CN102376275B - TFT-LCD (thin film transistor-liquid crystal display) driving circuit and liquid crystal display device - Google Patents
TFT-LCD (thin film transistor-liquid crystal display) driving circuit and liquid crystal display device Download PDFInfo
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Abstract
The embodiment of the invention discloses a TFT-LCD (thin film transistor-liquid crystal display) driving circuit and a liquid crystal display device, relating to the technical field of liquid crystal display and used for reducing the number of source drivers and reducing the manufacturing cost of a TFT-LCD under the condition of not affecting the normal charge of a pixel electrode. The TFT-LCD driving circuit comprises the source driver, and each output end of the source driver is connected with at least two data wires; furthermore, transfer switches of which the number corresponds to that of the data wires are arranged between the output ends of the source driver and the data wires, and the transfer switches are used for controlling the data transmission from the source driver to the data wires, wherein a sampling and holding unit is arranged between the transfer switches and the data wires, and the sampling and holding unit is used for saving display data which is provided from thesource driver to the data wires. The scheme provided in the embodiment of the invention is applicable to any thin-film transistor liquid crystal display equipment.
Description
Technical field
The present invention relates to technical field of liquid crystal display, relate in particular to a kind of TFT-LCD driving circuit and have the liquid crystal indicator of this driving circuit.
Background technology
In traditional TFT-LCD (Thin Film Transistor-Liquid Crystal Display, Thin Film Transistor-LCD), every data line (data line) all is connected with the output line of a source electrode driver (Source Driver); Like this, in a LCD, just the source electrode driver of needs and data line equal amount causes the cost of source drive unit higher.
In order to reduce the use of source electrode driver, reduce the cost of manufacture of TFT-LCD, there is following improvement project in the prior art:
Between source electrode driver and data line, change-over switch is set, the output line of a source electrode driver is connected with many data lines simultaneously by described change-over switch, i.e. control by described change-over switch makes same source electrode driver timesharing ground provide the demonstration data for many data lines.Simultaneously, in order to make the demonstration data that record in the pixel electrode after the change-over switch on the data line disconnects, can continue to keep stable, therefore in this improvement project, also added the data write time of controlling described many data lines with many grid lines of described many data line equivalent respectively.When the change-over switch on data line disconnects therein, can adjust in time signal on the corresponding grid line corresponding TFT gate turn-off to guarantee the accuracy of recorded data in the pixel electrode.
State in realization in the process of improvement project of TFT-LCD, the inventor finds that there are the following problems at least in the prior art: in above-mentioned improvement project, though reduced the quantity of source electrode driver, can reduce the cost of manufacture of TFT-LCD; But, control the on off state of the pixel of described many data line correspondences respectively by acquiring grid line, can make the corresponding minimizing of duration of charging of pixel electrode of described many data line correspondences, the grid line of setting up simultaneously can have influence on the aperture opening ratio of TFT-LCD.
Summary of the invention
Embodiments of the invention provide a kind of TFT-LCD driving circuit and liquid crystal indicator, in order to not influence the quantity that reduces source electrode driver under the situation that pixel electrode charges normal, reduce the cost of manufacture of TFT-LCD.
For achieving the above object, embodiments of the invention adopt following technical scheme:
A kind of TFT-LCD driving circuit, comprise source electrode driver, each output terminal of this source electrode driver links to each other and is connected at least two data lines, and between the output terminal of described source electrode driver and described data line, being provided with the change-over switch corresponding with described data line equivalent, this change-over switch is used for the data of control from described source electrode driver to described data line and transmits; Wherein, be provided with sample holding unit between described change-over switch and described data line, described sample holding unit is used for preserving the demonstration data that described source electrode driver offers described data line.
A kind of liquid crystal indicator has above-mentioned TFT-LCD driving circuit in this liquid crystal indicator.
TFT-LCD driving circuit and liquid crystal indicator that the embodiment of the invention provides, an output terminal by a source electrode driver provides the demonstration data for many data lines, can reduce the usage quantity of source electrode driver, thereby reduces the cost of manufacture of TFT-LCD; And, preserve the demonstration data that source electrode driver offers data line by the sample holding unit that between change-over switch and data line, arranges, can be after the change-over switch corresponding with described data line disconnects, make described sample holding unit still keep higher voltage, so just can guarantee the duration of charging of pixel electrode, and can not have influence on the demonstration data that recorded in the pixel electrode.Compared with prior art, the TFT-LCD driving circuit and the liquid crystal indicator that provide in the embodiment of the invention, the quantity that reduces source electrode driver under the situation that pixel electrode charges normal can not influenced, reduce the cost of manufacture of TFT-LCD, the aperture opening ratio to TFT-LCD does not have harmful effect yet simultaneously.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, the accompanying drawing of required use is done to introduce simply in will describing embodiment below, apparently, accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the electrical block diagram of the TFT-LCD driving circuit in the embodiment of the invention;
Fig. 2 is the electrical block diagram of the TFT-LCD driving circuit in the embodiment of the invention one;
Fig. 3 is the implementation one of the sample holding unit among Fig. 2;
Fig. 4 is the implementation two of the sample holding unit among Fig. 2;
Fig. 5 is the electrical block diagram of the TFT-LCD driving circuit in the embodiment of the invention two;
Fig. 6 is the electrical block diagram of the Gamma voltage regulator circuit in the embodiment of the invention four;
Fig. 7 is the another kind of implementation synoptic diagram of TFT-LCD driving circuit in the embodiment of the invention;
Fig. 8 is the synoptic diagram of the Digital Implementation of the Gamma voltage regulator circuit in four in the embodiment of the invention;
Reference numeral: the output terminal of 101-source electrode driver; The 102-data line; The 103-change-over switch; The 104-sample holding unit; The 141-operational amplifier; 142,143-electric capacity; 105-data write switch; The 601-first resistance regulating circuit; The 602-second resistance regulating circuit.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.
