CN1116664C - Bias producing method and device for LCD driver - Google Patents
Bias producing method and device for LCD driver Download PDFInfo
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- CN1116664C CN1116664C CN 96104215 CN96104215A CN1116664C CN 1116664 C CN1116664 C CN 1116664C CN 96104215 CN96104215 CN 96104215 CN 96104215 A CN96104215 A CN 96104215A CN 1116664 C CN1116664 C CN 1116664C
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Abstract
The present invention relates to a generating method of the bias electric potential of a driver of a liquid crystal display. The bias electric potential is generated by an electric potential divider, and a synchronous switching signal is output by a signal generating device when the waveform of the liquid crystal display is switched; according to the switching signal generated by the signal generating device, a switching device which is connected with the electric potential divider is switched on for reducing the divider resistance of the electric potential divider when the waveform of the liquid crystal display is switched; the switching device is not switched on usually to maintain the divider resistance of the electric potential divider in a certain value. A device for generating the bias electric potential of the driver of the liquid crystal display is composed of the electric potential divider, the signal generating device for generating the switching signal and the switching device.
Description
The present invention relates to a kind of bias producing method and device thereof of LCD driver, be particularly related to and a kind ofly can reduce leakage current at ordinary times, and the bias producing method and the device thereof of the LCD driver of required immediate current can dynamically supply the liquid crystal display waveform and switch the time.
General LCD (Liquid Crystal Display; Be called for short LCD) purposes extremely wide, the device of display frame such as electronic watch, palm type electronic game machine for example, known internal structure, then major part is as shown in Figure 1.
The structure of this Fig. 1 comprises a LCD driver 10, this LCD utilizes a potential divider 20 with resistance R to come an external power source Vcc dividing potential drop, and drive LCD driver 10 according to bias (bias levels) Va～Ve of gained, so, can make these LCD driver 10 output corresponding liquid crystal display waveforms (LCD wavefo-rm) on a display panels 30 (LCD panel), it comprises shared signal (commonsignals) COM1～COM8 and segment signal (segment signals) SEG1～SEG40.
Because the bias Va～Ve of LCD driver is a plurality of resistance R dividing potential drops generations by potential divider 20, thereby constitute a DC circuit (DC path), and in order to reduce the DC current Id through this circuit, adopt high resistance measurement mostly, for example 100K Ω or 200K Ω, but, thus, when the liquid crystal display waveform switches, but dynamically the electric current supply seems not enough, therefore, the known practice is externally to set up capacitor C, go into weld pad (I/O Pad) 5 by the output of chip 1 and be connected with this potential divider 20, with the pressure stabilization function of capacitor C, the immediate current I of institute's palpus when providing the liquid crystal display waveform to switch
t
The known structure chip of above-mentioned generation bias such as the I.C. product line of OKI semiconductor company, it is numbered MSM5238GS, MSM5259GS or MSM5278GS etc.This structure has following defective but inevitably:
1, for LCD palm type electronic game machine at a low price, adding electric capacity can increase material cost, and is to cooperate the required output of this electric capacity to go into weld pad assembly cost is risen.
2, must set up output and go into weld pad because of adding electric capacity, and this weld pad number can't reduce, and causes the space of integrated-semiconductor device chip to make it with advanced person's manufacturing process to reduce.
Have two as for the known method that addresses the aforementioned drawbacks at present:
1, saves electric capacity, reduce the resistance value of this minute pressure drag R, so that bigger electric current to be provided, but so can produce a big leakage current, for example, the resistance R of former potential divider 20 is 100K Ω, power Vcc is 5V, then the former DC current through this DC circuit is Id=5V/ (100K Ω * 5)=10 μ A, if resistance R is reduced to 15K Ω, then former DC circuit will form big electric current I d=5V/ (15K Ω * 5)=67 a μ A, because therefore such leakage current and noting be used in the operation of chip causes significant wastage.
2, form electric capacity at chip internal, but, its difficulty is to increase chip area, and still differs several orders of magnitude (order) with required electric capacity.
In view of the above problems, an object of the present invention is a kind of bias generation device of LCD driver, it must not add electric capacity required immediate current when can dynamic provisioning liquid crystal display drive waveforms switching.
