TWI706407B - Driving method for dynamically adjusting frame rate and electronic device thereof - Google Patents

Abstract

A driving method for dynamically adjusting frame rate and an electronic device thereof are disclosed. The driving method is for driving the display, and a driving controller is used to update a display according to a first frame rate. The driving method includes a system processor calculating the required transmission time according to data volume of a to-be-displayed image. The driving controller adjusts the first frame rate of the display to a second frame rate according to the transmission time, and generates a trigger signal. The system processor enters the frame skip period according to the trigger signal, transmits the image data of the to-be-displayed image to store in the buffer unit of the driving controller through a transmission interface during the frame skip period. After the end of the frame skip period, the display is adjusted to the first frame rate, and the display is updated according to the image data stored in the buffer unit.

Description

Driving method and electronic device for dynamically adjusting picture update frequency

This case is related to a display driving technology, in particular to a driving method for dynamically adjusting the screen update frequency and its electronic device.

Electronic wearable devices with displays, such as smart watches or smart bracelets, are limited by the slow transmission speed of the hardware interface, which limits the resolution or color depth of the display. Electronic wearable devices are more limited by battery capacity, so the design of displays will take low power consumption as an important goal.

Since electronic wearable devices have low demand for multimedia, it is most suitable to use a low frame rate driving method. In addition to saving the power consumption of display updates, the system can also reduce the processing and transmission of display data In order to save power consumption and hardware resources, the use of a driving method with a low image update frequency will cause the problem of unsmooth images. In addition, in order to save power consumption and hardware resources, most of the electronic wearable devices with displays use mid- and low-end systems, but their transmission interface has the problem of insufficient data transmission bandwidth, which may cause image fragmentation and delay.

This case proposes a driving method for dynamically adjusting the image update frequency to drive a display, and a drive controller is used to update the display according to a first image update frequency. The driving method includes a system processor calculating the required transmission time based on the amount of data of a to-be-displayed screen. According to the transmission time, the first image update frequency of the display is adjusted to the second image update frequency, and a trigger signal is generated. The system processor enters a frame jump period according to the trigger signal, and transmits the frame data of the to-be-displayed frame through a transmission interface during the frame jump period and stores it in the buffer unit of the drive controller. During the end of the frame jump, the display is adjusted back to the original first screen update frequency, and the screen is updated according to the screen data stored in the buffer unit.

This case also proposes an electronic device that dynamically adjusts the image update frequency, including a display, a drive controller, a buffer unit, and a system processor. The drive controller is electrically connected to the display and the buffer unit for updating the display according to the first image update frequency. The system processor is electrically connected to the drive controller, and is connected to the buffer unit through a transmission interface. The system processor calculates the required transmission time to the drive controller according to the amount of data of a picture to be displayed, and the drive controller displays the display according to the transmission time The first frame update frequency is adjusted to the second frame update frequency and a trigger signal is generated. The system processor enters a frame jump period according to the trigger signal, and transmits the frame data of the frame to be displayed through the transmission interface during the frame jump It is stored in the buffer unit, and when the frame jump period ends, the drive controller adjusts the display to the first screen update frequency, and performs screen update according to the screen data stored in the buffer unit.

In one embodiment, the transmission time is proportional to the number of frame jumps. The number of frame jumps is the product of the total data amount of the display and the update frequency of the first frame divided by the speed of the transmission interface. Among them, the total data volume is the product of the resolution and chroma of the display.

In one embodiment, the trigger signal has a continuous first level and a second level, and when the trigger signal is at the second level, the system processor is enabled to enter the frame jump period.

In one embodiment, the trigger signal is a tearing effect (Tearing Effect, TE) signal.

Therefore, this case can dynamically adjust the screen update frequency according to the amount of data, without reducing the resolution and chroma of the display, and without affecting the image quality, using the driving method of dynamically adjusting the image update frequency to solve the data transmission bandwidth Insufficient problem, and avoid causing screen jitter or delay.