Below in conjunction with accompanying drawing TFT-LCD driving circuit and the liquid crystal indicator that provides in the embodiment of the invention is described in detail.
As shown in Figure 1, the TFT-LCD driving circuit that provides in the embodiment of the invention, comprise source electrode driver, the output terminal 101 of this source electrode driver is connected with at least two data lines 102, and between the output terminal 101 of described source electrode driver and described data line 102, being provided with the change-over switch 103 corresponding with described data line 102 equivalent, this change-over switch 103 is used for control, and 102 data transmit from described source electrode driver to data line; Wherein, be provided with sample holding unit 104 between described change-over switch 103 and described data line 102, described sample holding unit 104 is used for preserving the demonstration data that described source electrode driver offers described data line 102.
Be a kind of situation in the scheme protected of the present invention in the situation that the output terminal 101 of the source electrode driver shown in Fig. 1 connects 4 data lines 102.Wherein, SW1, SW2, SW3, SW4 are respectively the control ends of the change-over switch of 4 data line correspondences; By control end SW1, SW2, when 4 change-over switches of SW3, SW4 control are opened successively by turns, source electrode driver is exported the corresponding data that show respectively by output terminal 101 and is given the signal of data line 102, and the demonstration data that the while source electrode driver is exported by output terminal 101 also can be stored in the sample holding unit 104.Like this, after the change-over switch of a data line correspondence disconnects therein, output terminal at sample holding unit 104, just the input end of this data line still keeps high-tension state, the influence of caused change in voltage when making the data that write in the pixel electrode can not be subjected to change-over switch to disconnect, and then guarantee to be written to the accuracy of the data in the pixel electrode.
In fact, in the present embodiment, the quantity of described data line 102 can be more than or equal to 2, but the quantity that it is noted that described data line 102 simultaneously is not can infinite expanding.Because, the time that every capable pixel is opened, the chances are 16.6 μ s, and in the prior art the required duration of charging of each sub-pix can control less than 4 μ s, therefore when certain delegation's pixel is opened, can open 4～5 data lines by control change-over switch 103 in turn and write the demonstration data by same output terminal for the sub-pix of these 4～5 data line correspondences provides by source electrode driver.Along with the development of liquid crystal drive technology or the improvement of technology, the required duration of charging of each sub-pix may reduce gradually, like this, just can utilize a source electrode driver to drive the more data line and for the more data line provides the demonstration data, the cost when being reduced in the driving circuit of making among the TFT-LCD greatly.
Preferably, can utilize the same output of a source electrode driver to bring in to 3 data lines provide the demonstration data, and these 3 data lines are distinguished the three kinds of sub-pixs of red, green, blue (RGB) in the corresponding same row pixel; Like this, just can directly adjust some parameter on the described data line in the source electrode driver part, such as gamma voltage.
Above-mentioned TFT-LCD driving circuit, same output terminal by a source electrode driver provides the demonstration data for many data lines, can make same source electrode driver provide the demonstration data for the more data line, and then reduce the usage quantity of source electrode driver, reduce the cost of manufacture of TFT-LCD; And, preserve the demonstration data that source electrode driver offers data line by the sample holding unit that between change-over switch and data line, arranges, can be after the change-over switch corresponding with described data line disconnects, make described sample holding unit still keep higher voltage, so just can guarantee the duration of charging of pixel electrode, and can not have influence on the demonstration data that recorded in the pixel electrode.Simultaneously, utilize the TFT-LCD driving circuit that provides in the present embodiment, can not produce harmful effect to the aperture opening ratio of TFT-LCD.
Below will be mainly with the same output terminal of a source electrode driver connect 3 data lines and this 3 data lines respectively the situation of three kinds of sub-pixs of red, green, blue of corresponding same row pixel be example, and do further in conjunction with the TFT-LCD driving circuit that instantiation comes the embodiment of the invention is provided and to describe in detail.
