Embodiments of the present disclosure relate to the field of display, and more particularly, to a display driving apparatus, a display driving component, and a display device.
In a display driving apparatus, a Low Voltage Differential Signal (LVDS for short) generated by a signal source such as a graphics card etc. is transmitted to a timing control Integrated Circuit (IC) in the display driving apparatus. The timing control IC converts the received signal into a display data signal and a display control signal and transmits the signals to a display driving IC to control a display operation of a display panel. As the transmitted signals are high-frequency signals, the signals transmitted from the timing control IC to the display driving IC may be reflected on a transmission line, which causes signal oscillation on the transmission line.
According to an aspect of the embodiments of the present disclosure, there is proposed a display driving apparatus, comprising:
a display controller configured to generate a plurality of output signals, wherein the display controller has a plurality of output ports for outputting the generated plurality of output signals respectively;
display drivers configured to generate a display signal according to at least a part of the plurality of output signals output by the output ports; and
termination impedance matching networks connected between the display controller and the display drivers via a plurality of signal lines.
According to an embodiment of the present disclosure, for each of the display drivers, the display controller is connected to the display driver via at least one pair of signal lines of the plurality of signal lines, and the termination impedance matching networks each comprise impedance matching sub-networks connected between two signal lines of each pair of signal lines.
According to an embodiment of the present disclosure, the impedance matching sub-networks have the same impedance value.
According to an embodiment of the present disclosure, the impedance matching sub-networks each have an impedance value in a range of about 80 ohms to 85 ohms.
According to an embodiment of the present disclosure, the impedance matching sub-networks each comprise at least one resistor.
According to an embodiment of the present disclosure, the display controller and the display drivers are arranged in a substantial T-shaped layout.
According to an embodiment of the present disclosure, the termination impedance matching networks are as close as possible to the corresponding display drivers.
According to an embodiment of the present disclosure, the display controller comprises a timing control Integrated Circuit (IC) configured to receive an external signal and convert the received external signal into the plurality of output signals.
According to an embodiment of the present disclosure, the plurality of output signals are high-frequency signals transmitted in a form of Low Voltage Differential Signal (LVDS).
According to another aspect of the embodiments of the present disclosure, there is proposed a display driving component, comprising:
a printed circuit board;
a display controller configured to generate a plurality of signals, wherein the display controller has a plurality of output ports for outputting the generated plurality of signals respectively; and
display drivers configured to generate a display signal according to at least a part of the plurality of signals output by the output ports;
wherein the printed circuit board has termination impedance matching networks provided thereon, which are connected between the display controller and the display drivers via a plurality of signal lines on the printed circuit board.
According to an embodiment of the present disclosure, the display controller is located on a central line of the printed circuit board.
According to an embodiment of the present disclosure, the display controller is located at a center of the printed circuit board.
According to an embodiment of the present disclosure, the display controller and the display drivers are arranged in a substantial T-shaped layout.
According to an embodiment of the present disclosure, the termination impedance matching networks are as close as possible to the corresponding display drivers.
According to an embodiment of the present disclosure, the display controller comprises a timing control Integrated Circuit (IC) configured to receive an external signal and convert the received external signal into the plurality of output signals.
According to an embodiment of the present disclosure, the plurality of output signals are high-frequency signals transmitted in a form of Low Voltage Differential Signal (LVDS).
According to an embodiment of the present disclosure, for each of the display drivers, the display controller is connected to the display driver via at least one pair of signal lines of the plurality of signal lines, and the termination impedance matching networks each comprise impedance matching sub-networks connected between two signal lines of each pair of signal lines.
According to an embodiment of the present disclosure, the impedance matching sub-networks have the same impedance value.
According to an embodiment of the present disclosure, the impedance matching sub-networks each have an impedance value in a range of about 80 ohms to 85 ohms.
According to an embodiment of the present disclosure, the impedance matching sub-networks each is at least one resistor.
According to yet another aspect of the embodiments of the present disclosure, there is proposed a display device comprising the display driving apparatus according to the embodiments of the present disclosure.
According to a further aspect of the embodiments of the present disclosure, there is proposed a display device comprising the display driving component according to the embodiments of the present disclosure.
In order to more clearly describe the technical solutions according to the embodiments of the present disclosure or in the conventional technologies, the accompanying drawings needed to be used in the description of the embodiments will be briefly described below. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other accompanying drawings can also be obtained based on these accompanying drawings without any creative work. In the accompanying drawings,
In order to make the purposes, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the embodiments described are a part of the embodiments of the present disclosure instead of all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without contributing any creative work are within the protection scope of the present disclosure. It should be noted that throughout the accompanying drawings, the same elements are represented by the same or similar reference signs. In the following description, some specific embodiments are for illustrative purposes only and are not to be construed as limiting the present disclosure, but merely examples of the embodiments of the present disclosure. The conventional structure or construction will be omitted when it may cause confusion with the understanding of the present disclosure. It should be noted that shapes and dimensions of components in the figures do not reflect true sizes and proportions, but only illustrate contents of the embodiments of the present disclosure.