10: Electronic device

12: display

14: drive controller

16: buffer unit

18: system processor

20: Transmission interface

S10~S16: steps

P _fs : During frame jump

T1: First screen update frequency

T2: second screen update frequency

FIG. 1 is a circuit block diagram of an electronic device according to an embodiment of the present application.

2 is a schematic flowchart of a driving method according to an embodiment of the invention.

FIG. 3 is a schematic diagram of waveforms of a driving method according to an embodiment of the invention.

FIG. 1 is a circuit block diagram of an electronic device according to an embodiment of the present case. As shown in FIG. 1, an electronic device 10 includes a display 12, a drive controller 14, a buffer unit 16, a system processor 18, and a transmission Interface 20. The driving controller 14 is electrically connected to the display 12 for updating the display 12 according to the first image update frequency. The buffer unit 16 is electrically connected to the drive controller 14 for storing screen data. The system processor 18 is electrically connected to the drive controller 14 and connected to the buffer unit 16 through the transmission interface 20. In some embodiments, the electronic device 10 is an electronic wearable device, which can be, but is not limited to, an electronic wearable device with a display such as a smart watch or a smart bracelet.

In some embodiments, the display 12 may be any suitable display, such as a liquid crystal display (LCD), an organic light emitting diode display (OLED), an active matrix organic light emitting diode display (AMOLED), or an electroluminescent display ( ELD) etc.

In some embodiments, the buffer unit 16 is a buffer memory, such as random access memory (RAM), which can be implemented by dynamic random access memory (DRAM) or static random access memory (SRAM), but this case does not Not limited to this. In addition, the buffer unit 16 and the drive controller 14 can also be integrated into a single chip module at the same time.

In some embodiments, the system processor 18 may adopt, but is not limited to, a medium and low-end system chip or processor.

In some embodiments, the transmission interface 20 can be a serial peripheral interface (Serial Peripheral Interface, SPI), but this case is not limited to this.

In the electronic device 10, the general driving method of the display 12 is that the system processor 18 transmits the picture data of the picture to be displayed to the buffer unit 16 through the transmission interface 20, and temporarily stores it in the buffer unit 16, and the drive controller 14 then The screen data in the buffer unit 16 is sent to the display 12 according to the first screen update frequency of the display 12 to update the screen of the display 12. At this time, since the data amount of the screen data of the screen to be displayed is less than the transmission amount of the transmission interface 20, the display 12 will update the screen normally without the visual perception of broken or delayed screen.

When the data volume of the screen data of the screen to be displayed is greater than the transmission volume of the transmission interface 20, the driving method of dynamically adjusting the screen update frequency can be adopted to drive the display 12 to update the screen according to the different data volume, so as to solve the problem of the transmission interface 20. The problem of insufficient bandwidth while maintaining picture quality.

2 is a schematic flowchart of a driving method according to an embodiment of the present invention and FIG. 3 is a schematic waveform diagram of a driving method according to an embodiment of the present invention. Please refer to FIG. 1, FIG. 2 and FIG. 3 at the same time. As shown in step S10, the system processor 18 will calculate the required transmission time according to the data amount of the next screen to be displayed. In one embodiment, the transmission time is proportional to the number of frame skips, and the number of frame skips ( SkipFrame ) is the total data amount of the display 12 and the preset frame rate ( FrameRate ) ( The product of the first image update frequency divided by the speed of the transmission interface 20 is shown below, where the total data volume of the display 12 is the product of the resolution and color depth of the display 12.

In one embodiment, the resolution of the display 12 is 240*240, the chroma is 24 bit (RGB-888), the default image update frequency is 45Hz, the transmission interface 20 speed is 24M bps, and the number of frame jumps = (240*240*24*45)/24M=2.592, the unconditional carry method is adopted, so the number of frame jumps can be determined to be 3 frames, and the transmission time of 3 frames can be obtained.

