backlight driving device is characterized in that, comprising:
One direct current/AC voltage convertor has one first output and one second output, this first output and this second output the two in order to export an alternating voltage;
N transformer, each transformer all have an elementary winding, and wherein N is a natural number;
N switch, each switch all whether this first output is seen through those elementary windings in order to decision one of them be electrically connected to this second output; And
One control circuit periodically controls the of short duration conducting of those switches or periodically controls the of short duration startup of cutting out and control this AC/DC voltage changer of those switches and cut out with a predefined procedure with a predefined procedure.
5. scanning type backlight driving device as claimed in claim 4 is characterized in that, wherein this control circuit comprises in the mode of each K switch and controls the of short duration conducting of those switches, and wherein K is a natural number, and N/K is an integer.
6. scanning type backlight driving device as claimed in claim 4 is characterized in that, wherein those switches all comprise with an electronic switch assembly or a mechanical switch assembly and realizing,
Wherein this electronic switch assembly comprises it being a two-way switch, and this mechanical switch assembly comprises it being a relay.
7. liquid crystal indicator comprises:
One display floater; And
One scan formula backlight driving device comprises:
One direct current/AC voltage convertor has one first output and one second output, this first output and this second output the two in order to export an alternating voltage;
N transformer, each transformer all have an elementary winding, and wherein N is a natural number;
N switch, each switch all this first output is seen through those elementary windings one of them be electrically connected to this second output; And
One control circuit controls periodically with a predefined procedure that those switches are of short duration closes.
8. liquid crystal indicator comprises:
One display floater; And
A kind of scanning type backlight driving device comprises:
One direct current/AC voltage convertor has one first output and one second output, this first output and this second output the two in order to export an alternating voltage;
N transformer, each transformer all have an elementary winding, and wherein N is a natural number;
N switch, each switch all whether this first output is seen through those elementary windings in order to decision one of them be electrically connected to this second output; And
One control circuit is periodically controlled the of short duration conducting of those switches with a predefined procedure.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910047557XA CN101834520B (en) | 2009-03-13 | 2009-03-13 | Scanning type backlight driving device and liquid crystal display device using same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910047557XA CN101834520B (en) | 2009-03-13 | 2009-03-13 | Scanning type backlight driving device and liquid crystal display device using same |
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| Publication Number | Publication Date |
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| CN101834520A true CN101834520A (en) | 2010-09-15 |
| CN101834520B CN101834520B (en) | 2013-02-20 |
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| CN200910047557XA Expired - Fee Related CN101834520B (en) | 2009-03-13 | 2009-03-13 | Scanning type backlight driving device and liquid crystal display device using same |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105405407A (en) * | 2014-09-12 | 2016-03-16 | 群创光电股份有限公司 | Display device and backlight drive method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR100488448B1 (en) * | 2001-11-29 | 2005-05-11 | 엘지전자 주식회사 | Generator for sustain pulse of plasma display panel |
| US6778415B2 (en) * | 2003-01-22 | 2004-08-17 | O2Micro, Inc. | Controller electrical power circuit supplying energy to a display device |
| CN2896432Y (en) * | 2005-12-02 | 2007-05-02 | 咸阳华立电子设备有限公司 | Liquid crystal display-screen cold-cathode fluorescent back-light-source driver |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105405407A (en) * | 2014-09-12 | 2016-03-16 | 群创光电股份有限公司 | Display device and backlight drive method thereof |
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