1. Field
The present disclosure herein relates to an electronic device such as a display device.
2. Description of the Related Art
Since a differential signal transmission is advantageous in aspects of electromagnetic interference (EMI) and electromagnetic compatibility (EMC), compared with a single-ended signal transmission, the differential signal transmission is increasingly used in data interface of a storage application, a multi-bit data bus of a DRAM, a module interface of a mobile apparatus, etc. as well as a variety of digital display devices such as a plasma display panel (PDP) driver circuitry, a liquid crystal display (LCD) driver circuitry, etc. The differential signal transmission uses two physical signal lines, i.e., a signal line for transmitting a positive (+) signal, and a signal line for transmitting a negative (−) signal, so as to transmit 1-bit data. Therefore, the differential signal transmission is advantageous in aspects of EMI/EMC, compared with the single-ended transmission, and guarantee uniform return path. Also, in the differential signal transmission, since signal lines transmitting a differential signal pair are designed to be disposed adjacent to each other, it is regarded that noise is cancelled in a far-field and thus the differential signal transmission has a strong characteristic with respect to an external noise such as crosstalk.
However, in the case where data signals are transmitted at the same time through a plurality of data signal lines arranged adjacent to each other, the differential signal transmission has a limitation that the EMI characteristic is deteriorated.
The present disclosure provides a display device and a method of controlling the same that can minimize interference between adjacent data signal lines and prevent EMI characteristic from being lowered.
Embodiments of the inventive concept provide display devices including a plurality of source drivers, and a timing controller generating a plurality of output clock signals respectively corresponding to the plurality of source drivers and providing a data signal to each of the plurality of source drivers in synchronization with the plurality of output clock signals. The output clock signals have a different phase relative to the output clock signals corresponding to adjacent source drivers among the plurality of source drivers.
In some embodiments, the timing controller may further provide a clock signal to the plurality of source drivers, and each of the plurality of source drivers may recover the data signal provided from the timing controller in synchronization with the clock signal.
In other embodiments, the data signal and the clock signal provided from the timing controller to the plurality of source drivers may be differential signals, respectively.
In still other embodiments, the timing controller may include a clock generator generating a plurality of internal clock signals having different phases, and a plurality of data output circuitries corresponding to respective source drivers of the plurality of source drivers, the data output circuitries selecting any one of the plurality of internal clock signals as the output clock signal, and outputting the data signal to be provided to the corresponding source driver in synchronization with the selected output clock signal.
In even other embodiments, each of the plurality of data output circuitries may include a selector selecting any one of the plurality of internal clock signals as the output clock signal in response to a select signal, a parallel-to-serial converter converting a parallel data signal inputted from an outside to a serial data signal and outputting the converted serial data signal as the data signal in synchronization with the output clock signal, and a differential driver converting the data signal to a differential signal and providing the converted differential signal to the corresponding source driver.
In yet other embodiments, the select signal may enable the selectors in the respective data output circuitries corresponding to adjacent source drivers to select internal clock signals having predetermined phase differences from the plurality of internal clock signals.
In further embodiments, the select signal may enable the selectors in the respective data output circuitries corresponding to at least two adjacent source drivers to select internal clock signals having complementary phases from the plurality of internal clock signals.
In still further embodiments, the plurality of source drivers may be grouped into a first group of source drivers and a second group of source drivers according to an arrangement of the plurality of source drivers. The timing controller may provide a first clock signal to the first group of source drivers and a second clock signal to the second group of source drivers, the first clock signal being different from the second clock signal.
In even further embodiments of the inventive concept, display devices include a plurality of source drivers, and a timing controller providing a data signal to each of the plurality of source drivers. The timing controller includes a clock generator generating a plurality of internal clock signals having different phases, and a plurality of data output circuitries corresponding to respective source drivers, the data output circuitries selecting any one of the plurality of internal clock signals, and outputting the data signal to be provided to the corresponding source driver in synchronization with the selected internal clock signal.
