CN203150074U - External compensation induction circuit and display device - Google Patents
External compensation induction circuit and display device Download PDFInfo
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- CN203150074U CN203150074U CN2013201168157U CN201320116815U CN203150074U CN 203150074 U CN203150074 U CN 203150074U CN 2013201168157 U CN2013201168157 U CN 2013201168157U CN 201320116815 U CN201320116815 U CN 201320116815U CN 203150074 U CN203150074 U CN 203150074U
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Abstract
The utility model discloses an external compensation induction circuit and a display device. The external compensation induction circuit comprises a fully differential operational amplifier, a first capacitor, a second capacitor and an output circuit for increasing the induction speed of the external compensation induction circuit. The negative input end of the fully differential operational amplifier is connected with a display screen. The positive input end of the fully differential operational amplifier is connected with a reference voltage. The negative output end of the fully differential operational amplifier is connected with the first control end of the output circuit. The positive output end of the fully differential operational amplifier is connected with the second control end of the output circuit. The two ends of the first capacitor are respectively connected with the negative input end of the fully differential operational amplifier and the input end of the output circuit. One end of the second capacitor is connected with the output end of the output circuit while the other end is grounded. The utility model discloses the external compensation induction circuit, an induction method thereof and the display device. By adopting a dual-output level amplification induction current, the external compensation induction circuit enables a quick response to an output voltage. Therefore, the external compensation speed is increased.
Description
Technical field
The utility model relates to organic light emission display technique field, particularly a kind of external compensation sensor circuit and display device.
Background technology
Organic light emitting display diode (OLED, Organic Light-Emitting Diode) is applied in the high-performance display device more and more as a kind of current mode luminescent device.Traditional passive matrix organic light emitting display pipe (Passive Matrix OLED) needs the driving time of shorter single pixel along with the increase of display size, thereby needs to increase transient current, increases power consumption.The application of big electric current simultaneously can cause on nano indium tin metal oxide (ITO, the Indium Tin Oxides) line pressure drop excessive, and makes the OLED operating voltage too high, and then reduces its efficient.And active matrix organic light-emitting display tube (AMOLED, Active Matrix OLED) can address these problems well by the switching tube input OLED electric current of lining by line scan.
In the back plate design of AMOLED, the problem that mainly needs solution is the luminance non between the pixel unit circuit.
At first, AMOLED adopts thin film transistor (TFT) (TFT, Thin-Film Transistor) to make up pixel unit circuit and provides corresponding electric current for the OLED device.In the prior art, adopt low-temperature polysilicon film transistor (LTPS TFT, Low Temperature Poly-Silicon TFT) or oxide thin film transistor (Oxide TFT) mostly.Compare with general amorphous silicon film transistor (amorphous-Si TFT), LTPS TFT and Oxide TFT have higher mobility and stable properties more, are more suitable for being applied to during AMOLED shows.But because the limitation of crystallization process, the LTPS TFT that makes at the large-area glass substrate, usually has heterogeneity such as electrical parameters such as threshold voltage, mobilities, this heterogeneity can be converted into current difference and the luminance difference of OLED display device, and by the perception of human eye institute, i.e. look inequality (mura) phenomenon.Though the homogeneity of Oxide TFT technology is better, but it is similar with a-Si TFT, under long-time pressurization and high temperature, drift can appear in its threshold voltage, because the display frame difference, the threshold drift amount difference of panel each several part TFT can cause display brightness difference, because this species diversity is image-related with demonstration before, therefore often is rendered as ghost phenomena.
Second, in the large scale display application, because there is certain resistance in the backboard power lead, and the drive current of all pixels is all provided by ARVDD, therefore it is high than the supply voltage in territory, far field from the power supply position to compare near the supply voltage of the ARVDD power supply power supply band of position in backboard, and this phenomenon is called as power voltage-drop (IR Drop).Because the voltage of ARVDD is relevant with electric current, IR Drop also can cause the current difference of zones of different, and then produces the mura phenomenon when showing.Adopt the LTPS technology of P type (P-Type) TFT structure pixel cell especially responsive to this problem, because its memory capacitance is connected between ARVDD and the TFT grid, the voltage of ARVDD changes, and can directly influence the voltage Vgs of drive TFT tube grid.
