Global Current Sensing Circuit for Display Luminance Stability
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Solution Overview
Problem
The fluctuation in global current due to changes in electrical characteristics of transistors in a display device leads to luminance degradation over time.
Innovation Solution
A global sensing current generating circuit that includes a plurality of sensing current generating circuits, a single current sensing line, and a current summing circuit to sense and compensate for fluctuations in the global current, using driving transistors and capacitors to sample threshold voltages and adjust luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transistor electrical characteristics are used for display operation, then the display device can function normally, but the threshold voltage changes over time causing global current fluctuation and luminance degradation
Solution Approach 1:
The patent applies preliminary action by sensing the global current before it causes visible luminance degradation and compensating in advance. The sensing current generating circuits continuously monitor the global current flowing through the pixel array, and the timing controller adjusts the luminance of image data proactively to prevent luminance fluctuation, rather than reacting after degradation occurs.
Solution Approach 2:
The patent implements feedback by using the sensed global current value to adjust subsequent display operations. The timing controller receives the global current sensing value from the sensing current generating circuits, compares it with reference values, and adjusts the luminance of image data accordingly, creating a closed-loop control system that maintains stable display performance despite transistor characteristic changes.
2Measurement precision
If multiple sensing current generating circuits are used to sense global current, then sensing accuracy improves, but circuit complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the sensing function into multiple sensing current generating circuits distributed across different regions of the pixel array. Each circuit independently senses the global current flowing through its region, and the results are combined to achieve comprehensive and accurate global current measurement, improving sensing precision through spatial distribution.
Solution Approach 2:
The patent combines the outputs of multiple sensing current generating circuits through a current summing circuit. The sensing currents from multiple circuits are summed together to produce a comprehensive global current sensing value, merging individual regional measurements into a unified accurate representation of the total global current.
Data Source
AI summary
A global sensing current generating circuit and a display device including the same, and more particularly to a global sensing current generating circuit that senses a global current in a display area, and a display device that compensates for a fluctuation in the global current based on a current value of the sensed global current.