CN101834520B - 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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- CN101834520B CN101834520B CN200910047557XA CN200910047557A CN101834520B CN 101834520 B CN101834520 B CN 101834520B CN 200910047557X A CN200910047557X A CN 200910047557XA CN 200910047557 A CN200910047557 A CN 200910047557A CN 101834520 B CN101834520 B CN 101834520B
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- 238000004804 winding Methods 0.000 claims abstract description 30
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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 relevant for a kind of need and use its liquid crystal indicator.
Background technology
For now, liquid crystal indicator (liquid crystal display, LCD) is still and adopts widely cold cathode fluorescent lamp pipe (cold cathode fluorescent lamp, CCFL) to be used as backlight.Owing to when showing dynamic menu, if every cold cathode fluorescent lamp pipe all is in complete bright state, will so 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.In other words, these fluorescent tubes are to light in mode in turn.Thus, but just pulsed (impulse type) principle of luminosity of emulation cathode ray tube (cathode ray tube, CRT) display covers the ghost of liquid crystal indicator without luminous dark state zone territory with fluorescent tube.
Fig. 1 has namely illustrated known scanning type backlight driving device, this scanning type backlight driving device be by No. 006778415, US Patent No. 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 the of 10～16), and adopt a plurality of transformers (transformer, as indicate shown in the of 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.The armature winding of each transformer (primary winding, be called again winding one time, as indicate shown in the of 112) be used for receiving the alternating voltage that the AC/DC voltage changer is exported, and the secondary winding of each transformer (secondarywinding, be called again secondary winding, as indicate shown in the of 114) then be used for connecting load, namely connect the cold cathode fluorescent lamp pipe.As long as allow in turn output AC voltage of these AC/DC voltage changers, just can see through transformer and light in turn the cold cathode fluorescent lamp pipe.
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 be known by its circuit framework and to know, each transformer AC/DC voltage changer of need arranging in pairs or groups.So, not only make the volume of circuit very large, 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 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, so that the cost of liquid crystal indicator is 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 natural number.The AC/DC voltage changer has the first output and the second output, and the first output and the second output the two in order to export an alternating voltage.Each transformer all has an armature winding, and one of them is electrically connected to the second output and each switch all sees through the first output those armature 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 again 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 natural number.The AC/DC voltage changer has the first output and the second output, and the first output and the second output the two in order to export an alternating voltage.Each transformer all has an armature winding, and each switch all is electrically connected to the second output in order to one of them that determines whether the first output to be seen through those armature windings.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 armature winding in the corresponding transformer.See through control circuit and come the conducting state of switch is controlled, just can drive backlight with the scan-type point method of going out, and whole circuit also only needs an AC/DC voltage changer, significantly reduce volume and the cost of circuit.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 control signal C1～C4 of Fig. 2;
Fig. 4 is the wherein another kind of sequential that illustrates control signal C1～C4 of 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 again switch 232,234,236,238.AC/DC voltage changer 210 also has output 216 and 218 except having input 212 and 214.In addition, each transformer all has an armature winding and a level winding.Take transformer 240 as example, it just has armature 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 the of 282～288).
Should be noted that, in this example, switch 232,234,236,238 all operates 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 armature windings.Take switch 232 as example, it sees through armature winding 242 with output 216 exactly and is electrically connected to output 218.As for control circuit 220, it is in order to produce control signal C1～C4, and export respectively these control signals to switch 232,234,236 and 238 control end, control periodically with a predefined procedure in order to utilize these control signals that these switches are of short duration closes (off).In addition, in this example, control circuit 220 more in order to output control 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, the direct voltage (DC) that AC/DC voltage changer 210 will receive its input 212 and 214 is converted to alternating voltage (AC), 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 armature winding in the corresponding transformer, and then determine whether light 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 whole circuit also only needs an AC/DC voltage changer, significantly reduce volume and the cost of circuit.
Fig. 3 is the wherein a kind of sequential that illustrates control signal C1～C4 of Fig. 2.Please be simultaneously with reference to Fig. 3 and Fig. 2.Simple and clear, when the control signal was electronegative potential, corresponding switch just presented conducting state; Otherwise when the control 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 in turn closed condition 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 to extinguish in turn according to switch 232,234,236 and 238 closing sequence.So, namely 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 that illustrates control signal C1～C4 of Fig. 2.Please be simultaneously with reference to Fig. 4 and Fig. 2.Simple and clear, when the control signal was electronegative potential, corresponding switch just presented conducting state; Otherwise when the control 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 in turn closed condition, namely 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.
Although 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 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 natural number, and N/K is integer.
Although in Fig. 2, switch 232,234,236 and 238 all operates 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 is electrically connected to output 218 in order to one of them that determines whether output 216 to be seen through those armature windings.As for control circuit 220, it is that utilization is controlled signal C1～C4 and periodically controlled the of short duration conducting of these switches with a predefined procedure.
Control signal C1～C4 of Fig. 5 also can sequential shown in Figure 3 describe.Please be simultaneously with reference to Fig. 5 and Fig. 3, simple and clear, when the control signal was electronegative potential, corresponding switch just presented closed condition; Otherwise when the control 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 in turn conducting state 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 sequentially to come to light in turn according to switch 512,514,516 and 518 conducting.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 control 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 the control signal was electronegative potential, corresponding switch just presented closed condition; Otherwise when the control 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 in turn conducting state, namely 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.
Although 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 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 natural number, and N/K is integer.
It is worth mentioning that, 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 armature winding in the corresponding transformer.See through control circuit and come the conducting state of switch is controlled, just can drive backlight with the scan-type point method of going out, and whole circuit also only needs an AC/DC voltage changer, significantly reduce volume and the cost of circuit.
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.
Although the present invention discloses as above with preferred embodiment; so it is not to limit the present invention; have in the technical field under any and usually know the knowledgeable; 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 (6)
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 has an armature winding, and wherein N is natural number;
N switch, each switch all this first output is seen through those armature 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;
Wherein this control circuit comprises and controls in the mode of each K switch that those switches are of short duration closes, and K is natural number, and N/K is integer.
2. 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.
3. 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 has an armature winding, and wherein N is natural number;
N switch, each switch all are electrically connected to this second output in order to one of them that determines whether this first output to be seen through those armature windings; 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;
Wherein this control circuit comprises in the mode of each K switch and controls the of short duration conducting of those switches, and K is natural number, and N/K is integer.
4. scanning type backlight driving device as claimed in claim 3 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.
5. 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 has an armature winding, and wherein N is natural number;
N switch, each switch all this first output is seen through those armature 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;
Wherein this control circuit comprises and controls in the mode of each K switch that those switches are of short duration closes, and K is natural number, and N/K is integer.
6. 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 has an armature winding, and wherein N is natural number;
N switch, each switch all are electrically connected to this second output in order to one of them that determines whether this first output to be seen through those armature windings; 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;
Wherein this control circuit comprises in the mode of each K switch and controls the of short duration conducting of those switches, and K is natural number, and N/K is integer.
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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 |
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| 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 CN101834520A (en) | 2010-09-15 |
| CN101834520B true 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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| CN105405407A (en) * | 2014-09-12 | 2016-03-16 | 群创光电股份有限公司 | Display device and backlight driving method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1421838A (en) * | 2001-11-29 | 2003-06-04 | Lg电子株式会社 | Continuous pulse generator 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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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1421838A (en) * | 2001-11-29 | 2003-06-04 | Lg电子株式会社 | Continuous pulse generator 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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| CN101834520A (en) | 2010-09-15 |
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