The 3rd, OLED device also can cause the heterogeneity of electric property owing to the thickness inequality when evaporation.For adopting N-Type TFT to make up a-Si or the Oxide TFT technology of pixel cell, its memory capacitance is connected between drive TFT grid and the OLED anode, when data voltage is transferred to grid, if each pixel OLED anode voltage difference, the grid voltage Vgs difference of actual loaded on TFT then, thus the drive current difference causes display brightness difference.
AMOLED can be divided into three major types according to driving type: digital, current type and voltage-type.Wherein digital driving method is realized GTG by the mode that TFT is controlled driving time as switch, need not to compensate heterogeneity, but its frequency of operation increases with display size and rises at double, cause very big power consumption, and reach the physics limit of design within the specific limits, therefore be not suitable for the large scale display application.Current type drives method and realizes GTG by the electric current that varies in size directly is provided to the mode of driving tube, it can compensate TFT heterogeneity and IR Drop preferably, but when writing low GTG signal, little electric current can cause the write time long to stray capacitance charging bigger on the data line, and this problem is especially serious and be difficult to overcome in large scale shows.Voltage-type driving method and traditional active matrix liquid crystal display (AMLCD, Active Matrix Liquid Crystal Display) driving method is similar, the voltage signal of an expression GTG is provided by drive IC, this voltage signal can be converted into the current signal of driving tube in image element circuit inside, thereby driving OLED realizes intensity gray scale, it is fast that this method has actuating speed, realize simple advantage, be fit to drive large size panel, by industry-wide adoption, but need extra TFT and the capacitor element of design to compensate the TFT heterogeneity, IR Drop and OLED heterogeneity.
Towards compensation V
ThnThe heteropical dot structure of heterogeneity, drift and OLED has a variety of, and wherein the main design difficulty of external compensation is current-sensing circuit, and in order to improve reading speed, each the row Pixel among the PANEL distinguishes corresponding sensor circuit unit usually.The major function of sensor circuit is that the current conversion with output or input is that voltage signal is passed to follow-up ADC module and done further processing, traditional sensor circuit is made up of current integrator, but traditional sensor circuit can't be made response fast when pixel current is less.
The utility model content
(1) technical matters that will solve
The technical problems to be solved in the utility model is: how a kind of external compensation sensor circuit and display device are provided, can improve the output voltage response speed of sensor circuit, thereby improve the speed of external compensation.
(2) technical scheme
For solving the problems of the technologies described above, the utility model provides a kind of external compensation sensor circuit, and described external compensation sensor circuit comprises fully differential operational amplifier, first electric capacity, second electric capacity and is used for amplifying faradic output circuit;
The negative input end of described fully differential operational amplifier is connected with display screen, and positive input terminal connects reference voltage, and negative output terminal is connected with first control end of described output circuit, and positive output end is connected with second control end of described output circuit;
The two ends of described first electric capacity are connected with the negative input end of described fully differential operational amplifier and the input end of described output circuit respectively;
One end of described second electric capacity is connected with the output terminal of described output circuit, other end ground connection.
Preferably, be provided with between the negative input end of described fully differential operational amplifier and the display screen between the output terminal that is provided with second switch, second electric capacity and described output circuit between the two ends of first switch, described first electric capacity and be provided with the 3rd switch.
Preferably, described output circuit comprises first output circuit and second output circuit, and the M that the described second output circuit output current is the described first output circuit output current times, wherein M is greater than 1 and less than 100.
