200849185 九、發明說明： 【發明所屬之技術領域】 本發明係有關於一種預充電電路，且特別關於可適 用於各種電子裝置之液晶顯示裝置。 【先前技術】 、在液晶顯示裝置中，需要供給驅動用之源極電壓， 然而在此情況下，除了需要性能良好之電源以便一舉將 7壓從初期狀態提升至高電壓，並且由於需要耗費時間 提升電壓的緣故，在顯示期間之前會施加兩種驅動電壓 間大約中間值的電壓，執行所謂預充電處理 (參考專利文獻1)。當執行預充電處理，很容易在短時 間2提昇至原本的驅動電壓，不僅可以提昇顯像速度， 同時也有防止在某個晝素電壓劇烈變化而導致鄰接晝素 動作受到影響的效果。 曰為了施加預充電電壓，大多數是利用設置於一般液 晶顯不裝置内的直流/直流轉換器（DC/DC c〇nverte〇等的 專用電源來提供。 另一方面’由於液晶顯示裝置中使用之液晶材料一 旦持續施加相同電壓會導致特性改變，也就是產生所謂 的衫像殘留效應（sticking effect)，因此，為了防止上述效 通吊進行反轉驅動’亦係使用交流電場在每一顯示 期間内對於液晶層施加極性相反的驅動電壓。 例如’在列反轉驅動的情況下，對向電極之電位係 0773-A33168TWF;KB06008 6 200849185 在每個歹]反轉日$父替，並藉由對向電極電位以及從列 驅動用電路（源極驅動電路）輸出之類比電壓的差，在 晝素液晶上施加交流電場。在此情況下，每一個列交替 週期（line time)中是從源極驅動電路輸出任意之電壓。 另=方面，在源極驅動電路之輸出電壓反轉時，預 充電線係在一定時間連接到做為等效電容負載之全部源 極線在此日守間内’全部源極線是短暫地成為同一電位。 =於在預充電線是連接到具有比全部源極線電容更大電 =的外。卩電谷，所以藉由對此電容進行充放電而平均化 母列在預充電貫行時的源極線電位。 在具有預充電電路之液晶顯示裝置中，當顯示靜止 影像時，此電容之電位由於從源極線充放電的結果，而 自動地成為源極驅動電路可輸出電壓範圍的中間附近電 位。藉此，源極驅動電路對於源極線電容負載的驅動能 力，，、要忐夠在列交替週期（linetime)内充分地寫入從預 充電後之中間電壓至目標電壓間的差值電壓即可，具有 較南的設計自由度。 但疋’當顯示動態影像時，由於受到從源極線電容 向預充電線電容進行充放電的電荷量不平衡現象所影 響’電谷電位與電壓範圍中間附近之電壓間有較大偏移 的值，而產生不穩定之晝面。 以提升顯像速度並且避免來自鄰接晝素影響的角度 來看’即使在此電容電位偏離源極驅動電路可輸出電壓 範圍之中間附近電位的狀況下，仍需要將預充電電壓設 0773-A33168TWF;KB06008 7 200849185 在其中間附近之電位。 專利文獻1 :特關半！Λ 行開十10-11032號公報。 【發明内容】 如上所述，以往為了 雷、、盾袒碰—+ r 带待適當的電墨值，是由外邱 電源如供一定電壓至預充疋由外邛 像的情況，利用來自源t…、 述顯示靜止影 電，可以自動地Λ 士進行預充電時之電荷充放 源來維持電位。 个而要利用外部電 然而在習知預充電電路中，入b 外邱；隹并古4带 L ^疋否^要從從電荷 : 、，由於直流/直流（DC/DC)轉換哭 電力的問題。…持續動作，因此出現浪費無謂 另外’由於在啟動時預充電線電容是處於完全 的狀態，所以需要充夠的充雷捭 電 内旦面顯不内谷出現閃爍等等異常晝面的問題。 曰顧為/解決上述問題，本發明之目的在於提供一種液 曰曰顯示裝置之預充電電路’不需要專用之預充電電源， ，且即使在靜止晝面等不f要對於預充電線維持電位的 情況下也可以抑制無謂的電力消耗，另外，在啟動 可以得到穩定的影像。 斤本發明提供一種預充電電路，其包括··第一導電型 之第一薄膜電晶體，其汲極端與電源連接；第二導電型 之第二薄膜電晶體，其汲極端與接地端連接，其源極端 0773-A33168TWF;KB06008 8 200849185200849185 IX. Description of the Invention: TECHNICAL FIELD The present invention relates to a precharge circuit, and more particularly to a liquid crystal display device applicable to various electronic devices. [Prior Art] In the liquid crystal display device, it is necessary to supply the source voltage for driving, but in this case, in addition to the need for a power supply with good performance in order to raise the 7 voltage from the initial state to the high voltage in one fell swoop, and it takes time to increase For the reason of the voltage, a voltage of about an intermediate value between the two driving voltages is applied before the display period, and a so-called precharge processing is performed (refer to Patent Document 1). When the precharge processing is performed, it is easy to raise the original driving voltage in a short time 2, which not only enhances the developing speed, but also prevents the influence of the adjacent pixel function from being affected by a drastic change of a certain pixel voltage.曰In order to apply the precharge voltage, most of them are provided by a dedicated DC power supply such as a DC/DC converter (a DC/DC c〇nverte〇) provided in a general liquid crystal display device. The continuous application of the same voltage to the liquid crystal material causes a change in characteristics, that is, a so-called sticking effect, so that in order to prevent the above-described effect of the inversion drive, the AC electric field is used during each display