As shown in step S12, after obtaining the transmission time, the system processor 18 informs the drive controller 14 of the transmission time by means of instructions, so that the drive controller 14 can update the original first screen frequency T1 of the display 12 according to the transmission time. It is adjusted to the new second screen update frequency T2, and after the screen update frequency is adjusted, the drive controller 14 generates a trigger signal and transmits it to the system processor 18. In one embodiment, the trigger signal is a tearing effect (TE) signal.

As shown in step S14, when the system processor 18 receives the trigger signal, it can know that the screen data in the buffer unit 16 can be updated, that is, the system processor 18 will enter a frame skip period according to the trigger signal ( frame skip period) P _fs , and during this frame skip period P _fs , the system processor 18 transmits the frame data of the frame to be displayed through the transmission interface 20 and stores it in the buffer unit 16. In one embodiment, the trigger signal has a continuous first level and a second level. When the trigger signal is at the second level, the system processor 18 will be enabled to enter the frame skip period P _fs . As shown in Figure 3, in the TE signal as the trigger signal, the first level is the high voltage level and the second level is the low voltage level. When the rising edge of the TE signal starts, the TE signal is at a high voltage. When the level is set, the drive controller 14 will obtain the image data from the buffer unit 16 to update the image of the display 12; when the falling edge of the TE signal starts and the TE signal is at a low level voltage, it means that the frame jump period P _fs At this time, the system processor 18 starts to transmit the screen data of the next screen to be displayed through the transmission interface 20 and store it in the buffer unit 16 to update the screen data in the buffer unit 16.

As shown in step S16, after the frame jump period P _{fs is} ended, the drive controller 14 adjusts the display 12 from the second frame update frequency T2 back to the original first frame update frequency T1, and according to the first frame update frequency T1, The screen data stored in the buffer unit 16 is sent to the display 12 for screen update.

Of course, the system processor 18 will determine the screen update frequency according to the amount of data of each frame to be displayed. If the amount of data is small (only part of the image frames are updated), the original first frame update frequency T1 is maintained. It is necessary to adjust the picture update frequency according to the transmission time to reduce it to the second picture update frequency T2, and enter the frame skip period P _fs , so that during this frame skip period P _fs loads the picture data into the buffer unit 16 .

In some embodiments, in order to avoid that the picture quality is affected by the loading of a large amount of picture data, the above-mentioned transmission time (the length of the frame jump period P _fs ) is less than or equal to 200 milliseconds (ms) to avoid excessively long The transmission time affects the screen display.

Please refer to Figure 1 and Figure 3 at the same time, no matter what kind of display 12 is used The sub-devices 10 all use the driving method of dynamically adjusting the image update frequency to drive the display 12 to update the image. When displaying screen information, as mentioned above, two major actions are required. One is that the system processor 18 writes screen data to the buffer unit 16 of the drive controller 14 through the transmission interface 20, and the other is that the drive controller 14 uses the buffer. The screen data within the single 16 yuan update the display 12. It takes a certain amount of time to complete these two actions. If the speed of the two is different, the displayed result will be different. In one embodiment, if the speed at which the system processor 18 writes screen data to the buffer unit 16 is greater than the speed at which the drive controller 14 updates the screen of the display 12, at the beginning of the rising edge of the TE signal, the drive controller 14 will respond according to the first image Update the frequency T1 and use the screen data temporarily stored in the buffer unit 16 to update the display 12. At the beginning of the falling edge of the TE signal, the system processor 18 will start to write screen data to the buffer unit 16 through the transmission interface 20. The writing speed of the processor 18 is faster than the speed of the drive controller 14 to update the display 12, so the picture can be displayed smoothly without picture delay or fragmentation. At this time, it can be shown that the data amount of the screen data written by the system processor 18 is less than the transmission amount of the transmission interface 20, because the amount of data is small, there is no need to perform frame skip. Conversely, if the speed at which the drive controller 14 updates the screen of the display 12 is faster than the speed at which the system processor 18 writes screen data to the buffer unit 16, it means that the amount of screen data may be too large and is limited by the transmission interface 20. The system processor 18 is too late to write data into the buffer unit 16, so the picture is prone to delay or fragmentation. At this time, if the aforementioned driving method of dynamically adjusting the picture update frequency is adopted, this problem can be effectively solved.

