CN100468497C - Current drive circuit and display using same - Google Patents

Current drive circuit and display using same Download PDF

Info

Publication number
CN100468497C
CN100468497C CNB2003801091826A CN200380109182A CN100468497C CN 100468497 C CN100468497 C CN 100468497C CN B2003801091826 A CNB2003801091826 A CN B2003801091826A CN 200380109182 A CN200380109182 A CN 200380109182A CN 100468497 C CN100468497 C CN 100468497C
Authority
CN
China
Prior art keywords
circuit
current
charge
transistor
switch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CNB2003801091826A
Other languages
Chinese (zh)
Other versions
CN1742306A (en
Inventor
木村肇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Semiconductor Energy Laboratory Co Ltd
Original Assignee
Semiconductor Energy Laboratory Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Semiconductor Energy Laboratory Co Ltd filed Critical Semiconductor Energy Laboratory Co Ltd
Publication of CN1742306A publication Critical patent/CN1742306A/en
Application granted granted Critical
Publication of CN100468497C publication Critical patent/CN100468497C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Abstract

A current drive circuit wherein the signal writing speed and the device driving speed can be improved even when a signal current is small and a display using such a current drive circuit are disclosed. A current drive circuit for supplying a signal current to a node of a circuit to be driven through a signal line is provided with a precharge means for supplying a precharge voltage to the node through the signal line. The precharge means comprises a supply means for supplying the precharge voltage to the node and the signal line before the supply of the signal current.

