CN106373536A - Liquid crystal capacitor driving circuit and method - Google Patents
Liquid crystal capacitor driving circuit and method Download PDFInfo
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- CN106373536A CN106373536A CN201610811636.3A CN201610811636A CN106373536A CN 106373536 A CN106373536 A CN 106373536A CN 201610811636 A CN201610811636 A CN 201610811636A CN 106373536 A CN106373536 A CN 106373536A
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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
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3696—Generation of voltages supplied to electrode drivers
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- Liquid Crystal Display Device Control (AREA)
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Abstract
The invention discloses a liquid crystal capacitor driving circuit suitable for electrical connection with a liquid crystal capacitor. The liquid crystal capacitor driving circuit comprises a transmission unit, a conversion unit, an output unit and a determining unit, wherein the transmission unit receives multiple digital pixel data and sequentially transmitting the data; the conversion data receives each piece of the pixel data and generates corresponding driving voltages; the output unit comprises an operation amplifier which is provided with a pre-stage control group, a first switch group and a second switch group; and the determining unit, according to two pieces of the pixel data, sequentially transmitted by the transmission unit, generates a comparison result, and the pre-stage control group controls the first switch group to output first currents to the liquid crystal capacitor, and according to the comparison result, controls the second switch group whether to output second currents to the liquid crystal capacitor or not.
Description
Technical field
The invention relates to a kind of drive circuit, particularly relate to a kind of liquid crystal capacitance for LCD screen and drive electricity
Road.
Prior art
The picture of LCD screen is to be made up of multiple pixels (pixel) arranged in arrays, the quantity definition of these pixels
The resolution of this LCD screen, for example, resolution is 1920x1080, that is, full hd (full high
Definition, also referred to as full HD) LCD screen of specification, the quantity of its pixel having is about 2,000,000, and for example
Resolution is 3840x2160, that is, the liquid crystal of ultra hd (ultra high definition, also referred to as ultra high-definition) specification
Screen, the quantity of its pixel having is about 8,200,000, and each of which pixel is required for being driven by drive circuit
Dynamic, and drive each time and all need to consume electric energy that is to say, that the resolution of LCD screen is higher, represent and drive all pixels institute
The electric energy needing is also bigger.
Refering to Fig. 1, the liquid crystal capacitance drive circuit 9 of prior art is applied to the liquid crystal that electrical connection one controls pixel to show
Electric capacity cs, this liquid crystal capacitance drive circuit 9 comprises 91, digital analog converter 92 of a latch group, and a computing
Amplifier 93.This latch group 91 receives a digital pixel data (pixel data) and is sent to this digital simulation
Transducer 92, this pixel data is converted to a corresponding analog drive voltage and is transmitted by this digital analog converter 92
To this operational amplifier 93, this operational amplifier 93 drives this liquid crystal capacitance cs with this analog drive voltage again, to provide electric current
To the cs charge or discharge of this liquid crystal capacitance, this pixel energy is made to show correct brightness according to the voltage that liquid crystal capacitance cs provides.
In order to the cs charge/discharge of this liquid crystal capacitance, cooperation refers to Fig. 2 and Fig. 3, and the inside of existing operational amplifier 93 has
One ab class (class ab) amplifier, this ab class A amplifier A has multiple (expression, the multiple crystalline substance being connected in parallel to each other of m table with m=8
The quantity of body pipe, m is natural number, m >=1) p-type transistor, and multiple (being represented with m=4) n-type transistor.For example, exist
During very first time t1 shown in Fig. 3, according to some pixel data, if the output voltage vout at this liquid crystal capacitance cs two ends needs
Charged to maximum voltage vmax from minimum voltage vmin, then operational amplifier 93 can be by these p-type transistor and n-type transistor
Simultaneously turn on, flow through these p-type transistor and to this liquid crystal capacitance cs charging to form charging current i+, and shown in Fig. 3
During the second time t2, according to one other pixel data, if this output voltage vout needs to be discharged to from maximum voltage vmax
Small voltage vmin, similarly, these p-type transistor and n-type transistor can be simultaneously turned on, to form one by this operational amplifier 93
Individual discharge current i- is flowed to these n-type transistor and discharged by this liquid crystal capacitance cs.Supplementary notes: when these p-type crystal
When pipe and n-type transistor simultaneously turn on, have a fixed current istd and flow through these n-type transistor by these p-type transistor,
Therefore, according to Kirchhoff's current law (KCL) (kirchhoff's current law, kcl), when this liquid crystal capacitance cs charges
When, total current iin flowing through these p-type transistor is this charging current i+ and the sum of this fixed current istd, and works as this liquid crystal
When electric capacity cs discharges, total current iout flowing through these n-type transistor is this discharge current i- and this fixed current istd
Sum.Specifically, when this liquid crystal capacitance cs voltage vout change scope very greatly when (for example shown in Fig. 3 by minimum electricity
Pressure vmin charges to maximum voltage vmax, or is discharged to minimum voltage vmin by maximum voltage vmax), that is, need larger filling
Electric current i+ or discharge current i-, to the cs charge or discharge of this liquid crystal capacitance, just can make the response speed of voltage vout sufficiently fast
Speed, if however, the scope of this voltage vout change is less, do not need too big charging current i+/discharge current i-, you can make
The cs charge/discharge within the time limit of this liquid crystal capacitance completes, and charging current i+/discharge current i- is bigger, represents to this liquid crystal capacitance
Power consumption during cs charge/discharge is bigger, along with LCD screen constantly develops toward high-resolution, therefore, for save energy,
Really a set of energy-conservation that may achieve is needed but not affect to drive the mechanism of efficiency.