Another object of the present invention is a kind of bias producing method of LCD driver, it is reducing leakage current by the resistance of high value at ordinary times, and can be dynamically when the liquid crystal display drive waveforms be switched, resistance by a low resistance in parallel, enough immediate currents are provided, reduce the spiking (spike) of this waveform.
One of feature of the present invention is that the bias generation device of this LCD driver has a low resistance in parallel with the divider resistance of potential divider, in order to bigger electric current dynamically to be provided.
Whether two of feature of the present invention is to decide described low resistance in parallel with divider resistance with a switching device shifter.
Three of feature of the present invention is, utilize a signal generation device to produce the liquid crystal display switching signal, so that when the liquid crystal display waveform switches, the switch of control switch device dynamically, and make low resistance in parallel according to this, and then produce bigger immediate current with divider resistance.
For achieving the above object, the bias generation device of a kind of LCD driver of the present invention comprises:
One potential divider is in series by a plurality of divider resistances, and forms one with this divider resistance and have the DC circuit of a plurality of nodes, and according to the bias of this node, makes above-mentioned LCD driver export a plurality of liquid crystal display waveforms;
One signal generation device, the synchronous switching signal when switching in order to output and above-mentioned liquid crystal display waveform; And
One switching device shifter, have a plurality of and above-mentioned divider resistance switch unit in parallel, this switch unit can be according to the switching signal value of above-mentioned signal generation device, when this liquid crystal display waveform switches, form second resistance in parallel, and open circuit in all the other times formation with this divider resistance.
Wherein, above-mentioned switching device shifter also can be a plurality of switch units with internal resistance, it is in parallel with above-mentioned each divider resistance, this switch can be according to the switching signal value of described signal generation device, conducting when this liquid crystal display waveform switches, make this internal resistance in parallel, and in all the other not conductings of time, formation is opened circuit with divider resistance.
The bias generation device of another kind of LCD driver of the present invention comprises:
One potential divider, be in series by the polycomponent piezoresistance, and form one with this divider resistance and have the DC circuit of a plurality of nodes, and each component piezoresistance all contains second resistance that one first resistance and one is connected with it, can make above-mentioned LCD driver export a plurality of liquid crystal display waveforms in order to bias according to this node;
One signal generation device, the synchronous switching signal when switching in order to output and above-mentioned liquid crystal display waveform; And
One switching device shifter has a plurality of and above-mentioned second resistance switch unit in parallel, and this switch unit can be according to the switching signal value of above-mentioned signal generation device, conducting when this liquid crystal display waveform switches, form short circuit, and in all the other not conductings of time, formation is opened circuit.
In addition, the bias producing method of first kind of LCD driver of the present invention comprises the following steps:
(a) utilize a potential divider that is in series by a plurality of divider resistances, form one with this divider resistance and have the DC circuit of a plurality of nodes;
(b) according to the bias of this node, so that above-mentioned LCD driver is exported a plurality of liquid crystal display waveforms;
(c) utilize a signal generation device, the synchronous switching signal when switching with output and above-mentioned liquid crystal display waveform; And
(d) utilize a switching device shifter with a plurality of switch units, make this switch unit in parallel with above-mentioned divider resistance, and make the switching signal value of this switch unit according to above-mentioned signal generation device, when this liquid crystal display waveform switches, form second resistance in parallel, and open circuit in all the other times formation with this divider resistance.
The bias producing method of second kind of LCD driver of the present invention comprises the following steps:
(a) utilize a potential divider that is in series by a plurality of divider resistances, form one with this divider resistance and have the DC circuit of a plurality of nodes;
(b), make above-mentioned LCD driver export a plurality of liquid crystal display waveforms according to the bias of this node;
(c) utilize a signal generation device, the synchronous switching signal when output is switched with above-mentioned liquid crystal display waveform; And
(d) utilize one to have a plurality of switching device shifters that contain the switch unit of internal resistance, make this switch unit in parallel with above-mentioned divider resistance, and make the switching signal value of this switch unit according to above-mentioned signal generation device, conducting when this liquid crystal display waveform switches, make this internal resistance in parallel with divider resistance, and in all the other not conductings of time, formation is opened circuit.
