CN109166540B - Alternating current public voltage generating circuit and liquid crystal display device - Google Patents
Alternating current public voltage generating circuit and liquid crystal display device Download PDFInfo
- Publication number
- CN109166540B CN109166540B CN201811058925.6A CN201811058925A CN109166540B CN 109166540 B CN109166540 B CN 109166540B CN 201811058925 A CN201811058925 A CN 201811058925A CN 109166540 B CN109166540 B CN 109166540B
- Authority
- CN
- China
- Prior art keywords
- voltage
- resistor
- operational amplifier
- module
- terminal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 15
- 230000003321 amplification Effects 0.000 claims description 28
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 28
- 238000010586 diagram Methods 0.000 description 13
- 238000000034 method Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Images
Classifications
-
- 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
- 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
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2230/00—Details of flat display driving waveforms
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Control Of Voltage And Current In General (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
The invention provides an alternating current public voltage generating circuit which comprises a main controller, a voltage supply module, an amplifying module and an adding module. The main controller outputs a corresponding voltage supply control signal, and outputs an initial AC voltage having the same period and waveform type as the AC common voltage through an internal digital-to-analog converter. The voltage supply module receives a voltage supply control signal to output a first voltage and amplify the control voltage. The amplifying module receives the initial alternating voltage and the amplifying control voltage and outputs a second voltage. The addition module is used for adding the first voltage and the second voltage to obtain an alternating current public voltage. The invention also provides a liquid crystal display device. The alternating current public voltage generating circuit and the liquid crystal display device not only can obtain the bias voltage by only using the main controller without replacing the resistor when the waveform of the alternating current public voltage changes, but also simplify the circuit, reduce the cost and save the layout occupation space on the printed circuit board.
Description
Technical Field
The invention relates to the field of liquid crystal display, in particular to an alternating current public voltage generating circuit and a liquid crystal display device.
Background
In an existing Liquid Crystal Display (LCD), a corresponding pixel voltage is applied to an internal pixel electrode, a corresponding common voltage is applied to an internal common electrode, and then a corresponding electric field is generated to control Liquid Crystal molecules to deflect to adjust light transmittance of a Liquid Crystal layer, thereby implementing image Display. The common voltage may be a dc common voltage or an ac common voltage.
Fig. 1 is a circuit connection diagram of an ac common voltage generating circuit of the related art. As shown in fig. 1, the master controller controls the DAC (digital to analog converter) to generate a waveform DAC-OUT (see fig. 2a) having a period, a shape, and a peak-to-valley difference consistent with the desired AC common voltage AC-VCOM according to the waveform of the AC common voltage AC-VCOM, wherein the valley voltage value of the waveform DAC-OUT is 0V. And a stable negative voltage is generated by a voltage type charge pump phase discriminator, and the required negative bias voltage CVREF is obtained by dividing the voltage by resistors R1 and R2, wherein the absolute value of the required negative bias voltage CVREF is half of the difference value between the wave crest and the wave trough of the required alternating current common voltage AC-VCOM waveform. Finally, the waveform DAC-OUT, the negative bias voltage CVREF, and the DC common voltage DC-VCOM are added by an adder to obtain the AC common voltage AC-VCOM (see fig. 2c), wherein the added waveform of the waveform DAC-OUT and the negative bias voltage CVREF is shown in fig. 2 b.
As can be seen from the figure, the voltage dividing resistors R1 and R2 of the AC common voltage generating circuit of the prior art are used to obtain the negative bias voltage, and when the AC common voltage AC-VCOM has different amplitude, the voltage dividing resistors R1 and R2 need to be calculated and replaced to obtain the required negative bias voltage. And the structure of the generating circuit is more complicated, and the generating circuit comprises more devices, so that the cost is higher, and a larger area on a Printed Circuit Board (PCB) is occupied.
Disclosure of Invention
In view of the above, an object of the present invention is to provide an ac common voltage generating circuit, which can solve the problems of complicated structure, high cost, and the like of the conventional ac common voltage generating circuit.
