CN115223498A - Gamma voltage generating circuit, display device and gamma voltage generating method - Google Patents
Gamma voltage generating circuit, display device and gamma voltage generating method Download PDFInfo
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- 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
- G09G3/22—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 using controlled light sources
- G09G3/30—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 using controlled light sources using electroluminescent panels
- G09G3/32—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
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- 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
- G09G3/22—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 using controlled light sources
- G09G3/30—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 using controlled light sources using electroluminescent panels
- G09G3/32—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3233—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
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- 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
- G09G3/22—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 using controlled light sources
- G09G3/30—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 using controlled light sources using electroluminescent panels
- G09G3/32—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3258—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the voltage across the light-emitting element
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- G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
Abstract
The application discloses a gamma voltage generating circuit, a display device and a gamma voltage generating method. The gamma voltage generating circuit includes: a ramp signal generator for generating a ramp signal; the counter is used for counting within preset time and generating a counting signal, each counting value of the counting signal corresponds to a gray scale signal, the gray scale signal is selected from one part of the ramp signal, the step length of the counter is different, and the counting duration maintained by each counting value of the counting signal is determined by a gamma curve; and each sampling module receives the corresponding data signal, compares the counting signal with the data signal, and latches the gray-scale signal when the counting signal is consistent with the data signal so as to obtain the gamma voltage corresponding to the data signal. The gamma voltage generating circuit does not need data bit expansion, and has the advantages of high precision, low power consumption and small occupied area.
Description
Technical Field
The present invention relates to the field of display technologies, and in particular, to a gamma voltage generating circuit, a display device, and a gamma voltage generating method.
Background
With the development of science and technology, display devices are widely applied to various scenes. Because the brightness perceived by the human visual system and the brightness actually displayed by the display device are in a nonlinear relationship, the gamma correction needs to be carried out on the video data of the display device, so that the display brightness is adapted to the perception requirement of human eyes.
Gamma correction originally stems from the non-linearity of the electrical-to-optical conversion in Cathode Ray Tube (CRT) display devices, where the electron beam produced by the Tube and the resulting image brightness correspond exponentially to the input voltage. Whereas, in the case of the OLED display device, the emission luminance is linear with the current flowing through the OLED device, but actually, the human visual system is also non-linear with respect to the perception of luminance variation. Gamma correction is a transfer function introduced to overcome this non-linearity and is widely used in video streaming, computer graphics, and other imaging systems. There are two popular gamma correction methods: one is digital gamma correction, that is, a display system is tested, corrected video driving data is adjusted step by step and stored in a memory in advance, a Look-Up Table (LUT) method is adopted to realize data nonlinear transformation in the display process, and meanwhile, a digital-to-analog conversion part is linear, that is, the method performs nonlinear transformation on input data in a digital domain; the other is analog gamma correction, namely, a gray level voltage generating circuit is formed by a precise resistor and an operational amplifier to provide multi-level nonlinear gamma voltages.
However, in order to perform nonlinear transformation of data in digital gamma correction, bit width expansion needs to be performed, and generally 8 bits are expanded into 10 bits, or 8 bits are expanded into 12 bits. After data bits are expanded, all the following digital image processing algorithms and digital-to-analog conversion circuits operate on the basis of the expanded bits, and the area and the power consumption are large. The difficulty of analog gamma correction is that as the number of gray scales increases, the complexity of the additionally required analog circuit also increases greatly.
Accordingly, it is desirable to provide a further improved gamma voltage generating circuit to solve the above-mentioned problems.
Disclosure of Invention
In view of the foregoing problems, it is an object of the present invention to provide a gamma voltage generating circuit, a display device and a gamma voltage generating method, which have the advantages of high precision, low power consumption and small occupied area.
According to a first aspect of the present invention, there is provided a gamma voltage generating circuit comprising: a ramp signal generator for generating a ramp signal, the ramp signal being converted from a first voltage to a second voltage for a predetermined time; a counter for counting within the predetermined time and generating a count signal, each count value of the count signal corresponding to a gray scale signal selected from a portion of the ramp signal; and each sampling module receives a corresponding data signal and compares the counting signal with the data signal, and when the counting signal is consistent with the data signal, the sampling module latches the gray scale signal to obtain a gamma voltage corresponding to the data signal, wherein the step length of the counter is different, and the counting duration maintained by each counting value of the counting signal is determined by the gamma curve.