Description

Current driving circuit
Technical field
The present invention relates to the display device of current driving circuit and this circuit of use, be specifically related to a kind of current drive illuminant element that can be used to adopt brightness to change and change as the image element circuit of the active matrix type display of the display element of pixel and the current driving circuit of source electrode drive circuit along with electric current.
Background technology
Use light emitting diode self-emission devices such as (LED) to be subjected to people's attention in recent years as the so-called self-luminous display device of the display element of pixel.As the light-emitting component that is used for this self-luminous display device, Organic Light Emitting Diode (OLED) etc. are just being concentrated people's attention, and it has been used for the display frame etc. of display equipment and mobile phone.
Therefore light-emitting components such as OLED are emissive types, compare with LCD, have the following advantages: the identity height of pixel, do not need backlightly, and response speed is fast etc.In addition, the brightness of light-emitting component can be controlled by the current value that flows through light-emitting component.
In using the display device of this emissive type light-emitting component, simple matrix mode and active matrix mode arranged as its type of drive is known.Though the simple matrix mode is simple in structure, but be difficult to realize problems such as display large-scale, high brightness owing to exist, therefore just actively carried out for the research of the active matrix mode of the electric current by controlling the inflow light-emitting component at the thin film transistor (TFT) (TFT) of image element circuit inner setting in recent years.
For the display device of this active matrix mode, the electric current of existence inflow light-emitting component changes, makes brightness the problem of deviation to occur because of the characteristic deviation of drive TFT.For the display device of active matrix mode, though using the drive TFT of the electric current that drive to flow into light-emitting component in image element circuit 100, the electric current that flows into light-emitting component makes brightness deviation occur because of the characteristic deviation of these drive TFT changes.Therefore proposed various circuit, even make the characteristic of the drive TFT that image element circuit is interior that deviation be arranged, the electric current that flows into light-emitting component does not change yet, thus the deviation of control brightness.
Patent documentation 1: special table 2002-517806 communique
Patent documentation 2: the international communique that discloses No. 01/06484
Patent documentation 3: special table 2002-514320 communique
Patent documentation 4: the international communique that discloses No. 02/39420
All disclose the structure of active matrix type display in the patent documentation 1 to 4, in patent documentation 1 to 3, disclose the circuit structure that the characteristic deviation of the drive TFT that a kind of electric current that flows into light-emitting component disposes in not with image element circuit changes.And in patent documentation 4, disclose a kind of be used to control because of source electrode drive circuit in the circuit structure of the drive current variations that causes of the deviation of TFT.
Figure 30 is the circuit diagram of one of disclosed traditional active matrix type display example in the expression patent documentation 1.
This display device is made of the source electrode drive circuit 200 that is configured to rectangular a plurality of image element circuits 100 and is used to drive image element circuit 100.Its formation is: make the marking current that has corresponding to the signal level of image information supply with each pixel from signal wire 20, the light-emitting component 40 that the drive current that is directly proportional with this marking current is supplied with in the image element circuits 100 from power lead 30.
Image element circuit 100 is made of following element: current drive illuminant element OLED40; Carry out the luminous TFT52 of ON and OFF switching according to the control signal of control line 10c; According to the selection TFT51 that the control voltage of control line 10b carries out ON and OFF switches, makes the marking current corresponding to the current level of the image information of supplying with signal wire to pass through; Supply is from the drive TFT 50 of the drive current of power lead 30; Be connected the grid of drive TFT 50 and the maintenance electric capacity 60 between source electrode; Control signal according to control line 10a is carried out the switching of ON and OFF, connects the maintenance TFT53 of drive TFT 50 grids and drain electrode selectively.In addition, source electrode drive circuit 200 has output and contains marking current I corresponding to the signal level of image information VideoDiagrammatic sketch image signal input current source 70.
The following describes the action of this circuit.
As shown in figure 31, at first by being applied to the control voltage of control line 10a, 10b, make to keep TFT53, selection TFT51 conducting.Like this, shown in the dotted line among the figure, the specified signal electric current I of determining by picture signal input current source 70 Vide oFlow by drive TFT 50 and selection TFT51 from power lead 30.
At this moment, in order to make marking current I VideoBetween the gate-to-source of drive TFT 50, flow, apply voltage V between necessary gate-to-source Gs, this voltage is keeping maintenance on the electric capacity 60.If this voltage keeps and reaches steady state (SS) on maintenance electric capacity 60, then electric current no longer flows into and keeps TFT53.
Then, shown in figure 32, make to keep TFT53 to end.
Like this, voltage V between gate-to-source GsKeeping keeping marking current I on the electric capacity 60 VideoBy sustaining voltage V Gs, continuously flow into drive TFT 50.Then, as shown in figure 33, make and select TFT51 to end, make luminous TFT52 conducting.Like this, marking current I VideoBegin to flow into OLED40.
Here, the drain electrode of drive TFT 50-voltage between source electrodes V DsValue different under the situation of Figure 32 and Figure 33.But, if drive TFT 50 is in saturation region operation, even voltage V between source electrode-drain electrode then DsChange, as long as voltage V between gate-to-source GsIdentical, identical electric current I is just arranged VideoFlow.Even the therefore deterioration in characteristics of OLED, current-voltage characteristic changes, and is generally constant owing to flow into the electric current of OLED, therefore has the advantage that brightness is difficult for deterioration.
In addition, even the drain electrode of drive TFT 50-voltage between source electrodes changes,, just there is identical electric current to flow usually as long as at the voltage constant that keeps keeping on the electric capacity 60.Therefore, can not produce the problem that marking current changes because of the deviation of making in the drive TFT 50 yet.
Above example relates to and is used to compensate the technology that marking current that the deviation because of OLED40 in the image element circuit and drive TFT 50 causes changes, but also can produce identical problem in source electrode drive circuit.
Disclosed in patent documentation 4 is a kind of circuit structure that is used for preventing that the marking current that causes because of the deviation of making the TFT in the source electrode drive circuit from changing.
Summary of the invention
Like this, at traditional current driving circuit and use in the display device of this circuit, the electric current that makes marking current and the electric current that is used for drive TFT or marking current flow into light-emitting component when luminous equates or keeps proportional relation and constitute.
Yet at the drive current of the drive TFT that is used for driven light-emitting element hour and will carry out low key tone when showing with light-emitting component, marking current also is directly proportional with it and diminishes.In addition, in general, the wiring parasitic electric capacity that uses for marking current is supplied with drive TFT and light-emitting component is very big, thus when occurring the stray capacitance of wiring charged constant become big, in marking current hour signal writing speed and the slack-off problem of element drives speed.The present invention proposes in order to solve above-mentioned problem, and its purpose is: a kind of current driving circuit is provided and uses the display device of this circuit, even this current driving circuit a little less than marking current the time, also can make signal writing speed and element drives speed improve.
It is the identical circuit (pre-charge circuit) of circuit structure of driven object circuit that the present invention forms in the circuit of current source is arranged with the object of write signal.
Write fashionablely at signal, in pre-charge circuit, determine to apply the voltage on the signal wire when becoming steady state (SS).Suppose that this voltage is V p, then this voltage makes marking current supply signal wire as pre-charge voltage before, can apply voltage V pAs pre-charge voltage.
Applying pre-charge voltage V pThe time, be not steady current but big electric current flows into signal wire, so the current potential of signal wire is charged to pre-charge voltage V rapidly pThen, the marking current that will have according to the current level of image information is applied on the signal wire.Thus, can eliminate the influence of deviation, in correct signal input driven object circuit.In addition, because the current potential of signal wire is pre-charged to pre-charge voltage V p, therefore, even the marking current value diminishes, the speed of write signal can be not slack-off yet.
Have again, be applied to marking current on the signal wire and not necessarily will have current level corresponding to image information.Also can carry out precharge, apply electric current with required current level by the voltage of required size.
In addition, pre-charge voltage is not only to be determined by the circuit (pre-charge circuit) identical with the circuit structure of driven object circuit.Also available other means are determined pre-charge voltage.
Have, the structure of sort circuit and gimmick thereof (driving method) not only can be used for display device, and can be applicable to various circuit again.
Current driving circuit of the present invention is characterised in that: in a kind of current driving circuit of the node (nodes between a plurality of wirings) of marking current being supplied with the driven object circuit by signal wire, setting is supplied with the precharge unit of above-mentioned node by above-mentioned signal wire with pre-charge voltage, and above-mentioned precharge unit has the feed unit of above-mentioned pre-charge voltage being supplied with above-mentioned node and above-mentioned signal wire before above-mentioned marking current is supplied with.
In above-mentioned current driving circuit, above-mentioned precharge unit can be provided with the setup unit of the value that above-mentioned pre-charge voltage is set at value that the node potential of the above-mentioned node under the normal condition when supplying with above-mentioned driven object circuit with above-mentioned marking current equates or is as the criterion with this value.
In addition, in above-mentioned current driving circuit, above-mentioned precharge unit also can be provided with a plurality of setup units of the above-mentioned pre-charge voltage of a plurality of settings and the selection feed unit of supplying with above-mentioned node and above-mentioned signal wire according to the size of above-mentioned marking current, with above-mentioned pre-charge voltage selectively.
In addition, the invention is characterized in: in a kind of current driving circuit of the node of marking current being supplied with the driven object circuit by signal wire, be provided with: the pre-charge circuit of pre-charge voltage being supplied with above-mentioned node and above-mentioned signal wire; The generation unit of above-mentioned marking current being supplied with above-mentioned pre-charge circuit and above-mentioned pre-charge voltage being produced; And the feed unit of before above-mentioned marking current is supplied with above-mentioned driven object circuit, with above-mentioned pre-charge voltage, supplying with above-mentioned node and above-mentioned signal wire.
In addition, the invention is characterized in: in a kind of current driving circuit of the node of marking current being supplied with the driven object circuit by signal wire, be provided with: the pre-charge circuit of pre-charge voltage being supplied with above-mentioned node; And will above-mentioned pre-charge voltage be produced in advance corresponding to the above-mentioned pre-charge circuit of the current supply of above-mentioned marking current and before above-mentioned marking current is supplied with above-mentioned driven object circuit, above-mentioned pre-charge voltage will be supplied with the feed unit of above-mentioned node and signal wire.
Above-mentioned driven object circuit comprises the 1st driving element in above-mentioned current driving circuit, and above-mentioned pre-charge circuit comprises the 2nd driving element, and the above-mentioned the 1st and above-mentioned the 2nd driving element can be same size or with its size that is as the criterion.In more detail, preferably the above-mentioned the 1st and above-mentioned the 2nd driving element be respectively the 1st transistor and the 2nd transistor, the ratio of the above-mentioned the 1st transistorized channel width W and channel length L is substantially equal to the ratio of the above-mentioned the 2nd transistorized channel width W and channel length L.
In addition, in above-mentioned current driving circuit, also can be provided with the unit of with amplifier above-mentioned pre-charge voltage being supplied with above-mentioned node and above-mentioned signal wire by impedance conversion.
In addition, in above-mentioned current driving circuit, also can be provided with a plurality of setup units of the above-mentioned pre-charge voltage of a plurality of settings and supply with the selection feed unit of above-mentioned node and above-mentioned signal wire according to the size of above-mentioned marking current, with above-mentioned pre-charge voltage selectively.
Can be provided with wiring resistance R according to above-mentioned signal wire LWith stray capacitance C L, above-mentioned pre-charge voltage supplied with Tb is set at T between the precharge phase of above-mentioned node and above-mentioned signal wire b=R L* C LThe unit.
Can be provided with above-mentioned marking current supply with above-mentioned driven object circuit during T aBe T a＜T bThe time, be set at T a=T bThe unit.
In addition, the invention is characterized in: in a kind of display device that possesses vision circuit and current driving circuit, vision circuit provides image information by the electric current line with the form of electric current, current driving circuit is supplied with above-mentioned electric current line with above-mentioned image information as marking current, and above-mentioned current driving circuit is provided with and will supplies with the current source of the source electrode driver of above-mentioned electric current line from node corresponding to the marking current of above-mentioned image information, pre-charge voltage is supplied with the pre-charge circuit of above-mentioned node and above-mentioned electric current line and the feed unit of above-mentioned pre-charge voltage being supplied with above-mentioned node and above-mentioned electric current line before above-mentioned marking current is supplied with.
In above-mentioned display device, can be provided with the unit of with amplifier above-mentioned pre-charge voltage being supplied with above-mentioned electric current line by impedance conversion.
In addition, the invention is characterized in: a kind ofly be provided with signal wire that image information is transmitted as marking current, comprising and supply with the image element circuit of the 1st driving element of the proportional drive current of above-mentioned marking current by power lead and comprise in the display device of source electrode drive circuit in the diagrammatic sketch image signal input current source of above-mentioned marking current being supplied with above-mentioned signal wire, before above-mentioned marking current is supplied with above-mentioned signal wire, the pre-charge circuit of the above-mentioned signal wire of precharge is built in the above-mentioned source electrode drive circuit.
Above-mentioned pre-charge circuit can include selectively be connected between above-mentioned picture signal input current source and the said power, and output corresponding to the 2nd driving element of the pre-charge voltage of above-mentioned marking current.
Also can be provided with the unit of with amplifier above-mentioned pre-charge voltage being supplied with above-mentioned signal wire by impedance conversion.
In addition, be provided with the signal wire that image information is transmitted as marking current, comprise to supply with the image element circuit of the 1st driving element of the proportional drive current of above-mentioned marking current and comprise above-mentioned marking current is supplied with in the display device of source electrode drive circuit in diagrammatic sketch image signal input current source of above-mentioned signal wire by power lead, will be before above-mentioned marking current be supplied with above-mentioned signal wire, the pre-charge circuit of the above-mentioned signal wire of precharge is built in the above-mentioned source electrode drive circuit, above-mentioned pre-charge circuit includes and selectively is connected between above-mentioned picture signal input current source and the said power, and output is corresponding to the 2nd driving element of the pre-charge voltage of above-mentioned marking current, the above-mentioned the 1st and above-mentioned the 2nd driving element be same size or with its size that is as the criterion.In more detail, preferably the above-mentioned the 1st and above-mentioned the 2nd driving element be respectively the 1st transistor and the 2nd transistor, the ratio of the above-mentioned the 1st transistorized channel width W and channel length L is substantially equal to the ratio of the above-mentioned the 2nd transistorized channel width W and channel length L.
Also can be provided with above-mentioned pre-charge voltage be set at above-mentioned signal is supplied with the above-mentioned the 1st or normal condition during above-mentioned the 2nd driving element under the value that equates of voltage or with the unit of its value that is as the criterion.
Have, so-called " connection " is synonym with " being connected on electric " in the present invention again.Therefore, in structure disclosed by the invention, not only comprise predetermined annexation, also can dispose other element (for example other element and switch etc.) that can be electrically connected therein.
Description of drawings
Fig. 1 is the diagrammatic sketch of expression current driving circuit one embodiment of the present invention, (A) is its circuit diagram, (B) is the diagrammatic sketch of explanation precharge action, the diagrammatic sketch of action when (C) being the input of explanation electric current.
Fig. 2 is the diagrammatic sketch of expression another embodiment of current driving circuit of the present invention.
Fig. 3 is the diagrammatic sketch of the another embodiment of expression current driving circuit of the present invention.
Fig. 4 is the expression current driving circuit of the present invention diagrammatic sketch of an embodiment again.
Fig. 5 is that expression is used for generating automatically Fig. 4 embodiment pre-charge voltage V P1～V P4The diagrammatic sketch of circuit structure.
Fig. 6 is T between the explanation precharge phase bAnd T during the supply of marking current in the driven object circuit after finishing between precharge phase aThe diagrammatic sketch of relation.
Fig. 7 is the transistor T that expression will constitute the driven object circuit R1The diagrammatic sketch of the current driving circuit of the change of polarity when being the p channel-type.
Fig. 8 is that expression makes the transistor T in the pre-charge circuit R2With the transistor T in the driven object circuit R1The polarity unanimity and the diagrammatic sketch of the circuit structure when changing to the p channel-type.
Fig. 9 is used for the current drives action situation when not carrying out precharge relatively and the diagrammatic sketch that is illustrated.
Figure 10 is the diagrammatic sketch that the display device circuit structure of current driving circuit of the present invention is adopted in expression.
Figure 11 is the diagrammatic sketch of current driving circuit one embodiment in the expression display device of the present invention.
Figure 12 is the diagrammatic sketch of another embodiment of current driving circuit in the expression display device of the present invention.
Figure 13 is the diagrammatic sketch of the another embodiment of current driving circuit in the expression display device of the present invention.