The third liquid crystal display of the present invention drives the current potential production method, and it comprises the following steps:
(a) utilize a potential divider that is in series by a plurality of divider resistances, form one with this divider resistance and have the DC circuit of a plurality of nodes, and each component piezoresistance all contains second resistance of one first resistance and a series connection with it;
(b) bias according to this node produces liquid crystal display driving current potential, so that above-mentioned LCD driver is exported a plurality of liquid crystal display waveforms;
(c) utilize a signal generation device, the synchronous switching signal when switching with output and described liquid crystal display waveform; And
(d) utilize a switching device shifter with a plurality of switch units, make this switch unit in parallel with described second resistance, and make the switching signal value of this switch unit according to described signal generation device, conducting when this liquid crystal display waveform switches, form short circuit, and in all the other not conductings of time, formation is opened circuit.
For above-mentioned and other purposes of the present invention, feature and advantage can be become apparent, a preferred embodiment cited below particularly, and in conjunction with the accompanying drawings, elaborate.
Fig. 1 is the structural drawing that shows the bias generation device of known LCD driver;
Fig. 2 is the calcspar that shows the bias generation device of LCD driver of the present invention;
Fig. 3 be show LCD driver of the present invention the bias generation device first
Embodiment;
Fig. 4 A be show LCD driver of the present invention the bias generation device second
Embodiment;
Fig. 4 B is among the displayed map 4A, an embodiment of part switching device shifter 53;
Fig. 4 C is the equivalent circuit diagram of displayed map 4B;
Fig. 5 be show LCD driver of the present invention the bias generation device the 3rd
Embodiment;
Fig. 6 is the pulse waveform sequential chart that shows that the liquid crystal display waveform switches;
Fig. 7 shows typical liquid crystal display waveform.
With reference to Fig. 2, Fig. 2 is the calcspar that shows the bias generation device of LCD driver of the present invention, the bias generation device 50 of this LCD driver is connected with a LCD driver 40, and 40 of this LCD driver receive a clock pulse signal CLK from signal generation device 55.
This liquid crystal display drives potential generating device 50 and comprises a potential divider 51, it is with a voltage source V dividing potential drop, and produce a bias to drive this LCD driver 40, and making it export the liquid crystal display waveform to a display panels 30 according to the clock pulse signal CLK that receives, it comprises a plurality of shared signal COM (Common Sigals) and segment signal SEG (Segment Signals).
Wherein, signal generation device 55 can be in order to foundation system clock sysck (systemclock), output and synchronous switching signal LCDPULSE and the time clock signal CLK of above-mentioned liquid crystal display waveform (COM and SEG) when switching.
One switching device shifter 53, it is connected with above-mentioned potential divider 51, switching signal value in order to according to described signal generation device in this liquid crystal display waveform (COM and SEG) conducting when switching, reduces the resistance of described potential divider 51, so that enough immediate currents to be provided, and reduce the spiking of liquid crystal display waveform effectively, but at ordinary times, 53 not conductings of this switching device shifter, with the resistance of keeping this potential divider is certain value, can reduce leakage current by this.
The following example is prerequisite with the said structure promptly, and is illustrated according to this.
First embodiment
With reference to Fig. 3, Fig. 3 is an embodiment who shows the bias generation device 50 of LCD driver of the present invention, and this bias generation device 50 is to be connected with a LCD driver 40, and it comprises a potential divider 51, one switching device shifter 53, and a signal generation device 55.
Ve=1 during Ve=0 STANDBY=0 during STANDBY=1
Va＝4/5Vcc Va＝Vcc
Vb＝3/5Vcc Vb＝Vcc
Vc＝2/5Vcc Vc＝Vcc
Vd＝1/5Vcc Vd＝Vcc
Wherein, bias Va～the Ve of this LCD driver can be in order to drive LCD driver 40 output corresponding liquid crystal display waveforms, and can switch to Vcc with standby signal STANDBY, it comprises shared signal COM1～COM8, and segment signal SEG1～SEG40.