Wherein, in following examples, described change-over switch is selected metal oxide semiconductor field effect tube (MOS-FET is called for short metal-oxide-semiconductor) for use; The source electrode of this MOS and drain electrode are serially connected between the output terminal 101 and sample holding unit 104 of source electrode driver, and its grid connects change-over switch control end (such as SW1, SW2 or SW3).
Embodiment one:
TFT-LCD driving circuit as shown in Figure 2 is identical with TFT-LCD driving circuit ultimate principle described in Fig. 1; But, in the scheme of Fig. 2, the output terminal 101 (Sm) of source electrode driver connects 3 data lines 102 simultaneously, and three kinds of sub-pixs of red, green, blue of the corresponding same row pixel of these 3 data lines, 102 difference.Between the output terminal 101 of described source electrode driver and data line 102, also be serially connected with change-over switch 103 and sample holding unit 104.
The same output terminal of a source electrode driver is connected with 3 change-over switches simultaneously, and then is connected with 3 sample holding units, 3 data lines; That is to say, can make an output line of source electrode driver to provide the signal that shows data for 3 row sub-pixs in timesharing ground by the control of described 3 change-over switches.Correspondingly, provide the quantity of the sub-pix of data-signal can reach in the past 3 times by same source electrode driver; Like this, comparing with generalized case just only needs the source electrode driver of original 1/3 quantity just passable, has significantly reduced the use amount of source electrode driver, can reduce the cost of manufacture of TFT-LCD.
In the present embodiment, the voltage that provides by control SW1, SW2, SW3 can be controlled the data-signal input of three kinds of sub-pixs of red, green, blue in the same row pixel.Particularly, the voltage that provides by control SW1, SW2, SW3 can be opened the change-over switch of three kinds of sub-pix correspondences of red, green, blue successively, by turns, namely has only the change-over switch that connects on the data lines to be in open mode in the same row pixel at one time.
Illustrate, situation as shown in Figure 2, when the grid line of certain delegation's pixel correspondence is in high level state, at first, provide a high level by SW1 for the change-over switch of red sub-pixel correspondence, described change-over switch is opened, this moment, the output terminal Sm of source electrode driver provided the demonstration data for the red sub-pixel corresponding data line, and write the demonstration data in the red sub-pixel of same row; Simultaneously, described demonstration data also are stored in the sample holding unit.When being converted to low level, SW1 simultaneously SW2 is converted to high level, this moment, the change-over switch of red sub-pixel correspondence disconnected, the change-over switch of green sub-pix correspondence is opened, the output terminal Sm of source electrode driver begins to green sub-pix corresponding data line provides the demonstration data, and writes the demonstration data in the green sub-pix of same row.At this moment, because the sample holding unit of red sub-pixel correspondence still is in high level state, so the charged state of red sub-pixel can't be affected because of the disconnection of change-over switch.
Afterwards, the pixel charging process after the change-over switch of green sub-pix correspondence disconnected, the change-over switch of blue sub-pix correspondence is opened, similar with said process, repeat no more.
Like this, the duration of charging of three kinds of sub-pixs of red, green, blue is just different; But, enough fast as long as each sub-pix is full of the time of electricity, do not influence display effect.For example, the TFT-LCD of present embodiment adopts 1280*1024 pixel, and the frame refresh rate of 60Hz carries out picture and shows that the time that every capable pixel is opened is about 16.6 μ s, and the duration of charging of three kinds of sub-pixs of RGB can reach 16,12,8 μ s respectively; And the actual required duration of charging of each sub-pix is no more than 4 μ s, so in such scheme, the duration of charging that provides respectively for three kinds of sub-pixs of RGB is enough to finish its charging process, can guarantee charging effect, and then also can not produce harmful effect to display effect.
Further, in the present embodiment, described sample holding unit 104 can have following two kinds of implementations:
One, as shown in Figure 3, described sample holding unit 104 comprises: an operational amplifier 141 and an electric capacity 142;
The input end in the same way (+) of described operational amplifier 141 connects described change-over switch 103, and its reverse input end (-) is connected described data line 102 simultaneously with output terminal;
One end of described electric capacity 142 connects the reference voltage V com of described TFT-LCD, and the other end is connected in the same way between the input end of described change-over switch 103 and described operational amplifier 141.
When source electrode driver provides the demonstration data by output terminal 101 for data line 102, when described display data signal is passed through sample holding unit 104, can charge to electric capacity 142; Then, make the input end in the same way of operational amplifier 141 remain on the state of a high level by this electric capacity 142.Because the input end in the same way of operational amplifier and the level between the reverse input end are consistent, so the reverse input end of operational amplifier 141 and output terminal remain on the state of a high level too again.Like this, even change-over switch disconnects, but the demonstration data of source electrode driver output have been stored in the sample holding unit 104.When source electrode driver provided the demonstration data for the next line pixel, the data that are kept in the sample holding unit 104 just can change.
Because the internal resistance of operational amplifier itself is quite big, external voltage changes little to the influence of its output end voltage, has the function of keeping voltage preferably; Therefore, the electric capacity to electric capacity 142 does not have special requirement in the present embodiment, and it can be the electric capacity that electric capacity is less.