Figure 14 is the interior current driving circuit of the expression display device of the present invention diagrammatic sketch of an embodiment again.
Figure 15 is the performance plot of expression change in voltage on the electric current line when joining current driving circuit of the present invention in the source electrode drive circuit.
Figure 16 is the diagrammatic sketch that is used to illustrate the operating principle of current driving circuit of the present invention.
Figure 17 is the diagrammatic sketch of expression current driving circuit embodiment of the present invention.
Figure 18 is the circuit diagram of the active matrix type display of one embodiment of the invention.
Figure 19 is the diagrammatic sketch of the circuit operation of Figure 18 circuit when being used to precharge is described.
Figure 20 is used to illustrate that marking current writes the diagrammatic sketch of the circuit operation of fashionable Figure 18.
Figure 21 is the diagrammatic sketch of the circuit structure of expression another embodiment of the present invention.
Figure 22 is the diagrammatic sketch of the circuit structure of expression further embodiment of this invention.
Figure 23 is the diagrammatic sketch that expression is used for one of the circuit structure example of source follower of the present invention.
Figure 24 is the diagrammatic sketch of the circuit structure embodiment of expression the present invention when the digital gray scale circuit mode.
Figure 25 is the diagrammatic sketch that has improved the pre-charge circuit in the circuit structure of digital gray scale mode shown in Figure 24.
Figure 26 is the diagrammatic sketch of the concrete structure of expression computing circuit shown in Figure 25 and memory circuit.
Figure 27 is the diagrammatic sketch of the latch pulse control signal of the storage control signal of expression control store circuit shown in Figure 26 and control store circuit.
Figure 28 is the diagrammatic sketch of the control action of explanation precharge control line shown in Figure 25.
Figure 29 is the diagrammatic sketch of the basic structure of expression active matrix type display.
Figure 30 is the circuit diagram of one of the traditional active matrix type display of expression example.
Figure 31 is the 1st figure of the circuit operation of explanation Figure 30.
Figure 32 is the 2nd figure of the circuit operation of explanation Figure 30.
Figure 33 is the 3rd figure of the circuit operation of explanation Figure 30.
Figure 34 is the diagrammatic sketch of expression another embodiment of current driving circuit of the present invention.
Figure 35 is the diagrammatic sketch that display device structure of the present invention is adopted in expression.
Figure 36 is the diagrammatic sketch that adopts electronic equipment of the present invention.
Figure 37 is the diagrammatic sketch of expression one example structure of incoming video signal in the 1st latch circuit of Figure 35.
Figure 38 is the diagrammatic sketch of the detailed structure of expression Figure 37.
Figure 39 is there is not the structure of the 2nd latch circuit in expression one example in Figure 38 a diagrammatic sketch.
Figure 40 is the diagrammatic sketch of the detailed description of expression Figure 39.
Figure 41 is the diagrammatic sketch of expression one routine benchmark with the structure of configuration pre-charge circuit in the current source circuit.
The diagrammatic sketch of Figure 42 to be expression one example be provided with respectively in separately pre-charge circuit and driven object circuit structure of different current sources.
Preferred forms of the present invention
According to embodiment, describe embodiments of the present invention in detail below.
The operating principle of current driving circuit of the present invention is described with Figure 16.
Current driving circuit constitute with marking current I by signal wire 400, from the marking current source the 300 node P that supply with driven object circuit 150.
Driven object circuit 150 is by thin film transistor (TFT) Tr 1, connect between its gate-to-source the maintenance capacitor C and can switch switch SW between the control gate-to-drain 1Constitute.Make transistor Tr 1Drain electrode on node P, be connected with signal wire 400.
In addition, when on 1 signal wire, connecting a plurality of driven object circuit 150, also can between node P and signal wire 400, be provided with to switch and use switch.But the configuration of switching with switch can be configured in Anywhere, every can the control signal current lead-through and non-conduction place just.
Marking current I passes through switch SW from marking current source 300 2Supply with signal wire 400.And signal wire 400 passes through switch SW 3Be connected with pre-charge circuit 500.Pre-charge circuit 500 can have various circuit structures, and marking current I supplies with driven object circuit 150, and pre-charge circuit 500 is supplied with the node potential value pre-charge voltage V about equally of the node P when becoming steady state (SS) p
With Fig. 9 with do not carry out precharge situation and make comparisons, the action of Figure 16 is described simultaneously.
Shown in Fig. 9 (A), if make switch SW 1Conducting is not carried out precharge and with marking current I for node P 0Supply with the driven object circuit, then electric current I 1To transistor Tr 1Mobile, electric current I 2To keeping capacitor C to flow.Fig. 9 (C) is the electric current I that expression flows into the driven object circuit 1, I 2The diagrammatic sketch of time-varying relationship.And Fig. 9 (D) is the time dependent diagrammatic sketch of voltage among the expression node P.In addition, V ThThe expression transistor Tr 1Threshold voltage (boundary voltage).
Like this, if do not carry out precharge, then the current potential of node P becomes steady state (SS), time of reaching before the certain voltage becomes very long.This is because signal wire 400 and transistor Tr 1Stray capacitance big, for to it the charging, need the time.If marking current I 0Value little, the unit interval quantity delivered of the required electric charge of potential change of node P is reduced.Consequently: in signal wire 400 and transistor Tr 1Stray capacitance charging in need more time.On the contrary, if marking current I 0Value big, the unit interval quantity delivered of the required electric charge of potential change of node P is increased.Therefore, signal wire 400 and transistor Tr 1The charging of stray capacitance in the shorter time, finish.
The current driving circuit of the following situation of Fig. 9 (B) expression just makes switch SW 3Pre-charge circuit 500 is adopted in conducting, adopts the low slightly pre-charge voltage V of current potential of the node P when becoming steady state (SS) p, in advance node P is carried out precharge, then, make switch SW 2Conducting makes switch SW 3End, by signal wire 400 with marking current I 0Supply with node P.And voltage time dependent situation this moment of the node P of Fig. 9 (E) expression driven object circuit.
In addition, pre-charge voltage preferably is made as the identical current potential of current potential of the node P when becoming steady state (SS) in Fig. 9 (E).Even but do not become identical current potential, be pre-charged to the current potential that is as the criterion with the steady state (SS) current potential, also can how much foreshorten to the time that becomes steady state (SS), so be useful.We can say that promptly the current potential of the node P when if the current potential of the node P of pre-charge voltage before than precharge more approaches to become steady state (SS), then precharge is effective.
When precharge, make switch SW 1With switch SW 3Conducting is with pre-charge voltage V pSupply with node P.Rise to pre-charge voltage V at node P then pMoment of current potential, make switch SW 3End, make switch SW 2Conducting is with marking current I 0Supply with node P.Like this, transistor Tr 1Change steady state (SS) at short notice into.Therefore, shown in Fig. 9 (E), driven object circuit 150 arrives steady state (SS) at the utmost point in the short time.
Like this, if before marking current is supplied with, be provided with pre-charge voltage V pSupply with between the precharge phase of node P and signal wire 400, and between this precharge phase, finish the back and supply with marking current I 0Even then marking current is little, the signal writing speed also can be accelerated.
Have, the current potential of the node P when becoming steady state (SS) depends on marking current I again 0Size, transistor Tr 1Characteristic (mobility, threshold voltage etc.) and size (grid width W, grid length L etc.).Therefore, the most handy balance the pre-charge voltage V of above-mentioned each parameter pCarry out precharge.This be because: if current potential and the pre-charge voltage V of the node P when becoming steady state (SS) pSkew then also needs the extra time will becoming steady state (SS).Preferably pre-charge voltage is made as the identical current potential of current potential of the node P when becoming steady state (SS).This be because: if precharge finishes, then become steady state (SS) simultaneously with it.Therefore, if marking current I 0Size variation, then, pre-charge voltage is become optimum value preferably according to its size.
Have, the current potential of expression node P is in electronegative potential, current potential the situation into steady state (SS) of forming that raises then at first in Fig. 9 (D) again, but also can consider to be at first noble potential, current potential reduces situation about forming to steady state (SS) then.At this moment, keep the electric charge of capacitor C to pass through transistor Tr 1Discharge always.And the current potential of node P reduces gradually, reaches steady state (SS).
But, at marking current I 0The very little situation of value under, if the current potential of node P reduces, then because transistor Tr 1Gate-to-source between voltage reduce, the current value that therefore flows through between source electrode-drain electrode also reduces.Consequently: before the electric charge that keeps capacitor C discharges, need for a long time.Therefore, at marking current I 0The very little situation of value under, preferably use the pre-charge voltage V of the current potential of the node P when becoming steady state (SS) pNode P is carried out precharge.Then, in case on the maintenance capacitor C, charge, just can become steady state (SS) rapidly.For example, if marking current I 0Value be worth less than certain, then in order to make transistor Tr 1Gate-to-source between voltage (absolute value) less than threshold voltage (for example 0V etc.), can carry out precharge.
Have, the diagrammatic sketch among Figure 16 and Fig. 9 is represented notion of the present invention again, but actual circuit is not limited thereto structure.For example the allocation position that has or not, keeps capacitor C of the allocation position of each switch, each switch, respectively keep having or not of capacitor C etc. all to be not limited thereto structure.And direction and transistorized polarity that electric current flows also are not limited thereto structure.In addition, the number of the number in marking current source 300 and pre-charge circuit 500 also is not limited thereto structure, can be deformed into other structure simply.For example also the maintenance capacitor C can be do not disposed, switch SW can also be do not disposed 1And make drain terminal and gate terminal short circuit.In addition, though keep capacitor C to be connected, other wirings of gate terminal and some are connected with gate terminal, source terminal.
Have again, in Figure 16 and Fig. 9, pre-charge voltage supplied with node P after, resupply marking current, but be not limited thereto, also can be in conjunction with other pre-charge methods.For example also can after supplying with pre-charge voltage, carry out other precharge, resupply marking current.Perhaps also can after supplying with a plurality of pre-charge voltages successively, resupply signal.
(embodiment 1)
Figure 17 is the circuit diagram of the current driving circuit of the expression embodiment of the invention.Figure 17 represents the concrete structure that an example and pre-charge circuit shown in Figure 16 500 are relevant.
As mentioned above, pre-charge voltage V pSometimes also with steady state (SS) under the current potential of node P unequal, but can be set at close with it voltage.Pre-charge voltage V pCan determine suitable value by the size of marking current I.Therefore, in the circuit of Figure 17, according to the size of marking current I, with pre-charge voltage V pCarry out a plurality of settings and supply with node P selectively.
For example be designed to: pre-charge voltage V is provided when making marking current I for 0～10mA in advance P1, pre-charge voltage V is provided during for 10mA～20mA P2, pre-charge voltage V is provided during for 20mA～30mA P3, the pre-charge circuit that these pre-charge voltages are provided is connected with terminal A, B, C.And can use change-over circuit 501, according to the intensity of marking current I, switch SW successively 4To SW 6, supply with node P.
Have, as mentioned above, if the size variation of marking current I, then best pre-charge voltage (current potential of the node P when promptly becoming steady state (SS)) also changes again.The pre-charge voltage V that provides when therefore, preferably for example marking current I is for 10mA～20mA P2Size be value between best pre-charge voltage (current potential of the node P when becoming steady state (SS)) when belonging to marking current I and being 10mA and the marking current I best pre-charge voltage when being 20mA.
For example, pre-charge voltage V P2The best pre-charge voltage of size when no matter being 10mA and the intermediate value voltage of the best pre-charge voltage during 20mA, or the best pre-charge voltage during 10mA, or the best pre-charge voltage during 20mA can.But, if at V P2In arbitrary voltage of best pre-charge voltage when best pre-charge voltage when adopting 10mA and 20mA, then require to be taken as one little pre-charge voltage of marking current value (the best pre-charge voltage when being 10mA in this case).This be owing to: compare when becoming steady state (SS) (under the large-signal electric current best pre-charge voltage), input value is little then marking current with the big marking current of input value, when the marking current that input value is little, input value is big then marking current, can become steady state (SS) rapidlyer.That is to say that the best pre-charge voltage with 20mA the time carries out precharge to be compared, the best pre-charge voltage during with 10mA carries out precharge, can more promptly become steady state (SS).As mentioned above, this be because: if the best pre-charge voltage during with 20mA carries out precharge, then transistor T R1Gate-to-source between the absolute value of voltage between the gate-to-source of absolute value when becoming steady state (SS) of voltage.Therefore, the absolute value of voltage reduces always gradually between the gate-to-source of transistor Tr after the precharge 1.So, keep the electric charge of capacitor C to be difficult to pass through transistor T R1Discharge.Therefore, elongated to the time that becomes steady state (SS).Therefore, preferably carry out precharge with the best pre-charge voltage under the small-signal current.
Have again, in Figure 17, supply with pre-charge voltage, but be not limited thereto with three terminal A, B, C.Numbers of terminals can be got any value.
In addition, in the occasion that is connected with terminal A, B, C, its range of current not necessarily must be taken as uniformly-spaced.For example can provide pre-charge voltage V during for 0～5mA at marking current I P1, pre-charge voltage V is provided when 5mA～15mA P2, pre-charge voltage V is provided when 15mA～30mA P3Like this, be preferably in the little occasion of marking current, divide range of current to such an extent that more carefully supply with pre-charge voltage.This be because: if marking current is little, then need more time reaching steady state (SS).Therefore, the scale division value of pre-charge voltage is reduced, make the difference of the current potential of the node P when becoming steady state (SS) and pre-charge voltage as far as possible little.
Have, Figure 17 is the example of part during more detailed expression the with Fig. 9, structure illustrated in fig. 16 again.Therefore, Fig. 9, content illustrated in fig. 16 also are suitable in Figure 17.
(embodiment 2)
Fig. 1 is an embodiment of expression current driving circuit of the present invention, (A) is its circuit diagram, (B) is the diagrammatic sketch of explanation precharge action, and (C) diagrammatic sketch of action when being the input of explanation electric current.Be that Fig. 1 is the diagrammatic sketch of relevant, different with Figure 17 concrete structure of expression one example and pre-charge circuit shown in Figure 16 500.
For present embodiment, pre-charge circuit 500 have with driven object circuit 150 in transistor Tr 1The roughly the same size of size (or the ratio of identical grid width W and grid length L: W/L), by same conductive-type transistor Tr 2Constitute.By this structure, with marking current from the marking current source 300 supply with pre-charge circuits 500 and the current potential of the node P of the size of the pre-charge voltage Vp that produces when becoming steady state (SS) with marking current supply driven object circuit 150 about equally.
Like this, by with pre-charge voltage V The node potential value about equally of node P under the steady state (SS) when regarding as with marking current supply driven object circuit 150 can make writing speed further improve.
Shown in Fig. 1 (B), switch SW when precharge is moved 4With switch SW 5Closed (conducting), marking current is supplied with pre-charge circuit 500.Like this, pre-charge voltage V pIn transistor Tr 2Drain electrode on produce.In addition, because switch SW 4(become conducting) in the closure, so signal wire 400 is by 300 pairs of chargings such as stray capacitance of marking current, this current potential reaches pre-charge voltage Vp.After arriving this state, make switch SW 4And switch SW 5End, make switch SW 3Conducting.And then, make the switch SW in the driven object circuit 150 1And switch SW 2Conducting.
Like this, shown in Fig. 1 (C), marking current is supplied with driven object circuit 150 by signal wire 400, with the current supply transistor Tr 1With the maintenance capacitor C.
In case reach steady state (SS), then the current potential of node P just and transistor Tr 1The mobile necessary potential of electric current that makes size equal marking current equates.Then, because SW 1After ending, but keeping on the capacitor C also stored charge, therefore under the state that keeps from the marking current in marking current source 300, electric current is in transistor Tr 1The relaying afterflow is moving.
Like this, by using transistor Tr 2, the best pre-charge voltage according to the marking current size is produced.That is to say that even the size variation of marking current is corresponding therewith, pre-charge voltage also becomes optimum value.Consequently: even the size variation of marking current also can be carried out precharge rapidly.In addition, if transistor Tr 2With transistor Tr 1Characteristic do not have deviation, then after precharge, just can become steady state (SS) at once.
Have, the size of the marking current among Fig. 1 (B) during precharge is big or small consistent with the middle marking current of Fig. 1 (C) preferably, but be not limited thereto again.For example, also can be only when precharge, the size of marking current be reduced a little.Consequently: pre-charge voltage can be set as the value that is lower than ideal value.
Perhaps, adjustable transistor Tr 2Size (for example, increase grid width W or reduce grid length L), pre-charge voltage is made as more lower slightly value.At this moment, can obtain and only the size of marking current is reduced the same effect a little when the precharge.Like this, as mentioned above, pre-charge voltage is made as the value that is lower than ideal value, hour more effective in the value of quiescent current.
In addition, at a plurality of driven object circuit 150 of configuration, and successively during current input signal, for example, when a plurality of pixel of configuration, can will not bring into play the circuit of function as driven object circuit 150, as transistor Tr yet 2That is to say, if marking current is imported the driven object circuit 150 in somewhere, then also can be with the driven object circuit 150 at other place as transistor Tr 2, pre-charge voltage is generated.
Therefore example when Fig. 1 represents Fig. 9, the more detailed expression of part-structure illustrated in fig. 16, can adopt Fig. 9, content illustrated in fig. 16 in Fig. 1.The configuration of alternation switch and annexation etc. that is to say, even also can constitute same circuit.
(embodiment 3)
The example of the configuration of alternation switch and annexation in Fig. 2 presentation graphs 1.On the same part of Fig. 2 and Fig. 1, has prosign.For embodiment shown in Figure 2, though different with Fig. 1 are to have omitted switch SW 5Circuit structure, but other structures are identical.