Content of the invention
Therefore, the purpose of the present invention is to provide a kind of more energy efficient liquid crystal capacitance drive circuit.
Then, liquid crystal capacitance drive circuit of the present invention is applied to a liquid crystal capacitance of electrical connection one LCD screen, this liquid
Brilliant capacitor drive circuit comprises a delivery unit, converting unit, an output unit, and a judging unit；This biography
Unit is sent to receive multiple digital pixel datas and transmit in order；This converting unit electrically connects this delivery unit and is derived from receiving
Each pixel data of this delivery unit, and according to each pixel data produce one to should pixel data driving electricity
Pressure；This output unit electrically connects this converting unit and this liquid crystal capacitance, and includes an operational amplifier, this operation amplifier utensil
There are a prime control group, a first switch group being electrically connected between this prime control group and this liquid crystal capacitance, and one
It is electrically connected to the second switch group between this prime control group and this liquid crystal capacitance；Judging unit be electrically connected to this delivery unit and
Between this output unit, and produce a comparative result signal according to two pixel datas of this delivery unit successively transmission；When
This delivery unit transmits each pixel data to this converting unit, and the prime control group of this operational amplifier receives and is derived from this turn
Change unit and to should pixel data this driving voltage, and control this first switch group export first electric current to this liquid crystal
Electric capacity, so that this liquid crystal capacitance is charged or discharged to this driving voltage, this prime control group according to comparative result signal control
Make whether this second switch group exports second electric current to this liquid crystal capacitance.
In certain embodiments, each pixel data is binary data, and judging unit includes one and electrically connects this biography
Send the memorizer of unit, and the comparator of an electrical connection delivery unit and memorizer, memorizer receives and stores delivery unit
The place value judging position in this pixel data successively first transmitting in two pixel datas of transmission, this comparator receives this biography
This pixel data of transmission after sending in two pixel datas of unit priority transmission, and judge this pixel data transmitting afterwards
In judge whether the place value of position identical with the place value of memory storage, and producing ratio is compared with consequential signal.
In certain embodiments, this memorizer is a latch.
In certain embodiments, this comparator is an XOR gate.
In certain embodiments, liquid crystal capacitance drive circuit also electrically connects a control unit；Wherein, judging unit also wraps
Include electrical connection comparator, a control unit, and the buffer of output unit, buffer inputs are from the comparative result of comparator
Signal, and according to a drive signal being derived from this control unit, the prime of comparative result signal output to output unit is controlled
Group.
In certain embodiments, this buffer is one and door.
In certain embodiments, each pixel data judge the highest significant position that position is this pixel data.
Liquid crystal capacitance driving method of the present invention is executed by a liquid crystal capacitance drive circuit, this liquid crystal capacitance drive circuit electricity
Connect the liquid crystal capacitance of LCD screen, and comprise delivery unit, converting unit, judging unit, and output unit, this output unit
Including operational amplifier, this operational amplifier have prime control group, be electrically connected to this prime control group and this liquid crystal capacitance it
Between first switch group, and be electrically connected to the second switch group between this prime control group and this liquid crystal capacitance, this liquid crystal capacitance
Driving method comprises:
A () delivery unit receives and transmits the first pixel data to converting unit；
B () delivery unit receives and transmits the second pixel data to converting unit, and the second pixel data is sequence in the first picture
Prime number is according to afterwards；
C () judging unit produces a comparative result signal according to the first pixel data and the second pixel data；And
D this prime control group of () this operational amplifier receives one and is derived from this converting unit and is relevant to this second pixel data
Driving voltage, and control this first switch group export the first electric current to this liquid crystal capacitance so that this liquid crystal capacitance be electrically charged or
It is discharged to this driving voltage, prime control group extremely should according to whether comparative result signal control second switch group exports the second electric current
Liquid crystal capacitance.