Optionally, each of the sampling modules includes: a comparator that compares the count signal with the data signal and provides an invalid control signal when the count signal is identical with the data signal; and the switching tube is used for switching off a current path from the ramp signal to a source line according to the invalid control signal so as to latch the gray-scale signal corresponding to the counting signal, thereby obtaining the gamma voltage corresponding to the data signal.
Optionally, the switching tube sends the gamma voltage to the source line, and the gamma voltage is stored on a parasitic capacitance of the source line.
Optionally, the method further includes: and the reset transistor is connected between the parasitic capacitor and an input power supply and is used for resetting the gamma voltage according to a reset signal.
Optionally, the method further includes: the buffer is connected between the sampling modules and the ramp signal generator, or the buffers are respectively connected between the sampling modules and the ramp signal generator and used for buffering the ramp signal.
According to a second aspect of the present invention, there is provided a display device comprising:
the gamma voltage generating circuit as described above, receiving a data signal and providing a gamma voltage corresponding to the data signal; and a display panel connected to the gamma voltage generating circuit for displaying a picture according to the gamma voltage.
According to a third aspect of the present invention, there is provided a gamma voltage generating method comprising: generating a ramp signal converted from a first voltage to a second voltage for a predetermined time; counting within the preset time and generating a counting signal, wherein each counting time of the counting signal corresponds to a gray-scale signal, and the gray-scale signal is selected from a part of the ramp signal; and receiving a corresponding data signal, comparing the counting signal with the data signal, and latching the gray-scale signal to obtain a gamma voltage corresponding to the data signal when the counting signal is consistent with the data signal, wherein the counting time length maintained by each counting value of the counting signal is determined by a gamma curve.
Optionally, the method for obtaining the gamma voltage comprises: comparing the count signal with the data signal and providing an invalid control signal when the count signal is consistent with the data signal; turning off a current path of the ramp signal to a source line according to the inactive control signal to latch the gray-scale signal corresponding to the count signal, thereby obtaining the gamma voltage corresponding to the data signal.
Optionally, the method further includes: resetting the gamma voltage according to a reset signal before generating the ramp signal.
According to the gamma voltage generating circuit, the display device and the gamma voltage generating method, the gamma voltage is generated in a digital-analog mixing mode, data signals do not undergo gamma conversion, and bit expansion is not needed, for example, the number of bits of the data signals is 8 bits and does not need to be expanded to 10 bits or 12 bits, so that the occupied area of the circuit and the power consumption of the circuit are greatly reduced, and the 10-bit or 12-bit gray scale precision is realized by using the 8-bit width.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:
FIG. 1 shows a schematic diagram of a display device according to an embodiment of the invention;
FIG. 2 shows a circuit schematic of a pixel cell according to an embodiment of the invention;
FIG. 3 illustrates a schematic diagram of a gamma voltage generation circuit according to an embodiment of the present invention;
FIG. 4 illustrates a waveform diagram of a gamma voltage generating circuit according to an embodiment of the present invention;
FIG. 5 illustrates a schematic diagram of a gamma voltage generating method according to an embodiment of the present invention.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. Moreover, certain well-known elements may not be shown in the figures.
In the following description, numerous specific details of the invention, such as structure, materials, dimensions, processing techniques and techniques of the devices are described in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
It should be understood that, in the embodiments of the present application, a and B are connected/coupled to indicate that a and B may be connected in series or in parallel, or a and B may pass through other devices, which is not limited in the embodiments of the present application.
The gamma voltage generating circuit mainly functions to generate a plurality of gamma voltages, and a source driving circuit in the display device selects one of the plurality of gamma voltages as a gray-scale voltage within one frame period. The gamma voltage generation circuit and the gamma voltage generation method can be applied to various display devices, such as smart televisions, smart phones, tablet computers, notebook computers, desktop computers, vehicle-mounted displays, outdoor advertising screens, monitors, mobile internet devices, internet of things devices and the like. The gamma voltage generating circuit provided by the embodiment of the invention generates gamma voltage by using a digital-analog mixing mode, and has the advantages of high precision, low power consumption and small occupied area.
