This application claims the priority benefit of Taiwan application serial no. 112151264, filed on Dec. 28, 2023. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
The disclosure relates to an electronic device and particularly relates to a display device, a display driving integrated circuit (IC), and an operating method of a display driving IC.
An application processor (AP) is able to load display frame data, vertical synchronization information, and horizontal synchronization information into a data stream and subsequently provide the data stream to a display driving integrated circuit (IC) through a data lane of a mobile industry processor interface (MIPI). The vertical synchronization information may be a vertical sync start marker as defined by an MIPI standard, while the horizontal synchronization information may be a horizontal sync start marker defined by the MIPI standard. The display driving IC may drive a display panel based on display frame data, the vertical synchronization information, and the horizontal synchronization information provided by the AP.
The disclosure provides a display device, a display driving integrated circuit (IC), and an operating method of a display driving IC to drive a display panel.
According to an embodiment of the disclosure, the display driving IC includes an interface circuit, a synchronization signal generating circuit, and a driving circuit. The interface circuit receives a data stream and an external horizontal synchronization signal from a processor, where the data stream includes display frame data, vertical synchronization information, and horizontal synchronization information. The synchronization signal generating circuit is coupled to the interface circuit to receive the vertical synchronization information, the horizontal synchronization information, and the external horizontal synchronization signal. The synchronization signal generating circuit generates an internal vertical synchronization signal based on the vertical synchronization information and the horizontal synchronization information. The synchronization signal generating circuit dynamically updates a delay value based on a phase relationship among the vertical synchronization information, the horizontal synchronization information, and the external horizontal synchronization signal. The synchronization signal generating circuit delays the external horizontal synchronization signal based on the delay value to generate an internal horizontal synchronization signal. The driving circuit is coupled to the interface circuit to receive the display frame data and coupled to the synchronization signal generating circuit to receive the internal vertical synchronization signal and the internal horizontal synchronization signal. The driving circuit drives a display panel based on the display frame data, the internal vertical synchronization signal, and the internal horizontal synchronization signal.
According to an embodiment of the disclosure, the operating method of the display driving IC includes following steps. A data stream and an external horizontal synchronization signal are received from a processor by an interface circuit of the display driving IC, where the data stream includes display frame data, vertical synchronization information, and horizontal synchronization information. An internal vertical synchronization signal is generated based on the vertical synchronization information and the horizontal synchronization information by a synchronization signal generating circuit of the display driving IC. A delay value is dynamically updated based on a phase relationship among the vertical synchronization information, the horizontal synchronization information, and the external horizontal synchronization signal by the synchronization signal generating circuit. The external horizontal synchronization signal is delayed based on the delay value by the synchronization signal generating circuit to generate an internal horizontal synchronization signal. A display panel is driven based on the display frame data, the internal vertical synchronization signal, and the internal horizontal synchronization signal by a driving circuit of the display driving IC.
According to an embodiment of the disclosure, the display device includes a processor, a display driving IC, and a display panel. The display driving IC is coupled to the processor to receive a data stream and an external horizontal synchronization signal, where the data stream includes display frame data, vertical synchronization information, and horizontal synchronization information. The display driving IC generates an internal vertical synchronization signal based on the vertical synchronization information and the horizontal synchronization information. The display driving IC dynamically updates a delay value based on a phase relationship among the vertical synchronization information, the horizontal synchronization information, and the external horizontal synchronization signal, and the display driving IC delays the external horizontal synchronization signal based on the delay value to generate an internal horizontal synchronization signal. The display panel is coupled to the display driving IC, where the display driving IC drives the display panel based on the display frame data, the internal vertical synchronization signal, and the internal horizontal synchronization signal.
