What Is an LCD Controller?
An LCD Controller is a device that transforms input video signals into a displayable format on an LCD panel. It operates under instructions from the system control CPU, writing drawing data into built-in or external image memory, and then reading and outputting this data to the LCD panel. This process significantly reduces the load on the system control CPU for rendering images.
Applications of the LCD Controller
LCD Controllers are primarily used to offload image processing tasks from the system control CPU. They capture camera images, adjust data to match the LCD panel’s display resolution, and independently display images. These controllers often feature interfaces compatible with HDMI output, allowing simultaneous display on LCD panels and output to peripheral devices through HDMI.
Principle of LCD Controller
1. Data Storage
LCD Controllers store image data in VRAM (Video Random Access Memory). They read this data from the memory and output it to the LCD panel.
2. Image Data Processing
Processing tasks include rotation for portrait or landscape display, scaling for adjusting moving images to the panel’s pixel count, and FRC (Frame Rate Converter) processing to align CPU writing speed with LCD speed.
3. Data Communication
The controller communicates with the system control CPU via interfaces like I2C or SPI buses. It converts input video signals into RGB data for the LCD panel, synchronized with horizontal and vertical display positioning signals (HSYNC and VSYNC).
Other Information on LCD Controllers
1. Typical Number of Display Pixels
Common display pixel resolutions for TV sets include:
- SD Broadcast: 720 × 480 pixels (480P)
- HD Broadcast: 1,280 × 720 pixels (720P)
- Full HD Broadcast: 1920 × 1080 pixels (1080P)
- 4K Broadcast: 3,840 × 2,160 pixels (2160P)
- 8K Broadcast: 7,680 × 4,320 pixels
All these standards utilize LCD Controllers for image control.
2. Low Power Consumption Technology
For mobile devices, low power consumption is crucial. LCD Controllers are designed to reduce power by deactivating unused functions, implementing detailed clock control for processing blocks, and adjusting the video memory operating clock. Active block control, a hardware feature, automatically adjusts processing clocks based on the operation.