One switching device shifter 53 is to be made of a plurality of switch unit Sa～Se, and each switch unit includes the low resistance of a switch SW and a series connection, and for example 10K Ω is connected in parallel in order to each divider resistance with above-mentioned potential divider 51.
One signal generation device 55, be to be used for producing a liquid crystal display switching signal LCDPULSE, with the switch conduction that determines this switching device shifter 53 whether, for example, this switching signal LCDPUSLE can be in order to when above-mentioned liquid crystal display waveform switches, the switch SW of each switch unit Sa～Se in the synchro control switching device shifter 53, make its conducting as output logic 1 current potential, at this moment, the 100K Ω of former divider resistance will be in parallel with low resistance 10K Ω, and produce the parallel resistance of lower 9.09K Ω, thus, can make bias Va～Ve of node a～e that enough immediate current I are arranged
t, to drive the switching of liquid crystal display waveform.
Simultaneously, during not carrying out that the liquid crystal display waveform switches, this signal generation device 55 promptly produces the liquid crystal display switching signal LCDPULSE of a logical zero current potential, make not conducting of the low-resistance switch SW of described series connection (open circuit), so will keep the high value that former divider resistance is 100K Ω, if bias Ve is a logical zero current potential ground connection, and external power source Vcc is 5V, then DC current Id will have only 5V/500K Ω=10 μ A.
In addition, in the bias generation device of LCD driver of the present invention, at the node e place of bias Ve, be to control with a standby signal STANDBY, that is, when LCD enters standby mode (standby mode), can export the standby signal STANDBY of a logical zero current potential, by reverse swing door circuit 52, the bias of node f (equaling Ve) is by lift-rising to a current potential, as Vcc, so can make the DC current Id that produces leakage current be reduced to 0.
Second embodiment
With reference to Fig. 4 A～4C, they are another embodiment that show bias generation device 50 of the present invention, and wherein, with aforementioned element with same numeral, the element of expression identical function no longer repeats at this.
The maximum of present embodiment is characterised in that, switching device shifter 53 is to have an internal resistance R by a plurality of
1Switch SW constitute, each divider resistance of itself and above-mentioned potential divider 51 is connected in parallel, and when this switch SW conducting, can produce a low internal resistance R
1, it is in parallel with divider resistance, and when not conducting of switch SW, does not then have any electric current and flow through.
Shown in Fig. 4 B, above-mentioned have an internal resistance R
1The preferred embodiment of switch SW as being long-channel transmission gate circuit (long channel transmission gate); Fig. 4 B is the part-structure of displayed map 4A, and it shows the situation that a transmission gate circuit 54 is in parallel with the divider resistance of node a, and Fig. 4 C then is its schematic equivalent circuit.
This transmission gate circuit 54 is a CMOS structure, comprise a NMOS semiconductor Q1 and a PMOS semiconductor Q2, it has grid G 1, G2 respectively, and the switching signal LCDPULSE that produces by above-mentioned signal generation device 55, then with signal LCDPULSE jointly as complementary grid voltage, in addition, be source S at the power Vcc end, be drain D at node a place.
When the liquid crystal display waveform is desired to switch, signal generation device 55 can be exported the switching signal LCDPULSE of a logical one current potential, so NMOS semiconductor Q1 and all conductings of PMOS semiconductor Q2, this transmission gate circuit 54 is just like the low resistance R of a connection power Vcc and node a
1, it is in parallel with divider resistance 100K Ω, produces less parallel resistance.
Otherwise, signal generation device 55 can be exported the switching signal LCDPUL-SE of a logical zero current potential, make, NMOS semiconductor Q1 and PMOS semiconductor Q2 can't conductings, formation is opened circuit, so, potential divider 51 still is one to be in series by a plurality of divider resistance 100K Ω, and reduces DC current with high value.
The 3rd embodiment
With reference to Fig. 5, it is another embodiment that shows bias generation device 50 of the present invention, and wherein, with above-mentioned element with same numeral, the element of expression identical function no longer repeats at this.