Embodiments of the present application will be described below with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of a display device according to an embodiment of the present invention.
As shown in fig. 1, the display device 100 includes a plurality of pixel units 110 arranged in an array in a display region, and a gamma voltage generating circuit 10, a source driving circuit 120, a gate driving circuit 130, and a power chip 140 in a non-display region. The source driving circuit 120 supplies the data signal to the gamma voltage generating circuit 10, and the gamma voltage generating circuit 10 supplies the gamma voltage corresponding to the data signal according to the data signal and transmits a plurality of gamma voltages to the pixel units 110 of each column via the source lines S1 to Sn; the gate driving circuit 130 supplies scan signals to the pixel units 110 in each row via the gate lines G1 to Gm; the power supply chip 140 is connected to each of the pixel units 110, respectively, and supplies the power supply voltage ELVDD to each of the pixel units 110.
Taking the display device 100 as an AMOLED display device as an example, fig. 2 shows a circuit schematic diagram of a pixel unit. As shown in fig. 2, the pixel unit 110 includes an organic light emitting diode OLED, a switching tube T1, a switching tube T2, and a storage capacitor Cs. The on and off of the switch tube T1 is controlled by a scanning signal; the storage capacitor Cs is used for receiving the gray scale voltage through the switch tube T1 and storing the gray scale voltage; and a switch tube T2 for supplying a driving voltage or a driving current to the light emitting elements OLED in the display panel according to the power voltage and the stored gray scale voltage in an off phase of the switch tube T1.
In a frame period, the gate of the switching tube T2 receives the corresponding gamma voltage Vgma, the source voltage is ELVDD, the light emitting element OLED is controlled by a constant current, and the current flowing through the light emitting element OLED is controlled by the gate-source voltage (ELVDD-Vgma) of the switching tube T2, so that the light emitting element OLED starts emitting light, and multi-level gray scale display is realized by setting gray scale voltages DATA of different magnitudes.
Fig. 3 illustrates a schematic diagram of a gamma voltage generating circuit according to an embodiment of the present invention.
As shown in fig. 3, the gamma voltage generating circuit 10 includes a ramp generator 11, a counter 12, and a plurality of sampling blocks 13 for generating gamma voltages, the number of sampling blocks 13 corresponding to the number of source lines, for example.
The RAMP signal generator 11 is configured to generate a RAMP signal RAMP, and the RAMP signal RAMP is converted from a first voltage to a second voltage within a predetermined time.
The counter 12 is used for counting within a predetermined time and generating a count signal counter. Each count value of the count signal counter corresponds to a gray-scale signal selected from a part of the RAMP signal RAMP (see fig. 4).
Each sampling module 13 receives a corresponding data signal, compares the count signal with the data signal, and when the count signal counter is consistent with the data signal, the sampling module 13 latches the gray scale signal at that moment to obtain the gamma voltage corresponding to the data signal.
In the embodiment of the present application, the circuit structures of the sampling modules 13 are the same, each sampling module 13 at least includes a comparator and a switch tube, taking the sampling module 13 including the comparator U1 and the switch tube K1 as an example, the comparator U1 compares the count signal counter with the DATA signal DATA1, and provides an invalid control signal when the count signal counter is consistent with the DATA signal DATA 1; the switching tube K1 turns off the current path from the RAMP signal RAMP to the source line according to the inactive control signal to latch the gray-scale signal corresponding to the count value at that time, thereby obtaining the gamma voltage corresponding to the DATA signal DATA 1.
After generating the gamma voltage, the switching tube K1 transmits the gamma voltage to the source line S1, and the gamma voltage is stored in the parasitic capacitance C of the source line S1 p 1.
Alternatively, since the switching tube K1 is turned on and the voltage on the DATA line S1 is unstable when the count value of the count signal counter does not reach the DATA signal DATA1, the above process of obtaining the gamma voltage is performed before the time for displaying the picture in the one-line picture duration.
