Display Driver IC Clock Data Restoration Circuit
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Solution Overview
Problem
The existing serial peripheral interface (SPI) in display devices wastes resources and increases electromagnetic interference due to continuous clock generation even when the touch sensing circuit is not operating, and its large signal swing range contributes to high electromagnetic interference.
Innovation Solution
An integrated circuit with a clock data restoration circuit that extracts and maintains a clock from image signals, allowing for efficient resource use and reduced electromagnetic interference by using different interfaces for data transmission, such as CEDS for image data and LVDS for touch sensing data, eliminating the need for continuous clock transmission during non-operational periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the SPI interface is used for transmitting touch sensing data, then the touch sensing circuit can communicate with the microcontroller, but the microcontroller must continuously generate the clock even when the touch sensing circuit is not operating, causing waste of resources
Solution Approach 1:
The patent applies periodic action by enabling the touch sensing circuit to operate only during specific periods when touch sensing is required, rather than continuously. The microcontroller generates clocks periodically based on the actual operating needs of the touch sensing circuit, allowing it to remain idle during display-only periods when no touch sensing is performed. This resolves the contradiction by making clock generation periodic rather than continuous, eliminating resource waste while maintaining ease of operation for touch sensing data transmission.
2Ease of operation
If the SPI interface is used for transmitting touch sensing data, then the communication between microcontroller and touch sensing circuit is established, but the large signal swing range (up to 3.3V) causes high electromagnetic interference
Solution Approach 1:
The patent applies parameter changes by fundamentally altering the signal transmission parameters - switching from the SPI interface with large voltage swing (up to 3.3V) to the CEDS interface with much smaller voltage swing. This parameter change in signal amplitude directly reduces the electromagnetic interference generated during data transmission, while the CEDS protocol maintains the necessary communication functionality between the integrated circuit and microcontroller.
3Reliability
If the touch sensing circuit operates continuously to maintain readiness, then it can respond immediately to touch events, but resources are wasted during periods when the panel is performing display operation and touch sensing is not needed
Solution Approach 1:
The patent applies dynamics by making the touch sensing circuit's operational state dynamic rather than static. The circuit can switch between active and idle states based on real-time needs - being active when touch sensing is required and idle during display-only periods. This dynamic operation maintains reliability by ensuring the circuit is ready when needed while reducing resource waste by allowing it to enter low-power states during display operation, resolving the contradiction between continuous readiness and resource efficiency.
Data Source
AI summary
According to an embodiment, it is possible to efficiently use resources by restoring a clock from an image signal including a clock in image data and using the restored clock in a section in which the image signal is not received.