Shown in Fig. 2 (B), when precharge, make switch SW 3With SW 4Conducting makes pre-charge voltage V on pre-charge circuit 500 pProduce.By marking current source 300 charging, be pre-charged to and become V pThe electric current input action is in switch SW 3Under the state of conducting, make switch SW 4End, carry out equally with situation shown in Figure 1.
Present embodiment has the advantage of comparing the number of switches minimizing with the situation of Fig. 1.
Like this, the quantity of switch and allocation position have various distortion, if carry out and Fig. 1 and the same action of Fig. 2, then are not limited to the structure of Figure 1 and Figure 2.
In addition, as shown in figure 34, also the pre-charge circuit of Fig. 1, Fig. 2 and the pre-charge circuit of Figure 17 can be made up.Switch SW in Figure 34 7, SW 8With transistor Tr 2Part be equivalent to pre-charge circuit part among Fig. 1, Fig. 2.At first use change-over circuit 501 and switch SW 3～SW 6, carry out precharge by the electric charge of supplying with by terminal A, B, C, use switch SW then 7, SW 8And transistor Tr 2Part, carry out precharge, also have, also can carry out the action of current input signal.In addition, also can this pre-charge method in addition of recombinant.
(embodiment 4)
Fig. 3 is the diagrammatic sketch of the another embodiment of expression current driving circuit of the present invention.Be with the difference of embodiment shown in Figure 1: in pre-charge circuit 500 and switch SW 4Between inserted impedance conversion with amplifier 600.Other circuit structure is identical with situation shown in Figure 1, because its action is also identical, so detailed.
Impedance conversion can be made of voltage follower circuit, analog buffer circuit, source follower, operational amplifier etc. with amplifier 600.Impedance conversion has the function of switching input side impedance and outgoing side impedance with amplifier 600, and input voltage and output voltage remain on same current potential.
Therefore, the pre-charge voltage V of pre-charge circuit 500 pAlso remain on the voltage V of same current potential at the outgoing side of amplifier 600 p, because the output impedance of amplifier 600 becomes very low, therefore can increase current driving ability, signal wire 400 is carried out the high speed charging.Has the advantage that to carry out the precharge action with the short time thus.
Have again, same with Figure 34, also Fig. 3, Figure 17 and Fig. 1, Fig. 2 etc. can be made up and constitute.
Example when Fig. 3 represents the more detailed expression of part-structure of explanation among Fig. 9,16 is arranged again.In addition, expression is that an example has been improved the situation when Fig. 1, Fig. 2 are a part of.Therefore, also be suitable for Fig. 1, Fig. 2, Fig. 9, content illustrated in fig. 16 here.
(embodiment 5)
Fig. 4 represents the another embodiment of current driving circuit of the present invention.By marking current I aScope switch selection signal electric current I a, and supply with signal wire 400.At this moment, can set a plurality of pre-charge voltage V according to the size of marking current in advance p, and according to marking current I aSize it is selected, switches.
That is to say that Fig. 4 is one of the structure example that is described in more detail Figure 17.The circuit of output signal electric current is with 300 expressions of marking current source among Figure 17.Just, making the situation of the various variations that the size of marking current produces carry out concept nature to current source 300 describes.And 4 current sources are arranged in Fig. 4, represent the situation of the mode of Control current value in number.Here, the current value separately of 4 current sources is 2 power, and is as I, 2I, 4I, 8I, corresponding with each bit respectively.And pass through switch SW 6～SW 9Whether Control current is from the current source output corresponding to each bit respectively.Switch SW 6～SW 9Can control by numerical data D1～D4.And current value can be determined by the aggregate value of the electric current that is output.Thus, can control the current value of 4 bits (16 kinds) size.
Have again,, the invention is not restricted to this though in Fig. 4, be 4 bits.Can easily change bit number by the number of change current source and the size of electric current.
In addition, in Figure 17,, adopt change-over circuit 501 as the circuit that is used for selecting pre-charge voltage according to the size of marking current.According to the size of marking current, switch SW successively by change-over circuit 501 4To SW 6, supply with pre-charge voltage.In Fig. 4,, described precharge and selected circuit 700 as an example of the detailed structure of change-over circuit 501.
That is to say, as shown in Figure 4, use 4 kinds of (4 bit) current sources, preestablish marking current I aSize, make it and pre-charge voltage V P1～V P4Correspondence is selected circuit 700 by precharge, and just energy will be according to marking current I aThe pre-charge voltage V of size P1～V P4Supply with driven object circuit 150.Precharge select circuit 700 by the combination phase inverter and " with " logic element constitutes.
Have, precharge selects the structure of circuit 700 to be not limited to the structure of Fig. 4 again.Can adopt various circuit to constitute according to the size of the structure of current source 300, pre-charge voltage and voltage number etc.
Use numerical data D1～D4, the size of control signal electric current, and use same numerical data to carry out the selection of pre-charge voltage.Owing to be the selection of determining pre-charge voltage according to the size of marking current, therefore use numerical data D1～D4, carry out the selection of pre-charge voltage.That is to say that numerical data can both be controlled for the size of control signal electric current and the size of pre-charge voltage.
Have, select in the circuit (change-over circuit) 700 in precharge shown in Figure 4, the size by electric current is uniformly-spaced to be categorized as 4 zones.Be that A is that 0～4I, B are that 4I～8I, C are that 8I～12I, D are 12I～16I.And the size of marking current is determined by the size of numerical data D1～D4.Therefore, select the size of control signal electric current in circuit (change-over circuit) 700 to enter in which zone of regional A～D in precharge.And according to this result, gauge tap SW 10～SW 13Conducting, end, supply with pre-charge voltage.
Have again,, as A:0～4I, B:4I～8I, C:8I～12I, D:12I～16I, with territorial classification, but be not limited thereto with equally spaced calibration according to the size of electric current.As shown in Figure 17, require to classify at marking current hour thinlyyer.This be because: at marking current hour, reaching becomes steady state (SS) and needs more time.In addition, be to select and export in Figure 17, and be to select and export in Fig. 4 from 4 kinds of pre-charge voltages from 3 kinds of pre-charge voltages.But be not limited thereto.Also can classify carefullyyer and the supply pre-charge voltage.At this moment, precharge selects circuit 700 to depend on the division width of marking current in number of regions, each zone, the quantity of pre-charge voltage etc.Can be according to various situations, any structure of design alternative easily.
In Fig. 4, form following structure: with switch SW 6Whether Control current flows out from the current source of current value I, with switch SW 7Whether Control current flows out from the current source of current value 2I ..., but be not limited thereto.As long as form the structure that can Control current whether flows out from the current source of each bit, any structure can.
Supposition driven object circuit 150 is vision signal (picture signal) for pixel, numerical data D1～D4 below.And, suppose that numerical data D1～D4 is a digital voltage signal.
At this moment, by the vision signal control signal current source 300 and the switch SW of digital voltage 3～SW 9Thereby, can make analog signal current supply with signal wire 400.That is to say marking current source 300 and switch SW 3～SW 9Can be the analog video electric current with the digital video voltage transitions.Therefore, can think marking current source 300, switch SW 3And SW 6～SW 9Be a kind of, can think a kind of signal-line driving circuit (source drive) (or its part) of vision signal being supplied with pixel (driven object circuit 150) and signal wire 400 DA change-over circuit and the incorporate circuit of voltage-current converter circuit.
Have, circuit 700, each pre-charge voltage, switch SW are selected in precharge again 4, SW 10～SW 13Supply with signal wire 400 by vision signal control pre-charge voltage with digital voltage.Here, pre-charge voltage is the analogue value.Therefore, we can say precharge selection circuit 700, each pre-charge voltage, switch SW 4, SW 10～SW 13Be to be analog video voltage with the digital video voltage transitions.Therefore, can think that precharge selects circuit 700, each pre-charge voltage, switch SW 4, SW 10～SW 13Can regard D as
The A change-over circuit is a signal-line driving circuit (source drive) (or its part) of vision signal being supplied with pixel (driven object circuit 150) and signal wire 400.
Have, as well-known technology, the circuit that digital voltage is converted to aanalogvoltage has resistance Splittable DA (digital-to-analog) change-over circuit (R-DAC) and electric capacity Splittable DA change-over circuit (C-DAC) etc. again.Therefore, as the unit of supplying with pre-charge voltage, not only use this precharge of Fig. 4 to select circuit 700, switch SW 4And SW 10～SW 13, also use resistance Splittable DA change-over circuit (R-DAC) and electric capacity Splittable DA change-over circuit (C-DAC), also can export pre-charge voltage with thinner scale division value.If use resistance Splittable DA change-over circuit (R-DAC) and electric capacity Splittable DA change-over circuit (C-DAC), then can supply with the reference voltage of several pre-charge voltages as the DA change-over circuit.And, the pre-charge voltage of supplying with DA change-over circuit dividing potential drop again can be supplied with pixel (driven object circuit 150) and signal wire 400 as pre-charge voltage.But, omit its detailed description here.
Have again, in the marking current source 300 of Fig. 4, use 4 current sources, but be not limited thereto, can use the current source of any amount.
Have again, the precharge of Fig. 4 select in the circuit 700 by with phase inverter and " and " logic element makes up and constitutes, but be not limited thereto.Can use various digital circuits and mimic channel, can easily constitute.
In addition, number of switches among Fig. 4 and configuration, various annexations etc. all are not limited to the circuit of Fig. 4.Change to the circuit that carries out same action easily.
Have again, as shown in figure 34, in Fig. 4, also the circuit of Fig. 1 and Fig. 2 can be made up.In addition, circuit that also can constitutional diagram 3 in Fig. 4.That is to say, can use the impedance conversion amplifier.
Situation when Fig. 4 represents an example with Fig. 9, Figure 16, the more detailed expression of part-structure illustrated in fig. 17 is arranged again.Therefore, also can adopt the content of explanation among Fig. 9, Figure 16, Figure 17 etc. here.
Have, suppose that driven object circuit 150 is pixel, marking current source 300 grades are the part of signal-line driving circuit, but are not limited thereto.
Can suppose that also driven object circuit 150 is signal-line driving circuit (a part or be disposed at wherein current source), marking current source 300 grades are the circuit with the current supply signal-line driving circuit.
Fig. 5 represents to be used for generating automatically the embodiment pre-charge voltage V of Fig. 4 (and Figure 17) P1～V P4Circuit structure.It is suitable with the circuit of the structure of having used Fig. 3.
Correspond respectively to the regional separately A～D of marking current, prepare pre-charge circuit (transistor) 500A, 500B, 500C, 500D.It is supplied with marking current (0I, 4I, 8I, 12I), produce pre-charge voltage, take out pre-charge voltage with amplifier 600A, 600B, 600C, 600D, according to the selection of precharge selection circuit 700, as pre-charge voltage V by impedance conversion P1～V P4Supply with driven object circuit 150.
Have again, identical about the action of this circuit with the situation of the embodiment shown in Fig. 1～Fig. 4, Fig. 9, Figure 16, Figure 17 etc., so, detailed.Therefore, the content of explanation here also is suitable for there.
For example, the transistor polarity of pre-charge circuit (transistor) 500A, 500B, 500C, 500D and size etc. are preferably identical with driven object circuit 150.
Have again,, be not limited thereto though 4 pre-charge voltages are all produced.For example, (when the pre-charge voltage of 0I≤Ia＜4I) produced, that use among Fig. 5 was minimum value (0I) corresponding to regional A making.In this case, also can not use pre-charge circuit (transistor) 500A and amplifier 600A etc., and directly supply with suitable voltage.
Have, the pre-charge circuit among Fig. 5 (transistor) 500A, 500B, 500,500D can be configured to the pre-charge circuit special use, also can utilize a driven object circuit 150 and a part thereof again.Perhaps also can utilize a marking current source 300 and a part thereof.
Have, as shown in Figure 3, that use among Fig. 5 is impedance conversion amplifier 600A, 600B, 600C, 600D, but is not limited thereto again.As shown in Figure 1, the situation of the impedance conversion do not used with amplifier also arranged.
Fig. 6 has considered at the signal wires 4 with marking current 300 transmission from the marking current source
There is the wiring resistance R on 00 LAnd cross capacitance C LDeng the situation of parasitic load, expression is with pre-charge voltage V pT between the precharge phase of supply node P bAnd finish between precharge phase the back marking current to the supply of driven object circuit 150 during T aRelation.
Shown in Fig. 6 (A), if there is parasitic load (wiring resistance R on the signal wire 400 L, cross capacitance C L), then make switch SW 3Conducting.The current potential pre-charge voltage V about equally of node P when applying size and becoming steady state (SS) by pre-charge circuit 500 pTime T bBe defined as T b=R L* C L
In addition, can make then T between precharge phase bSupply during T a, set than T between precharge phase bLong, T between the precharge phase that more than calculates bSatisfy T a＜T bWhen concerning, should be made as T a=T bIn addition, T during complete oDetermine according to specification etc.
T is arranged again bThe time constant of sizableness when parasitic load being charged in adopting ideal source.That is to say that if having the time of time constant size, then the current potential of signal wire 400 is substantially equal to pre-charge voltage.Therefore, preferably with T bSize be made as time constant approximately.But, when the effective supply pre-charge voltage, do not use the ideal source supply power, therefore, compare with the situation of supposition ideal source, in charging, need the more time.Therefore, T bSize longer slightly than time constant sometimes.So the length of Ta and Tb is not limited to the situation of Fig. 6.
To constitute the transistor Tr of driven object circuit 150 in the circuit of Fig. 7 presentation graphs 2 1The current driving circuit of the change of polarity when being the p channel-type.
At this moment, as shown in the figure, be alternation switch SW only 1With the annexation that keeps capacitor C, and other circuit structures are identical.That is to say, keep capacitor C to be connected transistor Tr 1Gate-to-source between, switch SW 1Be connected between gate-to-drain.Owing to constitute the transistor Tr of driven object circuit 150 1Reversing, therefore, must change annexation.
In addition, in pre-charge circuit 500, adopt and the driving transistors Tr that is used for driven object circuit 150 1Measure-alike, transistor Tr that conductivity type is identical 2The time, must change annexation equally.That is to say, be connected transistor Tr 2Gate-to-drain between.
Fig. 8 is illustrated in the transistor Tr that makes in the circuit of Fig. 3 in the pre-charge circuit 500 2With the transistor Tr in the driven object circuit 150 1The polarity unanimity, change to the p channel-type, adopt the circuit structure of impedance conversion when the amplifier 600 again.
Like this, as Fig. 7, shown in Figure 8, change is used for the driving transistors Tr of driven object circuit 150 not changing the mobile direction of marking current 1And transistor Tr 2Polarity (conductivity type) time, can connect and forming circuit by change.
Have again,, in the circuit of Fig. 2 and Fig. 3, changed transistorized polarity (conductivity type) here, even in other circuit, also can similarly change.
In addition, when the direction that the change marking current flows, can not change annexation, and only change transistorized polarity (conductivity type).
Up to the present, driven object circuit 150 there is not to do very specific description.Therefore, then driven object circuit 150 is carried out more specific description.
Figure 10 represents to adopt the circuit structure of the display device of current driving circuit of the present invention.
Display device is made of image element circuit 100 and source electrode drive circuit 200 at least.The same section additional phase of the structure of image element circuit 100 and conventional circuit structure shown in Figure 30 with symbol, it describes omission in detail.In addition, the world that has been disclosed in the previous application of the applicant about the detailed content of display device shown in Figure 10 discloses in No. 03/027997 communique.In addition, the spy who has been disclosed in the previous application of the applicant about the display device identical with the structure of Figure 10 be willing to 2002-143882 number, special be willing to 2002-143885 number, special be willing to 2002-143886 number, special be willing to 2002-143887 number, specially be willing in 2002-143888 number.Therefore, the technology of these previous applications can be combined with the application's technology.
The action of this image element circuit 100 is as follows: at first make by control line 10b and select the TFT51 conducting, vision signal (magnitude of voltage) is input to from video signal cable and keeps electric capacity 60.In image element circuit 100, be provided with current source circuit, certain electric current is flowed out.And current source circuit, drive TFT 50 and light-emitting component 40 are connected in series.Whether flow into light-emitting component 40 (whether luminous) from current source circuit, i.e. the performance of gray scale, the enablement and disablement by drive TFT 50 switches to be controlled.The enablement and disablement of drive TFT 50 switches, by the vision signal control that keeps electric capacity 60 from the video signal cable input.
In order to reduce the influence of characteristics of transistor deviation, be disposed at the current source circuit in the image element circuit 100, can use the electric current of source electrode driver to set.In source electrode drive circuit 200, current source is arranged, make the current source circuit in the current supply image element circuit 100.That is to say that the current source circuit in the image element circuit 100 is equivalent to driven object circuit 150, the current source that is positioned at source electrode drive circuit 200 is equivalent to marking current source 300, and electric current line 35 is equivalent to signal wire 400.
Have, electric current flows to driven object circuit 150 from marking current source 300 in Fig. 1～Fig. 4 etc. again.And represent that in Figure 10 electric current flows to the situation in marking current source 300 from driven object circuit 150.
The driven object circuit 150 of supplying with marking current of the present invention is positioned at image element circuit 100, is controlled by electric current line 35 and control line 10c, supplies with marking current from power lead 30, and various circuit structures can be arranged.
(embodiment 6)
Therefore, according to Figure 11～Figure 14, the embodiment when driven object circuit 150 is positioned at image element circuit 100 is described.
In the embodiment shown in fig. 11 source electrode drive circuit 200 by the current source 70 of source electrode driver, be used for pre-charge voltage is supplied with the pre-charge circuit 80 and the switch SW of driven object circuit 150 A, SW B, SW CConstitute.
Pre-charge circuit 80 by with driven object circuit 150 in the p channel transistor Tr of transistor Tr same conductivity 2Constitute, form grid and the shared diode syndeton that is connected of drain electrode.One end of pre-charge circuit 80 is connected with power lead 30, and the other end passes through SW CBe connected with the drain electrode of the current source 70 of source electrode driver.In addition, switch SW is passed through in the drain electrode of the current source 70 of source electrode driver BBe connected with electric current line 35.And electric current line 35 passes through switch SW A, be connected pre-charge circuit 80 and switch SW CShared tie point on.
That is to say, in Figure 11, adopt circuit shown in Figure 1.
The following describes the action of current driving circuit in this source electrode drive circuit.
At first when precharge is moved, switch SW BEnd actuating switch SW A, switch SW C, the pre-charge voltage supplying electric current line 35 that produces in pre-charge circuit 80 carries out precharge.
