OLED Data Driver Channel Switching for Signal Sampling
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Solution Overview
Problem
In OLED display panels, non-uniform electrical characteristics among subpixels due to deterioration can lead to reduced image quality, necessitating a method to detect and compensate for these variations.
Innovation Solution
A data driver with sample-and-hold circuits and a switching block that samples and amplifies sensing signals from the display panel, using channel switching to generate reference sensing values by averaging outputs from non-adjacent sample-and-hold circuits, thereby compensating for output deviations and simplifying compensation algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sample-and-hold circuits are used to sample sensing signals from different subpixels, then the sensing capability is improved, but output deviations between the circuits reduce measurement precision
Solution Approach 1:
The sensing period is divided into multiple sub-periods, with each sub-period dedicated to a specific sample-and-hold circuit. This segmentation allows each circuit to be fully utilized and its output to be independently processed, thereby improving overall measurement precision while maintaining consistency through structured timing control
Solution Approach 2:
The patent implements periodic sensing operations where each sample-and-hold circuit operates in alternating periods. By periodically switching between circuits in a predetermined sequence and averaging their outputs over complete cycles, the system achieves both improved measurement precision and consistent reliability across all circuits
2Productivity
If sensing signals are sampled using multiple sample-and-hold circuits in parallel, then the sensing speed is improved, but device complexity increases
Solution Approach 1:
Instead of complex simultaneous parallel processing, the patent uses periodic sequential sampling where multiple circuits operate in alternating time slots. This approach achieves high sensing speed by utilizing all circuits efficiently over time, while keeping the device complexity manageable through simple time-division multiplexing control
Solution Approach 2:
Each sample-and-hold circuit is designed to be multi-functional, serving both as a sampling element and as part of the averaging computation system. The circuits share common control signals and output structures, allowing them to perform multiple roles and reducing overall device complexity while maintaining high sensing productivity
3Device complexity
If output deviations between sample-and-hold circuits are not compensated, then device complexity is reduced, but image quality deteriorates
Solution Approach 1:
The patent implements an internal feedback mechanism where the output of each sample-and-hold circuit is fed into an averaging computation that compensates for individual circuit deviations. This feedback loop automatically corrects manufacturing variations and ensures uniform image quality without requiring complex external compensation mechanisms
Solution Approach 2:
The system performs self-compensation by using its own multiple sample-and-hold circuits to detect and correct output deviations through internal averaging. This self-service approach eliminates the need for separate external calibration equipment or complex compensation circuits, maintaining low device complexity while achieving high image uniformity
Data Source
AI summary
Provided are a data driver and a display driving circuit including the data driver. A data driver configured to drive a display panel including a plurality of subpixels connected to a plurality of sensing lines includes: a plurality of sample-and-hold circuits configured to perform a sampling operation on a plurality of sensing signals received via the plurality of sensing lines; a switching block configured to provide a first sensing signal among the plurality of sensing signals to a first sample-and-hold circuit in a first sensing period, and in a second sensing period, provide the first sensing signal to a second sample-and-hold circuit not being adjacent to the first sample-and-hold circuit in a second sensing period; and a converting circuit configured to generate a plurality of sensing values by amplifying and analog-to-digital converting on outputs of the plurality of sample-and-hold circuits.