CN105489187B - Circuit for generating common voltage for liquid crystal panel and liquid crystal display thereof - Google Patents
Circuit for generating common voltage for liquid crystal panel and liquid crystal display thereof Download PDFInfo
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- CN105489187B CN105489187B CN201610053671.3A CN201610053671A CN105489187B CN 105489187 B CN105489187 B CN 105489187B CN 201610053671 A CN201610053671 A CN 201610053671A CN 105489187 B CN105489187 B CN 105489187B
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- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 77
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Classifications
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/04—Structural and physical details of display devices
- G09G2300/0421—Structural details of the set of electrodes
- G09G2300/0426—Layout of electrodes and connections
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- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Liquid Crystal Display Device Control (AREA)
Abstract
The disclosure relates to a circuit for generating a common voltage for a liquid crystal panel and a liquid crystal display thereof, belonging to the technical field of electronic displays. The circuit includes: a voltage generating unit generating a first voltage; and the voltage follower is based on a discrete triode and is coupled with the voltage generation unit, and the first voltage is used as an input voltage to generate a common voltage for the liquid crystal panel. The invention can enhance the driving capability of the public voltage to the liquid crystal display and simultaneously reduce the cost.
Description
Technical field
This disclosure relates to electronic display technology field, more particularly to produce the circuit of the common electric voltage for liquid crystal panel
And its liquid crystal display.
Background technology
Electronic console, such as liquid crystal display (LCD), it is generally used for electronic equipment such as notebook computer, flat board electricity
On brain, mobile device, TV and other electronic equipments.LCD passes through the light of liquid crystal layer by adjusting in different colours pixel
Amount carrys out display image.For example, by changing the voltage difference between the pixel electrode in pixel and public electrode, electricity can be produced
.Electric field can cause liquid crystal layer to change its direction of rotation, and this may finally cause more or less light to be transmitted through it can
The pixel that can be seen there.The voltage difference (commonly referred to as data-signal) of each pixel, Ke Yi are fed to by changing
Image is produced on LCD.
Public voltage generating circuit (VCOM) allows to adjust the common electric voltage for being applied to pixel, so as to open and close picture
Element.In the prior art as shown in figure 1, carrying out partial pressure using divider resistance (R1 and R2) produces VCOM, using electric capacity (C1) to institute
State VCOM voltages and carry out voltage stabilizing.Although this simple in construction, driving force deficiency, if load becomes big suddenly, electric current is taken out
Even directly the voltage of supply voltage (AVDD) can be pulled down.Although it can also be improved in the prior art using other manner
The driving force of the VCOM circuits, but cost is higher.
Therefore, it is necessary to circuit and its liquid crystal display of a kind of new generation for the common electric voltage of liquid crystal panel.
Above- mentioned information is only used for strengthening the understanding to the background of the disclosure, therefore it disclosed in the background section
It can include not forming the information to prior art known to persons of ordinary skill in the art.
The content of the invention
The disclosure provides a kind of circuit and its liquid crystal display for producing the common electric voltage for liquid crystal panel, solves above-mentioned
The problem of existing VCOM circuit drives scarce capacity or higher cost.
Other characteristics and advantage of the disclosure will be apparent from by following detailed description, or partially by the disclosure
Practice and acquistion.
According to the one side of the disclosure, there is provided a kind of circuit for producing the common electric voltage for liquid crystal panel, including：Voltage
Generation unit, produce first voltage；Voltage follower, based on discrete triode, coupled with the voltage generating unit, with institute
First voltage is stated as input voltage, generates the common electric voltage for liquid crystal panel.
According to an embodiment of the disclosure, wherein the voltage generating unit includes partial pressure unit, the partial pressure unit
Partial pressure is carried out to input voltage to produce the first voltage.
According to an embodiment of the disclosure, in addition to power voltage input terminal, the power voltage input terminal includes the
One supply voltage and second source voltage.
According to an embodiment of the disclosure, wherein the voltage follower includes bipolar transistor and is coupled to described
The output resistance of the emitter stage of bipolar transistor, the colelctor electrode of the bipolar transistor are coupled to the first power supply electricity
Pressure, the base stage of the bipolar transistor are coupled to the first voltage, the output electricity of the emitter stage of the bipolar transistor
Resistance is coupled to the second source voltage, and the emitter stage of the bipolar transistor exports the common electric voltage, wherein described the
Two supply voltages are grounded.