Its two, as shown in Figure 4, described sample holding unit 104 comprises an electric capacity 143, an end ground connection of this electric capacity 143, the other end is connected between described change-over switch 103 and the described data line 102.
When the output terminal 101 by source electrode driver provides the demonstration data for data line 102, when described display data signal is passed through sample holding unit 104, can charge to electric capacity 143; Then, can make the input end of data line 102 remain on the state of a high level by this electric capacity 143.Even change-over switch 103 has disconnected, but the demonstration data of source electrode driver output have been stored in the sample holding unit 104.When source electrode driver provided the demonstration data for the next line pixel, the data that are kept in the sample holding unit 104 just can change.
Owing to only adopt an electric capacity to keep the level of data line input end, therefore, need to select the bigger electric capacity of electric capacity here; Preferably, the electric capacity of this electric capacity is more than 100 times of pixel capacitance, can select for use the electric capacity of electric capacity between 10pF to 1nF as the electric capacity 143 in the sampling hold circuit 104 usually.
In the present embodiment, be that to connect 3 data lines be example for same output terminal with a source electrode driver, but the implementation of above-mentioned sample holding unit is applicable to this a kind of situation incessantly, and the same output terminal that can also be applicable to a source electrode driver certainly connects the situation of 2 or 4 even more data lines.
The TFT-LCD driving circuit that utilizes the embodiment of the invention to provide, the same output terminal by a source electrode driver provides the demonstration data for many data lines, can reduce the usage quantity of source electrode driver, thereby reduces the cost of manufacture of TFT-LCD; And, preserve the demonstration data that source electrode driver offers data line by the sample holding unit that between change-over switch and data line, arranges, can be after the change-over switch corresponding with described data line disconnects, make described sample holding unit still keep higher voltage, so just can guarantee the duration of charging of pixel electrode, and can not have influence on the demonstration data that recorded in the pixel electrode.
Embodiment two:
In the present embodiment, TFT-LCD driving circuit shown in Figure 2 is done further improvement.Specifically as shown in Figure 5.
The TFT-LCD driving circuit that provides in the present embodiment on the basis of TFT-LCD driving circuit shown in Figure 2, is set up a data write switch 105 again; This data write switch 105 is located between described sample holding unit 104 and the described data line 102.
Described data write switch 105 can be metal-oxide-semiconductor; Its grid connects control end SW, and the signal of this control end SW can be provided by the time schedule controller of described TFT-LCD and amplify through the TFT-LCD driving circuit, and its source electrode is connected described sample holding unit 104 and described data line 102 respectively with drain electrode.
Like this, when control end SW1 and SW2 control its corresponding change-over switch respectively and open successively, control end SW is being in low level always, data write switch 105 is in off-state, the grid line that current needs carry out the pixel column correspondence that data write also is in off-state, need send demonstration data red, green sub-pix this moment to and only be stored in the sample holding unit 104 and can not be written in the pixel electrode.When control end SW3 controlled its corresponding change-over switch and opens, the level of regulating control end SW was simultaneously opened data write switch 105, and correspondingly the current need grid line of finishing the one-row pixels correspondence that data write is also opened; At this moment, the demonstration data of having preserved in the sample holding unit 104 of three kinds of sub-pix correspondences of red, green, blue will be written in the pixel electrode of current this delegation's pixel.
Utilize the TFT-LCD driving circuit in the present embodiment, not only the quantity that reduces source electrode driver under the situation that pixel electrode charges normal can not influenced, reduce the cost of manufacture of TFT-LCD, but also can control duration of charging of each sub-pix better, can avoid occurring the too short problem of duration of charging of a certain row sub-pix.
Embodiment three:
The principle of the TFT-LCD driving circuit among the TFT-LCD driving circuit that provides in the present embodiment and embodiment one, the embodiment two is basic identical.
But, in the present embodiment, described TFT-LCD driving circuit also comprises the time schedule controller (not shown) for the described change-over switch 103 of control; Be that described time schedule controller links to each other with the control end (SW1, SW2, SW3) of described change-over switch 103 by an amplifying circuit.
In the present embodiment, time schedule controller is incomplete same for the pulse height that SW1, SW2, SW3 provide; That is to say that described time schedule controller is incomplete same for the initial cut-in voltage that the change-over switch of three kinds of sub-pix correspondences of red, green, blue provides, the cut-in voltage that outputs on SW1, SW2, the SW3 after amplifying is also incomplete same then.