The maximum of present embodiment is characterised in that, be used as each divider resistance of node a～e in the potential divider 51, be to be in series by one group of high resistance and low resistance respectively, for example 90K Ω and 10K Ω, switching device shifter 53 then is made of a plurality of switch SW, and it is connected in parallel with the high resistance (as 90K Ω) of described divider resistance respectively.
So, when described liquid crystal display waveform switches, each switch SW in the synchronous control switch device 53 of meeting, as liquid crystal display switching signal LCDPULSE by signal generation device 55 output logics 1 current potential, make its conducting and form short circuit by this, therefore the divider resistance of this potential divider 51 is to be in series by lower resistance 10K Ω, and more immediate current I dynamically is provided
t, to drive the switching of liquid crystal display waveform.
Otherwise, then by the liquid crystal display switching signal LCDPULSE of signal generation device 55 output logics 0 current potential, making it close formation opens circuit, so each divider resistance of this potential divider 51, be to be the high resistance of a 100K Ω with connecting than low resistance 10K Ω by high electrical resistance 90K Ω, so, will the DC current Id that form leakage current be reduced.
Principle of work for the explanation previous embodiment, see also the 6th figure, this figure shows the pulse waveform sequential chart that the liquid crystal display waveform switches, wherein, CLK is the clock pulse signal (LCD Clock) that signal generation device 5 produces according to system clock sysck, with so that LCD driver 40 according to the bias output waveform, as shown in the figure, when desire drives shared signal COM1, when COM2 carries out the waveform switching, the synchronous generation switching signal LCD-PULSE of signal generation device 55 meetings, make that the high resistance measurement of former potential divider 51 is in parallel with the low resistance that the switch SW conducting produces with switching device shifter 53, and then can obtain bigger immediate current.
Wherein, above-mentioned potential divider 51 can constitute a dynamic divider resistance DYNR with switching device shifter 53 in parallel, during the switching signal LCDPULSE that signal generation device 55 produces, the switch conduction of switching device shifter 53, make the high resistance of former potential divider 51 in parallel with the low resistance of switching device shifter 53 and a resistance R
a, for example the divider resistance of node a is (100 * 10)/(100+10)=9.09K Ω at this moment among first embodiment.
Otherwise, the not conducting of switch of switching device shifter 53, at this moment, the divider resistance of potential divider 51 still is maintained high value R
b, 100K Ω for example, it is used for keeping low leakage current.
Can get the bias producing method of three kinds of LCD driver according to the foregoing description, they can be used for same LCD driver 40.
The bias producing method of first kind of LCD driver, in conjunction with the Fig. 3 and first embodiment, it comprises the following steps:
(a) utilize a potential divider 51 that is in series by a plurality of divider resistances (100K Ω), and it is connected with a voltage source Vcc, have a plurality of nodes (DC circuit of a～e) to form one with this divider resistance.
(b) (Va～Ve) makes a plurality of liquid crystal display waveforms of described LCD driver 40 outputs (COM1～COM8, SEG1～SEG40) according to the bias of this node.
(c) utilize a signal generation device 55, the synchronizing signal LCDPULSE when output is switched with described liquid crystal display waveform.
(d) utilize one to have a plurality of switch units (switching device shifter 53 of Sa～Se), make this switch unit in parallel with described divider resistance, and make the switching signal value of this switch unit according to described signal generation device, when this liquid crystal display waveform switches, form second resistance (10K Ω) in parallel, and open circuit in all the other times formation with this divider resistance.
The bias producing method of second kind of LCD driver, in conjunction with Fig. 4 A～4C and second embodiment, it comprises the following steps:
(a) utilize a potential divider 51 that is in series by a plurality of divider resistances (100K Ω), and it is connected with a voltage source Vcc, have a plurality of nodes (DC circuit of a～e) to form one with this divider resistance.
(b) (Va～Ve) makes above-mentioned LCD driver export a plurality of liquid crystal display waveforms (COM1～COM8, SEG1～SEG40) according to the bias of this node.
(c) utilize a signal generation device 55, the synchronous switching signal LCDPULSE when output is switched with described liquid crystal display waveform.