According to an embodiment of the disclosure, wherein the partial pressure unit includes first resistor and second resistance, wherein institute
Stating one end of first resistor, and first supply voltage is connected and the other end is connected with one end of the second resistance；Described
The other end of two resistance couples with the second source voltage；Node output between the first resistor and the second resistance
The first voltage.
According to an embodiment of the disclosure, wherein the partial pressure unit includes first resistor, variable resistance and second
Resistance, wherein one end of the first resistor and first supply voltage couple and the other end and the variable resistance the
One end couples；One end of the second resistance is connected with the second end of the variable resistance and the other end and the second source
Voltage couples；First voltage described in the three-polar output of the variable resistance.
According to an embodiment of the disclosure, wherein the partial pressure unit also includes：4th resistance, wherein the 4th electricity
One end of resistance couples with the 3rd end coupling of the variable resistance and the second end of the other end and the variable resistance.
According to an embodiment of the disclosure, in addition to：First electric capacity, wherein one end of first electric capacity and described the
One supply voltage is coupled and the other end is grounded.
According to an embodiment of the disclosure, in addition to：Output capacitance, wherein the output capacitance and the output resistance
It is in parallel.
According to the another further aspect of the embodiment of the present disclosure, there is provided a kind of liquid crystal display, including：Liquid crystal panel, it includes public affairs
Common electrode, pixel electrode and the liquid crystal cells between the public electrode and the pixel electrode；Any generation
The circuit of common electric voltage, its common electric voltage exported are coupled to the public electrode of the liquid crystal display.
According to the disclosure generation for liquid crystal panel common electric voltage circuit and its liquid crystal display, by using point
Buffer of the vertical triode as VCOM circuits, stable VCOM output voltages can be realized, while reduce cost.
It should be appreciated that the general description and following detailed description of the above are only exemplary and explanatory, not
The disclosure can be limited.
Brief description of the drawings
Accompanying drawing herein is merged in specification and forms the part of this specification, shows the implementation for meeting the present invention
Example, and for explaining principle of the invention together with specification.
Fig. 1 schematically shows the circuit diagram of the prior art for producing the common electric voltage for liquid crystal panel；
Fig. 2 is schematically shown according to circuit of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Figure；
Fig. 3 is schematically shown according to circuit of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Figure；
Fig. 4 A are schematically shown according to electricity of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Lu Tu；
Fig. 4 B are schematically shown according to electricity of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Lu Tu；
Fig. 4 C are schematically shown according to electricity of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Lu Tu；
Fig. 5 is schematically shown according to circuit of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Figure；
Fig. 6 is schematically shown according to circuit of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Figure；
Fig. 7 is schematically shown according to circuit of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Figure；
Fig. 8 schematically shows Dai Weinan equivalent electric of the generation based on Fig. 4 B for the circuit of the common electric voltage of liquid crystal panel
Road figure (VR=50%)；
Fig. 9 schematically shows the circuit model figure that the thevenin equivalent circuit based on Fig. 8 simplifies；
Figure 10 schematically shows the simulated effect figure (VR=50%) of the thevenin equivalent circuit based on Fig. 8；
Figure 11 schematically shows simulated effect figure of the generation based on Fig. 4 B for the circuit of the common electric voltage of liquid crystal panel
(VR=0%)；
Figure 12 schematically shows simulated effect figure of the generation based on Fig. 4 B for the circuit of the common electric voltage of liquid crystal panel
(VR=50%)；
Figure 13 schematically shows simulated effect figure of the generation based on Fig. 4 B for the circuit of the common electric voltage of liquid crystal panel
(VR=100%).
Embodiment
Example embodiment is described more fully with referring now to accompanying drawing.However, example embodiment can be with a variety of shapes
Formula is implemented, and is not understood as limited to example set forth herein；On the contrary, these embodiments are provided so that the disclosure will more
Fully and completely, and by the design of example embodiment comprehensively it is communicated to those skilled in the art.Accompanying drawing is only the disclosure
Schematic illustrations, be not necessarily drawn to scale.Identical reference represents same or similar part in figure, thus
Repetition thereof will be omitted.
In addition, described feature, structure or characteristic can be incorporated in one or more implementations in any suitable manner
In mode.In the following description, there is provided many details fully understand so as to provide to embodiment of the present disclosure.So
And it will be appreciated by persons skilled in the art that the technical scheme of the disclosure can be put into practice and omit one in the specific detail
Or more, or other methods, constituent element, device, step etc. can be used.In other cases, it is not shown in detail or describes
Known features, method, apparatus, realization, material or operation are to avoid that a presumptuous guest usurps the role of the host and so that each side of the disclosure becomes mould
Paste.