period. A driving voltage of opposite polarity is applied to the liquid crystal layer. For example, in the case of column inversion driving, the potential of the counter electrode is 0773-A33168TWF; KB06008 6 200849185 in each 歹] reversal day $father, and by An alternating electric field is applied to the pixel liquid crystal by the difference between the counter electrode potential and the analog voltage output from the column driving circuit (source driving circuit). In this case, each column alternates from the source in line time. The pole drive circuit outputs an arbitrary voltage. In addition, when the output voltage of the source drive circuit is reversed, the precharge line is connected at a certain time. As the source line of the equivalent capacitive load, in this day the 'all source lines are briefly the same potential. = The pre-charge line is connected to have a larger capacitance than the full source line = In addition, since the capacitor is charged and discharged, the source line potential of the mother column during pre-charging is averaged. In a liquid crystal display device having a precharge circuit, when a still image is displayed, this As a result of charging and discharging from the source line, the potential of the capacitor automatically becomes the potential near the middle of the output voltage range of the source drive circuit. Thereby, the drive capability of the source drive circuit for the source line capacitive load, It is sufficient to fully write the difference voltage from the intermediate voltage after pre-charging to the target voltage in the line alternate period, which has a souther design freedom. However, when displaying a motion picture, Due to the imbalance of the amount of charge that is charged and discharged from the source line capacitor to the precharge line capacitor, the voltage between the electric valley potential and the voltage near the middle of the voltage range is greatly offset. Stabilizing the surface. In order to improve the imaging speed and avoid the influence of the neighboring pixels, even if the potential of the capacitor deviates from the potential near the middle of the output voltage range of the source driver circuit, the precharge voltage is required. It is set to 0773-A33168TWF; KB06008 7 200849185 The electric potential in the middle of it. Patent Document 1: Specially-off half! Λ 开 十 10 10-11032. [Summary of the Invention] As described above, in the past, for lightning, shield collision - + r With the appropriate ink value, it is the case that the external Qiu power supply is supplied with a certain voltage to the pre-charged external image. With the source t..., the static image is displayed, the pre-charge can be automatically performed by the gentleman. The charge is charged and discharged to maintain the potential. However, it is necessary to use external power, however, in the conventional pre-charging circuit, into the outer Qiu; 隹 and ancient 4 belt L ^ 疋 no ^ from the charge:,, due to DC / DC (DC / DC) conversion, crying power problem. ...continuous action, so waste is unnecessary. In addition, since the pre-charging line capacitance is in a complete