In conjunction with Fig. 2 or shown in Figure 5, different by the cut-in voltage that SW1, SW2, SW3 are carried on each change-over switch (metal-oxide-semiconductor), the voltage difference that adds on the grid of the metal-oxide-semiconductor of three kinds of sub-pix correspondences of red, green, blue just.Can produce the influence of two aspects like this: one, after described change-over switch is connected, because the channel resistance when metal-oxide-semiconductor is opened is relevant with its grid voltage, therefore different grid voltages will produce different channel resistances, this channel resistance is connected with the resistance on the data line and is caused different charging loads and delay, and then influences the pixel duration of charging.Two, after described change-over switch disconnected, because the electric charge of stray capacitance will be redistributed, the voltage on the data line can occur one and jump voltage down, and following size of jumping voltage is directly proportional with the cut-in voltage of grid and the difference between the shutoff voltage; So different cut-in voltages can produce different following jumping voltage, the actual voltage that is loaded on the pixel electrode of result also has different following jumpings, and charging voltage is produced certain influence.
As the above analysis, adjust the size of the cut-in voltage of metal-oxide-semiconductor, can have influence on the variation of channel resistance of metal-oxide-semiconductor inside and the variation of the following jumping voltage on the data line, and then can utilize actual duration of charging and the charging voltage of the control of the cut-in voltage of metal-oxide-semiconductor being adjusted the different colours pixel that connects on each data line, also just be equivalent to RGB Gamma voltage is made adjusting.
In simulation process, setting is respectively 40V, 35V, 30V by the amplitude of the unbalanced pulse that SW1, SW2, SW3 provide, when shutoff voltage was 0.1V, the following jumping voltage that then occurs on the red, green, blue sub-pix corresponding data line was respectively 0.311V, 0.235V, 0.158V; And then the charging voltage of pixel electrode reality also can reduce 0.311V, 0.235V, 0.158V respectively.
In the present embodiment, by applying the amplitude that different cut-in voltages changes the downward modulation voltage that occurs on the channel resistance of described change-over switch and the data line for the change-over switch that connects on the different pieces of information line in the TFT-LCD driving circuit, and then adjust duration of charging and the actual charging voltage of the different colours pixel that connects on the described data line; Reach the effect of regulating RGB Gamma curve to a certain extent respectively.
If RGB Gamma voltage is fully independently regulated, then can realize by when different change-over switches is opened, being equipped with different Gamma reference voltages.Specifically referring to embodiment four.
Embodiment four:
The principle of the TFT-LCD driving circuit among the TFT-LCD driving circuit that provides in the present embodiment and embodiment one, the embodiment two is basic identical.
But, in the present embodiment, described TFT-LCD driving circuit also comprises the Gamma voltage regulator circuit, and the output terminal of this Gamma voltage regulator circuit connects described source electrode driver; And, comprise three control ends in this Gamma voltage regulator circuit, and described three control ends are respectively applied to regulate the Gamma reference voltage output of three kinds of sub-pixs of red, green, blue.
As shown in Figure 6, described Gamma voltage regulator circuit comprises: be serially connected at least two divider resistances between voltage input end AVdd and the earth terminal, the extension line between per two divider resistances is connected to described source electrode driver as output terminal; One end of at least two divider resistances of described serial connection is connected to described voltage input end AVdd by the first resistance regulating circuit 601, and the other end of at least two divider resistances of described serial connection is connected to described earth terminal by the second resistance regulating circuit 602;
The described first resistance regulating circuit 601 comprises first resistance R 11, second resistance R 21 and the 3rd resistance R 31 in parallel, and described first resistance R 11, second resistance R 21, the 3rd resistance R 31 are connected in series a switch again respectively;
The described second resistance regulating circuit 602 comprise the 4th in parallel resistance R 11 ', the 5th resistance R 21 ' and the 6th resistance R 31 ', described the 4th resistance R 11 ', the 5th resistance R 21 ', a switch of the 6th resistance R 31 ' be connected in series respectively.
Switch in the above-mentioned first resistance regulating circuit 601 and the second resistance regulating circuit 602 can be metal-oxide-semiconductor, and the grid of this metal-oxide-semiconductor is connected with the control end of outside; Particularly,
The switch of the switch of described first resistance R, 11 correspondences and described the 4th resistance R 11 ' correspondence is connected to the first control end SW1; The switch of the switch of described second resistance R, 21 correspondences and described the 5th resistance R 21 ' correspondence is connected to the second control end SW2; The switch of the switch of described the 3rd resistance R 31 correspondences and described the 6th resistance R 31 ' correspondence is connected to the 3rd control end SW3.
Described control end SW1, SW2, SW3 export high level signal successively, the output of the Gamma reference voltage of three kinds of sub-pixs of control red, green, blue:
When by SW1 output high level, the switch that R11 is connected with R11 ' all can be opened, and this moment, R11, R11 ' and middle resistance string constituted the Gamma reference voltage feed circuit of red sub-pixel;
When by SW2 output high level, the switch that R21 is connected with R21 ' all can be opened, and this moment, R21, R21 ' and middle resistance string constituted the Gamma reference voltage feed circuit of green sub-pix;
When by SW3 output high level, the switch that R31 is connected with R31 ' all can be opened, and this moment, R31, R31 ' and middle resistance string constituted the Gamma reference voltage feed circuit of blue sub-pix.
Above-mentioned Gamma voltage regulator circuit is mainly controlled the Gamma curve of RGB by the dynamic range of regulating Gamma voltage.