Some block diagrams shown in accompanying drawing are functional entitys, not necessarily must be with physically or logically independent entity phase
It is corresponding.These functional entitys can be realized using software form, or in one or more hardware modules or integrated circuit in fact
These existing functional entitys, or these functions reality is realized in heterogeneous networks and/or processor device and/or microcontroller device
Body.
Embodiment described in following exemplary embodiment does not represent all embodiment party consistent with the present invention
Formula.On the contrary, they are only the device consistent with some aspects being described in detail in such as appended claims, of the invention and side
The example of method.
Fig. 1 schematically shows the circuit diagram of the prior art for producing the common electric voltage for liquid crystal panel.
As shown in figure 1, carrying out partial pressure to supply voltage AVDD using divider resistance R1 and R2 produces VCOM, electric capacity C1 is used for
Voltage stabilizing.It is this simple in construction, but driving force is insufficient, if load (loading) becomes big suddenly, take out electric current even can directly by
AVDD voltage pulls down.
Fig. 2 is schematically shown according to circuit of the generation of disclosure example embodiment for the common electric voltage of liquid crystal panel
Figure.
As shown in Fig. 2 the circuit 200 includes：Voltage generating unit 210, produce first voltage；Voltage follower 220, base
In discrete triode, coupled with the voltage generating unit 210, using the first voltage as input voltage, generate and be used for
The common electric voltage VCOM of liquid crystal panel 230.
In exemplary embodiment, wherein the voltage generating unit 210 includes partial pressure unit, the partial pressure unit is to input
Voltage carries out partial pressure to produce the first voltage.
In exemplary embodiment, wherein the voltage generating unit 210 can also may be used with the adjustable power supply of an external voltage
The partial pressure generation first voltage, institute are carried out to it using arbitrary power supply in the electronic equipment for including liquid crystal display with direct
State voltage generating unit and can also be a dc-dc, be not limited thereto.
In exemplary embodiment, the voltage generating unit 210 can also include digital potentiometer, wherein the numerical control is electric
Position device realizes the effect to the input voltage partial pressure.
As shown in figure 3, also including power voltage input terminal, the power voltage input terminal includes the first supply voltage
VCC and second source voltage VSS.
In exemplary embodiment, wherein the second source voltage VSS is grounded.
In exemplary embodiment, wherein the second source voltage VSS can also include negative supply voltage, the negative supply
Voltage can be the negative terminal-VCC of the first supply voltage VCC or follow the negative low of liquid crystal display load change
Pressure.The second source voltage VSS in the disclosure is the ginseng of whole system (for example with the electronic equipment of liquid crystal display)
Voltage is examined, if the second source voltage VSS is negative voltage, the reference voltage for illustrating the system is negative voltage.
In exemplary embodiment, the first supply voltage VCC includes positive voltage.
In figure 3, wherein the partial pressure unit 300 includes first resistor R1 and second resistance R2, wherein first electricity
Resistance R1 one end is connected with the first supply voltage VCC and the other end is connected with one end of the second resistance R2；Described
The two resistance R2 other end couples with the second source voltage VSS；Between the first resistor R1 and the second resistance R2
Node export the first voltage.
In figure 3, the triode can be bipolar npn transistor, including base stage, collector and emitter.
In exemplary embodiment, wherein the voltage follower includes bipolar npn transistor Q1 and is coupled to described
The output resistance Ro, the NPN types bipolar transistor Q1 of bipolar npn transistor Q1 emitter stage colelctor electrode coupling
In the first supply voltage VCC, the base stage of the NPN types bipolar transistor Q1 is coupled to the first voltage, described
The output resistance Ro of the emitter stage of bipolar npn transistor is coupled to the second source voltage VSS, and the NPN types are bipolar
Property transistor Q1 emitter stage export the common electric voltage VCOM.
As shown in Figure 4 A, the voltage follower includes bipolar npn transistor Q2 and is coupled to the bipolar npn
The output resistance R10 of property transistor Q2 emitter stage.
It is in place of the circuit and Fig. 3 difference：Wherein described partial pressure unit 400 includes first resistor R6, variable resistor
Device R7 and second resistance R8, wherein one end of the first resistor R6 and the first supply voltage VCC couple and the other end with
The first end 410 of the variable resistance R7 couples；One end of the second resistance R8 and the second of the variable resistance R7
End 420 is connected and the other end couples with the second source voltage VSS；The 3rd end 430 output institute of the variable resistance R7
State first voltage.
