Controller Board Frequency Dispersion for EMI Reduction
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Solution Overview
Problem
Liquid crystal display (LCD) devices generate significant electromagnetic interference (EMI) due to the transmission of frame data between the timing controller and memory, affecting external electronic devices and humans.
Innovation Solution
A controller board with a frequency expanding part that disperses the frequency band of current frame image data within a reference frequency range, reducing EMI by altering the frequency band of the signal transmitted between the timing controller and memory, and incorporating a data transition minimize circuit to control signal toggles and output buffer control to optimize signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frame data is transmitted between timing controller and memory in 32-bit units, then image display functionality is achieved, but electromagnetic interference (EMI) is generated affecting external devices and humans
Solution Approach 1:
The patent applies parameter changes by modifying the frequency characteristics of the signal transmitted between timing controller and memory. Specifically, it changes from transmitting signals at a concentrated frequency to dispersing the frequency band, thereby transforming the signal parameters to reduce EMI while maintaining the 32-bit data transmission capability needed for image display functionality
2Object-generated harmful factors
If frequency band of current frame image data is dispersed within reference frequency range, then EMI amplitudes are substantially decreased, but device complexity increases due to frequency expanding part
Solution Approach 1:
The patent introduces a frequency expanding part as an intermediary component between the timing controller and memory. This intermediary disperses the frequency band of the transmitted signal, acting as a mediator that reduces EMI generation during data transmission while maintaining the essential data transfer functionality. The frequency expanding part serves as a buffer that transforms the signal characteristics without requiring complete system redesign
Data Source
AI summary
A controller board includes a memory and a timing controller. The memory stores previous frame image data. The timing controller outputs driving image data based on current frame image data supplied from an external device and the previous frame image data. The timing controller disperses a frequency band of the current frame image data within a reference frequency range to generate dispersed current frame image data and transmits the dispersed current frame image data to the memory.