The invention particularly provides an alternating current public voltage generating circuit which is used for generating alternating current public voltage and comprises a main controller, a voltage supply module, an amplifying module and an adding module. The main controller outputs a corresponding voltage supply control signal according to the peak-to-valley voltage difference of the alternating current public voltage and a received voltage value of the direct current public voltage, and outputs an initial alternating current voltage with the same period and waveform type as the alternating current public voltage through an internal digital-to-analog converter. The supply to press the module including supplying to press control input, negative pressure output, control output, supply to press the module supply press control input with main control unit links to each other and receives supply to press control signal supply the negative pressure output of pressing the module exports corresponding DC voltage, marks as first voltage supply the corresponding control voltage that enlargies of control output of the module that supplies to press. The amplifying module comprises an initial voltage input end, an amplifying control input end and a waveform output end, the initial voltage input end of the amplifying module is connected with the digital-to-analog converter inside the main controller and receives the initial alternating voltage, the amplifying control input end of the amplifying module receives the amplifying control voltage, and the waveform output end of the amplifying module outputs the amplified initial alternating voltage which is recorded as a second voltage. The addition module is used for adding the first voltage and the second voltage to obtain the alternating current public voltage.
Preferably, the amplifying module includes a first operational amplifier, a switching element, a first resistor, and a second resistor. The non-inverting input end of the first operational amplifier is the initial voltage input end of the amplifying module; the switch element comprises a control end, a first path end and a second path end, and the control end of the switch element is connected with the output end of the first operational amplifier; the first end of the first resistor is a waveform output end of the amplifying module and is also connected with a first pass end of the switch element, and the second end of the first resistor is an amplifying control input end of the amplifying module; the first end of the second resistor is connected with the inverting input end of the first operational amplifier and also connected with the second path end of the switch element, and the second end of the second resistor is grounded.
Preferably, the switching element is an NPN type three-stage transistor.
Preferably, a second operational amplifier is arranged between the negative pressure output end of the pressure supply module and the addition module; the non-inverting input end of the second operational amplifier is connected with the negative-pressure output end of the voltage supply module, and the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier.
Preferably, a third operational amplifier is arranged between the waveform output end of the amplifying module and the adding module; the non-inverting input end of the third operational amplifier is connected with the waveform output end of the amplifying module, and the inverting input end of the third operational amplifier is connected with the output end of the third operational amplifier.
Preferably, the addition module comprises a fourth operational amplifier, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; a first end of the third resistor receives the first voltage; a first end of the fourth resistor receives the second voltage; a non-inverting input end of the fourth operational amplifier is respectively connected with a second end of the third resistor and a second end of the fourth resistor, and an output end of the fourth operational amplifier outputs the alternating current common voltage; a first end of the fifth resistor is connected with an inverting input end of the fourth operational amplifier, and a second end of the fifth resistor is grounded; and the first end of the sixth resistor is connected with the first end of the fifth resistor, and the second end of the sixth resistor is connected with the output end of the fourth operational amplifier.
Preferably, the waveform type of the ac common voltage is one of a triangular wave, a sine wave, and a rectangular wave.
Preferably, the initial ac voltage has a valley voltage value of 0V and a peak voltage value of 3.3V.
Preferably, the absolute value of the first voltage is a sum of a half of a peak-to-valley voltage difference of the ac common voltage and a voltage value of the dc common voltage.
The invention also provides a liquid crystal display device which comprises the alternating current public voltage generating circuit.
The alternating current public voltage generating circuit and the liquid crystal display device not only can obtain the bias voltage by only using the main controller without replacing the resistor when the waveform of the alternating current public voltage changes, but also simplify the circuit, reduce the cost and save the layout occupation space on the printed circuit board.
In order to make the aforementioned and other objects, features and advantages of the invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
Fig. 1 is a circuit connection diagram of an ac common voltage generating circuit of the related art.
Fig. 2a, 2b and 2c are voltage waveform diagrams of fig. 1.
Fig. 3 is a circuit diagram of an AC-VCOM generating circuit according to a first embodiment of the invention.
FIG. 4 is a circuit diagram of an AC common voltage AC-VCOM generating circuit according to a second embodiment of the present invention;
fig. 5a, 5b, 5c and 5d are voltage waveform diagrams of a second embodiment of the present invention.
Detailed Description
To further illustrate the technical means and effects of the present invention for achieving the intended purpose, the following detailed description is given to specific embodiments, methods, steps, structures, features and effects of the ac common voltage generating circuit and the liquid crystal display device according to the present invention with reference to the accompanying drawings and preferred embodiments.
The foregoing and other aspects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments, as illustrated in the accompanying drawings. While the invention has been described in connection with specific embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.
First embodiment
Fig. 3 is a circuit diagram of an AC-VCOM generating circuit according to a first embodiment of the invention. As shown in fig. 3, the AC common voltage AC-VCOM generating circuit according to the first embodiment of the present invention for generating a predetermined AC common voltage AC-VCOM includes a main controller 10, a voltage supply module 20, an amplifying module 30 and an adding module 40.