In the present embodiment, control end SW1, SW2, control end SW1, SW2, the SW3 of corresponding change-over switch are the same to three kinds of sub-pixs of SW3 and red, green, blue respectively.Like this, can guarantee the charging of the Gamma reference voltage that provides and pixel in time synchronously.
In the Gamma of present embodiment voltage regulator circuit, also remain with wire jumper Jump interface, in order to when three kinds of sub-pixs of red, green, blue adopt identical Gamma voltage, can directly be communicated with wire jumper.As shown in Figure 6, between the described first resistance regulating circuit 601 and described voltage input end AVdd, be provided with wire jumper interface Jump3, between the described second resistance regulating circuit 602 and described earth terminal, be provided with wire jumper interface Jump4; Simultaneously,
Between at least two divider resistances of described voltage input end AVdd and described serial connection, also be serially connected with the first common resistance R1 and a wire jumper interface Jump1, between at least two divider resistances of described serial connection and described earth terminal, also be serially connected with the second common resistance R1 ' and a wire jumper interface Jump2.
Particularly, in the time need controlling respectively the Gamma voltage of three kinds of sub-pix correspondences of red, green, blue, Jump1 and Jump2 place are disconnected, simultaneously Jump3 is connected by wire jumper with the Jump4 place; When three kinds of sub-pixs of red, green, blue being adopted identical Gamma voltage, Jump1 can be connected by wire jumper with the Jump2 place, and Jump3 and Jump4 place are disconnected, Jump1 is communicated with AVdd and R1 like this, Jump2 is communicated with R1 ' and ground, and SW1, SW2, SW3 and R11, R21, R31, R11 ', R21 ', R31 ' are no longer worked.
In the present embodiment, by the output that the Gamma voltage regulator circuit is dynamically adjusted the Gamma reference voltage is set in the TFT-LCD driving circuit, the Gamma magnitude of voltage that provides it to need respectively for the sub-pix of different colours.Utilize the scheme in the present embodiment, can realize providing when showing signal for the red, green, blue sub-pix when source electrode driver timesharing ground, provide different Gamma reference voltage in the different periods for the sub-pix of different colours thereby regulate RGBGamma voltage respectively by above-mentioned Gamma voltage regulator circuit.
Certainly, also can adopt and use independently three groups of Gamma divider resistances and switching switch circuit to realize this function respectively, but circuit cost is higher.
In addition, can also realize above-mentioned functions by adopting digital Gamma circuit.As shown in Figure 8, select a kind of of three kinds of outputs of digital Gamma circuit by control end SW1, SW2, SW3 on Digital Gamma IC (digital gamma circuit) chip, for a kind of in three kinds of sub-pixs of red, green, blue provides Gamma reference voltage.
In the above-described embodiments, all less than consider with at least two data lines that the same output terminal of a source electrode driver links to each other between the position concern; But, because most cases is to utilize the same output terminal of a source electrode driver that three kinds of sub-pixs of the red, green, blue in the same row pixel are controlled, therefore giving tacit consent to described at least two data lines is adjacent settings.
But it should be noted that the scheme that provides in the embodiment of the invention has more than adjacent this a kind of scene that arranges of at least two data lines that is applicable to that described and same source electrode driver output terminal links to each other; At least two data lines that described and same source electrode driver output terminal links to each other can certainly be to arrange at interval.
Connecting two data lines simultaneously with the same output terminal of a source electrode driver is example, as shown in Figure 7, two data line branches that same source electrode driver output terminal is connected simultaneously be located at LCD about in two zones, the signal transmission direction of these source electrode driver output demonstration data is controlled by the change-over switch that links to each other respectively on described two data lines, and change-over switch is to control by control end SW1 and SW2.
Illustrate, in the present embodiment, the viewing area adopts 1280*1024 pixel to show; When SW1 output high level, during the SW2 output low level, a certain output terminal of source electrode driver and the left-half of viewing area are connected, and the demonstration data of output left-half; When SW2 output high level, during the SW1 output low level, the described same output terminal of source electrode driver and the right half part of viewing area are connected, and the demonstration data of output right half part.
In the present embodiment, any change need not take place in the existing single channel way of output in the time schedule controller.Be example in conjunction with situation shown in Figure 7 and with the viewing area for the 1280*1024 pixel, time schedule controller can territory, first output display area left-half the demonstration data of 640 row pixel correspondences, export the demonstration data of 640 row pixel correspondences of right half part afterwards again, therefore its single channel way of output is had no impact.
Yet, utilize circuit structure shown in Figure 7, two data lines far away at interval are connected to the same output terminal of source electrode driver, just need on technology, realize the dispensing of signal by the via hole cross-line; Because the circuit on the TFT-LCD array base palte is originally with regard to more complicated, therefore circuit structure shown in Figure 7 implements difficulty more greatly.
A kind of liquid crystal indicator also is provided in the embodiment of the invention, and this liquid crystal indicator has the TFT-LCD driving circuit described in above-described embodiment.