In certain embodiments, judging unit has a memorizer, and the first pixel data and the second pixel data are
There is the numerical data of multidigit, liquid crystal capacitance driving method also comprises a step (e) between step (a) and step (b):
Memorizer receive and store the first pixel data m position place value.
In certain embodiments, judging unit also has comparator, and in step (c), comparator receives from memorizer
Place value, and the second pixel data from delivery unit, and judge the place value from this memorizer and the second pixel data
Whether the place value of m position identical and producing ratio is compared with consequential signal.
In certain embodiments, the first pixel data and the second pixel data respectively binary data for eight, and
The m position of the m position of the first pixel data and the second pixel data is respectively this first pixel data and this second pixel data
Highest significant position.
In certain embodiments, liquid crystal capacitance drive circuit also electrically connects a control unit, and judging unit also has one
Individual buffer, in step (c), buffer inputs are derived from the comparative result signal of comparator, and are derived from control unit according to one
Drive signal by the prime control group of comparative result signal output to output unit.
In certain embodiments, in step (d), the second pixel data is converted to corresponding second pixel data by converting unit
Driving voltage and be supplied to the prime control group of operational amplifier.
The effect of present invention, is: produces one by judging unit according to two pixel datas of delivery unit successively transmission
Comparative result signal, further according to comparative result signal, the prime control group of operational amplifier controls whether second switch group exports the
Two electric currents, to liquid crystal capacitance, make liquid crystal capacitance drive circuit can adjust second switch group according to the change in voltage degree of liquid crystal capacitance
Whether turn on, and then adjust the size of the electric current to liquid crystal capacitance charge/discharge, and reach effect of energy-conservation.
Brief description
The others feature of volume of the present invention and effect, clearly will present, wherein in the embodiment with reference to schema:
Fig. 1 is circuit block diagram, illustrates that prior art liquid crystal capacitance drive circuit electrically connects a liquid crystal capacitance；
Fig. 2 is circuit diagram, and the internal circuit of the operational amplifier of prior art liquid crystal capacitance drive circuit is described；
Fig. 3 is oscillogram, illustrates prior art liquid crystal capacitance drive circuit to voltage during this liquid crystal capacitance charge/discharge and electric current
Relation；
Fig. 4 is circuit block diagram, illustrates that an embodiment of liquid crystal capacitance drive circuit of the present invention electrically connects a liquid crystal capacitance；
Fig. 5 is the circuit diagram within the operational amplifier of embodiment；
Fig. 6 is the action timing diagram of embodiment；
Fig. 7 is oscillogram, and when illustrating that the second switch group of embodiment turns on, this operational amplifier is to this liquid crystal capacitance charge/discharge
Voltage and current relationship；
Fig. 8 is oscillogram, and when illustrating that the second switch group of embodiment is not turned on, operational amplifier is to liquid crystal capacitance charge/discharge
Voltage and current relationship；
Fig. 9 is schematic diagram, and the relation between the most significant digit of two contextual pixel datas of embodiment is described；And
Figure 10 is schematic diagram, and the pass between the most significant digit of two other contextual pixel data of this embodiment is described
System.
Reference numeral explanation
1 delivery unit
2 converting units
3 output units
31 operational amplifiers
311 prime control groups
312 first switch groups
313 second switch groups
4 judging units
41 bins
42 comparators
43 buffers
9 liquid crystal capacitance drive circuits
91 bolt lock device groups
92 digital analog converters
93 operational amplifiers
100 control units
D0～dn pixel data
V0～v255 driving voltage
Vout voltage
Vmin minimum voltage
Vmax maximum voltage
Vsync synchronizing signal
Rn comparative result signal
En1 first drive signal
En2 second drive signal
En3 the 3rd drive signal
I+ charging current
I- discharge current
Iin electric current
Iout electric current
Ip1 electric current
Ip2 electric current
In1 electric current
In2 electric current
Istd fixed current
Vcc power end
Gnd earth terminal
The t1 very first time
T2 second time
T3 the 3rd time
T4 the 4th time
T5 the 5th time
T6 the 6th time
T7 the 7th time
T8 the 8th time
T_charge charge cycle
T_discharge discharge cycle
Cs liquid crystal capacitance
Specific embodiment
Refering to Fig. 4, an embodiment of liquid crystal capacitance drive circuit of the present invention is applied to such as one liquid crystal display screen of electrical connections
One liquid crystal capacitance cs of curtain, and the control unit 100 of for example, central processing unit, this liquid crystal capacitance cs may actually be liquid
Brilliant equivalent capacity, or alternatively additional actual capacitance, but be not limited thereto, this liquid crystal capacitance drive circuit comprises to pass
Send unit 1, converting unit 2, output unit 3, and judging unit 4.
This delivery unit 1 receives the pixel data of multiple numerals and transmits in order, in the present embodiment, each pixel
Data is the binary data of eight, and first of each pixel data is the most significant digit of this pixel data
(most significant bit,msb).