In exemplary embodiment, the variable resistance R7 can be programmable resistance, or also include a control
Circuit, the slip at the 3rd end 430 (for example, slide plate) for controlling the variable resistance, specific sliding position can root
According to the load coupled with the circuit (abbreviation VCOM circuits) for producing the common electric voltage for liquid crystal panel (for example, liquid crystal
Show device) required for the size of common electric voltage calculated and adjusted.
In Figure 4 A, wherein the partial pressure unit 400 also includes：4th resistance R9, wherein the one of the 4th resistance R9
End and the 3rd end 430 of the variable resistance R7 couple and the second end 420 of the other end and the variable resistance R7 couples.
In exemplary embodiment, the 4th resistance R9 is substantially in parallel with the variable resistance R7, when in the absence of institute
When stating the 4th resistance R9, the variable resistance R7 of partial pressure unit resistance mobility scale is relatively large, when need more
During the output voltage values of fine regulation VCOM circuits, parallel connection the 4th resistance R9 is equivalent to reducing the variable resistance
R7 resistance mobility scale, the accuracy of the output voltage values of VCOM circuits can be correspondingly improved.
In Figure 4 A, wherein the partial pressure unit 400 also includes：First electric capacity C4, wherein the one of the first electric capacity C4
End is grounded with the first supply voltage VCC couplings and the other end.The first electric capacity C4 rises to the first supply voltage VCC
Pressure stabilization function.
As shown in Figure 4 B, the circuit is Fig. 4 A bringing onto loads RL (for example, equivalent resistance of liquid crystal panel) circuit diagram, wherein
Emitter stage coupling and the other end and the second source voltage of the one end of the load RL with the bipolar npn crystal Q2
VSS is coupled.
In figure 4b, the circuit also includes：Output capacitance C1, wherein the output capacitance C1 and the output resistance
R10 is in parallel.
Fig. 4 C schematically show another circuit diagram for producing the common electric voltage for liquid crystal panel.
As shown in Figure 4 C, the difference of the circuit diagram and above-mentioned Fig. 4 B is：The circuit is except including the first power supply electricity
Press VCC1 and second source voltage VSS, in addition to the 3rd supply voltage VCC2, the current collection of the bipolar npn transistor Q2
Pole is coupled to the 3rd supply voltage VCC2.Other circuits form component and annexation is identical with above-mentioned Fig. 4 B.
Fig. 5 schematically shows another circuit diagram for producing the common electric voltage for liquid crystal panel.
As shown in figure 5, wherein described voltage follower 220 includes positive-negative-positive bipolar transistor Q3 and is coupled to described
The output resistance R10, the positive-negative-positive bipolar transistor Q3 of positive-negative-positive bipolar transistor Q3 emitter stage colelctor electrode coupling
In the second source voltage VSS, the base stage of the positive-negative-positive bipolar transistor Q3 is coupled to the first voltage, described
The output resistance R10 of positive-negative-positive bipolar transistor Q3 emitter stage is coupled to the first supply voltage VCC, and the positive-negative-positive is double
Polar transistor Q3 emitter stage exports the common electric voltage VCOM.
Fig. 6 schematically shows another circuit diagram for producing the common electric voltage for liquid crystal panel.
As shown in fig. 6, the difference of the circuit and above-mentioned Fig. 4 A is：The NPN bipolar transistors Q2 can be replaced
It is changed to PMOS FET M1, including grid G, drain D and source S.
For example, the FET common drain circuit of a high input impedance can be designed, source follower is referred to as,
Wherein described PMOS FETs M1 drain D is coupled to the first supply voltage VCC, the grid of the PMOS FETs M1
Pole G is coupled to the first voltage, and the source S of the PMOS FETs M1 exports the common electric voltage VCOM.
Fig. 7 schematically shows another circuit diagram for producing the common electric voltage for liquid crystal panel.
As shown in fig. 7, the difference of the circuit and above-mentioned Fig. 6 is：The PMOS FETs M1 could alternatively be
NMOS FETs M2.
In exemplary embodiment, resistance, the capacitance size of corresponding partial pressure unit can be selected according to physical circuit.