Based on the above, the display driving IC provided in one or more embodiments of the disclosure generates the internal horizontal synchronization signal through utilizing the external horizontal synchronization signal. Subsequently, the display driving IC employs the internal horizontal synchronization signal to drive the display panel. In the MIPI video mode, the display driving IC may utilize the internal horizontal synchronization signal to determine the timing of the next display frame. Therefore, within each display frame in the MIPI video mode, subsequent to the processor outputting data of a valid display frame (including the horizontal synchronization information of one frame) to the display driving IC, the processor discontinues the data stream (no longer outputting redundant horizontal synchronization information until the conclusion of one display frame). Since the processor does not need to output the redundant horizontal synchronization information, and correspondingly, the display driving IC does not have to receive and process (e.g., unpack) such redundant horizontal synchronization information, power consumption may be reduced. Moreover, the display driving IC is able to dynamically update the delay value of the internal horizontal synchronization signal based on the phase relationship between the horizontal synchronization information and the external horizontal synchronization signal. Consequently, the phase of the internal horizontal synchronization signal may be matched to the phase of the horizontal synchronization information provided by the processor.
Several exemplary embodiments accompanied with figures are described in detail below to further describe the disclosure in details.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
The terminology “couple (or connect)” used throughout the whole description of the disclosure (including the claims) may refer to any direct or indirect connection means. For instance, if the disclosure describes that a first device is coupled (or connected) to a second device, it should be interpreted that the first device may be directly connected to the second device, or that the first device may be indirectly connected to the second device through other devices or certain connection means. The terminologies such as “first” and “second” mentioned in the description of the disclosure (including the claims) are used to name different elements or to distinguish different embodiments or scopes and are not intended to limit the upper or lower limit of the number of the elements, nor are they intended to limit the manufacturing order or disposition order of the elements. Moreover, wherever possible, elements/components/steps with the same reference numbers in the drawings and the embodiments denote the same or similar parts. Cross-reference may be made to related descriptions of elements/components/steps with the same reference numbers or the same terminologies in different embodiments.
The display driving IC 120 may unpack the data stream AP_D1. The data stream AP_D1 includes display frame data AP_D2, vertical synchronization information VSS, and horizontal synchronization information HSS. The vertical synchronization information VSS may include a vertical sync start marker defined by the MIPI standard, and the horizontal synchronization information HSS may include a horizontal sync start marker defined by the MIPI standard. The display driving IC 120 may generate an internal vertical synchronization signal Int_Vs based on the vertical synchronization information VSS and the horizontal synchronization information HSS. Based on a phase relationship among the vertical synchronization information VSS, the horizontal synchronization information HSS, and the external horizontal synchronization signal EXT_HSYNC, the display driving IC 120 may dynamically determine/update a delay value. The display driving IC 120 may delay the external horizontal synchronization signal EXT_HSYNC based on the delay value to generate an internal horizontal synchronization signal Int_Hs. The display panel 130 is coupled to the display driving IC 120. The display driving IC 120 may drive the display panel 130 based on the display frame data AP_D2, the internal vertical synchronization signal Int_Vs, and the internal horizontal synchronization signal Int_Hs.
In the embodiment shown in
In terms of hardware, functions in association with the processor 110, the display driving IC 120, the interface circuit 121, the synchronization signal generating circuit 122, and/or the driving circuit 123 may be performed in various logic blocks, modules, and circuits of one or more controllers, microcontrollers, microprocessors, application-specific ICs (ASIC), digital signal processors (DSP), field programmable gate arrays (FPGA), central processing units (CPU), and/or other processing units. The processor 110, the display driving IC 120, the interface circuit 121, the synchronization signal generating circuit 122, and/or the driving circuit 123 may be implemented to perform the associated functions in form of hardware circuits, e.g., various logic blocks, modules, and circuits in the ICs, by applying hardware description languages (e.g., Verilog HDL or VHDL) or other suitable programming languages.