This converting unit 2 electrically connects this delivery unit 1 to receive each pixel data from this delivery unit 1, and
According to each pixel data produce one to should pixel data driving voltage, more specifically, in the present embodiment, should
Converting unit 2 is a digital analog converter (digital to analog converter, dac), and can be by each picture
The form of plain data from digital is converted to the driving voltage of an analog form.
Refering to Fig. 5, output unit 3 electrical connection converting unit 2 and liquid crystal capacitance cs, and include an operational amplifier 31.
This operational amplifier 31 has a prime control group 311, and is electrically connected between prime control group 311 and liquid crystal capacitance cs
First switch group 312, an and second switch group 313 being electrically connected between this prime control group 311 and liquid crystal capacitance cs.
Specifically, in the present embodiment, as shown in figure 5, first switch group 312 has two (representing in Figure 5) with m=2 each other
In parallel and be electrically connected to p-type mosfet (representing in Figure 5) between a power end vcc and liquid crystal capacitance cs with p-mos, and
One (being represented with m=1 in Figure 5) be electrically connected to N-shaped mosfet between this liquid crystal capacitance cs and an earth terminal gnd (
Represented with n-mos in Fig. 5), second switch group 313 is had six (being represented with m=6) and is connected in parallel to each other and is electrically connected to power end
P-type mosfet between vcc and liquid crystal capacitance cs, and three (being represented with m=3) be electrically connected to liquid crystal capacitance cs and earth terminal
N-shaped mosfet between gnd.
Judging unit 4 is electrically connected between delivery unit 1 and output unit 3, and two according to delivery unit 1 successively transmission
Individual pixel data produces a comparative result signal rn.Judging unit 4 includes one and electrically connects this delivery unit 1 and this control list
41, comparator 42 electrically connecting this delivery unit 1 and this memorizer 41 of memorizer of unit 100, and one electrically connect this ratio
Buffer 43 compared with device 42, control unit 100 and output unit 3.In the present embodiment, this memorizer 41 is a latch,
Comparator 42 is an XOR gate (xor gate), and buffer 43 is then one and door (and gate).Supplementary notes: pass
Send unit 1 to include multiple latch (not shown)s, therefore also there is the ability of storage numerical data.
Specifically, comparative result signal rn produced by judging unit 4 is to represent delivery unit 1 to be sent to converting unit
Difference size between 2 two pixel datas corresponding two driving voltages of difference adjacent in front and back, for the present embodiment,
Each pixel data is the binary data of eight, and the voltage range segmentation that also will simulate is 256 (2 8 powers) individual rank
Layer, and each pixel data then represents the one of which of 256 kinds of driving voltages, for convenience of description, here defines a minimum
Driving voltage v0, and a maximum drive voltage v255.
In each cycle, a pixel data can be changed into and be sent to after corresponding driving voltage by this converting unit 2
Output unit 3, output unit 3 drives liquid crystal capacitance cs with driving voltage again, and constantly repeats this process, therefore, at each
In cycle, the voltage vout on liquid crystal capacitance cs can change between v0 to v255.
For example, refering to Fig. 9, to should the pixel data of minimum driving voltage v0 be [00000000], and its highest
Significance bit be 0, and to should maximum drive voltage v255 pixel data be [11111111], and its highest significant position be 1, take
Join refering to Fig. 4, if in some cycle, the voltage of this liquid crystal capacitance cs is originally used for minimum driving voltage v0, and in the next one
In cycle, this liquid crystal capacitance cs need to be charged to maximum drive voltage v255, then this converting unit 2 is within two described cycles
The most significant digit of two pixel datas receiving respectively will be different from each other.
Again by way of further example for, simultaneously refer to Fig. 4 and Figure 10, if in some cycle, the voltage of this liquid crystal capacitance cs
It is originally used for a driving voltage v192 being closer to this maximum drive voltage v255, and in next cycle, liquid crystal capacitance cs
Maximum drive voltage v255 need to be charged to, the pixel data corresponding to driving voltage v192 is [11000000], its highest significant position
For 1, and the pixel data of corresponding maximum drive voltage v255 is [11111111], and its highest significant position is also 1, therefore this conversion
The most significant digit of two pixel datas that unit 2 receives within two described cycles respectively will be mutually the same.