state at the time of startup, it is necessary to charge a sufficient amount of charge. In view of the above problems, an object of the present invention is to provide a precharge circuit for a liquid helium display device that does not require a dedicated precharge power source, and maintains a potential for a precharge line even if it is in a stationary surface or the like. In the case of the case, it is possible to suppress unnecessary power consumption, and it is possible to obtain a stable image at the time of starting. The present invention provides a precharge circuit comprising: a first thin film transistor of a first conductivity type, the 汲 terminal is connected to a power source; and a second thin film transistor of a second conductivity type, the 汲 terminal is connected to the ground end, Its source extreme 0773-A33168TWF; KB06008 8 200849185
則與上述第一薄膜電晶體的源極端連接至共通之輸出 ^其中上述第二導電型與上述第一導電型相反；第一 電容7〇件，連接於上述輸出端與上述接地端之間；以及 偏壓電壓控制裝置，分別在上述第—薄膜電晶體之閑極 端施：第-偏壓電壓而在上述第二薄膜電晶體之閘極端 施加第二偏壓電壓，並且設定成上述第一薄膜電晶體盥 上述第二薄膜電晶體不會同時導通，並且在上述輸出端 上的輸出電壓值為上述電源之電壓與上述接地端之電壓 的中，值的狀態。其中’上述輸出電壓值降低時，透過 述第一薄膜電晶體之汲極和源極間供給電荷至輸出 端；上述輸出電壓值上昇時，透過上述第二薄膜電晶體 之汲極和源極間拉出電荷。 根據本發明另-實施例’提供—種液晶顯示裝置， 其包括-液晶顯示部，其將液晶元件連接於電晶體之顯 不早凡配置成矩陣狀’上述電晶體之源極連接於設在各 打之源極線’上述電晶體之閘極係連接於設在各列 極線。其特徵在於上述雜線是連接於如上所述之 電電路的輸出端。 ^ ’由於可以利用且穩 ，因此不需設置特別 高空間效率及降低成 對於本發明之預充電電路而言 定現存電源電壓來製作預充電電壓 之電源或大電容元件，可以達到提 本的目的。 【實施方式】 0773-A33168TWF;KB06008 9 200849185 ，下’參照圖式詳細說明本發明之實施例。 第1圖係表示可適用於本發明預充電電路 (precharge ehxuit)之較佳液晶顯示裝置之概略結構範 例的方塊圖。 _液晶顯示裝置即為液晶顯示面板·，而此液晶顯 不面板200是由液晶顯示部1〇〇與其週邊電路所形成。 液晶顯示部100中顯示單元DC是構成複數行複數And the source terminal of the first thin film transistor is connected to the common output, wherein the second conductive type is opposite to the first conductive type; the first capacitor 7 is connected between the output end and the ground end; And a bias voltage control device for applying a second bias voltage to the gate terminal of the second thin film transistor at the idle terminal of the first thin film transistor, and setting the first thin film The transistor 盥 the second thin film transistor is not turned on at the same time, and the output voltage at the output terminal is in a state of a value of a voltage of the power source and a voltage of the ground terminal. Wherein, when the output voltage value is decreased, charge is supplied to the output terminal between the drain and the source of the first thin film transistor; when the output voltage value is increased, the drain and the source of the second thin film transistor are transmitted. Pull out the charge. According to another embodiment of the present invention, there is provided a liquid crystal display device comprising: a liquid crystal display portion, wherein the liquid crystal element is connected to the transistor, and the source of the transistor is connected to the source. Each of the source lines of the above-mentioned transistor is connected to a gate line provided in each column. It is characterized in that the above-mentioned miscellaneous wire is connected to the output terminal of the electric circuit as described above. ^ 'Because it can be utilized and stabilized, it is not necessary to set a particularly high