Then, when the electric current input action, make switch SW AAnd switch SW CEnd switch SW BConducting is with the current source 70 supplying electric current lines 35 of marking current from source electrode driver.Have again, though in image element circuit 100, there is the driven object circuit 150 of supplying with marking current, for the transistor Tr in the driven object circuit 150 1With the transistor Tr that constitutes the pre-charge circuit 80 in the source electrode drive circuit 200 2, can be in advance be made as their size and conductivity type identical.
Switch SW among Fig. 1 1And switch SW 2Be equivalent to transistor 56 and transistor 55, at marking current when the current source 70 of source electrode driver is supplied with image element circuits 100, conducting.
Transistor Tr in Fig. 1 in the driven object circuit 150 1Be the N channel-type, and the transistor in the driven object circuit 150 of Figure 11 is the P channel-type.Its main cause is the direction difference that marking current flows.
Have again, in Figure 11, be equivalent to the switch SW of Fig. 1 1And switch SW 2Part constitute by transistor 56 and transistor 55.But be not limited thereto.The switch of Shi Yonging is not limited to electric switch and mechanical switch in the present invention, so long as have switching function, any element can.That is to say, if can Control current flow, any element can.For example, transistor, diode, logical circuit of being combined by them etc. can.That is to say that when using transistor as switch, owing to transistor only moves as switch, therefore transistorized polarity (conductivity type) is not particularly limited.But,, then preferably use the little polar transistor of cut-off current if require cut-off current little.In the little transistor of cut-off current, comprise transistor that is provided with the LDD district etc.In addition, the current potential of the transistorized source terminal of working as switch near the state of low potential side power supply (Vss, Vgnd, 0V etc.) under during action, preferably use the n channel-type.On the contrary, the current potential of source terminal near the state of hot side power supply (Vdd etc.) under during action, preferably use the p channel-type.This be because: owing to can increase the absolute value of voltage between gate-to-source, thereby move as switch easily.Have again, can use n channel-type and p channel-type, also can use CMOS type switch.
Figure 12 represents by the impedance conversion structure of amplifier 85 with pre-charge voltage supplying electric current line 35.That is to say, in Figure 12, adopt circuit shown in Figure 3.
In addition, in the embodiment shown in fig. 13 expression be omit a switch, only by switch SW AAnd switch SW BSituation about constituting.
In this circuit, when moving, precharge makes switch SW AAnd switch SW BAll conductings use 80 couples of node P of pre-charge circuit and electric current line 35 to carry out precharge.
Then, when electric current is imported, only make switch SW AEnd, make switch SW BUnder the state of conducting, directly marking current is supplied with signal wire 35 from current source 70.That is to say that what adopt is circuit shown in Figure 2 in Figure 13.
(embodiment 7)
The embodiment of Figure 14 represents to constitute the transistor Tr of the driven object circuit 150 in the image element circuit 100 1And pre-charge circuit 80 transistor Tr in the formation source electrode drive circuit 200 2The structure of structure when changing to the n channel-type respectively.That is to say that what adopt is circuit shown in Figure 7 in Figure 14.
Like this, as Figure 10～shown in Figure 14,, can constitute the display device of using current driving circuit of the present invention by adopting various structures.
Have again, in Figure 10～Figure 14, adopted Fig. 1～Fig. 3, circuit shown in Figure 7, but be not limited thereto.Also can adopt its structure in addition.In addition, up to the present the content of explanation also is applicable to Figure 10～Figure 14.
Change in voltage when Figure 15 represents to pack current driving circuit of the present invention into source electrode drive circuit on the electric current line 35.Expression makes the pre-charge voltage V that is applied by pre-charge circuit 80 PreThe change in voltage of electric current line 35 when 5V is changed to 2V is illustrated in pre-charge voltage V respectively PreDrive current line 35 at full throttle during for 2V.
(embodiment 8)
Below, the example the when image element circuit that is different from types such as Figure 10 is adopted in expression.
Figure 18 is the circuit diagram of one of the display device of expression use current driving circuit of the present invention example.In addition, additional prosign on the part identical in the following description with the traditional circuit of Figure 30～shown in Figure 33, it describes omission in detail.
The structure of image element circuit 100 is identical with circuit structure shown in Figure 30 in the embodiment shown in Figure 18.
The following describes structure corresponding to the source electrode drive circuit 200 of this image element circuit 100.
Signal wire 20 is provided with: switch picture signal input current source 70 during with the marking current input action and the switch 91 that is connected when precharge is moved; Picture signal input current source 70 is connected selectively the switch 92 of driving element 80; And the switch 93 that impedance conversion is connected selectively signal wire 20 with the lead-out terminal 86 of amplifier 85.
Amplifier 85 can be the circuit of increase to the current supply ability of lead-out terminal 86, can be made of operational amplifier etc.
Use operational amplifier in the embodiment shown in Figure 18.
Switch 91,92,93 all drives by the control signal of control line 10d, and in order to make switch 92 and 93 conductings simultaneously, to end, switch 91 drives via phase inverter 94, the conducting of switch 92,93, become by action opposite.Have, these switches 91 to 93 can be made of the transistor of any polarity again.
Driving element 80 is made of the p channel-type TFT that connects grid and drain electrode, similarly is connected the also identical and transistorized size both's unanimity of conductivity type with the drive TFT 50 that is positioned at image element circuit 100.In addition, preferably not only size but also characteristic are also consistent.
In order to make the transistor of this specific character unanimity, the identical Laser emission amount of irradiation when the most handy laser makes the semiconductor layer crystallization and constituting.
The drain electrode of driving element 80 is connected with the non-counter-rotating input end of amplifier 85, constitutes voltage follower circuit.In addition, source electrode is connected with power lead 30.
Because the input impedance height of amplifier 85, will with the voltage V that supplies with non-counter-rotating input end pThe voltage of identical current potential outputs to output terminal 16, and current driving ability is also big simultaneously, therefore, and can be with the current potential of big electric current high speed precharge via the signal wire 20 of switch 93 connections.
That is to say, in Figure 18, adopt circuit shown in Figure 3.Driving element 80 is equivalent to the pre-charge circuit 500 among Fig. 3 among Figure 18.Drive TFT 50 is equivalent to the driven object circuit 150 among Fig. 3 among Figure 18.
Below, the circuit operation of Figure 18 is described with Figure 19, Figure 20.In addition, in order to simplify narration, phase inverter 94 and signal wire 10a～10d in Figure 19, Figure 20, have been omitted.
Signal input action during Figure 19 represents between precharge phase.
At first between precharge phase, pass through the control voltage of control line 10d, make switch 93 and 92 conductings, switch 91 is ended.
Therefore, the electric current I in picture signal input current source 70 from the beginning DataDo not flow directly into image element circuit 100, and flow into driving element 80.Consequently: the drain voltage V that can determine driving element 80 p
With voltage V pIdentical voltage outputs to output terminal 86 by amplifier 85, and big drive current flows out from amplifier 85, and the drain potential of the drive TFT 50 in signal wire 20 and the image element circuit 100 becomes pre-charge voltage V rapidly pAt this moment, if the drive TFT 80 in drive TFT 50 in the image element circuit 100 and the source electrode drive circuit 200 has identical characteristic, then the signal input is finished.
But in fact the characteristic of drive TFT 50 and drive TFT 80 has deviation.Therefore, electric current input drive TFT 50 and current potential and voltage V when becoming steady state (SS) pOften not quite identical.Therefore, must current input signal I Data, make drive TFT become steady state (SS) and come compensate.Therefore, as shown in figure 20, switch 92 and 93 is ended, make switch 91 conductings.
Thus, the output voltage of amplifier 85 is disconnected, according to the marking current I from picture signal input source 70 Data, with correct signal input image element circuit 100.At this moment, since between precharge phase with the drain charge of signal wire 20 and drive TFT 50 near necessary current potential.Therefore, the signal input was finished in very short time.
That is to say the arrival steady state (SS).Identical when its transitional movement and Figure 32 and conventional circuit structure shown in Figure 33, so detailed.
Like this, in the present embodiment, make marking current supply with signal wire before, the pre-charge circuit of signal wire precharging to the regulation current potential is made of driving circuit TFT80 and amplifier 85, still, this pre-charge circuit must change according to the circuit structure of image element circuit 100.Have, the circuit structure for any image element circuit all is suitable for basically again.
That is to say, in the time of in pre-charge circuit, can producing and supply with driven object element in the image element circuit and become steady state (SS) or the current potential when becoming with its state that is as the criterion.
In addition, Figure 18 has adopted circuit shown in Figure 3, but is not limited thereto.Structure beyond it also can adopt.In addition, can adopt the content of explanation so far certainly.
Therefore, if electric current I DataValue little, then the most handy when becoming steady state (SS) the drain potential of the drive TFT 50 in signal wire 20 and the image element circuit 100 compare higher slightly pre-charge voltage Vp and carry out precharge.That is to say, preferably carry out precharge, thereby the absolute value that makes voltage between the gate-to-source of drive TFT 50 is less than ideal value by the pre-charge voltage that uses a little higher than ideal value.In addition, drive TFT 50 is P channel-types among Figure 18.Therefore, using the pre-charge voltage of a little higher than ideal value to carry out precharge, is identical with carry out precharge with best pre-charge voltage under small-signal current.As mentioned above, consequently can become steady state (SS) as quick as thought.
(embodiment 9)
Figure 21 is the diagrammatic sketch of another embodiment of expression, and the structure of image element circuit 100 is different with situation shown in Figure 180, and it uses drive TFT 50 and mirror image TFT50a simultaneously.In this structure, can pass through switch 54,55, be added to mirror image TFT50a from the marking current of signal wire 20.
In this case, can be in advance the transistor size of driving element 80a is made as identical with the transistor size of mirror image TFT50a, rather than identical with drive TFT 50.Current potential when so, being easy to steady state (SS) is consistent.
(embodiment 10)
Figure 22 represents the circuit structure of another embodiment, employing be circuit shown in Figure 8.The structure of the driving element 80b of formation source electrode drive circuit 200 is different with the situation of Figure 18 or Figure 21.
In the structure of embodiment shown in Figure 22, grid is connected to the datum line 35a that supplies with assigned voltage after shared the connection with drain electrode, and its source electrode is connected with the non-counter-rotating input end of amplifier 85.
And corresponding therewith, image element circuit 100 constitutes: make the reference potential from datum line 35a pass through the drain electrode that switch 55 is supplied with drive TFT 50a, make the source electrode of supplying with drive TFT 50a from the drive current of power lead 30 by switch 54 simultaneously.
If adopt the sort circuit structure, the transistor size of the drive TFT 50a that the transistor size that then must make the driving element 80b that constitutes the pre-charge circuit in the source electrode drive circuit 200 in advance and image element circuit 100 are interior is identical.Like this, the structure of pre-charge circuit must suitably change according to the structure of image element circuit 100.
But in the occasion of Figure 22, the current potential of the drain terminal of drive TFT 50a (being equivalent to driven object circuit 150) might change because of the voltage characteristic of light-emitting component 40 and change.If characteristic changing, then pre-charge voltage also changes.Therefore, for the influence that the voltage characteristic that is not subjected to light-emitting component 40 in Figure 22 changes, can the drain electrode of drive TFT 55a will be supplied with by switch 55 from the reference potential of datum line 35a.Therefore, can prevent that pre-charge voltage from changing.
Have, drive TFT 50,50a are the p channel-types in the above-described embodiments again, if but drive TFT is become the n channel-type, then must as one man in advance precharge driving element also be changed to the n channel-type with it.
Have again, in Figure 22, adopt circuit shown in Figure 8, but be not limited thereto.Also can adopt this structure in addition.In addition, also can adopt the content of explanation so far certainly.
Like this, for the various image element circuits of input current, can adopt various structures to carry out precharge.
The following describes the structure of the amplifier 85 that can be used for pre-charge circuit of the present invention.
As Figure 18, Figure 21 and shown in Figure 22, amplifier 85 also can adopt operational amplifier to constitute, but if the big circuit of current supply ability then is not limited thereto.In addition, so long as simply switch the impedance and the circuit exportable and the input same potential of input and output, the employing any structure can.
As a letter example, in Figure 23, represented to use the situation of source follower.
It by p channel-type TFT203,204 and n channel-type TFT201,204 constitute.If use the p channel-type in source follower, then output voltage only hangs down the amount of bias voltage than input voltage.
On the other hand, when using the n channel-type, then compare with input voltage, output voltage is the amount of low bias voltage only.Therefore, if circuit that is used in combination the n channel-type and the circuit that uses the p channel-type, design bias voltage and transistor size etc. then can constitute and can export and the circuit of the output voltage of input voltage same potential.In addition, also can only use a source follower, estimate the change of bias amount, import, and adjust output.Perhaps also can use differential amplifier circuit etc.
More than, the circuit structure of (when the signal of the analogue value is imported image element circuit) when the embodiment of Figure 18～Figure 22 explanation is to use the analog gray scale mode, and (when the signal of digital value is imported image element circuit) the present invention can implement too when using the digital gray scale mode.
Have again, also can when supplying with pre-charge voltage, supply with marking current.This be because: if just supplying with suitable pre-charge voltage,, almost can not influence determining of current potential even then marking current is also being supplied with yet.But, for embodiment 4～8, embodiment 10 and embodiment 12, owing to must make electric current inflow transistor Tr 2, therefore, can not when pre-charge voltage is supplied with the driven object circuit, also supply with marking current.In this case, also can prepare a marking current source in addition, from a marking current source with current supply driven object circuit, from another marking current source with the current supply transistor Tr 2Figure 42 represents one of this structure example.As shown in Figure 42: current source 300 is with current supply driven object circuit 150 in this structure, and current source 301 is with the current supply transistor Tr 2So, when supplying with pre-charge voltage, also can supply with marking current.
(embodiment 11)
Figure 24 is the embodiment of the circuit structure of the present invention when being illustrated in the digital gray scale circuit mode.In addition, as an example, image element circuit adopts the structure identical with the image element circuit of Figure 18 in Figure 24, but is not limited thereto.
For digital gray scale, pre-charge voltage can be with definite equally for analog gray scale.That is to say, if light-emitting component is in conducting (luminance), then can be at the marking current I of input during conducting DataAfter, the voltage (V in the time of will becoming steady state (SS) On) as pre-charge voltage.And, if light-emitting component is in by (non-luminance), then pre-charge voltage can be taken as the voltage that can not become luminance fully.Usually, can be made as to make and become 0 voltage as voltage between the transistorized gate-to-source of current source work.
As shown in figure 24, with data signal current I DataSupply with before the signal wire 20, on-off circuit 83 is connected with terminal 83a or terminal 83b.Which determine to be connected according to vision signal with.Thus, carry out the precharge action.At this moment, switch 93 conductings, switch 91 ends.
When vision signal conducting (luminous), switch 83 is connected with terminal 83a, and when vision signal was ended (non-luminous), 83b was connected with terminal.Then, switch 93 is ended, make switch 91 conductings, data signal current I DataInput image element circuit 100.
Like this, for digital gray scale, because in advance by the pre-charge voltage V of signal wire 20 with regulation OnBe applied to the drain electrode of drive TFT 50, therefore, the signal writing speed accelerates.
Have again, Figure 24 with adopt structure shown in Figure 17 suitable, but be not limited thereto.For example, also can as Fig. 3 etc., voltage be produced.Perhaps also can be through adopting this structure in addition.In addition, can adopt the content of explanation so far certainly.
Figure 25 is the diagrammatic sketch that has improved the pre-charge circuit in the circuit structure of digital gray scale mode shown in Figure 24.
It is made of following circuit: the memory circuit 207 that is used for keeping according to the signal of video signal cable 37 video data of last 1 row; By the input current video data, import the computing circuit 206 that the "or" else circuit from last 1 of memory circuit 207 capable video data constitutes simultaneously; By carry out from the signal of precharge control line 38 and the signal of computing circuit 206 etc. " with " "AND" circuit 205.And, only at video data and lastrow not simultaneously, make switch 93 conductings according to signal from precharge control line 38, signal wire 20 is carried out precharge.
In Figure 24, all carry out precharge at every turn.But, current potential and pre-charge voltage V under the actual steady state (SS) OnSize skew is arranged, perhaps numerical value is owing to deviation departs from.Therefore, consider that the current potential under the steady state (SS) is than pre-charge voltage V in lastrow OnMore approach the current potential under the steady state (SS) in the row of current selection, only not moving simultaneously at video data and lastrow.In addition, can only when continuing, bright signal (luminance) not carry out precharge yet.
In addition, only current video data with under the identical situation of data of 1 row, the output signal of the same level of logical circuit 206 outputs, switch 93 ends.
Figure 26 represents the concrete structure of computing circuit shown in Figure 25 206 and memory circuit 207.Memory circuit 207 is made of latch A and latch B, and latch A, latch B drive by latch 1 circuit 208, latch 2 circuit 209 and shift register 210 respectively.
Figure 27 is the diagrammatic sketch of control signal of the latch pulse of the storage control signal of expression control store circuit 207 shown in Figure 26 and control store circuit 207, like this, controls for the video data of lastrow.
Figure 28 is the diagrammatic sketch of the control action of explanation precharge control line 38 shown in Figure 25, and expression only when the video data of the 1st video data that is listed as and the 2nd row changes, is carried out precharge for signal wire 20.
Have, what illustrate in Figure 25 is when importing the vision signal identical with lastrow for the digital gray scale mode, does not carry out precharge situation, but be not limited thereto again.That is to say, also can provide for the analog gray scale mode.For example, if the difference of the vision signal of the vision signal of lastrow and the current row of choosing is big, then also can carry out precharge; If the difference of signal is little, then also can not carry out precharge.