Comprehensive above two understand: in two cycles adjacent in front and back, if two pictures of 2 received in sequence of converting unit
The most significant digit of prime number evidence is different, then the voltage vout amplitude of variation representing liquid crystal capacitance cs is larger, if conversely, converting unit
The most significant digit of two pixel datas of 2 received in sequence is identical, then represent the voltage vout amplitude of variation of liquid crystal capacitance cs
Less, more specifically, for the binary data of eight, the weight representated by its most significant digit is 27 powers,
It is exactly 128, therefore, if the pressure reduction between the driving voltage representated by two pixel datas is more than 128 stratum, that is, exceed
The half of big mobility scale, then the most significant digit of this two pixel datas must be different, therefore, before the present embodiment can be by comparing
Whether the most significant digit of latter two pixel data is identical and producing ratio, compared with consequential signal rn, to judge the voltage of liquid crystal capacitance cs
Vout intensity of variation is less or larger.
Belong to those skilled in the art of the present technique to know: if with a fixed current to a capacitor charge/discharge, this electricity
If the size of the voltage variety on container is to be positively correlated with the time to its charge/discharge that is to say, that making this capacitor exist
Charge/discharge in the shorter time completes, and just need to improve driving force with larger electric current, however, with larger electric current to electricity
Container charge/discharge can consume the real hardly possible of larger electric energy, therefore driving force and energy-conservation, and both take into account, and the core work(of the present embodiment
Effect is just: before this liquid crystal capacitance cs starts by charge/discharge, can judge the electricity of its current voltage vout and target in advance
Difference size between pressure vout, and control the second switch group 313 of output unit 3 whether to turn on, by adjust output unit 3
Charging current i+ to liquid crystal capacitance cs or discharge current i-, and obtain balance between driving force and energy-conservation consider.
Flow process below for the present embodiment describes in detail.Simultaneously refer to Fig. 4,
Fig. 5 and Fig. 6, first, during very first time t1 shown in Fig. 6, from the synchronizing signal of this control unit 100
Vsync is changed into 0 from 1, represents the initial of a cycle, and meanwhile, this delivery unit 1 is according to from the first of this control unit 100
Drive signal en1, the first pixel data d1 being received in advance and storing transmits to this converting unit 2, and this converting unit 2 will
This first pixel data d1 is converted to corresponding first driving voltage and transmits it to this output unit 3.In Fig. 4, n is nature
Number, n is more than or equal to 1.
Then, in the second time t2, this prime control group 311 of this operational amplifier 31 receives this first driving voltage,
And control this first switch group 312 to export the first electric current to this liquid according to from the second drive signal en2 of this control unit 100
Brilliant electric capacity cs, so that this liquid crystal capacitance cs is charged or discharged to this first driving voltage before one the 3rd time t3.Add
Bright: to be to be electrically charged or be discharged according to this liquid crystal capacitance cs, this first electric current can be this charging current i+ or this electric discharge
Electric current i-.
Then, in the 4th time t4, the memorizer 41 of judging unit 4 is according to the 3rd driving from this control unit 100
Signal en3 stores the place value of the most significant digit of this first pixel data d1.
Then, in the 5th time t5, as shown in Figure 6, this synchronizing signal vsync is changed into 0 from 1 again, represents another
Cycle initial, meanwhile, the second pixel that this delivery unit 1 receives in advance and stores according to this first drive signal en1
Data d2 is transmitted to this converting unit 2, and this second pixel data d2 is converted to corresponding second and drives electricity by this converting unit 2
Press and transmit it to this output unit 3.
Then it should be noted that: between the 5th time t5 and the 6th time t6, the comparator 42 of judging unit 4
Receive the place value of the most significant digit of this second pixel data d2, and this memorizer 41 stored in upper a cycle first
The place value of the most significant digit of pixel data d1, and compare both whether identical and one comparative result signal rn of generation.Specifically
For, because this comparator 42 is an XOR gate, therefore, if this first pixel data d1 and this second pixel data d2
The place value of big significance bit is identical, then comparative result signal rn is 0, if it is different, then this comparative result signal rn is 1.
Then, in the 6th time t6, the prime control group 311 of operational amplifier 31 receives the second driving voltage, and according to
This first switch group 312 is controlled to export the first electric current to liquid crystal capacitance cs, meanwhile, judging unit 4 according to this second drive signal en2
Buffer 43 also comparative result signal rn is transmitted to the prime control group of output unit 3 according to the second drive signal en2
311, if comparative result signal rn is 0, prime control group 311 controls second switch group 313 to be not turned on, if conversely, comparing knot
Fruit signal rn is 1, then prime control group 311 controls second switch group 313 to turn on, to export the second electric current to liquid crystal capacitance cs,
So that this goes out unit 3 is provided that bigger charging current i+ or discharge current i- to liquid crystal capacitance cs, make liquid crystal capacitance cs
Can be charged or discharged to this second driving voltage before seven time t7.
Finally, in the 8th time t8, the memorizer 41 of judging unit 4 according to the 3rd drive signal en3 store this second
The place value of the most significant digit of pixel data d2, for comparator 42 in next cycle as comparison data source.