space efficiency and reduce the power supply or the large-capacitance element which is used to prepare the pre-charge voltage for the pre-charging circuit of the present invention. . [Embodiment] 0773-A33168TWF; KB06008 9 200849185, the embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a block diagram showing a schematic configuration example of a preferred liquid crystal display device which can be applied to the precharge circuit of the present invention. The liquid crystal display device is a liquid crystal display panel, and the liquid crystal display panel 200 is formed by the liquid crystal display unit 1 and its peripheral circuits. The display unit DC in the liquid crystal display unit 100 constitutes a plurality of lines
列的矩陣狀，而在-個顯示單元DC中，薄膜電晶體TFT 的汲極與接地端之間並聯著電容c與液晶單元Lc，其中 薄膜電晶體TFT賴極連接於源極線SL，其祕連接於 閘極線GL。 ' 閘極線GL β又置於母一列，並且由閘極驅動電路μ 以列為單位依序致能。 另一方面，源極線SL則設置於每一行，並且由源 極驅動電路依序選擇而供給操作電壓，而利用設置於中 途的預充電電路，進行源極線之預充電處理。 ^上述預充電電路10、源極驅動電路20和閘極驅動 電路30疋由控制電路4〇所控制。由於源極驅動電路2〇 和閘極驅動電路30係為已知之技術，因此省略詳細說明。 第2圖係表示本發明之預充電電路實施例的電路 圖0 在連接至源極驅動電路2〇之電源線21與接地 (GND)線22之間，串聯著n通道TFr U與p通道TFT 12°兩個電晶體的源極側連接到共通之預充電輸出線（以 0773-A33168TWF;KB06008 10 200849185 下直接稱為輸出線）18。此輸出線18上預充電用電容19 是連接於接地端之間，並且透過輸出線18在預充電處理 時執行源極電容（未圖示）之充放電。另外，輸出線18 即第1圖的源極線SL。 在電源線21與接地線22之間，則串聯著電阻15、 16及17,其個別電阻值為Ra、Rb、Rc，並且以這些 阻=壓器進行分壓。在電阻15 & 16的連接點上產生之 電壓Va係施加通道TFTn之閘極端23，另外在 =及π的連接點上產生之電屢Vb係施加於p通道 12之閘極端24，分別做為偏壓電壓。 接著，說明此電路之動作。電源線21a matrix of columns, and in a display unit DC, a capacitor c and a liquid crystal cell Lc are connected in parallel between the drain and the ground of the thin film transistor TFT, wherein the thin film transistor TFT is connected to the source line SL, The secret is connected to the gate line GL. The gate line GL β is placed in the parent column again, and is sequentially enabled by the gate drive circuit μ in units of columns. On the other hand, the source line SL is provided in each row, and the source drive circuit sequentially selects and supplies the operation voltage, and the precharge circuit of the source line is performed by the precharge circuit provided in the middle. The precharge circuit 10, the source drive circuit 20, and the gate drive circuit 30 are controlled by the control circuit 4A. Since the source driving circuit 2 〇 and the gate driving circuit 30 are known techniques, detailed description is omitted. Figure 2 is a circuit diagram showing an embodiment of the precharge circuit of the present invention. Between the power supply line 21 connected to the source drive circuit 2 and the ground (GND) line 22, n-channel TFr U and p-channel TFTs 12 are connected in series. ° The source side of the two transistors is connected to a common pre-charged output line (in the case of 0773-A33168TWF; directly referred to as the output line under KB06008 10 200849185)18. The precharge capacitor 19 on the output line 18 is connected between the ground terminals, and the charge and discharge of the source capacitor (not shown) is performed through the output line 18 during the precharge processing. Further, the output line 18 is the source line SL of Fig. 1 . Between the power supply line 21 and the ground line 22, resistors 15, 16 and 17 are connected in series, and their individual resistance values are Ra, Rb, Rc, and are divided by these resistors. The voltage Va generated at the junction of the resistors 15 & 16 is applied to the gate terminal 23 of the channel TFTn, and the voltage Vb generated at the junction of = and π is applied to the gate terminal 24 of the p-channel 12, respectively. Is the bias voltage. Next, the operation of this circuit will be described. Power cord 21
