What Is a Flat Panel Liquid Crystal Display (LCD) Controller?
The flat panel liquid crystal display (LCD) controller is responsible for converting input video signals into a data format that can be displayed on an LCD panel. It is also responsible for outputting the data based on instructions from the CPU that control the system.
Based on instructions from the system control CPU, the LCD controller writes drawing data to the built-in or external image memory. At the same time, it reads the display data stored in the image memory and outputs it to the LCD panel.
The presence of the Flat panel liquid crystal display (LCD) controller reduces the load on the system control CPU for the drawing process.
Uses of the Flat Panel Liquid Crystal Display (LCD) Controllers
LCD panels range in size from LCDs for mobile terminals to LCD monitors and LCD panels integrated with PCs.
One example of how a flat panel liquid crystal display (LCD) controller reduces the load on the system control CPU for drawing processing is the display of camera images.
In general, flat panel liquid crystal display (LCD) controllers can capture camera images without burdening the CPU, process the data to match the display resolution (number of display pixels) of the LCD panel, and independently display the images on the LCD panel.
Some controllers also support HDMI output as an interface for connecting to peripheral devices, outputting video signals from the HDMI terminal to peripheral devices at the same time as display output to the LCD panel.
Principle of Flat Panel Liquid Crystal Display (LCD) Controllers
A flat panel liquid crystal display (LCD) controller communicates with the system control CPU via an interface such as I2C bus or SPI bus and outputs data to the LCD panel based on the instructions from the CPU.
As mentioned above, based on the input video signals, etc., the LCD controller converts them and outputs R, G, and B signals to the LCD panel. In this process, video signals are output in synchronization with HSYNC and VSYNC signals, which are synchronization signals used to determine the horizontal and vertical display positions.
LCD panels, which are the display destination, are available in various numbers of display pixels.
Typical display pixel counts for TVs are as follows: 720 x 480 pixels (480P) for SD broadcasts, 1280 x 720 (720P) for HD broadcasts, and 1920 x 1080 (1080P) for full HD broadcasts.
In addition, there is 4K broadcasting (3840 x 2160, also called 2160P), which has four times the number of pixels of Full HD broadcasting, and the latest domestic broadcasting standard is 8K broadcasting (7680 x 4320), which has 16 times the number of pixels of Full HD broadcasting.
Although the scale of each of these TV LCD panels differs, all of them use Flat panel liquid crystal display (LCD) controllers to control the displayed image.