The main controller 10 outputs a corresponding voltage supply control signal according to a peak-to-valley voltage difference of the AC common voltage AC-VCOM and a voltage value of a received DC common voltage DC-VCOM, and outputs an initial AC voltage MDAC-OUT having the same period and waveform type as the AC common voltage AC-VCOM through an internal digital-to-analog converter DAC. The voltage supply module 20 includes a voltage supply control input terminal 21, a negative voltage output terminal 22, and an amplification control output terminal 23, the voltage supply control input terminal 21 of the voltage supply module 20 is connected to the main controller 10 and receives a voltage supply control signal, the negative voltage output terminal 22 of the voltage supply module 20 outputs a corresponding dc voltage, which is denoted as a first voltage PWR-OUT, and the amplification control output terminal 23 of the voltage supply module 20 outputs a corresponding amplification control voltage PV. The amplifying module 30 includes an initial voltage input terminal 31, an amplification control input terminal 32 and a waveform output terminal 33, the initial voltage input terminal 31 of the amplifying module 30 is connected to the digital-to-analog converter DAC in the main controller 10 and receives the initial ac voltage MDAC-OUT, the amplification control input terminal 32 of the amplifying module 30 receives the amplification control voltage PV, and the waveform output terminal 33 of the amplifying module 30 outputs the amplified initial ac voltage MDAC-OUT, which is denoted as a second voltage T-OUT. The adding module 40 is respectively connected to the negative voltage output terminal 22 of the voltage supply module 20 and the waveform output terminal 33 of the amplifying module 30, and is configured to respectively receive the first voltage PWR-OUT and the second voltage T-OUT, and add the first voltage PWR-OUT and the second voltage T-OUT to obtain the AC common voltage AC-VCOM.
Specifically, the main controller 10 (e.g., a MCU) determines corresponding configuration parameters, such as a peak-to-valley voltage difference, a period, a waveform type, etc., according to the preset AC-VCOM. The main controller 10 outputs a corresponding voltage supply control signal to the voltage supply module 20 according to the peak-to-valley voltage difference value in the configuration parameters and a voltage value of a received DC common voltage DC-VCOM, the voltage supply module 20 outputs a corresponding DC voltage at a negative voltage output terminal 22 of the voltage supply module 20 according to the voltage supply control signal and records the DC voltage as a first voltage PWR-OUT, and outputs a corresponding amplification control voltage PV at an amplification control output terminal 23 of the voltage supply module 20. If the waveform of the AC common voltage AC-VCOM needs to be changed, the corresponding bias voltage only needs to be calculated and set the first voltage PWR-OUT by the main controller 10 according to the peak-to-valley voltage difference of the AC common voltage AC-VCOM and the voltage value of the DC common voltage DC-VCOM, without replacing the corresponding resistor.
Meanwhile, the main controller 10 outputs an initial AC voltage MDAC-OUT having the same period and waveform type as the AC common voltage AC-VCOM through the internal digital-to-analog converter DAC according to the period and waveform type among the configuration parameters. The DAC of the main controller 10 outputs the initial AC voltage MDAC-OUT to the initial voltage input terminal 31 of the amplifying module 30, and the amplification control output terminal 23 of the voltage supply module 20 outputs the corresponding amplification control voltage PV to the amplification control input terminal 32 of the amplifying module 30, so that the amplifying module 30 can amplify the peak-to-valley voltage difference of the initial AC voltage MDAC-OUT according to the amplification control voltage PV to obtain the amplified initial AC voltage MDAC-OUT, which is recorded as the second voltage T-OUT, and the peak-to-valley voltage difference of the second voltage T-OUT is equal to the peak-to-valley voltage difference of the AC common voltage AC-VCOM. The second voltage T-OUT is equal to the AC common voltage AC-VCOM in the period, the waveform type, and the peak-to-valley voltage difference, so that the second voltage T-OUT has the same shape as the AC common voltage AC-VCOM.
The negative voltage output terminal 22 of the voltage supply module 20 outputs the first voltage PWR-OUT to the addition module 40, and the waveform output terminal 33 of the amplification module 30 outputs the second voltage T-OUT to the addition module 40, so that the addition module 40 can add the first voltage PWR-OUT and the second voltage T-OUT to obtain the AC common voltage AC-VCOM. The first voltage PWR-OUT may have a voltage value corresponding to a voltage difference between the second voltage T-OUT and the AC common voltage AC-VCOM. After the second voltage T-OUT is superposed with the first voltage PWR-OUT, the peak voltage value of the second voltage T-OUT becomes the peak voltage value of the alternating current public voltage AC-VCOM, and the trough voltage value of the second voltage T-OUT becomes the trough voltage value of the alternating current public voltage AC-VCOM, so that the required alternating current public voltage AC-VCOM is obtained.