Preferably, described first output circuit comprises the first N-type metal-oxide-semiconductor and a P type metal-oxide-semiconductor, the grid of the described first N-type metal-oxide-semiconductor is first control end of described output circuit, the grid of a described P type metal-oxide-semiconductor is second control end of described output circuit, the drain electrode of the source electrode of the described first N-type metal-oxide-semiconductor and a described P type metal-oxide-semiconductor is connected to the input end of described output circuit, the grounded drain of the described first N-type metal-oxide-semiconductor, the source electrode of a described P type metal-oxide-semiconductor connects power supply;
Described second output circuit comprises the second N-type metal-oxide-semiconductor and the 2nd P type metal-oxide-semiconductor, the drain electrode of the source electrode of the described second N-type metal-oxide-semiconductor and described the 2nd P type metal-oxide-semiconductor is connected to the output terminal of described output circuit, the grounded drain of the described second N-type metal-oxide-semiconductor, the source electrode of described the 2nd P type metal-oxide-semiconductor connects power supply.
Preferably, in described second output circuit breadth length ratio of the second N-type metal-oxide-semiconductor be the breadth length ratio of the first N-type metal-oxide-semiconductor in described first output circuit M doubly, in described second output circuit breadth length ratio of the 2nd P type metal-oxide-semiconductor be the breadth length ratio of a P type metal-oxide-semiconductor in described first output circuit M doubly, wherein M is greater than 1 and less than 100.
The breadth length ratio of wherein said metal-oxide-semiconductor refers to the breadth length ratio of metal-oxide-semiconductor conducting channel.
The utility model also provides a kind of display device, and described display device comprises described external compensation sensor circuit.
(3) beneficial effect
External compensation sensor circuit of the present utility model and display device are amplified induction current by utilize the dual output level in the external compensation sensor circuit of pixel unit circuit, output voltage can be responded fast, thereby improve the speed of external compensation.
Description of drawings
Fig. 1 is the circuit diagram of the utility model embodiment external compensation sensor circuit;
Fig. 2 is the utility model embodiment external compensation sensor circuit output voltage sequential comparison diagram.
Embodiment
Below in conjunction with drawings and Examples, embodiment of the present utility model is described in further detail.Following examples are used for explanation the utility model, but are not used for limiting scope of the present utility model.
A kind of external compensation sensor circuit of the utility model embodiment as shown in Figure 1, described external compensation sensor circuit comprises fully differential operational amplifier 1, first electric capacity 2, second electric capacity 3 and is used for amplifying faradic output circuit 12;
The negative input end of described fully differential operational amplifier 1 is connected with display screen 11, and positive input terminal connects reference voltage, and negative output terminal is connected with first control end of described output circuit 12, and positive output end is connected with second control end of described output circuit 12;
The two ends of described first electric capacity 2 are connected with the negative input end of described fully differential operational amplifier 1 and the input end of described output circuit respectively;
One end of described second electric capacity 3 is connected other end ground connection with the output terminal of described output circuit 12.
Be provided with between the negative input end of described fully differential operational amplifier 1 and the display screen 11 between the output terminal that is provided with second switch 9, second electric capacity 3 and described output circuit 12 between the two ends of first switch 8, described first electric capacity 2 and be provided with the 3rd switch 10.
Described output circuit 12 comprises first output circuit and second output circuit, and the M that the described second output circuit output current is the described first output circuit output current times, wherein M is greater than 1 and less than 100.
Described first output circuit comprises the first N-type metal-oxide-semiconductor 4 and a P type metal-oxide-semiconductor 5, the grid of the described first N-type metal-oxide-semiconductor 4 is first control end of described output circuit, the grid of a described P type metal-oxide-semiconductor 5 is second control end of described output circuit, the drain electrode of the source electrode of the described first N-type metal-oxide-semiconductor 4 and a described P type metal-oxide-semiconductor 5 is connected to the input end of described output circuit, the grounded drain of the described first N-type metal-oxide-semiconductor 4, the source electrode of a described P type metal-oxide-semiconductor 5 connects power supply;
Described second output circuit comprises the second N-type metal-oxide-semiconductor 6 and the 2nd P type metal-oxide-semiconductor 7, the drain electrode of the source electrode of the described second N-type metal-oxide-semiconductor 6 and described the 2nd P type metal-oxide-semiconductor 7 is connected to the output terminal of described output circuit, the grounded drain of the described second N-type metal-oxide-semiconductor 6, the source electrode of described the 2nd P type metal-oxide-semiconductor 7 connects power supply.