In terms of software and/or firmware, the functions in association with the processor 110, the display driving IC 120, the interface circuit 121, the synchronization signal generating circuit 122, and/or the driving circuit 123 may be performed as programming codes. For instance, the processor 110, the display driving IC 120, the interface circuit 121, the synchronization signal generating circuit 122, and/or the driving circuit 123 may be implemented using general programming languages (such as C, C++, or assembly languages), or other suitable programming languages. The programming codes may be recorded/stored in a “non-transitory machine-readable storage medium”. In some embodiments, the non-transitory machine-readable storage medium may include, for instance, a semiconductor memory and/or a storage device. An electronic device (such as a CPU, a controller, a microcontroller, or a microprocessor) may read and execute the programming codes from the non-transitory machine-readable storage medium, thereby performing the functions in association with the processor 110, the display driving IC 120, the interface circuit 121, the synchronization signal generating circuit 122, and/or the driving circuit 123.
The synchronization signal generating circuit 122 is coupled to the interface circuit 121 to receive the vertical synchronization information VSS, the horizontal synchronization information HSS, and the external horizontal synchronization signal EXT_HSYNC. In step S220, the synchronization signal generating circuit 122 generates an internal vertical synchronization signal Int_Vs based on the vertical synchronization information VSS and the horizontal synchronization information HSS. In step S230, based on a phase relationship among the vertical synchronization information VSS, the horizontal synchronization information HSS, and the external horizontal synchronization signal EXT_HSYNC, the synchronization signal generating circuit 122 may dynamically determine/update a delay value. In step S240, the synchronization signal generating circuit 122 may delay the external horizontal synchronization signal EXT_HSYNC based on the delay value to generate an internal horizontal synchronization signal Int_Hs.
The driving circuit 123 is coupled to the interface circuit 121 to receive the display frame data AP_D2. The driving circuit 123 is further coupled to the synchronization signal generating circuit 122 to receive the internal vertical synchronization signal Int_Vs and the internal horizontal synchronization signal Int_Hs. In step S250, the driving circuit 123 may drive the display panel 130 based on the display frame data AP_D2, the internal vertical synchronization signal Int_Vs, and the internal horizontal synchronization signal Int_Hs. The implementation manner and the driving details of the display panel 130 should not be construed as limitations in this embodiment.
To sum up, the display driving IC 120 generates the internal horizontal synchronization signal Int_Hs by using the external horizontal synchronization signal EXT_HSYNC and then drives the display panel 130 by using the internal horizontal synchronization signal Int_Hs. In the MIPI video mode, the display driving IC 120 may count the internal horizontal synchronization signal Int_Hs to learn a timing of the next display frame. Therefore, in each display frame in the MIPI video mode, after the processor 110 outputs valid data of a display frame (including the horizontal synchronization information HSS of one frame) to the display driving IC 120, the processor 110 may pause the data transmission of the data stream (no longer outputting redundant horizontal synchronization information HSS) until the end of one display frame. Since the processor 110 does not need to output any redundant horizontal synchronization information HSS, and the display driving IC 120 does not need to receive and process (for instance, unpack) the redundant horizontal synchronization information HSS, power consumption may be reduced.