Vdd，接地绫22夕雪你％达ΛΛΓ 电饥δ又馬 、.按也踝22之電位设為ον，則偏壓電壓Va係表示 ydd · (Rb+Rc) / (Ra+Rb+Rc);Vdd, grounding 绫22 夕雪你%达ΛΛΓ Electric hunger δ又马,. Pressing the potential of 22 is set to ον, then the bias voltage Va is ydd · (Rb+Rc) / (Ra+Rb+Rc) ;
另外，偏壓電壓Vb係表示為： Vdd.Rc/(Ra+Rb + Rc)。 另外，Nit 道 TFTll&pit 道 tftu 通的臨界電M vth，並且N通道TFT 線、 電位低於v渴時，N料TFT u料在 =線=之 作是上提輸出線18之電位。 〃 匕，、動 田丨j ώ深i s之電位高於vh+士 L通道TFT12為導通狀態，其峨下拉輸出線^電 影像的預充電動作時， 結果使得此電路在顯示動態 0773-A33168TWF;KB06008 11 200849185 受到源極線電容負载所生 心屬與㈣二==線18㈣變動是介於 的充電動作和對接地線22的放電動作。1原線21 ：需要特別的預充電用電源或高電容元件。 此外，在顯示靜止影像的預充電動作時 Γ8之電位僅利用源極線電容的充放電即可在上述^ 犯圍以内’故上述電路不進行充放電而為停止狀態。對 於在上述停止時電路的電力消耗，則僅來自電阻15、16 及17所決疋的偏壓電流，並且由於電流量只需要能夠保 持閘極電位就足夠，是非常小的冑，所以也具有減少消 耗電流的效果。 第3圖表示顯示期間和預充電動作間關係的時序 圖0 首先在（n-1)期間，提供給液晶單元陣列中源極線 的源極電位是V!，在此期間結束後則設有預充電期間， 利用導通P通道TFT 12，讓源極電位變成大約是電壓Vi 一半的預充電電壓VPC。 在下一個顯示期間，將一般接地電位V0提供做為 源極電位，在這次電壓變化中，由於預充電電壓是大約 電壓V!的一半，因此電壓變動範圍較小，可以迅速且確 實地變更源極電位。 接在顯示區間η後者又是預充電期間，N通道TFT 11為導通狀態並使得輸出線18的電位上拉至預充電電壓 VPC。在後續的顯示期間（n + 1) ’源極電位再度上拉至 0773-A33168TWF;KB06008 12 200849185Further, the bias voltage Vb is expressed as: Vdd.Rc/(Ra+Rb + Rc). In addition, the Nd channel TFTll & pit channel tftu pass the critical power M vth, and the N channel TFT line, the potential is lower than the v thirst, the N material TFT u material is at the potential of the rising output line 18 at the = line =. 〃 匕,, 动田丨 j ώ deep is higher than the vh+士L channel TFT12 is in the on state, and the 峨 pull-down output line ^ electric image pre-charging action, the result makes this circuit display dynamic 0773-A33168TWF; KB06008 11 200849185 The change of the source line capacitance load and the (4) two == line 18 (four) variation are the charging action and the discharge operation to the ground line 22. 1 Main line 21: A special pre-charging power supply or high-capacitance element is required. Further, in the precharge operation for displaying a still image, the potential of Γ8 can be charged and discharged only by the source line capacitance, so that the above circuit is not stopped by charging and discharging. For the power consumption of the circuit at the time of the above stop, only the bias currents determined by the resistors 15, 16, and 17 are sufficient, and since the amount of current only needs to be able to maintain the gate potential, it is sufficient, and is very small, so Reduce the effect of current consumption. Fig. 3 is a timing chart showing the relationship between the display period and the precharge operation. First, during (n-1), the source potential supplied to the source line in the liquid crystal cell array is V!, and is provided after the end of the period. During the precharge period, the P-channel TFT 12 is turned on, and the source potential is changed to a