Timing Controller Data Rate Variation for EMI Reduction
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Solution Overview
Problem
Conventional point-to-point timing controllers experience high electromagnetic interference (EMI) peaks due to the use of a single data rate for transmitting frame data, making it difficult to apply spread spectrum techniques effectively.
Innovation Solution
Implementing a method where a timing controller applies multiple data rates to transmit frame data, with each frame using a unique data rate to reduce EMI peaks, and adjusting data amounts and rates for inactive data intervals like vertical and horizontal blanking intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single data rate is used to transmit frame data, then the transmission is simple and stable, but high electromagnetic interference (EMI) peaks occur
Solution Approach 1:
The patent applies dynamics by making the data rate variable rather than fixed. The timing controller dynamically selects different data rates from a set of predetermined rates (e.g., first, second, third data rates) based on frame characteristics. This dynamic adjustment spreads the electromagnetic interference energy across different frequencies and time periods, preventing concentrated EMI peaks that occur with single-rate transmission.
Solution Approach 2:
The patent implements parameter changes by modifying the data rate parameter across different frames. Specifically, different data rates are applied to different frames (e.g., odd frames use one rate, even frames use another), or data rates are varied within blanking intervals versus active video periods. This parameter variation effectively distributes EMI energy spectrally and temporally.
2Object-affected harmful factors
If spread spectrum techniques are applied, then EMI peaks are reduced, but the technique is difficult to apply to P2P timing controllers with high data rates
Solution Approach 1:
The patent applies segmentation by dividing the transmission into discrete frames, each transmitted at a different data rate from a predetermined set. Instead of applying spread spectrum continuously across the entire high-speed interface, the method segments the data stream into manageable frames and assigns different rates to each segment. This makes the EMI mitigation technique compatible with high-speed SerDes interfaces where continuous spread spectrum is difficult to implement.
Solution Approach 2:
The patent implements periodic action by systematically varying data rates in a periodic pattern across frames. For example, alternating frames use different data rates, or data rates are changed at regular intervals corresponding to frame boundaries or blanking periods. This periodic variation achieves spread-spectrum-like EMI reduction while maintaining the structured, periodic nature of display data transmission.
3Object-affected harmful factors
If different data rates are applied to different frames, then EMI peaks are reduced, but the data transmission complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing a set of predetermined data rates before transmission begins. The timing controller is configured with a library of available data rates (first, second, third, etc.) and pre-determined assignment rules. This preliminary preparation eliminates the need for complex real-time calculations during transmission, as the controller simply selects from pre-defined rate options based on simple frame identification or timing information.
Data Source
AI summary
A method for transmitting data from a timing controller to a source driver includes: applying a plurality of data rates to a discrete data rate setting; and transmitting image data of a plurality of frames by using the plurality of data rates, respectively, wherein for each of the frames, its corresponding image data is transmitting by using only one of the data rates.