In summary, this case updates the screen data in the buffer unit during the frame jump, and switches back to the original screen update frequency (the first screen update frequency) after the screen data transmission is completed, and there is no leakage problem Causes the picture to shake, and can maintain the picture quality. Therefore, this case can dynamically adjust the screen update frequency with different amounts of data, without reducing the resolution and chroma of the display, and without affecting the image quality, using the driving method of dynamically adjusting the screen update frequency to solve the problem of data transmission. The problem of insufficient bandwidth, and avoid causing screen jitter or delay.

The above-mentioned embodiments are only to illustrate the technical ideas and features of the case, and their purpose is to enable those who are familiar with the technology to understand the content of the case and implement them accordingly. When the scope of the patent in this case cannot be limited by them, that is, generally according to the case. Equal changes or modifications made to the spirit of the disclosure should still be included in the scope of the patent application in this case.

S10~S16: steps

Claims (12)

A driving method for dynamically adjusting the picture update frequency is used to drive a display, and a driving controller is used to update the display according to a first picture update frequency. The driving method includes: A system processor calculates the required transmission time based on the data volume of a screen to be displayed; Adjusting the first image update frequency of the display to the second image update frequency according to the transmission time, and generate a trigger signal; The system processor enters a frame jump period according to the trigger signal, and transmits the frame data of the to-be-displayed frame through a transmission interface during the frame jump period and stores it in the buffer unit of the drive controller; and After finishing the frame jump period, the display is adjusted to the first frame update frequency, and the frame is updated according to the frame data stored in the buffer unit. The driving method for dynamically adjusting the screen update frequency as described in claim 1, wherein the transmission time is proportional to the number of frame jumps. The driving method for dynamically adjusting the screen update frequency according to claim 2, wherein the frame jump number is the product of the total data amount of the display and the first screen update frequency divided by the transmission interface speed. The driving method for dynamically adjusting the screen update frequency as described in claim 3, wherein the total data amount is the product of the resolution and the chroma of the display. The driving method for dynamically adjusting the screen update frequency as described in claim 1, wherein the trigger signal has a continuous first level and a second level, and the system processor is enabled when the trigger signal is at the second level Enter the frame jump period. The driving method for dynamically adjusting the image update frequency as described in claim 1, wherein the trigger signal is a tearing effect (TE) signal. An electronic device for dynamically adjusting the frequency of picture update, including: A display A drive controller electrically connected to the display for updating the display according to a first image update frequency; A buffer unit electrically connected to the drive controller; and A system processor is electrically connected to the drive controller, and is connected to the buffer unit through a transmission interface. The system processor calculates the required transmission time to the drive controller according to the amount of data of a picture to be displayed. The controller adjusts the first image update frequency of the display to the second image update frequency according to the transmission time and generates a trigger signal. The system processor enters a frame jump period according to the trigger signal and executes a frame skip period. The screen data of the frame to be displayed is transmitted through the transmission interface during the jump and is stored in the buffer unit. When the frame jump period is ended, the drive controller adjusts the display to the first frame update frequency, and according to the buffer The screen data stored in the unit is updated. The electronic device for dynamically adjusting the screen update frequency as described in claim 7, wherein the transmission time is proportional to the number of frame jumps. The electronic device for dynamically adjusting the screen update frequency according to claim 8, wherein the frame jump number is the product of the total data amount of the display and the first frame update frequency divided by the speed of the transmission interface. The electronic device for dynamically adjusting the screen update frequency according to claim 9, wherein the total data amount is the product of the resolution and chroma of the display. The electronic device for dynamically adjusting the screen update frequency according to claim 7, wherein the trigger signal has a continuous first level and a second level, and the system processor is enabled when the trigger signal is at the second level Enter the frame jump period. The electronic device for dynamically adjusting the screen update frequency as described in claim 7, wherein the trigger signal is a tearing effect (TE) signal.

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