The AC common voltage AC-VCOM generating circuit of the present embodiment not only needs to obtain the bias voltage through the main controller 10 without replacing the resistor when the waveform of the AC common voltage AC-VCOM changes, but also simplifies the circuit, reduces the cost and saves the layout occupation space on the printed circuit board.
Second embodiment
Fig. 4 is a circuit diagram of an AC-VCOM generating circuit according to a second embodiment of the invention. The circuit connection of this embodiment is substantially the same as that of the first embodiment. The amplifying module 30 of the AC-common voltage AC-VCOM generating circuit of the present embodiment may include, as shown in fig. 4, a first operational amplifier U1, a switch element T1, a first resistor R1 and a second resistor R2. The non-inverting input of the first operational amplifier U1 is the initial voltage input 31. The switching element T1 includes a control terminal, a first path terminal and a second path terminal, and the control terminal of the switching element T1 is connected to the output terminal of the first operational amplifier U1. The first terminal of the first resistor R1 is the waveform output terminal 33, and is further connected to the first path terminal of the switching element T1, and the second terminal of the first resistor R1 is the amplification control input terminal 32. A first terminal of the second resistor R2 is connected to the inverting input terminal of the first operational amplifier U1 and also to the second path terminal of the switching element T1, and a second terminal of the second resistor R2 is grounded. In this embodiment, the switch element T1 may be an NPN type three-stage transistor, but the invention is not limited thereto, and for example, the switch element T1 may be an NMOS transistor or the like.
In this embodiment, as shown in fig. 4, a second operational amplifier U2 may be disposed between the negative output terminal 22 of the voltage supply module 20 and the adding module 40; the non-inverting input of the second operational amplifier U2 is connected to the negative output 22 of the voltage supply module 20, and the inverting input of the second operational amplifier U2 is connected to the output of the second operational amplifier U2. The non-inverting input terminal of the second operational amplifier U2 of the present embodiment receives the first voltage PWR-OUT and can output the first voltage PWR-OUT at the output terminal thereof, i.e., the second operational amplifier U2 can serve as an output buffer.
In this embodiment, as shown in fig. 4, a third operational amplifier U3 may be disposed between the waveform output terminal 33 of the amplifying module 30 and the adding module 40; the non-inverting input of the third operational amplifier U3 is connected to the waveform output 33 of the amplification block 30, and the inverting input of the third operational amplifier U3 is connected to the output of the third operational amplifier U3. The non-inverting input terminal of the third operational amplifier U3 of the present embodiment receives the second voltage T-OUT and can output the second voltage T-OUT at the output terminal thereof, i.e., the third operational amplifier U3 can serve as an output buffer.
In this embodiment, the summing block 40 includes a fourth operational amplifier U4, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6; a first end of the third resistor R3 receives the first voltage PWR-OUT; a first terminal of the fourth resistor R4 receives the second voltage T-OUT; the non-inverting input end of the fourth operational amplifier U4 is connected to the second end of the third resistor R3 and the second end of the fourth resistor R4, respectively, and the output end of the fourth operational amplifier U4 outputs an AC common voltage AC-VCOM; a first end of the fifth resistor R5 is connected with the inverting input end of the fourth operational amplifier U4, and a second end of the fifth resistor R5 is grounded; a first terminal of the sixth resistor R6 is connected to a first terminal of the fifth resistor R5, and a second terminal of the sixth resistor R6 is connected to an output terminal of the fourth operational amplifier U4.
Specifically, fig. 5a, 5b, 5c and 5d may be referred to as corresponding voltage waveform diagrams in operation of the AC common voltage AC-VCOM generating circuit of the present embodiment. The present invention is not limited to the waveform of the AC common voltage AC-VCOM, and the waveform may be one of a triangular wave, a sine wave, a rectangular wave, etc. in this embodiment, for example, only the AC common voltage AC-VCOM is exemplified as the triangular wave in the following.
The main controller 10 determines corresponding configuration parameters, such as a peak-to-valley voltage difference, a period, a waveform type, etc., according to the preset generated AC-VCOM. The main controller 10 outputs an initial AC voltage MDAC-OUT having the same period and waveform type as the AC common voltage AC-VCOM through the internal digital-to-analog converter DAC according to the period and waveform type among the configuration parameters. For example, the preset generated AC common voltage AC-VCOM is a triangular wave, and the main controller 10 outputs an initial AC voltage MDAC-OUT having the same period and waveform type as the AC common voltage AC-VCOM through the internal digital-to-analog converter DAC. For example, in this embodiment, the valley voltage value of the initial ac voltage MDAC-OUT is 0V, and the peak voltage value is 3.3V, which can refer to the voltage diagram of the initial ac voltage MDAC-OUT in fig. 5 a.