(d) utilize one to have a plurality of internal resistance (R
1) the switching device shifter 53 of switch unit (SW), make this switch unit in parallel, and make the switching signal value of this switch unit according to described signal generation device with described divider resistance, conducting when this liquid crystal display waveform switches makes this internal resistance (R
1) in parallel with divider resistance, in all the other not conductings of time, formation is opened circuit.
The bias producing method of the third LCD driver, in conjunction with Fig. 5 and the 3rd embodiment, it comprises the following steps:
(a) utilize a potential divider that is in series by the polycomponent piezoresistance, and it is connected with a voltage source Vcc, has a plurality of nodes (DC circuit of a～e), and each component piezoresistance all contains second resistance (90K Ω) that one first resistance (10K Ω) and one is connected with it to form one with this divider resistance;
(b) according to the bias of this node (Va～Ve), make a plurality of liquid crystal display waveforms of described LCD driver 40 outputs;
(c) utilize a signal generation device 55, the synchronous switching signal LCDPULSE when output is switched with described liquid crystal display waveform;
(d) utilize a switching device shifter 53 with a plurality of switch units (SW), make this switch unit in parallel with described second resistance (90K Ω), and make this switch unit can be according to the switching signal value of described signal generation device, conducting when this liquid crystal display waveform switches, form short circuit, and in all the other not conductings of time, formation is opened circuit.
Typical liquid crystal display waveform as shown in Figure 7, it is with shared signal COM1, COM2, COM3 and segment signal SEG
xBe example, wherein, LCD driver 40 is driven by the bias Va～Ve of each node.
Show by oscillograph, under different situations, utilize the bias producing method and the device of LCD driver of the present invention, can be when the liquid crystal display waveform switches, one less divider resistance dynamically is provided, reduce the generation of spiking, and at ordinary times, then utilize high resistance measurement to keep low leakage current.
Though the present invention discloses as above with preferred embodiment; right its is not in order to qualification the present invention, any those skilled in the art, without departing from the spirit and scope of the present invention; change and variation when doing some, so protection scope of the present invention should be as the criterion with the content that claims were limited.
Claims (20)
1. the bias generation device of a LCD driver comprises:
One potential divider is in series by a plurality of divider resistances, forms one with this divider resistance and has the DC circuit of a plurality of nodes, and according to the bias of this node, make described LCD driver export a plurality of liquid crystal display waveforms;
One signal generation device, the synchronous switching signal when switching in order to output and described liquid crystal display waveform; And
One switching device shifter, has a plurality of and described divider resistance switch unit in parallel, this switch unit can be according to the switching signal value of described signal generation device, conducting when this liquid crystal display waveform switches, form second resistance in parallel, and open circuit in all the other time not conductings formation with this divider resistance.
2. device as claimed in claim 1, wherein, the resistance of this divider resistance is higher than second resistance.
3. device as claimed in claim 1, wherein, this liquid crystal display waveform comprises liquid crystal display shared signal and liquid crystal display segment signal.
4. device as claimed in claim 1, wherein, this DC circuit is initiating terminal with the voltage source, and, connect a standby signal at the relative end of this initiating terminal, with so that described DC circuit when receiving this standby signal endways, lift-rising is to this voltage source, so that this DC circuit leakage current.
5. device as claimed in claim 1, wherein, this switch unit comprises second resistance of a switch and a series connection with it.
6. device as claimed in claim 5, wherein, this switch is that conducting when this liquid crystal display waveform switches makes this second resistance in parallel with described divider resistance according to described switching signal value, and in all the other not conductings of time, this switch unit is formed open circuit.
7. device as claimed in claim 6 wherein, when this switching signal value is the logical one current potential, will make the switch conduction of this switch unit, and it then makes the not conducting of switch of this switch unit when being the logical zero current potential.
8. device as claimed in claim 1, wherein, this switch unit is the switch that contains internal resistance.
9. device as claimed in claim 8, wherein, this switch with internal resistance is a transmission gate circuit.