For example, for Figure 17 and Fig. 4,, then can control and to carry out precharge with great voltage if marking current is positioned at a certain scope (zone).Therefore,, then also can not carry out precharge, only be in differently when regional, carry out precharge if the vision signal of last time input is promptly imported the vision signal in the pixel of lastrow and the vision signal of importing later on is in identical zone.
Have again, in Figure 10～Figure 14, Figure 18～Figure 25 etc., be configured in the image element circuit as the current source of driven object circuit 150.Therefore, pre-charge circuit is positioned at the circuit with the current supply image element circuit, promptly in the signal-line driving circuit.But, also can in signal-line driving circuit, establish current source.So, also can be equally applicable to the present invention with the current source in the signal-line driving circuit as driven object circuit 150.
In signal-line driving circuit, be furnished with under the situation of driven object circuit 150, can be provided with current source the current supply signal-line driving circuit.Wherein can dispose pre-charge circuit.Figure 29 represents the total of this situation, promptly by be configured to image element circuit 100AR that rectangular pixel constitutes, with the signal-line driving circuit 200AR of current supply image element circuit 100AR with the reference current source 300 of current supply signal-line driving circuit 200AR.
More than illustrated among Figure 10～Figure 14, Figure 18～Figure 25 etc., made electric current supply with the situation of image element circuit 100a etc. from signal-line driving circuit 200a etc., promptly driven object circuit 150 is arranged in the situation of image element circuit 100a etc.
Similarly, with electric current when reference current source 300 is supplied with signal-line driving circuit 200a etc., when being about to driven object circuit 150 and being configured among the signal-line driving circuit 200AR, the present invention also is suitable for.Have again, action and circuit structure etc. and Fig. 1～Fig. 9, Figure 16～Figure 17 etc. are identical, therefore, detailed.
To adoptable transistor kind without limits, can adopt following transistor in the present invention: use with amorphous silicon and polysilicon as the thin film transistor (TFT) (TFT) of the non-single crystal semiconductor film of representative, use transistor and other transistor of MOS transistor npn npn, junction transistor, bipolar transistor, use organic semiconductor and carbon nano-tube that semiconductor substrate and SOI substrate form.In addition, do not limit and be furnished with transistorized substrate kind, configurable on single crystalline semiconductor substrate, SOI substrate and glass substrate etc.
(embodiment 12)
Below, describe with regard to the structure and the action thereof of display device and signal-line driving circuit etc.In the part of signal-line driving circuit and pixel etc., can adopt circuit of the present invention.
As shown in figure 35, pel array 3501, gate line drive circuit 3502 and signal-line driving circuit 3510 are arranged in the display device.Gate line drive circuit 3502 will select signal to output to pel array 3501 successively.Signal-line driving circuit 3510 outputs to pel array 3501 successively with vision signal and precharging signal.In pel array 3501, according to the state of vision signal control light, thus display image.From the vision signal of signal-line driving circuit 3510 input pel arrays 3501 are electric currents, and precharging signal is a voltage.That is to say that be configured in display element and the element of controlling display element in each pixel, the vision signal (electric current) by from signal-line driving circuit 3510 inputs makes state variation.As the display element that is configured in the pixel, for example can adopt the element of EL element and FED (Field Emission Display) etc.
Have, gate line drive circuit 3502 and signal-line driving circuit 3510 can dispose a plurality of again.
The structure of signal-line driving circuit 3510 can be divided into a plurality of parts.As an example, be broadly divided into shift register the 3503, the 1st latch circuit (LAT1) the 3504, the 2nd latch circuit (LAT2) 3505, digital voltage-analog current change-over circuit 3506 and digital voltage-aanalogvoltage change-over circuit 3515.Digital voltage-analog current change-over circuit 3506 has the function that digital voltage is converted to analog current, also can have the function of carrying out the γ compensation.
In addition, pixel has display elements such as OLED.Has the circuit that electric current (vision signal) is outputed to display element, i.e. current source circuit.
Therefore, simply say the action of signal-line driving circuit 3510.Shift register 3503 usefulness multiple row trigger circuit formations such as (FF) according to the timing of the clock signal of importing (S-CLK), enabling pulse (SP), clock reverse signal signals such as (S-CLKb), are exported sampling pulse successively.
Sampling pulse by shift register 3503 outputs is transfused to the 1st latch circuit (LAT1) 3504.Vision signal according to the timing of input sampling pulse, keeps vision signal by video signal cable 3508 input the 1st latch circuits (LAT1) 3504 in each row.Have, if be furnished with digital voltage-analog current change-over circuit 3506, then vision signal is digital value again.In addition, the vision signal majority under this stage is a voltage.
But, if the 1st latch circuit 3504 and the 2nd latch circuit 3505 are the circuit that can preserve the analogue value, then often can digits deleted voltage-analog current change-over circuit 3506 or its part and digital voltage-aanalogvoltage change-over circuit 3515 or its part etc.At this moment, though the vision signal great majority are electric currents, also be the occasion of voltage sometimes.In addition, be two-value if output to the data of pel array 3501, promptly digital value then often can be omitted voltage-analog current change-over circuit 3506 or its part and digital voltage-aanalogvoltage change-over circuit 3515 or its part etc.
If in the 1st latch circuit (LAT1) 3504, vision signal is kept to terminal column and finishes, then in horizontal scan period by latching control line 3509 input and latch pulses (Latch Pulse), the vision signal that keeps in the 1st latch circuit (LAT1) 3504 is transferred to the 2nd latch circuit (LAT2) 3505 together.Then, remain on the 1 amount while input digit voltage-analog current change-over circuit 3506 and digital voltage-aanalogvoltage change-over circuit 3515 of going of the vision signal of the 2nd latch circuit (LAT2) 3505.Be input to pel array 3501 from the signal of digital voltage-aanalogvoltage change-over circuit 3515 outputs as precharging signal.Then, the signal from digital voltage-analog current change-over circuit 3506 outputs is input to pel array 3501 as vision signal.
The vision signal that keeps in the 2nd latch circuit (LAT2) 3505 is imported into digital voltage-analog current change-over circuit 3506 etc., and, input to pixel 3501 during, sampling pulse is exported once more in shift register 3503.That is to say, carry out 2 actions simultaneously.Therefore, can manage it order drives.After, repeat this action.
Below, the circuit structure of narration each several part.Shift register the 3503, the 1st latch circuit (LAT1) 3504 and the 2nd latch circuit (LAT2) 3505 etc. can be realized by well-known technology.
Digital voltage-analog current change-over circuit 3506 can constitute with structure shown in Figure 4.That is to say that the numerical data D1 among Fig. 4～D4 is equivalent to from the vision signal of the 2nd latch circuit (LAT2) 3505 outputs.By data D1～D4 (from the vision signal of the 2nd latch circuit (LAT2) 3505 outputs), make the switch SW among Fig. 4 6～SW 9Conducting, end.(with each bit corresponding current sources) outputs to driven object circuit 150 (pixel 3501) via signal wire 400 from marking current source 300 with analog current (vision signal).This switch and marking current source constitute digital voltage-analog current change-over circuit 3506 by each signal wire configuration.
Have again,, also can between gate-to-source, apply certain voltage, and realize by using transistor respectively in saturation region operation corresponding to the current source of each bit in the marking current source 300.If the transistor characteristic of working as current source (mobility and threshold voltage etc.) has deviation, then current value also has deviation but in this case.Therefore, also can carry out following action: electric current is flowed out with current source circuit 3514 from benchmark, on the marking current source 300 of each row, set electric current.At this moment, the current source corresponding to each bit in the marking current source 300 of each row in digital voltage-analog current change-over circuit 3506 becomes driven object circuit 150.So, can not only dispose the current source that is used for current supply driven object circuit 150 at benchmark in current source circuit 3514, can also dispose various pre-charge circuits.Figure 41 represents the example of this situation.What narrate in Figure 41 is the situation of 2 bits, and transistor 4111a is corresponding to the current source of the 1st bit (driven object circuit), and transistor 4111b is corresponding to the current source of the 2nd bit (driven object circuit).3514a is the benchmark current source corresponding to the 1st bit, and 3514b is the benchmark current source corresponding to the 2nd bit.
If use benchmark with current source circuit 3514, in corresponding to digital voltage-analog current change-over circuit 3506, in the marking current source 300 of each row, set electric current on the current source of each bit, then often also can dispose its circuit of control again.Perhaps, also can use shift register 3503 to control, perhaps utilize the 2nd latch circuit (LAT2) 3505 to control.
Have again, as circuit with current supply pixel 3501, the world that its details has been disclosed in the previous application of the applicant disclose No. 03/038793 communique, internationally disclose No. 03/038794 communique, internationally discloses No. 03/038795 communique, the world and disclose No. 03/038796 communique, the world and disclose in No. 03/038797 communique etc., can use this technology.
As well-known technology, digital voltage-aanalogvoltage change-over circuit 3515 can use resistance Splittable DA change-over circuit (R-DAC) and electric capacity Splittable DA change-over circuit formations such as (C-DAC).That is to say, can import several pre-charge voltages switch usefulness as DA reference voltage, use makes the suitable aanalogvoltage (pre-charge voltage) corresponding with it output to driven object circuit 150 (pixel 3501) by signal wire 400 from the vision signal of the 2nd latch circuit (LAT2) 3505 outputs.In addition, if the vision signal of exporting from the 2nd latch circuit (LAT2) 3505 is a N bit (2 NGray scale), then also can in digital voltage-aanalogvoltage change-over circuit 3515, form 2 NIndividual voltage in the input pixel, as shown in Figure 4, also can be selected circuit 700 and SW by using precharge 10～SW 13Deng, the pre-charge voltage that output is determined by each zone.
Have again, in digital voltage-aanalogvoltage change-over circuit 3515, must import several pre-charge voltages that become benchmark.Therefore, also can directly import pre-charge voltage, can also in reference voltage generating circuit 3516, generate pre-charge voltage.Then with its input.In this case, can use circuit shown in Figure 5.At this moment, the various current sources among Fig. 5 can special configuration, also can be used with the current source in current source circuit 3514 and the digital voltage-analog current change-over circuit 3506 etc. by common reference.In addition, the pre-charge circuit among Fig. 5 (transistor) 500A, 500B, 500C, 500D can special configuration, and the current source in also can shared pixel array 3501 grades is used.Perhaps, as Fig. 3, Figure 18～22 etc., also can use pre-charge circuit 500 and impedance conversion with amplifier 600 etc., with aanalogvoltage (pre-charge voltage) by each row configuration.
Have again, the not situation on same substrate of a signal-line driving circuit and a part thereof and pel array 3501 is also arranged, for example, can constitute and use IC chip in addition.
Have, the structure of signal-line driving circuit etc. is not limited to Figure 35 again.
For example, if the 1st latch circuit 3504 and the 2nd latch circuit 3505 are the circuit that can preserve the electric current of the analogue value, then also vision signal is imported the 1st latch circuit (LAT1) 3504 sometimes.Figure 37 represents the structure of this situation.
Circuit as vision signal being supplied with the 1st latch circuit (LAT1) 3504 is connected to vision signal supply circuit 3514.At this moment, vision signal supply circuit 3514 is equivalent to middle marking current source 300 and pre-charge circuits 500 such as Figure 16.And driven object circuit 150 is equivalent to the transistor of configuration in the 1st latch circuit (LAT1) 3504.Figure 38 represents one of the detailed structure of Figure 37 example.Use marking current source 3801 and pre-charge circuit 3802, the vision signal input is disposed at the transistor 3805 of the driven object circuit in the 1st latch circuit (LAT1) 3504.At this moment, because pre-charge circuit 3802 arranged, therefore write signal rapidly.Then, synchronous with latch signal, with the transistor 3805 of vision signal from the 1st latch circuit (LAT1) 3504, import the transistor 3803 in the 2nd latch circuit (LAT2) 3505.After, the transistor 3803 of vision signal from the 2nd latch circuit (LAT2) 3505 supplied with pixel 3804a, 3804b and 3804c etc.
Have, the example of representing in Figure 38 is again: when with electric current when vision signal supply circuit 3514 is supplied with transistor (driven object circuit) the 1st latch circuits (LAT1) 3504, use pre-charge circuit, input signal rapidly just, but be not limited thereto.When the transistor of electric current from the 1st latch circuit (LAT1) 3504 supplied with transistor (driven object circuit) in the 2nd latch circuit (LAT2) 3505, by in the 1st latch circuit (LAT1) 3504, disposing pre-charge circuit, also can carry out precharge.
Similarly, when the transistor of electric current from the 2nd latch circuit (LAT2) 3505 supplied with pixel (driven object circuit),, also can carry out precharge by in the 2nd latch circuit (LAT2) 3505, disposing pre-charge circuit.And also have the situation of not establishing the 2nd latch circuit 3505 this moment.Figure 39 represents the structure of this situation.As shown in figure 40, this moment, per 1 row disposed a plurality of transistor 4002a, 4002b in the 1st latch circuit (LAT1).And, make signal supply with a transistor from vision signal supply circuit 3514, signal is supplied with pixel from another transistor.And, use wiring 4001, successively their are switched and move, here,,, can carry out signal rapidly and write by on position separately, disposing pre-charge circuit with Figure 37,38 same.
Have again, in the structure of Figure 35 and Figure 37～40, also can adopt the structure of the various pre-charge circuits that so far illustrate etc.
(embodiment 13)
Below, as using electronic equipment of the present invention, can enumerate video camera, digital camera, eyepiece escope (helmet-mounted display), navigational system, sound reproducing device (automobile audio, combination audio etc.), notebook PC, game station, Portable information termainal (removable computer, mobile phone, portable game machine or e-book etc.), diagrammatic sketch with recording medium is as replay device (specifically, have can reset digital versatile dish recording mediums such as (DVD) and show the device of the display of its image) etc.The object lesson of these electronic equipments is shown among Figure 36.
Figure 36 (A) is a light-emitting device, and it comprises framework 13001, supporting station 13002, display part 13003, speaker portion 13004 and video input terminal 13005 etc.The present invention can be used in the electric circuit that constitutes display part 13003.In addition, according to the present invention, can finish the light-emitting device shown in Figure 36 (A).Because light-emitting device is emissive type, therefore do not need backlightly, can make the display part thinner than LCD.In addition, light-emitting device comprises the display device that PC is used, the TV broadcast reception is used, advertisement shows all information demonstration usefulness such as using.
Figure 36 (B) is a digital camera, and it comprises body 13101, display part 13102, imaging division 13103, operating key 13104, external connection port 13105 and shutter 13106 etc.The present invention can be used in the electric circuit that constitutes display part 13102.In addition, according to the present invention, can finish the digital camera shown in Figure 36 (B).
Figure 36 (C) is a notebook PC, and it comprises body 13201, framework 13202, display part 13203, keyboard 13204, external connection port 13205 and indication mouse 13206 etc.The present invention can be used in the electric circuit that constitutes display part 13203.In addition, according to the present invention, can finish the light-emitting device shown in Figure 36 (C).
Figure 36 (D) is a removable computer, and it comprises body 13301, display part 13302, switch 13303, operating key 13304 and infrared port 13305 etc.The present invention can be used in the electric circuit that constitutes display part 13302.In addition, according to the present invention, can finish the removable computer shown in Figure 36 (D).
Figure 36 (E) is the portable image playback apparatus (DVD replay device specifically) with recording medium, and it comprises body 13401, framework 13402, display part A13403, display part B13404, recording medium (DVD etc.) and reads in portion 13405, operating key 13406 and speaker portion 13407 etc.The main displays image information of display part A13403, the main display text information of display part B13404, the present invention can be used in and constitutes in display part A, B13403,13404 the electric circuit.Have again, in having the image playback apparatus of recording medium, also comprise home-use game machine etc.In addition, according to the present invention, can finish the DVD replay device shown in Figure 36 (E).
Figure 36 (F) is eyepiece escope (helmet-mounted display), and it comprises body 13501, display part 13502 and cradle portion 13503.The present invention can be used in the electric circuit that constitutes display part 13502.In addition, according to the present invention, can finish the eyepiece escope shown in Figure 36 (F).
Figure 36 (G) is a video camera, and it comprises body 13601, display part 13602, framework 13603, external connection port 13604, remote control acceptance division 13605, imaging division 13606, battery 13607, sound input part 13608 and operating key 13609 etc.The present invention can be used in the electric circuit that constitutes display part 13602.In addition, according to the present invention, can finish the video camera shown in Figure 36 (G).
Figure 36 (H) is a mobile phone, and it comprises body 13701, framework 13702, display part 13703, sound input part 13704, audio output unit 13705, operating key 13706, external connection port 13707 and antenna 13708 etc.The present invention can be used in the electric circuit that constitutes display part 13703.Have, display part 13703 can be by display white literal under black background again, the consumption electric current of control mobile phone.In addition, according to the present invention, can finish the mobile phone shown in Figure 36 (H).
Have, if the luminosity of luminescent material will improve from now on, the light that then also can scioptics etc. will contain the image information of output comes enlarging projection, is used for just throwing the projector of type or rear projection type again.
In addition, above-mentioned electronic equipment shows that the information that sends by the Internet and CATV electronic communication circuits such as (CATV (cable television)) has become great majority, shows that particularly the chance of animation information is increasing always.Because the response speed of luminescent material is very fast, so light-emitting device is desirable for animation display.
In addition, because the part in light-emitting device luminous consumes electric power, so require luminous component is diminished and display message as far as possible.Therefore, if with Portable information termainal, particularly the Word message of mobile phone and sound reproducing device is to use light-emitting device on the main display part, and then type of drive forms Word message preferably with non-luminous component as a setting in luminous component.
In a word, range of application of the present invention is extremely extensive, can be used in the electronic equipment of all scopes.In addition, the electronic equipment shown in here can adopt the semiconductor device of any structure of representing among the present invention.
The industrial possibility of utilizing
Current driving circuit of the present invention is provided with before signal code is supplied with holding wire, will believes Number line is pre-charged to the pre-charge circuit of regulation current potential, even therefore signal code is little, also can Enough solve the slack-off problem of signal writing speed.