When the amplifying module 30 starts to operate, there is no voltage across the second resistor R2, and the second terminal of the second resistor R2 is grounded, so that the voltages of the first terminal of the second resistor R2 and the second terminal of the second resistor R2 are both 0V, and the inverting input terminal of the first operational amplifier U1 is connected to the first terminal of the second resistor R2, so that the inverting input terminal of the first operational amplifier U1 receives 0V. The first operational amplifier U1 outputs a corresponding voltage according to the voltage difference between the non-inverting input terminal and the inverting input terminal. Therefore, when the voltage value of the initial ac voltage MDAC-OUT received by the non-inverting input terminal of the first operational amplifier U1 at a certain time is greater than the 0V voltage received by the inverting input terminal thereof, the first operational amplifier U1 outputs a corresponding voltage to the control terminal of the switching element T1 at the output terminal, and the voltage is greater than the voltage threshold when the switching element T1 is turned on, the switching element T1 turns on the first path terminal and the second path terminal thereof, so that the amplified control voltage PV received by the second terminal of the first resistor R1, the first resistor R1, the switching element T1, and the second resistor R2 form a circuit loop, and thus the first resistor R1 and the second resistor R2 in the circuit loop have corresponding currents at the same time.
In the process that the initial ac voltage MDAC-OUT changes from the valley voltage value to the peak voltage value, the currents of the first resistor R1 and the second resistor R2 are correspondingly increased, and the voltage difference between the two ends of the first resistor R1 and the two ends of the second resistor R2 is correspondingly increased. And the first terminal of the first resistor R1 is the waveform output terminal 33 of the amplifying module 30 for outputting the second voltage T-OUT, and the second terminal of the first resistor R1 is the amplification control input terminal 32 of the amplifying module 30 for receiving the amplification control voltage PV output from the amplification control output terminal 23 of the voltage supply module 20, so that the output second voltage T-OUT has the same period and waveform type as the initial ac voltage MDAC-OUT and changes from a peak voltage value to a valley voltage value. Accordingly, in the process of changing the initial ac voltage MDAC-OUT from the peak voltage value to the valley voltage value, the currents in the first resistor R1 and the second resistor R2 are correspondingly reduced, so that the voltage difference between the two ends of the first resistor R1 and the two ends of the second resistor R2 is correspondingly reduced, and the output second voltage T-OUT has the same period and waveform type as the initial ac voltage MDAC-OUT and is changed from a certain peak voltage value to a certain valley voltage value.
Thus, the second voltage T-OUT is the amplified initial ac voltage MDAC-OUT, for example, in this embodiment, the peaks of the second voltage T-OUT correspond to the troughs of the initial ac voltage MDAC-OUT, the troughs of the second voltage T-OUT correspond to the peaks of the initial ac voltage MDAC-OUT, and the second voltage T-OUT amplifies the voltage difference between the corresponding peaks and troughs of the initial ac voltage MDAC-OUT. Of course, in other embodiments of the present invention, the peaks of the second voltage T-OUT may correspond to the peaks of the initial ac voltage MDAC-OUT, the troughs of the second voltage T-OUT may correspond to the troughs of the initial ac voltage MDAC-OUT, and the second voltage T-OUT may amplify the voltage difference between the peaks and the troughs of the initial ac voltage MDAC-OUT. In this embodiment, the amplification factor of the initial ac voltage MDAC-OUT by the second voltage T-OUT is related to the current on the first resistor R1, and the calculation of the current is related to the amplified control voltage PV received by the second end of the first resistor R1 in the circuit loop, the resistance value of the first resistor R1, and the resistance value of the second resistor R2. In this embodiment, the waveform of the second voltage T-OUT may refer to the voltage diagram of the second voltage T-OUT in fig. 5b, the peak-to-valley voltage difference of the AC common voltage AC-VCOM may be VH V, and the peak-to-valley voltage difference of the initial AC voltage MDAC-OUT may be 3.3V, and the amplifying module 30 may amplify the peak-to-valley voltage difference of the initial AC voltage MDAC-OUT from 3.3V to VH V.