Similarly, the emitter stage of the positive-negative-positive bipolar transistor Q3, the PMOS FETs M1 drain D, described
The output resistance and/or output capacitance of NMOS FETs M2 source electrode can be coupled to the 3rd supply voltage
VCC2。
In exemplary embodiment, the triode can also be J-type FET Junction gate FET (Field
Effect Transistor), either a kind of modification of any of the above-described triode or its combination, are not formed to the disclosure herein
Limitation.
In exemplary embodiment, wherein the triode can also include the first triode and the second triode, described
One triode and second triode form darlington transistor array, make the electricity using the darlington transistor array
Press follower (also known as " emitter follower ").Emitter follower is done using Darlington transistor, output voltage is than input electricity
Force down the forward conduction voltage of two PN junctions；The darlington transistor array internal circuit of some models is special, such as
ULN2002A, it is such to reach woods in input to the Zener diode regulator for also having a 7V between the base stage of the first triode
If transistor array do emitter follower output voltage always meet together it is lower more than 8V than input voltage.
Circuit of the generation that disclosure embodiment proposes for the common electric voltage of liquid crystal panel.Using three discrete poles
Pipe, a voltage follower for collection or common drain circuit composition altogether is formed, input impedance can be increased, reduce output impedance, enhancing
VCOM driving forces, reduce cost.The circuit is specific to the less feature design of driving force needed for liquid crystal panel
, the commonly required driving force of other kinds of display requires higher, can only typically use integrated amplifier or phase inverter
The circuit of similar generation common electric voltage here is formed, and discrete component can not be used to form the circuit for producing common electric voltage.
Meanwhile the defeated of VCOM output voltages can be adjusted by adjusting VR (variable resistance) adjustable/variable resistances
Go out size.
Fig. 8 schematically shows Dai Weinan equivalent electric of the generation based on Fig. 4 B for the circuit of the common electric voltage of liquid crystal panel
Road figure is (assuming that variable resistance R7 VR=50%, i.e. its 3rd end such as slide plate are located at the centre of the variable resistance R7
Position).
As shown in figure 8, the input voltage VDD of the base stage coupling of the triode Q1 is 4.69V, the input of base stage
Resistance R15 is 51 Ω, and the colelctor electrode of the triode Q1 couples the first supply voltage VCC, the VCC 10.4V, the output
Resistance R13 resistance is that 2k Ω, the output capacitance C6 are 10 μ F, and the equivalent resistance RL of load (such as liquid crystal panel) is 3k
Ω, equivalent source VDD here, equivalent inpnt resistance R15 value are that the value in above-mentioned Fig. 4 B is equivalent by Dai Weinan
It is calculated.
Thevenin's theorem (being translated into Thevenin's theorem again) is also known as equivalent voltage source law, also known as Helmholtz-Dai Weinanding
Reason.Its content is：The both ends of one Linear Network containing independent voltage source, independent current and resistance, with regard to its External Model
For, it can electrically be combined with the series resistance of an independent voltage source V and a loose singly-terminal pair come equivalent.
In single-frequency AC system, this theorem is not only only applicable to resistance, is also applied for the impedance of broad sense.
For containing independent source, the one-port network (singly-terminal pair) of linear resistance and linear controlled source, an electricity can be used
The one-port network (singly-terminal pair) that potential source is in series with resistance carrys out equivalent, the voltage of this voltage source, is exactly this one-port network (two
Hold network) open-circuit voltage, this series resistance be exactly enter in terms of this one-port network (singly-terminal pair) both ends, work as network internal
The later equivalent resistance of all equal zero setting of independent source.
Thevenin's theorem is the most frequently used circuit reduction method.Because Thevenin's theorem is to be equivalent to active two-terminal network
Power branch, so referred to as equivalent source theorem.
After Dai Weinan equivalence replacements, DC Model of the circuit model into a typical collector altogether.It is carried out quiet
State is analyzed, and according to its DC channel, lists the equation of input circuit, you can obtain base stage quiescent current IBQ, emitter stage Static Electro
Flow IEQWith tube voltage drop UCEQ：
In common collector, input signal is to be inputted by the base stage of triode with emitter stage both ends, then in alternating current path
In see, output signal by triode emitter stage obtain.Because for AC signal, i.e., colelctor electrode is common in alternating current path
End, so being referred to as collector altogether.
Fig. 9 schematically shows the circuit model figure (VR=50%) that the thevenin equivalent circuit based on Fig. 8 simplifies.
As shown in figure 9, in order to know the relevant parameters such as its correlated inputs, output impedance, dynamic analysis are carried out to it below.
Triode in circuit shown in Fig. 8 is substituted with h parameter equivalents model the ac equivalent circuit for just obtaining common collector.