In described second output circuit breadth length ratio of the second N-type metal-oxide-semiconductor 6 be the breadth length ratio of the first N-type metal-oxide-semiconductor 4 in described first output circuit M doubly, in described second output circuit breadth length ratio of the 2nd P type metal-oxide-semiconductor 7 be the breadth length ratio of a P type metal-oxide-semiconductor 5 in described first output circuit M doubly, wherein M is greater than 1 and less than 100.
By in the external compensation sensor circuit of pixel unit circuit, utilizing the dual output level to amplify induction current, induction current is enlarged into original M doubly, M can respond output voltage greater than 1 and less than 100 fast, thereby improves the speed of external compensation.
A kind of display device of the utility model embodiment, described display device comprise external compensation sensor circuit recited above.
The inducing method of a kind of external compensation sensor circuit of the utility model embodiment, the method comprising the steps of:
S1 first switch 8 turn-offs, second switch 9 and 10 conductings of the 3rd switch, and the fully differential operational amplifier is biased in the unity gain state, first capacitor discharge;
8 conductings of S2 first switch, second switch 9 turn-offs, 10 conductings of the 3rd switch, the electric current of display screen is to the first electric capacity charge or discharge, and second output circuit amplifies M doubly with the charging and discharging currents of first output circuit, and wherein M is greater than 1 and less than 100;
S3 the 3rd switch 10 turn-offs storage voltage in second electric capacity 3.
Concrete, this method comprises three phases:
Phase one is the initial reset stage, and first switch 8 turn-offs, second switch 9 and 10 conductings of the 3rd switch, and this moment, amplifier was biased in the unity gain state, and fully differential operational amplifier 1 negative input end is all VREF mutually with output voltage.First electric capacity, 2 two ends are connected respectively to fully differential operational amplifier 1 negative input end and VREF voltage, make 2 discharges of first electric capacity.
Subordinate phase is integration phase, first switch 8 conductings this moment, and second switch 9 turn-offs, 10 conductings of the 3rd switch, to 2 chargings of first electric capacity or to its discharge, this moment, first electric capacity, 2 change in charge amounts were I from the pixel current of display screen 11 inside
INT, wherein I
INBe pixel current, t is the time of discharging and recharging.In fully differential operational amplifier first output circuit, the outflow electric current is I1, and inflow current is I2, and I1+I is then arranged
IN=I2, and second output circuit is the mirror image amplification of first output circuit, electric current is enlarged into M doubly, the 3rd switch 10 conductings this moment, and then the discharge current to second electric capacity 3 is M*I
IN, wherein M is the ratio of the second level and first order efferent duct breadth length ratio.Hence one can see that has been exaggerated M doubly to the charging and discharging currents of second electric capacity 3, therefore can be so that output have quicker response than conventional circuit structure.
Phase III is the maintenance stage, and this moment, the 3rd switch 10 cut out, and the VOUT output voltage is stored in second electric capacity 3, is further processed through follow-up ADC conversion again.
Its output voltage sequential comparison diagram of the external compensation sensor circuit of the utility model embodiment as shown in Figure 2, VREF is reference voltage among the figure, V
1And V
2Be respectively input and output voltage, can clearly find out, the technical scheme of the utility model embodiment is with respect to prior art, and its voltage induced speed obviously promotes, and its concrete pulling speed is original M times, and wherein M is greater than 1 and less than 100.
Above embodiment only is used for explanation the utility model; and be not to restriction of the present utility model; the those of ordinary skill in relevant technologies field; under the situation that does not break away from spirit and scope of the present utility model; can also make a variety of changes and modification; therefore all technical schemes that are equal to also belong to category of the present utility model, and scope of patent protection of the present utility model should be defined by the claims.
Claims (6)
1. an external compensation sensor circuit is characterized in that, described external compensation sensor circuit comprises fully differential operational amplifier, first electric capacity, second electric capacity and is used for amplifying faradic output circuit;
The negative input end of described fully differential operational amplifier is connected with display screen, and positive input terminal connects reference voltage, and negative output terminal is connected with first control end of described output circuit, and positive output end is connected with second control end of described output circuit;
The two ends of described first electric capacity are connected with the negative input end of described fully differential operational amplifier and the input end of described output circuit respectively;
One end of described second electric capacity is connected with the output terminal of described output circuit, other end ground connection.