precharge voltage VPC which is approximately half of the voltage Vi. During the next display period, the general ground potential V0 is supplied as the source potential. In this voltage change, since the precharge voltage is about half of the voltage V!, the voltage fluctuation range is small, and the source can be changed quickly and surely. Potential. In the display interval η which is again in the precharge period, the N-channel TFT 11 is turned on and the potential of the output line 18 is pulled up to the precharge voltage VPC. During the subsequent display period (n + 1) ’ source potential is again pulled up to 0773-A33168TWF; KB06008 12 200849185
Vi 〇 雖然在以上之實施例令，施加在用以調整預充電電 壓之電晶體的閘極電壓，是利用電阻分壓電壓的方式得 到適當的電壓，然而亦可以採用其他方式來達成。 第4圖係表示一電子裝置之範例，其包含具有上述 預充電電路之液晶顯示裝置。此電子裝置1〇〇〇例如是行 動電話，而液晶顯示面板200佔了此裝置表面的主要部 分。 就本發明所適用之電子裝置而言，除了上述行動電 話以外，亦可以是例如可攜式音樂撥放器、可攜式電視、 電子字典、導航設備、個人電腦、相機、攝影機、放影 機等所謂的電子裝置。 【圖式簡單說明】 第1圖表示適用於本發明預充電電路（precharge circuit)之較佳液晶顯示裝置的概略結構方塊圖。 第2圖表示本發明之預充電電路結構的電路圖。 第3圖表示使用本發明之預充電電路情況下動作的 時序圖。 第4圖表示一種電子裝置範例之立體圖，其具有包 含本發明預充電電路之液晶顯示裝置。 【主要元件符號說明】 10〜預充電電路； 20〜源極驅動電路； 3〇〜閘極驅動電路； 40〜控制電路； 〇773-A33168TWF;KB06008 13 200849185 100〜液晶顯示部； 11〜N通道TFT ; 15、16、17〜電阻元件； 19〜電容元件； 22〜接地端； VPC :預充電電壓； 1000〜電子裝置。Vi 〇 Although in the above embodiment, the gate voltage applied to the transistor for adjusting the precharge voltage is obtained by using a resistor divided voltage, it may be achieved by other means. Fig. 4 is a view showing an example of an electronic device including a liquid crystal display device having the above precharge circuit. The electronic device 1 is, for example, a mobile phone, and the liquid crystal display panel 200 occupies a major portion of the surface of the device. For the electronic device to which the present invention is applied, in addition to the above-mentioned mobile phone, it can also be, for example, a portable music player, a portable television, an electronic dictionary, a navigation device, a personal computer, a camera, a video camera, a video player. So-called electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing a schematic configuration of a preferred liquid crystal display device suitable for use in the precharge circuit of the present invention. Fig. 2 is a circuit diagram showing the structure of the precharge circuit of the present invention. Fig. 3 is a timing chart showing the operation in the case of using the precharge circuit of the present invention. Fig. 4 is a perspective view showing an example of an electronic device having a liquid crystal display device including the precharge circuit of the present invention. [Main component symbol description] 10~precharge circuit; 20~source drive circuit; 3〇~gate drive circuit; 40~ control circuit; 〇773-A33168TWF; KB06008 13 200849185 100~liquid crystal display unit; 11~N channel TFT; 15, 16, 17~ resistor element; 19~capacitor element; 22~ ground terminal; VPC: precharge voltage; 1000~ electronic device.
Va、Vb〜分壓電壓； 12〜P通道TFT ; 18〜輸出線； 21〜電源； 23、24〜閘極端； 200〜液晶顯不面板； 0773-A33168TWF;KB06008 14Va, Vb~divided voltage; 12~P channel TFT; 18~output line; 21~power supply; 23,24~gate extreme; 200~LCD display panel; 0773-A33168TWF;KB06008 14