After replacement and the circuit model that is simplified is as follows：
Wherein Rb=R15=51 Ω,R when having loade=(R13//RL) (wherein RL
It is the equivalent resistance of liquid crystal display for load), R when unloadede=R13。
Wherein UtIt is a physical quantity related to temperature, when temperature determines, the parameter U of the triode of finished product has been madet
It is a known constant,Obtain the first power that the order of magnitude is 10, dimension Ω.
Defined, can obtain according to voltage amplification factor：
As (1+ β) Re＞ ＞ Rb+rbe, thenI.e.Therefore collector is referred to as emitter follower altogether.Because
Output current is Ie, input current Ib, it is exaggerated (1+ β) times, input and the same phase of output voltage, andNo-voltage is put
Big ability, only amplify electric current, starting voltage Following effect.
It can be seen that emitter resistance ReIt is equivalent when arriving base loop, will increase (1+ β) times, therefore the input electricity of collector altogether
Resistance is more much bigger than the input resistance of grounded emitter circuit.
In order to calculate output resistance Ro, it is zero to make input signal, in output end plus alternating voltageObtain alternating currentThen output resistance
It can be seen that base loop resistance RbIt is equivalent when arriving emitter-base bandgap grading loop, it should be reduced to originalUsual RbValue
It is smaller, rbeAlso more in hundreds of Europe to several kilo-ohms, so RoCan be small to tens Europe.There it can be seen that the input of collector is electric altogether
Resistance is big, and output resistance is small, thus and carrying load ability small from electric current acquired by signal source is strong, with it connect two circuits (for example,
VCOM circuits and liquid crystal panel circuit), reduce circuit between be joined directly together caused influence, rise cushioning effect.
Collector has following characteristic altogether：Input signal and the same phase of output signal；No-voltage amplification, voltage gain are small
In 1 and close to 1, therefore collector has the title of " voltage follower " again altogether；Current gain is high, the electric current i in input circuitB<<
Electric current i in output loopEAnd iC.Here it is used as buffer stage and output stage.
Figure 10 schematically shows the simulated effect figure (VR=50%) of the thevenin equivalent circuit based on Fig. 8.
As shown in Figure 10, in simulated effect figure, the base stage input electricity for the triode Q1 that probe 5 (P5) place measures
Straightening flow component V (dc) is 4.69V, and DC current I is 14.6 μ A,；Probe 9 (P9) place measure output resistance R13 place with
The output voltage DC component V (dc) that probe 10 (P10) place measures at the load resistance R1 is 4.03V, probe 9 (P9) place
DC current I is 2.01mA, and the DC current I at probe 10 (P10) place is 1.34mA.As can be seen here, the same phase of input and output voltage
And size approaches, and electric current is exaggerated.Certainly, the voltage x current value in actual circuit in simulated effect figure with having somewhat
Difference.
Fig. 4 B are the single-tube circuits of a common-collector configuration, input signal and output it can be seen from Fig. 8 equivalent circuit
The common port of signal is the colelctor electrode of triode, so belonging to common-collector configuration.Again due to output signal from emitter stage draw, therefore
This circuit is also referred to as emitter-follower or emitter follower.
Collector is the circuit formed with a triode altogether, and its voltage gain is one, and voltage follow is done so being called
Device.Collector is input high impedance altogether, exports Low ESR, and this allows for it can play a part of impedance matching in circuit,
The circuit of rear stage is enabled to preferably to work.
Figure 11,12 and 13 schematically show emulation of the generation based on Fig. 4 B for the circuit of the common electric voltage of liquid crystal panel
Design sketch (is respectively variable resistance R7 VR=0%, i.e. its 3rd end such as slide plate is located at the variable resistance R7 most
Lower position；VR=50%；VR=100%).
In simulation process, the first supply voltage VCC of selection is 10.4V, VSS 0V, the first resistor
Resistance is 80k Ω, and the resistance of the second resistance is 100k Ω, and the resistance of the variable resistance is 47k Ω, the 4th electricity
Resistance R9 resistance is 2k Ω for 47k Ω, the first electric capacity C4 resistance for being 0.1 μ F, the output resistance R10, the output
Electric capacity C1 is 10 μ F, and load RL is 3k Ω.
In the example shown, the input voltage DC component V (dc) and electric current of the base stage of the triode Q2 are measured at probe P3
DC component I；The DC component V of the VCOM voltages of the emitter stage output of the triode Q2 is measured at probe P4 and probe P2
(dc) it is 3.28V, and measures the current dc component I at the current dc component I and probe P2 at probe P4 respectively.Measurement knot
Fruit is as shown in the table.