The liquid crystal indicator that provides in the embodiment of the invention, the same output terminal by a source electrode driver provides the demonstration data for many data lines, can reduce the usage quantity of source electrode driver, thereby reduces the cost of manufacture of TFT-LCD; And, preserve the demonstration data that source electrode driver offers data line by the sample holding unit that between change-over switch and data line, arranges, can be after the change-over switch corresponding with described data line disconnects, make described sample holding unit still keep higher voltage, so just can guarantee the duration of charging of pixel electrode, and can not have influence on the demonstration data that recorded in the pixel electrode.
In the scheme that the embodiment of the invention provides, parts such as the sample holding unit of setting up can be when making array base palte, make with devices such as TFT by composition technology, therefore can't increase the realization difficulty of technology, nor can improve the cost of manufacture of TFT-LCD.
The scheme that the embodiment of the invention provides goes in any liquid crystal display.
The above; only be the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.
Claims (19)
1. TFT-LCD driving circuit, comprise source electrode driver, each output terminal of this source electrode driver is connected with at least two data lines, and between the output terminal of described source electrode driver and described data line, being provided with the change-over switch corresponding with described data line equivalent, this change-over switch is used for the data of control from described source electrode driver to described data line and transmits; It is characterized in that, be provided with sample holding unit between described change-over switch and described data line, described sample holding unit is used for preserving the demonstration data that described source electrode driver offers described data line;
Wherein, described sample holding unit comprises: an operational amplifier and an electric capacity; The input end in the same way of described operational amplifier connects described change-over switch, and its reverse input end is connected described data line simultaneously with output terminal; One end of described electric capacity connects the reference voltage V com of described TFT-LCD, and the other end is connected in the same way between the input end of described change-over switch and described operational amplifier.
2. TFT-LCD driving circuit according to claim 1 is characterized in that, the quantity of at least two data lines that are connected with the same output terminal of source electrode driver is 3; And described 3 data lines are three kinds of sub-pixs of corresponding red, green, blue respectively.
3. TFT-LCD driving circuit according to claim 2 is characterized in that, the cut-in voltage that provides of corresponding change-over switch is incomplete same respectively for described at least two data lines for this TFT-LCD driving circuit.
4. TFT-LCD driving circuit according to claim 2 is characterized in that, also comprises the Gamma voltage regulator circuit in the described TFT-LCD driving circuit, and the output terminal of this Gamma voltage regulator circuit connects described source electrode driver;
Comprise three control ends in the described Gamma voltage regulator circuit, and described three control ends are respectively applied to regulate the Gamma reference voltage output of three kinds of sub-pixs of red, green, blue.
5. TFT-LCD driving circuit according to claim 4 is characterized in that, described Gamma voltage regulator circuit comprises: be serially connected at least two divider resistances between voltage input end and the earth terminal; One end of at least two divider resistances of described serial connection is connected to described voltage input end by the first resistance regulating circuit, and the other end of at least two divider resistances of described serial connection is connected to described earth terminal by the second resistance regulating circuit;
The described first resistance regulating circuit comprises first resistance, second resistance and the 3rd resistance in parallel, and described first resistance, second resistance, the 3rd resistance are connected in series a switch respectively;
The described second resistance regulating circuit comprises the 4th resistance, the 5th resistance and the 6th resistance in parallel, and described the 4th resistance, the 5th resistance, the 6th resistance are connected in series a switch respectively; And,
The switch of the switch of the described first resistance correspondence and described the 4th resistance correspondence is connected to first control end; The switch of the switch of the described second resistance correspondence and described the 5th resistance correspondence is connected to second control end; The switch of the switch of described the 3rd resistance correspondence and described the 6th resistance correspondence is connected to the 3rd control end.
6. TFT-LCD driving circuit according to claim 5 is characterized in that, is provided with the wire jumper interface between the described first resistance regulating circuit and described voltage input end, is provided with the wire jumper interface between the described second resistance regulating circuit and described earth terminal; Simultaneously,
Between at least two divider resistances of described voltage input end and described serial connection, be serially connected with first common resistance and a wire jumper interface, between at least two divider resistances of described serial connection and described earth terminal, be serially connected with second common resistance and a wire jumper interface.
7. TFT-LCD driving circuit according to claim 1 is characterized in that, also is provided with the data write switch between described sample holding unit and described data line.
8. TFT-LCD driving circuit according to claim 7 is characterized in that, described data write switch is the metal oxide semiconductor field effect tube metal-oxide-semiconductor;
The grid of described metal-oxide-semiconductor connects the time schedule controller of described TFT-LCD, and its source electrode is connected described sample holding unit and described data line respectively with drain electrode.
9. TFT-LCD driving circuit according to claim 1 is characterized in that, the adjacent setting of at least two data lines that is connected with the same output terminal of described source electrode driver; Perhaps, at least two data lines that are connected with the same output terminal of described source electrode driver arrange at interval.