After the 8th time t8, it is the initial of another cycle, and judging unit 4 will be repeated continuously aforementioned step
The actions such as rapid comparison, control and storage, therefore just repeat no more.In addition, supplementary notes: the first pixel data d1 is false
It is set to the first pixel data that delivery unit 1 in the present embodiment is received, therefore do not have more previous pixel data conduct
Ignore when the action between very first time t1 and the second time t2 of comparison other, therefore judging unit 4 is in preceding description.
The action driving the cs charge or discharge of this liquid crystal capacitance below for output unit 3 describes in detail, and respectively with liquid
Brilliant electric capacity cs is electrically charged, and second switch group 313 turns on, liquid crystal capacitance cs is discharged, and second switch group 313 turn on, liquid crystal
Electric capacity cs is electrically charged, and second switch group 313 is not turned on, and liquid crystal capacitance cs is discharged, and second switch group 313 is not turned on
As a example four kinds of situations.
Refer to Fig. 5 and Fig. 7, for example, in a charge cycle t_charge, if this first driving voltage is simultaneously
This minimum driving voltage v0, and when this second driving voltage is this maximum drive voltage v255, this second switch group 313 turns on,
Therefore this first switch group 312 and this second switch group 313 export charging current i+ jointly to this liquid crystal capacitance cs, more specifically
Say: electric current iin is divided into electric current ip1 and electric current ip2 after being flowed into by the power end vcc of this operational amplifier 31, and respectively flows through this
P-type mosfet of first switch group 312 and p-type mosfet of this second switch group 313, then, electric current ip1 and electric current ip2 are each
There is part to flow to this liquid crystal capacitance cs and form this charging current i+, and electric current ip1 and electric current ip2 does not flow to this liquid crystal capacitance cs
Part be then respectively defined as electric current in1 and electric current in2, and respectively flow through this first switch group 312 N-shaped mosfet and should
The N-shaped mosfet of second switch group 313, finally, electric current in1, electric current in2 and charging current i+ are confluxed for electric current iout and are flow to
The earth terminal gnd of this operational amplifier 31.It should be noted that: in the present embodiment, p-type mosfet of second switch group 313
Quantity is three times of first switch group 312, and the quantity of the N-shaped mosfet of second switch group 313 is also first switch group 312
Three times, in other words, when second switch group 313 turns on, the electric current flowing through second switch group 313 is also first switch group 312
Three times, more particularly: when second switch group 313 turns on, second switch group 313 provide driving this liquid crystal capacitance cs it
The 75% of total electric energy, and first switch group 312 provides the 25% of the total electric energy driving this liquid crystal capacitance cs, therefore, electric current ip1
It is essentially the 25% of electric current iin, electric current ip2 and is essentially the 75% of electric current iin, and electric current in2 is three times of electric current in1,
But it is not limited with above-mentioned in other embodiments.
With continued reference to Fig. 5 and Fig. 7, in discharge cycle t_discharge, if the first driving voltage is this maximum drive electricity
Pressure v255, and when the second driving voltage is this minimum driving voltage v0, second switch group 313 turns on, therefore one is derived from this liquid crystal
The discharge current i- of electric capacity cs flow to earth terminal gnd via first switch group 312 and second switch group 313, more specifically: electricity
Stream iin is divided into electric current ip1 and electric current ip2 by after power end vcc inflow, and respectively flows through the p-type of this first switch group 312
Mosfet and p-type mosfet of this second switch group 313, and electric current ip1 is the 25% of electric current iin, electric current ip2 is electric current iin
75%, then, the 25% of discharge current i- is confluxed for electric current in1 the N-shaped that flows through first switch group 312 with electric current ip1
Mosfet, the 75% of discharge current i- conflux for electric current in2 the N-shaped mosfet that flows through second switch group 313 with electric current ip2,
Finally, electric current in1 and electric current in2 confluxes for electric current iout and flow to this earth terminal gnd.
Refer to Fig. 5 and Fig. 8, in another charge cycle t_charge, if the first driving voltage is driving voltage simultaneously
V192, and when the second driving voltage is this maximum drive voltage v255, this second switch group 313 is not turned on, and therefore only first opens
Pass group 312 output charging current i+ to this liquid crystal capacitance cs, more specifically: electric current iin is flowed only through by after power end vcc inflow
P-type mosfet of first switch group 312, in other words, electric current ip2 is zero, and electric current ip1 is equal to electric current iin, then, electric current
Ip1 has part to flow into this liquid crystal capacitance cs and form charging current i+, and electric current ip1 does not flow into the part of this liquid crystal capacitance cs then
It is defined as electric current in1 and flows through the N-shaped mosfet of this first switch group 312, finally, electric current in1 and charging current i+ are confluxed
For electric current iout and flow to this earth terminal gnd.