Generally, as long as the vertical synchronization information VSS and the external horizontal synchronization signal EXT_HSYNC are not aligned, i.e., if there is a skew between the vertical synchronization information VSS and the external horizontal synchronization signal EXT_HSYNC, the display driving IC 120 may not be able to receive image frames properly. A left portion of
However, due to one or more reasons, the skew between the synchronization information (VSS and HSS) of each display frame and the external horizontal synchronization signal EXT_HSYNC may not be constant. For instance, after the processor 110 performs MIPI hopping, the skew between the synchronization information and the external horizontal synchronization signal EXT_HSYNC may be changed. Alternatively, when the processor 110 performs MIPI mode switching, such as switching between an MIPI command mode and the MIPI video mode, the skew between the synchronization information and the external horizontal synchronization signal EXT_HSYNC may also be changed. Alternatively, interference resulting from electrostatic discharge (ESD) may change the skew between the synchronization information and the external horizontal synchronization signal EXT_HSYNC. A right portion of
A middle portion of
A lower portion of
The synchronization signal generating circuit 122 may inspect the synchronization time point (e.g., a vertical synchronization time point VSS1 shown in
The synchronization signal generating circuit 122 may count a duration TLI from the external synchronization time point EHs1 to the horizontal synchronization time point HSS11 and dynamically update a delay value of the current frame based on the duration TL1. Next, the synchronization signal generating circuit 122 may delay the external horizontal synchronization signal EXT_HSYNC based on the updated delay value (i.e., the delay value corresponding to the duration TL1) to generate a plurality of horizontal synchronization points (e.g., the horizontal synchronization point IHs1 shown in
Similarly, the synchronization signal generating circuit 122 may count a duration TL2 from the external synchronization time point EHs2 (the first horizontal synchronization time point following the vertical synchronization time point VSS2 in the external horizontal synchronization signal EXT_HSYNC) to the horizontal synchronization time point HSS21 (the first horizontal synchronization time point following the vertical synchronization time point VSS2 in the horizontal synchronization information HSS) and dynamically update the delay value based on the duration TL2. The synchronization signal generating circuit 122 may generate a vertical synchronization time point IVs2 in the internal vertical synchronization signal Int_Vs based on the horizontal synchronization time point HSS21 and delay the external horizontal synchronization signal EXT_HSYNC based on the updated delay value (i.e., the delay value corresponding to the duration TL2) to generate a plurality of horizontal synchronization time points (e.g., a horizontal synchronization time point IHs2 shown in
Therefore, the update of the delay value of the current frame is independent from the update of the previous delay value of the previous frame. The display driving IC 120 may dynamically update the delay value of the internal horizontal synchronization signal Int_Hs based on the phase relationship between the horizontal synchronization information HSS and the external horizontal synchronization signal EXT_HSYNC, thereby matching the phase of the internal horizontal synchronization signal Int_Hs to the phase of the horizontal synchronization information HSS provided by the processor 110. Based on the internal horizontal synchronization signal Int_Hs whose phase matches the phase of the horizontal synchronization information HSS, the driving circuit 123 may correctly sample/latch the display frame data AP_D2.
However, due to one or more reasons, such as the interference from the ESD or other factors, the MIPI horizontal sync start marker may be lost. For instance, a horizontal synchronization time point HSS21 (the horizontal sync start marker) may not exist. In the absence of the horizontal synchronization time point HSS21, the duration TL2 counted by the synchronization signal generating circuit 122 is inaccurate. If the duration TL2 exceeds a certain threshold duration, the synchronization signal generating circuit 122 may discard the currently counted duration TL2. Instead, the synchronization signal generating circuit 122 retains the previous delay value of the previous frame (e.g., the delay value corresponding to the duration TL1) as the delay value of the current frame. The threshold duration may be any real number determined according to the actual design.
Due to one or more reasons, such as the interference from the ESD or other factors, one or more pulses of the external horizontal synchronization signal EXT_HSYNC may be lost. For instance, an external synchronization time point EHs2 (a pulse of the external horizontal synchronization signal EXT_HSYNC) between the vertical synchronization time point VSS2 and the horizontal synchronization time point HSS21 may not exist. In the absence of the external synchronization time point EHs2 between the vertical synchronization time point VSS2 and the horizontal synchronization time point HSS21, the synchronization signal generating circuit 122 may retain the previous delay value of the previous frame (e.g., the delay value corresponding to the duration TL1) as the delay value of the current frame.
Although the disclosure has been described above through embodiments, the embodiments do not serve to pose any limitation in the disclosure. Those with ordinary knowledge in the pertinent technical field are able to make some modifications to the disclosed embodiments without departing from the spirit and scope of the disclosure, and therefore the protection scope provided in the disclosure shall be determined by the following claims and their equivalents.
Number | Date | Country | Kind |
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112151264 | Dec 2023 | TW | national |