10. the bias generation device of a LCD driver comprises:
One potential divider, be in series by the polycomponent piezoresistance, and form one with this divider resistance and have the DC circuit of a plurality of nodes, and each component piezoresistance all contains second resistance of one first resistance and a series connection with it, can make described LCD driver export a plurality of liquid crystal display waveforms in order to bias according to this node;
One signal generation device, the synchronous switching signal when switching in order to output and described liquid crystal display waveform; And
One switching device shifter has a plurality of and described second resistance switch in parallel, and this switch can be according to the switching signal value of described switching signal generation device, and conducting when this liquid crystal display waveform switches form short circuit, and in all the other not conductings of time, formation is opened circuit.
11. device as claimed in claim 10, wherein, the resistance of this first resistance is less than second resistance.
12. device as claimed in claim 10, wherein, this liquid crystal display waveform comprises liquid crystal display shared signal and liquid crystal display segment signal.
13. device as claimed in claim 10, wherein, this DC circuit is initiating terminal with the voltage source, and at the relative end of this initiating terminal, connect a standby signal, with so that described DC circuit end when receiving this standby signal, lift-rising is to this voltage source, so that this DC circuit leakage current.
14. device as claimed in claim 10 wherein, when this switching signal value is the logical one current potential, will make the switch conduction of this switch unit, and it then makes the not conducting of switch of this switch unit when being the logical zero current potential.
15. the bias producing method of a LCD driver, it comprises the following steps:
(a) utilize a potential divider that is in series by a plurality of divider resistances, have the DC circuit of a plurality of nodes to form one with this divider resistance;
(b), make described LCD driver export a plurality of liquid crystal display waveforms according to the bias of this node;
Synchronous switching signal when (c) use one is switched with described liquid crystal display waveform; And
(d) utilize one to have a plurality of switching device shifters that contain the switch unit of internal resistance, make this switch unit in parallel with described divider resistance, and make this switch unit according to described switching signal value, conducting when this liquid crystal display waveform switches, make this internal resistance in parallel with divider resistance, and in all the other not conductings of time, formation is opened circuit.
16. method as claimed in claim 15, wherein, the resistance of the described divider resistance of step (d) is higher than the internal resistance of switch unit.
17. method as claimed in claim 15, wherein, be when utilizing this switching signal value in the step (d) for the logical one current potential, make this switch unit conducting, and it is in parallel with this divider resistance by this internal resistance, and when utilizing this switching signal value, making this not conducting of switch unit for the logical zero current potential, formation is opened circuit.
18. the bias producing method of a LCD driver, it comprises the following steps:
(a) utilize a potential divider that is in series by the polycomponent piezoresistance, have the DC circuit of a plurality of nodes to form one with this divider resistance; And each component piezoresistance all contains second resistance of one first resistance and a series connection with it;
(b), make described LCD driver export a plurality of liquid crystal display waveforms according to the bias of this node;
Synchronous switching signal when (c) use one is switched with described liquid crystal display waveform; And
(d) utilize a switching device shifter with a plurality of switch units, make this switch unit in parallel with described second resistance, and make this switch unit can be according to the switching signal value of described signal generation device, when this liquid crystal display waveform switches, form short circuit, and in all the other not conductings of time, formation is opened circuit.
19. method as claimed in claim 18, wherein, the resistance of described first resistance of step (d) is less than second resistance.
20. method as claimed in claim 18, wherein, step (d) is when utilizing this switching signal value for the logical one current potential, make this switch unit conducting, form a short circuit, and when utilizing this switching signal value for the logical zero current potential, make this not conducting of switch unit, formation is opened circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96104215 CN1116664C (en) | 1996-03-04 | 1996-03-04 | Bias producing method and device for LCD driver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96104215 CN1116664C (en) | 1996-03-04 | 1996-03-04 | Bias producing method and device for LCD driver |
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| CN1159043A CN1159043A (en) | 1997-09-10 |
| CN1116664C true CN1116664C (en) | 2003-07-30 |
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| CN 96104215 Expired - Lifetime CN1116664C (en) | 1996-03-04 | 1996-03-04 | Bias producing method and device for LCD driver |
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| KR100878244B1 (en) | 2002-09-12 | 2009-01-13 | 삼성전자주식회사 | circuit for generating driving voltages and liquid crystal device using the same |
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