In the embodiment of the present application, the step size of the counter 12 is different, and the counting time length maintained by each count value of the counting signal counter is determined by the gamma curve, so that the data signal does not need to be bit-extended. Within the display period of each line of the screen, the number of bits of the count signal counter is, for example, 8 bits, then the count signal counter counts from 0 to 255 for a predetermined time, and the count signal counter corresponds to 256-level gray scale voltages within the count period from 0 to 255, and the sampling module 13 latches the gray scale signal corresponding to the count value at that time when the count signal counter coincides with the DATA signal DATA1, thereby obtaining the gamma voltage corresponding to the DATA signal DATA 1.
According to the method and the device, the gamma voltage is generated in a digital-analog mixing mode, the data signals do not need to be subjected to bit expansion, for example, the number of bits of the data signals is 8 bits, and the data signals do not need to be expanded to 10 bits or 12 bits, so that the occupied area of a circuit and the power consumption of the circuit are greatly reduced, the 10-bit or 12-bit gray scale precision is realized by using the 8-bit width, and the high precision of the gamma voltage is ensured.
Optionally, the sampling module 13 further includes a reset transistor T r 1, connected to a parasitic capacitance C p 1 and an input power source VIN, for resetting the gamma voltage according to a RESET signal RESET.
Optionally, the RAMP signal RAMP generator generates the RAMP signal RAMP according to the RAMP control signal RAMP _ ctrl. The Ramp control signal Ramp _ ctrl is generated by the counter 12, and the Ramp control signal Ramp _ ctrl is related to the count signal counter and the RESET signal RESET.
Optionally, the gamma voltage generating circuit 10 further includes: a buffer 14 connected between the plurality of sampling blocks 13 and the RAMP signal RAMP generator 11, or a plurality of buffers 14 (not shown) respectively connected between the plurality of sampling blocks 13 and the RAMP signal RAMP generator 11, the buffers 14 being used to buffer the RAMP signal RAMP. The multi-path buffer 14 can reduce the load of a single buffer 14, improve the stability and the service life of the circuit and reduce the difficulty of circuit design.
If the DATA signal DATA and the counter signal counter have 10 bits and the significant bit is 8 bits, the gamma voltage generation circuit 10 according to the embodiment of the invention may be used to generate the gamma voltage. Compared with a traditional digital gamma circuit, the gamma voltage generating circuit 10 provided by the application does not need data digit expansion, the occupied area of the circuit and the power consumption of the circuit are reduced, and practical application shows that the power consumption of the gamma voltage generating circuit 10 provided by the application is reduced by about 50% compared with that of the traditional digital gamma circuit; compared with the traditional analog gamma circuit, the gamma voltage generating circuit 10 provided by the application greatly reduces the complexity of the circuit while maintaining high precision.
Fig. 4 illustrates a waveform diagram of a gamma voltage generating circuit according to an embodiment of the present invention.
As shown in fig. 4, as an embodiment, the number of bits of the count signal count <7:0> is 8 bits, the ramp signal linearly decreases from the first voltage V1 to the second voltage V2 within a predetermined time T, and the predetermined time T is included in the display duration of one line of the frame.
In a conventional digital gamma circuit, to complete the non-linear conversion of data, bit width expansion is required, generally 8 bits are expanded to 10 bits, or 8 bits are expanded to 12 bits, taking a count signal count <9:0> for expanding a count signal count <7:0> to 10 bits as an example, when a ramp signal starts to fall, the count signal count <9:0> is output to 0, when the ramp signal stops falling, the count signal count <9:0> is output to 1023, and each time the change of the count signal count <9:0> is equal in time difference.
In the gamma voltage generating circuit provided by the invention, the number of bits of the count signal count <7:0> is 8 bits, bit expansion is not needed, when a ramp signal starts to descend, the count signal count <7:0> is output to be 0, when the ramp signal stops descending, the count signal count <7:0> is output to be 255, and each time the change of the count signal count <7:0> is not equal in time difference, but controlled by a gamma curve.
FIG. 5 illustrates a schematic diagram of a gamma voltage generating method according to an embodiment of the present invention. As shown in fig. 5, the gamma voltage generating method according to the embodiment of the present invention includes steps S101 to S103, and the gamma voltage generating method does not need to perform bit expansion on the data signal, thereby greatly reducing the area occupied by the circuit and the power consumption of the circuit, and ensuring high accuracy of the gamma voltage.
In step S101, a ramp signal that is converted from a first voltage to a second voltage for a predetermined time is generated. Optionally, a ramp signal is generated according to the ramp control signal, and after the ramp signal is generated, the ramp control signal is buffered.