From the simulation result of above-mentioned circuit, input and output voltage is approached with phase and size, and electric current is exaggerated.
VCOM output voltage ranges are：3.28~4.78V, and scope that can be as needed selects suitable front end resistance, example
The slide plate position of variable resistance as described in by change.
The circuit of the disclosure can effectively reduce cost using discrete triode, can reach enhancing driving force, steady
Determine the purpose of VCOM voltages, and circuit structure is simple, cost advantage becomes apparent from, and reduces preparation technology cost.
Disclosure embodiment also provides a kind of liquid crystal display, including：Liquid crystal panel, it includes public electrode, pixel
Electrode and the liquid crystal cells between the public electrode and the pixel electrode；The electricity of any generation common electric voltage
Road, its common electric voltage exported are coupled to the public electrode of the liquid crystal display.
In exemplary embodiment, in addition to VCC power supplys, the circuit for producing common electric voltage includes buffering input VCOM electricity
The buffer of signal is pressed, the buffer is emitter follower, and the VCC power supplys produce under the partial pressure effect of partial pressure unit
VCOM control sources give the buffer, meanwhile, VCOM voltages also input to the liquid crystal display, are the liquid crystal display
Device provides public electrode voltages.
Disclosure embodiment provides a kind of electronic equipment, including：Processor, the processor are configurable to generate image
Signal；Liquid crystal display, the liquid crystal display are used to show described image signal；The liquid crystal display is coupled to institute
State the circuit of the generation common electric voltage of the public electrode outputting common voltage of liquid crystal display.
Circuit and its liquid crystal display of the generation of the disclosure for the common electric voltage of liquid crystal panel, using three discrete poles
Pipe, a voltage follower for collection or common drain circuit composition altogether is formed, can equally increase input impedance, reduce output impedance, increase
Strong VCOM driving forces, reduce cost.The disclosure designs specifically for the less feature of driving force needed for liquid crystal panel
, the commonly required driving force of other kinds of display requires higher, can only typically use integrated amplifier or phase inverter
The circuit of similar generation common electric voltage here is formed, and discrete component can not be used to form the circuit for producing common electric voltage.
Meanwhile the output size of VCOM output voltages can be adjusted by adjusting VR.
Those skilled in the art will readily occur to the present invention its after considering specification and putting into practice invention disclosed herein
Its embodiment.The application be intended to the present invention any modification, purposes or adaptations, these modifications, purposes or
Person's adaptations follow the general principle of the present invention and including the undocumented common knowledges in the art of the disclosure
Or conventional techniques.Description and embodiments are considered only as exemplary, and true scope and spirit of the invention are by following
Claim is pointed out.
The illustrative embodiments of the disclosure are particularly shown and described above.It should be appreciated that the disclosure is unlimited
In detailed construction described herein, set-up mode or implementation method；On the contrary, the disclosure is intended to cover included in appended claims
Spirit and scope in various modifications and equivalence setting.
Claims (8)
- A kind of 1. circuit for producing the common electric voltage for liquid crystal panel, it is characterised in that including：Voltage generating unit, produce first voltage；Voltage follower, based on discrete triode, coupled with the voltage generating unit, input is used as using the first voltage Voltage, generate the common electric voltage for liquid crystal panel；Wherein described voltage generating unit includes power voltage input terminal and the first electric capacity, and the power voltage input terminal includes the One supply voltage and second source voltage, one end of first electric capacity is coupled with first supply voltage and another termination Ground.
- 2. circuit according to claim 1, it is characterised in that wherein described voltage generating unit also includes partial pressure unit, The partial pressure unit carries out partial pressure to produce the first voltage to input voltage.
- 3. circuit according to claim 1, it is characterised in that wherein described voltage follower include bipolar transistor and The output resistance of the emitter stage of the bipolar transistor is coupled to, the colelctor electrode of the bipolar transistor is coupled to described One supply voltage, the base stage of the bipolar transistor are coupled to the first voltage, the emitter stage of the bipolar transistor Output resistance be coupled to the second source voltage, the emitter stage of the bipolar transistor exports the common electric voltage, its Described in second source voltage ground.
