Source Driver IC Internal Sensing Reference Voltage Generation
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Solution Overview
Problem
In organic light emitting display devices, the variation in electrical characteristics of pixels over time leads to luminance deviations and image quality deterioration, requiring external compensation, which increases the size and wiring complexity of the source driver integrated circuit (IC) due to the need for additional circuits and wiring for sensing reference voltages.
Innovation Solution
The source driver IC generates its own sensing reference voltage internally, eliminating the need for an external input pad and internal wiring by using an internal ground to initialize pixel voltages, reducing the IC's size and wiring through a switch circuit configuration that selectively connects the internal ground to the sensing line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external voltage source is used to supply sensing reference voltage to the source driver IC, then accurate pixel sensing can be achieved, but the IC size and wiring complexity increase
Solution Approach 1:
The source driver IC generates its own sensing reference voltage internally using an internal ground (GND) and a first switch circuit, eliminating the need for external voltage source and input pad. The internal ground serves the dual purpose of reference voltage generation and circuit grounding, allowing the IC to self-provide the necessary sensing reference without external assistance.
Solution Approach 2:
The patent merges the sensing reference voltage generation function with the internal ground system. By electrically connecting the internal ground to the sensing line through the first switch circuit during sensing mode, the ground potential is directly utilized as the sensing reference voltage, combining two functions (grounding and reference voltage provision) into a single internal resource.
2Reliability
If an external voltage source is used to supply sensing reference voltage, then reliable pixel initialization is achieved, but the number of input pads and internal wirings increases
Solution Approach 1:
The source driver IC uses its internal ground to generate the sensing reference voltage for pixel initialization, eliminating the need for external input pads and wiring. The internal ground automatically provides the reference potential needed for reliable pixel voltage initialization during sensing mode.
Solution Approach 2:
The patent extracts and eliminates the external voltage source and its associated input pad and internal wiring from the system. By taking out these external components and replacing them with an internal ground-based solution, the design achieves the same functional outcome with reduced complexity.
3Reliability
If pixel sensing circuit is mounted in the source driver IC for external compensation, then image quality deterioration is prevented, but the IC size increases
Solution Approach 1:
The patent combines the pixel sensing circuit with the internal ground system to create a compact solution for image quality compensation. The sensing circuit utilizes the internal ground as the reference voltage source, integrating the compensation functionality within the existing IC architecture without requiring additional external components or significant area expansion.
Data Source
AI summary
Provided a source driver integrated circuit (IC) and a display driving device eliminating an existing input pad and internal wiring of a source driver integrated circuit (IC) for receiving a sensing reference voltage from an external voltage source by allowing the sensing reference voltage for initializing pixels during sensing of the pixels to be generated by an internal voltage source, rather than the external voltage source.