The main controller 10 outputs a corresponding voltage supply control signal to the voltage supply module 20 according to the peak-to-valley voltage difference value in the configuration parameters and a voltage value of a received DC common voltage DC-VCOM, the voltage supply module 20 outputs a corresponding DC voltage, i.e., a first voltage PWR-OUT, at a negative voltage output terminal 22 of the voltage supply module 20 according to the voltage supply control signal, and outputs a corresponding amplification control voltage PV at an amplification control output terminal 23 of the voltage supply module 20. If the waveform of the AC common voltage AC-VCOM needs to be changed, the corresponding bias voltage only needs to be calculated and set the first voltage PWR-OUT by the main controller 10 according to the peak-to-valley voltage difference of the AC common voltage AC-VCOM and the voltage value of the DC common voltage DC-VCOM, without replacing the corresponding resistor. In this embodiment, the waveform of the first voltage PWR-OUT may refer to a voltage diagram of the first voltage PWR-OUT of fig. 5c, and the absolute value of the voltage of the first voltage PWR-OUT may be a sum of a half of a peak-to-valley voltage difference value of the alternating common voltage AC-VCOM (0.5VH) and a voltage value of the direct common voltage DC-VCOM, that is, the first voltage PWR-OUT is a sum of voltages of two parts, wherein the voltage of the first part is a half of a peak-to-valley voltage difference value of the alternating common voltage AC-VCOM (0.5VH), and the second part is the direct common voltage DC-VCOM.
The adding module 40 may adopt an adding circuit formed by the fourth operational amplifier U4, the third resistor R3, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6, or may adopt any form of adding circuit to add the first voltage PWR-OUT and the second voltage T-OUT to obtain the AC common voltage AC-VCOM. In this embodiment, the waveform of the AC common voltage AC-VCOM may refer to the voltage diagram of the AC common voltage AC-VCOM in fig. 5d, and it can be seen that the AC common voltage AC-VCOM in fig. 5d has the same waveform shape as that of the first voltage PWR-OUT in fig. 5b, but has a voltage offset with a voltage value of the second voltage T-OUT in fig. 5c, and then the first voltage PWR-OUT in fig. 5b and the second voltage T-OUT in fig. 5c may be voltage-superposed to obtain the AC common voltage AC-VCOM in fig. 5 d.
In the AC common voltage AC-VCOM generating circuit of the present embodiment, the amplifying module 30, the adding module 40, and the like may be formed by corresponding resistors and operational amplifiers, so that not only when the waveform of the AC common voltage AC-VCOM changes, the bias voltage is obtained only by the main controller 10 without replacing the resistor, but also the circuit is simplified, the cost is reduced, and the layout occupation space on the printed circuit board is saved.
Third embodiment
The embodiment also provides a liquid crystal display device, which comprises the alternating common voltage AC-VCOM generating circuit.
The liquid crystal display device of the present embodiment, which includes the AC common voltage AC-VCOM generating circuit, not only needs to obtain the bias voltage through the main controller 10 without replacing the resistor when the waveform of the AC common voltage AC-VCOM changes, but also the circuit is simplified, the cost is reduced, and the layout occupation space on the printed circuit board is saved.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. An alternating common voltage generating circuit for generating an alternating common voltage (AC-VCOM), comprising:
a main controller (10), wherein the main controller (10) outputs a corresponding voltage supply control signal according to a peak-to-valley voltage difference of the alternating common voltage (AC-VCOM) and a voltage value of a received direct common voltage (DC-VCOM), and outputs an initial alternating voltage (MDAC-OUT) having the same period and waveform type as the alternating common voltage (AC-VCOM) through an internal digital-to-analog converter;
the voltage supply module (20) comprises a voltage supply control input end (21), a negative pressure output end (22) and an amplification control output end (23), the voltage supply control input end (21) of the voltage supply module (20) is connected with the main controller (10) and receives the voltage supply control signal, a corresponding direct current voltage is output at the negative pressure output end (22) of the voltage supply module (20) and is recorded as a first voltage (PWR-OUT), and a corresponding amplification control voltage (PV) is output at the amplification control output end (23) of the voltage supply module (20);
the amplifying module (30) comprises an initial voltage input end (31), an amplification control input end (32) and a waveform output end (33), the initial voltage input end (31) of the amplifying module (30) is connected with a digital-to-analog converter inside the main controller (10) and receives the initial alternating voltage (MDAC-OUT), the amplification control input end (32) of the amplifying module (30) receives the amplification control voltage (PV), and the waveform output end (33) of the amplifying module (30) outputs the amplified initial alternating voltage (MDAC-OUT) which is recorded as a second voltage (T-OUT);
an addition module (40), the addition module (40) being configured to add the first voltage (PWR-OUT) and the second voltage (T-OUT) to obtain the alternating common voltage (AC-VCOM).