Claims (18)

1. current driving circuit wherein is provided with:
The driven object circuit, described driven object circuit comprises the first transistor;
Pre-charge circuit;
Marking current is imported the current source circuit of described driven object circuit;
First switch;
Second switch; And
Signal wire, described signal wire is electrically connected described driven object circuit and described pre-charge circuit and is electrically connected described driven object circuit and described current source circuit by second switch by first switch.
2. as the current driving circuit of record in the claim 1, it is characterized in that:
Described pre-charge circuit is provided with transistor seconds.
3. as the current driving circuit of record in the claim 1, it is characterized in that:
Described driven object circuit is located in the pixel; And
Described pre-charge circuit and described current source circuit are located in the source electrode drive circuit.
4. as the current driving circuit of record in the claim 1, it is characterized in that:
Described driven object circuit is located in digital voltage-analog current change-over circuit,
Described pre-charge circuit and described current source circuit are located in the reference current source circuit.
5. as the current driving circuit of record in the claim 1, it is characterized in that: also be provided with the amplifier circuit between described first switch and described pre-charge circuit.
6. as the current driving circuit of record in the claim 5, it is characterized in that:
Described amplifier circuit is a source follower.
7. as the current driving circuit of claim 2 record, it is characterized in that,
By the 3rd switch the grid of described the first transistor is connected to the drain electrode of described the first transistor,
The grid of described transistor seconds is connected to the drain electrode of described transistor seconds, and
The grid width of described transistor seconds is greater than the grid width of described the first transistor.
8. as the current driving circuit of claim 2 record, it is characterized in that,
By the 3rd switch the grid of described the first transistor is connected to the drain electrode of described the first transistor,
The grid of described transistor seconds is connected to the drain electrode of described transistor seconds, and
The grid length of described transistor seconds is less than the grid length of described the first transistor.
9. current driving circuit is characterized in that:
Be provided with
The driven object circuit, described driven object circuit comprises the first transistor;
A plurality of pre-charge circuits;
Marking current is imported a plurality of current source circuits of described driven object circuit,
First switch, and
Second switch; And
Signal wire, described signal wire is electrically connected described driven object circuit and described a plurality of pre-charge circuit and is electrically connected described driven object circuit and described a plurality of current source circuit by second switch by first switch.
10. as the current driving circuit of record in the claim 9, it is characterized in that:
Also be provided with
A plurality of amplifier circuits between described first switch and described a plurality of pre-charge circuit.
11. the current driving circuit as record in the claim 9 is characterized in that:
Each of described a plurality of pre-charge circuits contains transistor seconds.
12. the current driving circuit as record in the claim 9 is characterized in that:
Described driven object circuit is located in the pixel,
Described a plurality of pre-charge circuit and described a plurality of current source circuit are located in the source electrode drive circuit.
13. the current driving circuit as record in the claim 9 is characterized in that:
Described driven object circuit is located in digital voltage-analog current change-over circuit,
Described a plurality of pre-charge circuit and described a plurality of current source circuit are located in the reference current source circuit.
14. the current driving circuit as record in the claim 9 is characterized in that:
Described a plurality of pre-charge circuit output is selected from the pre-charge voltage of a plurality of magnitudes of voltage.
15. the current driving circuit as record in claim 2 or 11 is characterized in that:
The grid of described transistor seconds is connected with drain electrode.
16. the current driving circuit as record in the claim 10 is characterized in that:
Each of described a plurality of amplifier circuits is a source follower.
17. the current driving circuit as claim 11 record is characterized in that,
By the 3rd switch the grid of described the first transistor is connected to the drain electrode of described the first transistor,
The grid of described transistor seconds is connected to the drain electrode of described transistor seconds, and
The grid width of described transistor seconds is greater than the grid width of described the first transistor.
18. the current driving circuit as claim 11 record is characterized in that,
By the 3rd switch the grid of described the first transistor is connected to the drain electrode of described the first transistor,
The grid of described transistor seconds is connected to the drain electrode of described transistor seconds, and
The grid length of described transistor seconds is less than the grid length of described the first transistor.
CNB2003801091826A 2002-11-29 2003-11-27 Current drive circuit and display using same Expired - Fee Related CN100468497C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP348673/2002 2002-11-29
JP2002348673 2002-11-29
JP019240/2003 2003-01-28