10. TFT-LCD driving circuit, comprise source electrode driver, each output terminal of this source electrode driver is connected with at least two data lines, and between the output terminal of described source electrode driver and described data line, being provided with the change-over switch corresponding with described data line equivalent, this change-over switch is used for the data of control from described source electrode driver to described data line and transmits; It is characterized in that, be provided with sample holding unit between described change-over switch and described data line, described sample holding unit is used for preserving the demonstration data that described source electrode driver offers described data line;
Wherein, described sample holding unit comprises an electric capacity, an end ground connection of this electric capacity, and the other end is connected between described change-over switch and the described data line; And the electric capacity of described electric capacity is more than 100 times of pixel capacitance.
11. TFT-LCD driving circuit according to claim 10 is characterized in that, the quantity of at least two data lines that are connected with the same output terminal of source electrode driver is 3; And described 3 data lines are three kinds of sub-pixs of corresponding red, green, blue respectively.
12. TFT-LCD driving circuit according to claim 11 is characterized in that, the cut-in voltage that provides of corresponding change-over switch is incomplete same respectively for described at least two data lines for this TFT-LCD driving circuit.
13. TFT-LCD driving circuit according to claim 11 is characterized in that, also comprises the Gamma voltage regulator circuit in the described TFT-LCD driving circuit, the output terminal of this Gamma voltage regulator circuit connects described source electrode driver;
Comprise three control ends in the described Gamma voltage regulator circuit, and described three control ends are respectively applied to regulate the Gamma reference voltage output of three kinds of sub-pixs of red, green, blue.
14. TFT-LCD driving circuit according to claim 13 is characterized in that, described Gamma voltage regulator circuit comprises: be serially connected at least two divider resistances between voltage input end and the earth terminal; One end of at least two divider resistances of described serial connection is connected to described voltage input end by the first resistance regulating circuit, and the other end of at least two divider resistances of described serial connection is connected to described earth terminal by the second resistance regulating circuit;
The described first resistance regulating circuit comprises first resistance, second resistance and the 3rd resistance in parallel, and described first resistance, second resistance, the 3rd resistance are connected in series a switch respectively;
The described second resistance regulating circuit comprises the 4th resistance, the 5th resistance and the 6th resistance in parallel, and described the 4th resistance, the 5th resistance, the 6th resistance are connected in series a switch respectively; And,
The switch of the switch of the described first resistance correspondence and described the 4th resistance correspondence is connected to first control end; The switch of the switch of the described second resistance correspondence and described the 5th resistance correspondence is connected to second control end; The switch of the switch of described the 3rd resistance correspondence and described the 6th resistance correspondence is connected to the 3rd control end.
15. TFT-LCD driving circuit according to claim 14 is characterized in that, is provided with the wire jumper interface between the described first resistance regulating circuit and described voltage input end, is provided with the wire jumper interface between the described second resistance regulating circuit and described earth terminal; Simultaneously,
Between at least two divider resistances of described voltage input end and described serial connection, be serially connected with first common resistance and a wire jumper interface, between at least two divider resistances of described serial connection and described earth terminal, be serially connected with second common resistance and a wire jumper interface.
16. TFT-LCD driving circuit according to claim 10 is characterized in that, also is provided with the data write switch between described sample holding unit and described data line.
17. TFT-LCD driving circuit according to claim 16 is characterized in that, described data write switch is the metal oxide semiconductor field effect tube metal-oxide-semiconductor;
The grid of described metal-oxide-semiconductor connects the time schedule controller of described TFT-LCD, and its source electrode is connected described sample holding unit and described data line respectively with drain electrode.
18. TFT-LCD driving circuit according to claim 10 is characterized in that, the adjacent setting of at least two data lines that is connected with the same output terminal of described source electrode driver; Perhaps, at least two data lines that are connected with the same output terminal of described source electrode driver arrange at interval.
19. a liquid crystal indicator is characterized in that, has each described TFT-LCD driving circuit in claim 1 to 9 or 10 to 18 in this liquid crystal indicator.
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| KR102542853B1 (en) * | 2016-04-25 | 2023-06-14 | 삼성전자주식회사 | Led display module, display apparatus and controlling method thereof |
| CN106297690A (en) * | 2016-08-11 | 2017-01-04 | 深圳市华星光电技术有限公司 | Gamma reference voltage generator, production method and liquid crystal indicator |
| CN106128398B (en) | 2016-08-31 | 2019-01-01 | 深圳市华星光电技术有限公司 | Grid voltage driving device, method, driving circuit and liquid crystal display panel |
| CN108986731B (en) * | 2018-08-07 | 2021-10-08 | 京东方科技集团股份有限公司 | Display panel, compensation method thereof and display device |
| CN112397035B (en) * | 2019-08-12 | 2023-03-03 | 京东方科技集团股份有限公司 | Source driver, driving system, liquid crystal display device and correction method thereof |
| CN113223469B (en) * | 2021-03-15 | 2023-02-10 | 重庆惠科金渝光电科技有限公司 | Display device and display panel thereof |
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