2. external compensation sensor circuit as claimed in claim 1, it is characterized in that, be provided with between the negative input end of described fully differential operational amplifier and the display screen between the output terminal that is provided with second switch, second electric capacity and described output circuit between the two ends of first switch, described first electric capacity and be provided with the 3rd switch.
3. external compensation sensor circuit as claimed in claim 2, it is characterized in that, described output circuit comprises first output circuit and second output circuit, and the M that the described second output circuit output current is the described first output circuit output current times, wherein M is greater than 1 and less than 100.
4. external compensation sensor circuit as claimed in claim 3, it is characterized in that, described first output circuit comprises the first N-type metal-oxide-semiconductor and a P type metal-oxide-semiconductor, the grid of the described first N-type metal-oxide-semiconductor is first control end of described output circuit, the grid of a described P type metal-oxide-semiconductor is second control end of described output circuit, the drain electrode of the source electrode of the described first N-type metal-oxide-semiconductor and a described P type metal-oxide-semiconductor is connected to the input end of described output circuit, the grounded drain of the described first N-type metal-oxide-semiconductor, the source electrode of a described P type metal-oxide-semiconductor connects power supply;
Described second output circuit comprises the second N-type metal-oxide-semiconductor and the 2nd P type metal-oxide-semiconductor, the drain electrode of the source electrode of the described second N-type metal-oxide-semiconductor and described the 2nd P type metal-oxide-semiconductor is connected to the output terminal of described output circuit, the grounded drain of the described second N-type metal-oxide-semiconductor, the source electrode of described the 2nd P type metal-oxide-semiconductor connects power supply.
5. external compensation sensor circuit as claimed in claim 4, it is characterized in that, in described second output circuit breadth length ratio of the second N-type metal-oxide-semiconductor be the breadth length ratio of the first N-type metal-oxide-semiconductor in described first output circuit M doubly, in described second output circuit breadth length ratio of the 2nd P type metal-oxide-semiconductor be the breadth length ratio of a P type metal-oxide-semiconductor in described first output circuit M doubly, wherein M is greater than 1 and less than 100.
6. a display device is characterized in that, described display device comprises any described external compensation sensor circuit of claim 1-5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013201168157U CN203150074U (en) | 2013-03-14 | 2013-03-14 | External compensation induction circuit and display device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013201168157U CN203150074U (en) | 2013-03-14 | 2013-03-14 | External compensation induction circuit and display device |
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| CN203150074U true CN203150074U (en) | 2013-08-21 |
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| CN2013201168157U Withdrawn - After Issue CN203150074U (en) | 2013-03-14 | 2013-03-14 | External compensation induction circuit and display device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103137072A (en) * | 2013-03-14 | 2013-06-05 | 京东方科技集团股份有限公司 | External compensation induction circuit, induction method of external compensation induction circuit and display device |
| US9812061B2 (en) | 2015-02-24 | 2017-11-07 | Au Optronics Corp. | Display apparatus and operation method thereof |
-
2013
- 2013-03-14 CN CN2013201168157U patent/CN203150074U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103137072A (en) * | 2013-03-14 | 2013-06-05 | 京东方科技集团股份有限公司 | External compensation induction circuit, induction method of external compensation induction circuit and display device |
| CN103137072B (en) * | 2013-03-14 | 2015-05-20 | 京东方科技集团股份有限公司 | External compensation induction circuit, induction method of external compensation induction circuit and display device |
| US9601050B2 (en) | 2013-03-14 | 2017-03-21 | Boe Technology Group Co., Ltd. | External compensation sensing circuit and sensing method thereof, display device |
| US9812061B2 (en) | 2015-02-24 | 2017-11-07 | Au Optronics Corp. | Display apparatus and operation method thereof |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20130821 Effective date of abandoning: 20150520 |
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| RGAV | Abandon patent right to avoid regrant |