Related Child Applications (1)

Application Number Title Priority Date Filing Date
CN2009100033095A Division CN101471030B (en) 2002-11-29 2003-11-27 Display

Publications (2)

Publication Number Publication Date
CN1742306A CN1742306A (en) 2006-03-01
CN100468497C true CN100468497C (en) 2009-03-11

Family

ID=36094000

Family Applications (2)

Application Number Title Priority Date Filing Date
CNB2003801091826A Expired - Fee Related CN100468497C (en) 2002-11-29 2003-11-27 Current drive circuit and display using same
CN2009100033095A Expired - Fee Related CN101471030B (en) 2002-11-29 2003-11-27 Display

Family Applications After (1)

Application Number Title Priority Date Filing Date
CN2009100033095A Expired - Fee Related CN101471030B (en) 2002-11-29 2003-11-27 Display

Country Status (1)

Country Link
CN (2) CN100468497C (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102377119B1 (en) * 2014-12-30 2022-03-22 엘지디스플레이 주식회사 Display device
CN111415623B (en) * 2020-03-31 2021-05-14 合肥京东方显示技术有限公司 Pixel driving circuit, driving method thereof, display panel and display device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6310589B1 (en) * 1997-05-29 2001-10-30 Nec Corporation Driving circuit for organic thin film EL elements
JP3629939B2 (en) * 1998-03-18 2005-03-16 セイコーエプソン株式会社 Transistor circuit, display panel and electronic device
JP2001296837A (en) * 2000-04-13 2001-10-26 Toray Ind Inc Driving method for current controlled type display device
JP4929431B2 (en) * 2000-11-10 2012-05-09 Ｎｌｔテクノロジー株式会社 Data line drive circuit for panel display device

Also Published As

Publication number Publication date
CN101471030B (en) 2011-01-12
CN101471030A (en) 2009-07-01
CN1742306A (en) 2006-03-01

Similar Documents

Publication Publication Date Title
JP5322353B2 (en) Semiconductor device and electronic equipment
CN100538792C (en) Semiconductor device
CN100541567C (en) Display device and drive controlling method thereof
KR100558779B1 (en) Current drive circuit and drive method thereof, and electroluminescent display apparatus usng the circuit
CN1754316B (en) Semiconductor device and method for driving the same
US7864143B2 (en) Display device and driving method thereof
CN102201196B (en) Semiconductor device
US20070146250A1 (en) Display device
US7511687B2 (en) Display device, electronic apparatus and navigation system
US20100053128A1 (en) Current sample and hold circuit and method and demultiplexer and display device using the same
JP5143239B2 (en) Semiconductor device, display device and electronic apparatus
CN100449594C (en) Semiconductor device
CN100565637C (en) Semiconductor device and the display device of having used this device
JP5057637B2 (en) Semiconductor device
CN100437701C (en) Current source circuit, a signal line driver circuit and a driving method thereof and a light emitting device
KR101110764B1 (en) Semiconductor device and driving method thereof
US8378939B2 (en) Semiconductor device
CN100468497C (en) Current drive circuit and display using same
CN100541581C (en) Semiconductor devices and driving method thereof

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20090311

Termination date: 20201127