In yet further embodiments, each of the plurality of data output circuitries may include a selector selecting any one of the plurality of internal clock signals as an output clock signal in response to a select signal, a parallel-to-serial converter converting a parallel data signal inputted from an outside to a serial data signal and outputting the converted serial data signal as the data signal in synchronization with the output clock signal, and a differential driver converting the data signal to a differential signal and providing the converted differential signal to the corresponding source driver.
In other embodiments, the select signal may enable the selectors in the respective data output circuitries corresponding to adjacent source drivers to select internal clock signals having difference phases from the plurality of internal clock signals.
In still other embodiments of the inventive concept, electronic devices include a plurality of first semiconductor chips, a second semiconductor chip generating a plurality of output clock signals corresponding to respective first semiconductor chips and providing a data signal to each of the plurality of first semiconductor chips in synchronization with the plurality of output clock signals, and a printed circuit board having a plurality of signal lines arranged thereon, the plurality of signal lines transmitting the data signals provided from the second semiconductor chip to the plurality of first semiconductor chips. The output clock signals have a different phase relative to the output clock signals corresponding to adjacent first semiconductor chips among the plurality of first semiconductor chips.
In even other embodiments, the second semiconductor chip may further provide a clock signal to the plurality of first semiconductor chips, and each of the plurality of first semiconductor chips may recover the data signal provided from the second semiconductor chip in synchronization with the clock signal.
In yet other embodiments, the second semiconductor chip may include a clock generator generating a plurality of internal clock signals having different phases, and a plurality of data output circuitries respectively corresponding to the plurality of source drivers, selecting any one of the plurality of internal clock signals as the output clock signal, and outputting the data signal to be provided to the corresponding source driver in synchronization with the selected output clock signal.
In further embodiments of the inventive concept, control methods for generating a data signal to be provided to a source driver include generating a plurality of internal clock signals having different phases, selecting any one of the plurality of internal clock signals as an output clock signal, converting a received parallel data signal to a serial data signal, outputting the serial data signal as a data signal in synchronization with the selected output clock signal, and providing the data signal to the source driver.
In still further embodiments, the above control method may further include converting the data signal to a differential signal, and the differential signal may be provided to the source driver.
In even further embodiments of the inventive concept, methods of controlling a display device for generating a data signal to be provided to a plurality of source drivers include generating a plurality of internal clock signals having different phases, selecting each of the plurality of internal clock signals as output clock signals corresponding to respective source drivers of the plurality of source drivers, converting parallel data signals corresponding to respective source drivers of the plurality of source drivers to serial data signals, outputting the serial data signals corresponding to respective source drivers of the plurality of source drivers as data signals in synchronization with the output clock signals corresponding to respective source drivers of the plurality of source drivers, and providing the data signals to the plurality of corresponding source drivers.
In yet further embodiments, the selecting of each of the plurality of internal clock signals as the output clock signals includes matching the plurality of internal clock signals with the corresponding source drivers, such that the output clock signals corresponding to adjacent source drivers have different phases.
In other embodiments, the selecting of each of the plurality of internal clock signals as the output clock signal includes matching the plurality of internal clock signals with the corresponding source drivers, such that the output clock signals corresponding to at least two adjacent source drivers have complementary phases.
The above and other features and advantages will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings, in which:
Korean Patent Application No. 10-2009-0094741, filed on Oct. 6, 2009, in the Korean Intellectual Property Office, and entitled: “Electronic Device, Display Device and Method of Controlling the Display Device,” is incorporated by reference herein in its entirety.
Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout
Exemplary embodiments of the inventive concept will be described below in more detail with reference to the accompanying drawings.
Although a liquid crystal display device is shown in
Referring to
The TFT substrate 111 is a transparent glass substrate on which a plurality of TFTs as switching elements are arranged in a matrix configuration. A source line is connected to source terminals of the TFTs, and a gate line is connected to gate terminals of the TFTs. Also, a common electrode made of a transparent conductive material is connected to drain terminals of the TFTs.
In the liquid crystal display device 100 having the above-described constitution, when a power is applied to the gate terminals of the TFTs to turn on the TFTs, an electric field is formed between pixel electrodes and the common electrode. Due to the formed electric field, an arrangement of liquid crystal molecules constituting the liquid crystal layer disposed between the TFT substrate 111 and the color filter substrate 112 is changed and transmittance of light supplied from a light source is also changed to obtain an image having a desired gray scale.
