Double-Rate Display Driver Latch Circuit for Low-EMI Data Sharing
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Solution Overview
Problem
Display systems using the Double Rate Driving (DRD) method face challenges in reducing Electromagnetic Interference (EMI) and power consumption, particularly when driving a display panel with a shared data line configuration, as existing drivers require complex latch structures and high-frequency operations to manage time division data distribution efficiently.
Innovation Solution
A driving apparatus with a latch structure that includes first and second latch circuits, selection circuits, and a digital analog converter (DAC) configuration, allowing for efficient distribution of display data in a time division manner, minimizing EMI and part count, and enabling a low power mode by latching and reusing horizontal data for still images, thus reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a driver operates at high frequency to implement high resolution, then productivity is improved, but power consumption increases
Solution Approach 1:
The driver alternates between normal mode and low power mode in periodic cycles. During normal mode, the driver operates at high frequency to display moving images with high resolution. During low power mode, the driver reduces operation frequency to consume less power when displaying still images, achieving periodic switching between high productivity and low energy consumption states
2Productivity
If a driver repeatedly outputs source signals for horizontal data with the same pattern, then productivity is improved for still images, but power consumption increases due to unnecessary operations
Solution Approach 1:
The driver dynamically adjusts its operating mode based on the type of image being displayed. When detecting a still image with repeated horizontal data patterns, the driver transitions to low power mode where it outputs source signals only once per horizontal cycle and reuses the latched data, rather than continuously processing and outputting the same pattern, thereby reducing power consumption while maintaining productivity for still images
3Device complexity
If a driver is designed with a latch structure to distribute display data in time division manner, then device complexity is reduced, but EMI occurs due to high frequency switching
Solution Approach 1:
The latch structure operates periodically by latching horizontal data once per horizontal cycle and then reusing the latched data through selection circuits that switch between first and second latched data sets. This periodic latching action reduces the frequency of data updates compared to continuous processing, thereby reducing EMI while maintaining the simplified device complexity advantage of the latch structure
Data Source
AI summary
Disclosed is a driving apparatus for a display, which drives pixels using a double rate driving (DRD) method. The driving apparatus includes a first latch circuit storing first pixel data, a second latch circuit storing second pixel data, a first selection circuit selecting one of the first pixel data and the second pixel data and outputting selection data, and a second selection circuit selecting one of the selection data of a pair of adjacent first selection units and outputting source data.