With continued reference to Fig. 5 and Fig. 8, in another discharge cycle t_discharge, if the first driving voltage is this maximum
Driving voltage v255, and when the second driving voltage is driving voltage v192, second switch group 313 is not turned on, and it is derived from liquid crystal electricity
The discharge current i- holding cs only flow to earth terminal gnd via first switch group 312, more specifically: electric current iin is by this power end
Vcc flows only through p-type mosfet of this first switch group 312 after flowing into, in other words, electric current ip2 is zero, and electric current ip1 is equal to
Electric current iin, then, discharge current i- and electric current ip1 confluxes for electric current in1 (i.e. electric current iout) by by first switch group 312
N-shaped mosfet flow to earth terminal gnd.
Relatively Fig. 7 and Fig. 8 simultaneously arranges in pairs or groups and understands refering to Fig. 5: in the figure 7, voltage vout excursion on liquid crystal capacitance cs
Larger, therefore this second switch group 313 turns on, charging current i+ that therefore output unit 3 is provided that or discharge current i- are larger, and
Can there is stronger driving force, and in fig. 8, the voltage vout excursion on liquid crystal capacitance cs is less to be driven without with all one's effort
Dynamic, therefore second switch group 313 is not turned on, therefore in addition to reducing the size of charging current i+ and discharge current i-, electric current ip2 and
Electric current in2 is also zero, and decreases power consumption, reaches effect of energy-conservation.
In sum, the judging unit 4 of liquid crystal capacitance drive circuit of the present invention liquid crystal capacitance cs start charge/discharge it
Before, can judge difference size between its current voltage vout and the voltage vout of target in advance and producing ratio compared with consequential signal
Rn, prime control group 311 controls second switch group 313 whether to turn on further according to comparative result signal rn, to adjust to liquid crystal electricity
Hold charging current i+ of cs or the size of discharge current i-, so that when the voltage vout excursion on liquid crystal capacitance cs is larger,
Output unit 3 is provided that enough driving forces, and when the voltage vout excursion on liquid crystal capacitance cs is less, can reduce
The power consumption of output unit 3 and reach energy-conservation, thus, balance can be obtained between driving force and energy-conservation consider, therefore really
The purpose of the present invention can be reached.
Only as described above, only embodiments of the present invention, when the scope of present invention enforcement being limited with this, all
It is the simple equivalence changes and modification made according to scope of the present invention patent and patent specification content, all still belong to the present invention
In the range of patent covers.
Claims (13)
1. a kind of liquid crystal capacitance drive circuit is it is adaptable to electrically connect the liquid crystal capacitance of LCD screen, this liquid crystal capacitance drive circuit
Comprise:
Delivery unit, receives the pixel data of multiple numerals and transmits in order；
Converting unit, electrically connects this delivery unit to receive each pixel data from this delivery unit, and according to each
Individual pixel data produce one to should pixel data driving voltage；
Output unit, electrically connects this converting unit and this liquid crystal capacitance, and includes an operational amplifier, this operation amplifier utensil
There are a prime control group, a first switch group being electrically connected between this prime control group and this liquid crystal capacitance, and one
It is electrically connected to the second switch group between this prime control group and this liquid crystal capacitance；And
Judging unit, is electrically connected between this delivery unit and this output unit, and two according to this delivery unit successively transmission
Individual pixel data produces a comparative result signal；
When this delivery unit transmits each pixel data to this converting unit, the prime control group of this operational amplifier receives
From this converting unit and to should pixel data this driving voltage, and control first switch group export first electric current to liquid
Brilliant electric capacity, so that liquid crystal capacitance is charged or discharged to driving voltage, prime control group simultaneously controls the according to comparative result signal
Whether two switches set export the second electric current to this liquid crystal capacitance.
2. liquid crystal capacitance drive circuit as claimed in claim 1, wherein, each pixel data is binary data, judges
Unit includes electrically connecting the bin of delivery unit, and the comparator of electrical connection delivery unit and bin, and bin receives simultaneously
The place value judging position in the pixel data first transmitting in two pixel datas that storage delivery unit successively transmits, comparator connects
Receive delivery unit successively in two pixel datas of transmission after transmission pixel data, and in the pixel data of transmission after judging
Judge whether this place value that the place value of position is stored with this bin is identical, and produce this comparative result signal.
3. liquid crystal capacitance drive circuit as claimed in claim 2, wherein, this bin is a latch.
4. liquid crystal capacitance drive circuit as claimed in claim 2, wherein, this comparator is an XOR gate.
5. liquid crystal capacitance drive circuit as claimed in claim 2, also electrically connects a control unit；Wherein, judging unit is also
Including electrical connection comparator, a control unit, and the buffer of output unit, buffer inputs are derived from this of comparator and compare
Consequential signal, and it is derived from the drive signal of this control unit by the prime of comparative result signal output to output unit according to one
Control group.