- 4. circuit according to claim 2, it is characterised in that wherein described partial pressure unit includes first resistor and the second electricity Resistance, whereinOne end of the first resistor is connected with first supply voltage and the other end is connected with one end of the second resistance；The other end of the second resistance couples with the second source voltage；Node between the first resistor and the second resistance exports the first voltage.
- 5. circuit according to claim 2, it is characterised in that wherein described partial pressure unit include first resistor, can power transformation Device and second resistance are hindered, whereinOne end of the first resistor is coupled with first supply voltage and the first end of the other end and the variable resistance Coupling；One end of the second resistance is connected with the second end of the variable resistance and the other end and the second source voltage Coupling；First voltage described in the three-polar output of the variable resistance.
- 6. circuit according to claim 5, it is characterised in that wherein described partial pressure unit also includes：4th resistance, wherein Threeth end coupling and the other end and the second of the variable resistance of the one end of 4th resistance with the variable resistance End coupling.
- 7. circuit according to claim 3, it is characterised in that also include：Output capacitance, wherein the output capacitance and institute State output resistance parallel connection.
- A kind of 8. liquid crystal display, it is characterised in that including：Liquid crystal panel, it includes public electrode, pixel electrode and the liquid between the public electrode and the pixel electrode Brilliant unit；Circuit of any generation for the common electric voltage of liquid crystal panel, its common electric voltage exported in the claim 1-7 It is coupled to the public electrode of the liquid crystal display.
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106297695A (en) * | 2016-08-29 | 2017-01-04 | 合肥惠科金扬科技有限公司 | A kind of TFT LCD liquid crystal display screen delay circuit |
| CN107192443A (en) * | 2017-05-23 | 2017-09-22 | 杭州兆华电子有限公司 | A kind of CRY2110 noise transducers |
| CN108198531B (en) | 2018-01-09 | 2021-02-09 | 京东方科技集团股份有限公司 | Common voltage generation circuit, common voltage generation method and display device |
| CN108508957A (en) * | 2018-04-12 | 2018-09-07 | 淮安信息职业技术学院 | A kind of low-temperature coefficient generating circuit from reference voltage and detection device |
| CN109509449B (en) * | 2018-12-19 | 2021-07-06 | 惠科股份有限公司 | Current regulating circuit, driving circuit and display device |
| CN110010098B (en) * | 2019-04-23 | 2020-10-13 | 深圳市华星光电技术有限公司 | Voltage conversion circuit |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10301087A (en) * | 1997-04-24 | 1998-11-13 | Hitachi Ltd | Liquid crystal display device |
| KR20010054194A (en) * | 1999-12-03 | 2001-07-02 | 윤종용 | Circuit for providing a common voltage to a liquid crystal display |
| CN1881136A (en) * | 2005-06-13 | 2006-12-20 | 鸿富锦精密工业（深圳）有限公司 | Memory voltage signal generation circuit |
| CN1963907A (en) * | 2005-11-10 | 2007-05-16 | 昆达电脑科技(昆山)有限公司 | Temperature compensating circuit of LCD element |
| EP1845515A2 (en) * | 2006-04-12 | 2007-10-17 | Funai Electric Co., Ltd. | Liquid crystal display device and common electrode voltage generating circuit |
| CN201780436U (en) * | 2010-09-07 | 2011-03-30 | 华映光电股份有限公司 | Display device |
| CN102053412A (en) * | 2009-11-05 | 2011-05-11 | 乐金显示有限公司 | Liquid crystal display |
-
2016
- 2016-01-27 CN CN201610053671.3A patent/CN105489187B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10301087A (en) * | 1997-04-24 | 1998-11-13 | Hitachi Ltd | Liquid crystal display device |
| KR20010054194A (en) * | 1999-12-03 | 2001-07-02 | 윤종용 | Circuit for providing a common voltage to a liquid crystal display |
| CN1881136A (en) * | 2005-06-13 | 2006-12-20 | 鸿富锦精密工业（深圳）有限公司 | Memory voltage signal generation circuit |
| CN1963907A (en) * | 2005-11-10 | 2007-05-16 | 昆达电脑科技(昆山)有限公司 | Temperature compensating circuit of LCD element |
| EP1845515A2 (en) * | 2006-04-12 | 2007-10-17 | Funai Electric Co., Ltd. | Liquid crystal display device and common electrode voltage generating circuit |
| CN102053412A (en) * | 2009-11-05 | 2011-05-11 | 乐金显示有限公司 | Liquid crystal display |
| CN201780436U (en) * | 2010-09-07 | 2011-03-30 | 华映光电股份有限公司 | Display device |
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