Inside the Panel Self Refresh Technology
The Panel Self Refresh technology works by using a new DisplayPort command, “capture static frame.” When this command is issued by the video engine, the display will capture the last image (frame) sent, storing it in its RAM memory (frame buffer). After this command is issued, the DisplayPort main link is turned off, and the Panel Self Refresh mode is enabled.
To exit the Panel Self Refresh mode, a wake-up command is issued through the DisplayPort auxiliary (AUX) link. After a brief synchronization period (“link training”), which lasts a few milliseconds, the display will be ready to receive new images (frames), and the system will be working as it did before entering the Panel Self Refresh mode.
In Figures 1 and 2, you can see a system supporting Panel Self Refresh technology. In Figure 1, the system is working normally, while in Figure 2, the system entered the Panel Self Refresh mode. The blocks in black are turned off for power saving.