2. The ac common voltage generating circuit according to claim 1, wherein the amplifying block (30) includes a first operational amplifier (U1), a switching element (T1), a first resistor (R1), and a second resistor (R2);
the non-inverting input end of the first operational amplifier (U1) is an initial voltage input end (31) of the amplifying module (30);
the switching element (T1) comprises a control terminal, a first path terminal and a second path terminal, and the control terminal of the switching element (T1) is connected with the output terminal of the first operational amplifier (U1);
the first end of the first resistor (R1) is a waveform output end (33) of the amplifying module (30) and is also connected with a first path end of the switch element (T1), and the second end of the first resistor (R1) is an amplifying control input end (32) of the amplifying module (30);
the first end of the second resistor (R2) is connected with the inverting input end of the first operational amplifier (U1) and also connected with the second path end of the switch element (T1), and the second end of the second resistor (R2) is grounded.
3. The ac common voltage generating circuit according to claim 2, wherein said switching element (T1) is an NPN type three-stage transistor.
4. An alternating common voltage generating circuit according to claim 1, characterized in that a second operational amplifier (U2) is provided between the negative voltage output terminal (22) of the voltage supply module (20) and the adding module (40); the non-inverting input end of the second operational amplifier (U2) is connected with the negative pressure output end (22) of the voltage supply module (20), and the inverting input end of the second operational amplifier (U2) is connected with the output end of the second operational amplifier (U2).
5. An alternating common voltage generating circuit according to claim 1, characterized in that a third operational amplifier (U3) is provided between the waveform output terminal (33) of the amplifying module (30) and the adding module (40); the non-inverting input of the third operational amplifier (U3) is connected to the waveform output (33) of the amplification module (30), and the inverting input of the third operational amplifier (U3) is connected to the output of the third operational amplifier (U3).
6. The ac common voltage generating circuit according to claim 1, wherein the adding block (40) includes a fourth operational amplifier (U4), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), and a sixth resistor (R6); a first terminal of the third resistor (R3) receives the first voltage (PWR-OUT); a first terminal of the fourth resistor (R4) receives the second voltage (T-OUT); a non-inverting input terminal of the fourth operational amplifier (U4) is connected to the second terminal of the third resistor (R3) and the second terminal of the fourth resistor (R4), respectively, and an output terminal of the fourth operational amplifier (U4) outputs the alternating common voltage (AC-VCOM); a first end of the fifth resistor (R5) is connected with an inverting input end of the fourth operational amplifier (U4), and a second end of the fifth resistor (R5) is grounded; a first terminal of the sixth resistor (R6) is connected to a first terminal of the fifth resistor (R5), and a second terminal of the sixth resistor (R6) is connected to an output terminal of the fourth operational amplifier (U4).
7. The alternating common voltage generating circuit according to claim 1, wherein the waveform type of the alternating common voltage (AC-VCOM) is one of a triangular wave, a sine wave, and a rectangular wave.
8. The ac common voltage generating circuit according to claim 1, wherein the initial ac voltage (MDAC-OUT) has a valley voltage value of 0V and a peak voltage value of 3.3V.
9. The alternating common voltage generating circuit according to claim 1, wherein an absolute value of a voltage of said first voltage (PWR-OUT) is a sum of a half of a peak-to-valley voltage difference of said alternating common voltage (AC-VCOM) and a voltage value of said direct common voltage (DC-VCOM).