6. liquid crystal capacitance drive circuit as claimed in claim 5, wherein, this buffer is one and door.
7. the liquid crystal capacitance drive circuit as described in claim 2 to 6 any of which item, wherein, the sentencing of each pixel data
Disconnected position is the highest significant position of this pixel data.
8. a kind of liquid crystal capacitance driving method, is executed by a liquid crystal capacitance drive circuit, and this liquid crystal capacitance drive circuit is electrically connected
Connect the liquid crystal capacitance of LCD screen, and comprise a delivery unit, converting unit, a judging unit, and an output
Unit, this output unit includes an operational amplifier, this operational amplifier have a prime control group, one be electrically connected to
First switch group between this prime control group and this liquid crystal capacitance, and one be electrically connected to this prime control group and this liquid crystal electricity
Second switch group between appearance, this liquid crystal capacitance driving method comprises:
A () delivery unit receives and transmits first pixel data to converting unit；
B () delivery unit receives and transmits second pixel data to converting unit, and the second pixel data is to sort the
After one pixel data；
C () judging unit is according to this first pixel data and this second pixel data producing ratio compared with consequential signal；And
D the prime control group of () operational amplifier receives from this converting unit and is relevant to the driving electricity of the second pixel data
Pressure, and control first switch group to export the first electric current to liquid crystal capacitance, so that this liquid crystal capacitance is charged or discharged to this driving
Voltage, according to comparative result signal, prime control group simultaneously controls whether second switch group exports the second electric current to this liquid crystal capacitance.
9. liquid crystal capacitance driving method as claimed in claim 8, wherein, judging unit has a bin, and the first picture
Prime number evidence and the second pixel data are the numerical datas with multidigit, and liquid crystal capacitance driving method also comprises one in step (a)
And the step (e) between step (b): bin receive and store the first pixel data m position place value.
10. liquid crystal capacitance driving method as claimed in claim 9, wherein, judging unit also has a comparator, in step
C (), comparator receives the place value from bin, and the second pixel data from delivery unit, and judges from storage
Whether the place value of device is identical with the place value of the m position of the second pixel data and produces this comparative result signal.
11. liquid crystal capacitance driving methods as claimed in claim 10, wherein, the first pixel data and the second pixel data are
The binary data of eight, and the m position of the m position of the first pixel data and the second pixel data is respectively the first pixel data
And second pixel data highest significant position.
12. liquid crystal capacitance driving methods as claimed in claim 10, wherein, liquid crystal capacitance drive circuit also electrically connects a control
Unit processed, judging unit also has a buffer, and in step (c), buffer inputs are derived from the comparative result letter of this comparator
Number, and according to a drive signal being derived from this control unit, the prime of comparative result signal output to this output unit is controlled
Group.
The 13. liquid crystal capacitance driving methods as described in claim 8 to 12 any of which item, in step (d), converting unit is by
Two pixel datas are converted to the driving voltage of corresponding second pixel data and are supplied to the prime control group of operational amplifier.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101320178A (en) * | 2007-06-08 | 2008-12-10 | 奇美电子股份有限公司 | LCD device, liquid crystal display panel and its driving method |
| CN102201216A (en) * | 2007-06-08 | 2011-09-28 | 奇美电子股份有限公司 | Liquid crystal display, liquid crystal display panel and driving method thereof |
| CN102243851A (en) * | 2011-05-17 | 2011-11-16 | 友达光电股份有限公司 | Liquid crystal display device with common voltage compensation mechanism and common voltage compensation method |
| KR20130108872A (en) * | 2012-03-26 | 2013-10-07 | 엘지디스플레이 주식회사 | Liquid crystal display device |
| KR20150002390A (en) * | 2013-06-29 | 2015-01-07 | 엘지디스플레이 주식회사 | Data driving apparatus for liquid crystal display device |
-
2016
- 2016-09-08 CN CN201610811636.3A patent/CN106373536B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101320178A (en) * | 2007-06-08 | 2008-12-10 | 奇美电子股份有限公司 | LCD device, liquid crystal display panel and its driving method |
| CN102201216A (en) * | 2007-06-08 | 2011-09-28 | 奇美电子股份有限公司 | Liquid crystal display, liquid crystal display panel and driving method thereof |
| CN102243851A (en) * | 2011-05-17 | 2011-11-16 | 友达光电股份有限公司 | Liquid crystal display device with common voltage compensation mechanism and common voltage compensation method |
| KR20130108872A (en) * | 2012-03-26 | 2013-10-07 | 엘지디스플레이 주식회사 | Liquid crystal display device |
| KR20150002390A (en) * | 2013-06-29 | 2015-01-07 | 엘지디스플레이 주식회사 | Data driving apparatus for liquid crystal display device |
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