Unless otherwise defined, technical terms or scientific terms used in the embodiments of the present disclosure should be of ordinary meanings to those skilled in the art. “First”, “second” and similar words used in the embodiments of the present disclosure do not represent any order, quantity or importance, but are merely used to distinguish between different constituent parts.
There are usually two reasons for signal reflection during communication: impedance discontinuity and impedance mismatch. The impedance discontinuity means that a signal suddenly encounters a small impedance of a transmission line or even no impedance at the end of the transmission line, and thus a reflected signal is generated at this end. One of ways to eliminate this reflection is to bridge a termination resistor with the same impedance as a characteristic impedance of the transmission line at the end of the transmission line so that the impedance of the transmission line is continuous. As the transmission of the signal on the transmission line is bidirectional, a termination resistor with the same impedance may be connected at the other end of the transmission line. The impedance mismatch refers to impedance mismatch between a data transceiver and a transmission line. Reflection caused by this reason mainly occurs when a communication line is in an idle mode, which results in a disordered data transmission of the entire network. In order to reduce the effect of a reflected signal on the communication line, methods such as noise suppression and addition of bias resistors are often used.
An LVDS device is a high speed and low power consumption circuit design. An LVDS has characteristics such as a current driving mode and a low voltage swing, which may provide a higher signal transmission rate, and a differential transmission mode may be used to reduce both signal noises and Electromagnetic Interference (EMI). In the field of display, an LVDS signal is generated by a constant current source at a system end, for example, the constant current source may be a 3.5 mA current source. Then, current is transmitted to, for example, a timing control Integrated Circuit (IC) in a display driving apparatus via one path (for example, a positive pole) of differential signal lines. As the timing control IC exhibits a high resistance to direct current, the current results in a voltage of 350 mV. At the same time, the current flows back to the current source via the other path (for example, a negative pole) of the differential signal lines. After receiving, for example, the LVDS/an external signal from a Display Port (DP), the timing control IC performs signal conversion to provide an output signal of the timing control IC. The output signal of the timing control IC may comprise a data signal for driving a display panel and various control signals. In this conversion process, for example, a data transmission rate of the LVDS signal may be as high as 655 Mbps, and a data transmission rate of the output signal may be as high as 1.923 Gbps. The timing control IC transmits data to a source driving IC in a form of LVDS. In a case of such high-frequency data transmission, a wavelength of the signal is relatively short compared to the transmission line, and therefore a reflected wave may be formed by the signal at the end of the transmission line, thereby interfering with the original signal. In addition, as the frequency of the output signal of the timing control IC increases, some source driving ICs may have an insufficient driving capacity when a loading capability reaches a critical value, which results in poor display conditions and occurrence of snowflake points or line defects.
According to an embodiment of the present disclosure, reflection of a signal arriving at the end of a transmission line can be alleviated by adding terminal impedance matching networks. By adding the termination impedance matching networks, impedance matching between a signal source and the transmission line can be realized to reduce reflection and avoid oscillation, while reducing noises and radiation and preventing overshoot.
For example, in the example of
According to the embodiment of the present disclosure, the impedance matching sub-networks 1031 and 1032 may have the same impedance value as each other. According to a resistance calculation formula, a resistance value of a conductor is R=ρl/S, where p is a resistivity of a resistive material, l is a length of the resistive material, and S is a cross-sectional area of the resistive material. Therefore, in a case of a constant length, the smaller the cross-sectional area, the greater the resistance value. As a result, if the resistance value R becomes large, in a case of a constant resistivity and a constant length, it needs to adjust S. As the smaller the S, the greater the R, if S is too small, it may put forward a test to a manufacturing capability of a Printed Circuit Board (PCB). In consideration of the manufacturing capability of the PCB, in the case shown in
As shown in
Similarly, in the example of
According to the present embodiment, the terminal impedance matching networks 3031-3033 may have the same structure as that of the terminal impedance matching network 103 of
All the
According to an embodiment of the present disclosure, there is further provided a display driving component.
For example, in the example of
Unlike the embodiment shown in
Similarly to that described with reference to
The embodiments of the present disclosure further provide a display device comprising the display driving apparatus according to the embodiment of the present disclosure as described above.
The embodiments of the present disclosure further provide a display device comprising the display driving component according to the embodiment of the present disclosure as described above.
The display device according to the embodiment of the present disclosure may be any product or component having a display function such as an electronic paper, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, etc.
According to an embodiment of the present disclosure, reflection of a signal arriving at the end of a transmission line can be alleviated by adding terminal impedance matching networks. By adding the termination impedance matching networks and properly setting a number and positions of the terminal impedance matching networks, impedance matching between a signal source and the transmission line can be realized to reduce reflection and avoid oscillation, while reducing noises and radiation and preventing overshoot.
While the present disclosure has been particularly shown and described with reference to the exemplary embodiments of the present disclosure, it will be understood by those of ordinary skill in the art that these embodiments can be changed variously in form and detail without departing from the spirit and scope of the present disclosure defined by the attached claims.
Number | Date | Country | Kind |
---|---|---|---|
201710268846.7 | Apr 2017 | CN | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/CN2017/115896 | 12/13/2017 | WO | 00 |