The source and gate PCBs 120, 130 are respectively connected to the liquid crystal display panel 110 through a source drive circuit film 140 and a gate drive circuit film 150, and provide an image signal and scan signals for driving the liquid crystal display panel 110, respectively. The source and gate drive circuit films 140, 150 are configured, as one example, by a tape carrier package (TCP) or a chip on film (COF). The source and gate drive circuit films 140, 150 further include respective source and gate drive chips 141, 151 controlling a timing of a drive signal so as to apply the drive signal provided from the source PCB 120 to the liquid crystal display panel 110 at a proper timing.
The numbers of the source drive chips 141 and the gate drive chips 151 provided in the liquid crystal display device 100 are determined by the resolution of the liquid crystal display panel, the number of channels of the drive chip, the operating frequency, and etc.
Although not shown in
Referring to
Referring to
Referring to
In this embodiment, the source drive chips 420a-420p are divided into two groups, i.e., a first group and a second group. The first group includes the source drive chips 420a-420h, and the second group includes the source drive chips 420i-420p. The first group of source drive chips 420a-420h recover the respective data signals DA0-DA7 inputted in synchronization with the first clock signal CK_L from the timing controller 405. The second group of source drive chips 420i-420p recover the respective data signals DA8-DA15 inputted in synchronization with the second clock signal CK_R from the timing controller 405. Thus, the reason why the source drive chips 420a-420p are divided into two groups and the first clock signal CK_L and the second clock signal CK_R are provided to the respective groups is to minimize influences of noise and attenuation due to an increase in the length of signals lines transmitting the clock signals.
The timing controller 405 generates output clock signals CLK0_OUT-CLK15_OUT corresponding to the source drive chips 420a-420p, and outputs data signals DA0-DA 15 to the source drive chips 420a-420p in synchronization with the generated output clock signals CLK0_OUT-CLK15_OUT.
Referring to
According to this embodiment, transmission timings of the data signals DA0-DA7 transmitted to the first group of source drive chips 420a-420h from the timing controller 405 are different from one another, and transmission timings of the data signals DA8-DA15 transmitted to the second group of source drive chips 420i-420p are different from one another. Therefore, the EMI characteristic of the display device shown in
Referring to
Referring to
Although
The source drive chip 420a includes a selector 731, a parallel-to-serial converter 732, and a differential driver 733. The selector 731 receives all of the internal clock signals ICLK0-ICLK15 generated in the PLL 710 and selects any one of the internal clock signals ICLK0-ICLK15 as an output clock signal CLK0_OUT in response to a phase select signal PSEL. The parallel-to-serial converter 732 converts a parallel data signal DATA0 provided from a host to a serial data signal DA0_OUT, synchronizes the converted serial data signal DA0_OUT with the output clock signal CLK0_OUT and outputs the synchronized serial data signal DA0_OUT to the differential driver 733. The differential driver 733 converts the serial data signal DA0_OUT to a differential signal pair DA0_A, DA0_AB and outputs the converted differential signal pair DA0_A, DA0-AB. The differential signal pair DA0_A, DA0_AB is a data signal DA0 provided to the source drive chip 420a shown in
Although not shown in
According to this embodiment, since the transition timings of the output clock signals CLK0_OUT-CLK15_OUT are dispersed during one period, the output timings of the data signals DA0-DA15 outputted from the timing controller 405 are also dispersed. Therefore, the EMI generated in the PCB 410 shown in
Referring to
While this embodiment describes the display device as one example of an electronic device, the inventive concept may be applied to other electronic devices in which a signal is transmitted between at least two chips, for example, between a timing controller chip and a source drive chip.
Referring to
According to the present disclosure, interference between adjacent data signal lines can be minimized and lowering in the EMI characteristic can be prevented.
The above-disclosed subject matter is to be considered illustrative and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the inventive concept. Thus, to the maximum extent allowed by law, the scope of the inventive concept is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
Number | Date | Country | Kind |
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10-2009-0094741 | Oct 2009 | KR | national |