In step S102, counting is performed for a predetermined time, and a count signal is generated, each counting period of the count signal corresponding to a gray-scale signal selected from a portion of the ramp signal. In the embodiment of the present invention, the counting time length maintained by each counting value of the counting signal is determined by the gamma curve, and the counting signal can be seen from count <7:0> in fig. 4, in this example, the grayscale accuracy of 10 bits or 12 bits is achieved by using a bit width of 8 bits.
In step S103, a corresponding data signal is received, the count signal is compared with the data signal, and when the count signal is identical with the data signal, the gray-scale signal is latched to obtain a gamma voltage corresponding to the data signal. In this step, specifically, the count signal is compared with the data signal, and an invalid control signal is supplied when the count signal coincides with the data signal; and according to the invalid control signal, cutting off a current path from the ramp signal to the source line so as to latch the gray-scale signal corresponding to the counting signal, thereby obtaining the gamma voltage corresponding to the data signal.
Optionally, the method further includes: before generating the ramp signal, the gamma voltage is reset according to the reset signal.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.
Claims (10)
1. A gamma voltage generation circuit, comprising:
a ramp signal generator for generating a ramp signal, the ramp signal being converted from a first voltage to a second voltage for a predetermined time;
a counter for counting within the predetermined time and generating a count signal, each count value of the count signal corresponding to a gray scale signal selected from a portion of the ramp signal; and
a plurality of sampling modules, each of which receives a corresponding data signal and compares the count signal with the data signal, and when the count signal is identical to the data signal, the sampling modules latch the gray scale signal to obtain a gamma voltage corresponding to the data signal,
the step lengths of the counters are different, and the counting time length maintained by each counting value is determined by a gamma curve.
2. The gamma voltage generation circuit of claim 1, wherein each of the sampling modules comprises:
a comparator that compares the count signal with the data signal and provides an invalid control signal when the count signal is identical with the data signal;
and the switching tube is used for switching off a current path from the ramp signal to a source line according to the invalid control signal so as to latch the gray-scale signal corresponding to the counting signal, thereby obtaining the gamma voltage corresponding to the data signal.
3. The gamma voltage generation circuit of claim 2, wherein the switching tube transmits the gamma voltage to the source line, the gamma voltage being stored on a parasitic capacitance of the source line.
4. The gamma voltage generation circuit of claim 3, further comprising: and the reset transistor is connected between the parasitic capacitor and an input power supply and is used for resetting the gamma voltage according to a reset signal.
5. The gamma voltage generation circuit of claim 1, further comprising: the buffer is connected between the sampling modules and the ramp signal generator, or the buffers are respectively connected between the sampling modules and the ramp signal generator and used for buffering the ramp signal.
6. A display device, comprising:
the gamma voltage generating circuit of any one of claims 1 to 5, receiving a data signal and providing a gamma voltage corresponding to the data signal; and
and the display panel is connected to the gamma voltage generating circuit and is used for displaying pictures according to the gamma voltage.
7. A gamma voltage generating method, comprising:
generating a ramp signal converted from a first voltage to a second voltage for a predetermined time;
counting within the predetermined time and generating a count signal, each count value of the count signal corresponding to a gray scale signal selected from a portion of the ramp signal; and
receiving corresponding data signals, comparing the counting signals with the data signals, latching the gray scale signals when the counting signals are consistent with the data signals to obtain gamma voltages corresponding to the data signals,
wherein, the counting time length maintained by each counting value of the counting signal is determined by a gamma curve.
8. The gamma voltage generating method of claim 7, wherein the data signal is not subjected to gamma conversion, and the count signal is determined by a gamma curve.
9. The gamma voltage generating method of claim 7, wherein the method of obtaining the gamma voltage comprises:
comparing the count signal with the data signal and providing an invalid control signal when the count signal is consistent with the data signal;
turning off a current path of the ramp signal to a source line according to the inactive control signal to latch the gray-scale signal corresponding to the count signal, thereby obtaining the gamma voltage corresponding to the data signal.
10. The gamma voltage generation method of claim 7, further comprising: resetting the gamma voltage according to a reset signal before generating the ramp signal.
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