10. A liquid crystal display device comprising the alternating common voltage generating circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811058925.6A CN109166540B (en) | 2018-09-11 | 2018-09-11 | Alternating current public voltage generating circuit and liquid crystal display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811058925.6A CN109166540B (en) | 2018-09-11 | 2018-09-11 | Alternating current public voltage generating circuit and liquid crystal display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109166540A CN109166540A (en) | 2019-01-08 |
| CN109166540B true CN109166540B (en) | 2020-11-24 |
Family
ID=64894977
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811058925.6A Active CN109166540B (en) | 2018-09-11 | 2018-09-11 | Alternating current public voltage generating circuit and liquid crystal display device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109166540B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109686338A (en) * | 2019-02-28 | 2019-04-26 | 昆山龙腾光电有限公司 | Public voltage generating circuit and its display device |
| CN110767193A (en) * | 2019-11-11 | 2020-02-07 | 昆山龙腾光电股份有限公司 | Alternating-current public voltage generating circuit and method and display device |
| TWI738417B (en) * | 2020-07-10 | 2021-09-01 | 友達光電股份有限公司 | Display device and driving method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI338876B (en) * | 2006-04-11 | 2011-03-11 | Chimei Innolux Corp | Adjustment circuit for common voltage |
| CN104766578A (en) * | 2015-04-14 | 2015-07-08 | 深圳市华星光电技术有限公司 | Multi-voltage generation device and liquid crystal display |
| CN107342063A (en) * | 2017-08-11 | 2017-11-10 | 昆山龙腾光电有限公司 | Common voltage drive circuit and display device |
| CN107437407A (en) * | 2017-08-11 | 2017-12-05 | 昆山龙腾光电有限公司 | Public voltage generating circuit and liquid crystal display device |
| CN107452347A (en) * | 2016-05-31 | 2017-12-08 | Iml国际 | Variable VCOM level generators |
| CN207663771U (en) * | 2017-08-30 | 2018-07-27 | 昆山龙腾光电有限公司 | Circuit occurs for common voltage |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW200828244A (en) * | 2006-12-25 | 2008-07-01 | Himax Tech Ltd | Common voltage adjustment apparatus |
| US8736592B2 (en) * | 2010-01-18 | 2014-05-27 | Iml International | Digitally controlled voltage generator |
-
2018
- 2018-09-11 CN CN201811058925.6A patent/CN109166540B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI338876B (en) * | 2006-04-11 | 2011-03-11 | Chimei Innolux Corp | Adjustment circuit for common voltage |
| CN104766578A (en) * | 2015-04-14 | 2015-07-08 | 深圳市华星光电技术有限公司 | Multi-voltage generation device and liquid crystal display |
| CN107452347A (en) * | 2016-05-31 | 2017-12-08 | Iml国际 | Variable VCOM level generators |
| CN107342063A (en) * | 2017-08-11 | 2017-11-10 | 昆山龙腾光电有限公司 | Common voltage drive circuit and display device |
| CN107437407A (en) * | 2017-08-11 | 2017-12-05 | 昆山龙腾光电有限公司 | Public voltage generating circuit and liquid crystal display device |
| CN207663771U (en) * | 2017-08-30 | 2018-07-27 | 昆山龙腾光电有限公司 | Circuit occurs for common voltage |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109166540A (en) | 2019-01-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109166540B (en) | Alternating current public voltage generating circuit and liquid crystal display device | |
| TWI307203B (en) | A pulse width modulation system with nonlinear ramp | |
| US9294057B2 (en) | Efficient low noise high speed amplifier | |
| CN112042117A (en) | Class D amplifier with multiple independent output stages | |
| US7663429B2 (en) | Driver amplifier circuit having reduced DC bias | |
| US10147376B2 (en) | Common electrode driving module and liquid crystal display panel | |
| JP2004180382A (en) | Step-down circuit, power circuit, and semiconductor integrated circuit | |
| JP2011150341A (en) | Gamma voltage output circuit of source driver | |
| KR20110091247A (en) | Power source circuit of display device and display device having the power source circuit | |
| US11290070B2 (en) | Common-mode leakage error calibration for current sensing in a class-D stage using a pilot tone | |
| US20070063762A1 (en) | Semiconductor device with charge pump booster circuit | |
| CN108649959B (en) | Digital-analog converter and digital power amplifier subsystem | |
| US7474082B2 (en) | Voltage converting apparatus with auto-adjusting boost multiple | |
| CN109256104A (en) | display device, display panel power supply system and circuit thereof | |
| US7439801B2 (en) | Amplifier circuit with multiple power supplies | |
| TWI547922B (en) | Power supply system and display apparatus | |
| JP4575542B2 (en) | LCD drive circuit | |
| JP2006189593A (en) | Liquid crystal display device | |
| JP2012070599A (en) | Switching regulator and display device using the same | |
| CN102884723A (en) | Current-voltage converter having a current reflector, input stage of an amplifier and corresponding amplifier | |
| TWI423729B (en) | Source driver having amplifiers integrated therein | |
| JP2010193259A (en) | High voltage output type amplifier | |
| JPH10268253A (en) | Reference voltage generation circuit | |
| JP2012217223A (en) | Variable gain inverting amplifier circuit | |
| CN109716647B (en) | Amplifying device comprising compensation circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Address after: 215301, 1, Longteng Road, Kunshan, Jiangsu, Suzhou Applicant after: InfoVision Optoelectronics(Kunshan)Co.,Ltd. Address before: 215301, 1, Longteng Road, Kunshan, Jiangsu, Suzhou Applicant before: INFOVISION OPTOELECTRONICS (KUNSHAN) Co.,Ltd. |
|
| CB02 | Change of applicant information | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |