Pixel Driving Circuit Overcurrent Protection via Grayscale Clamping
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Solution Overview
Problem
Display devices face issues with excessive driving current due to noise, leading to abnormal brightness and potential burning of lines or devices, as well as the occurrence of afterimages and increased visibility of image noise.
Innovation Solution
A pixel driving circuit with a control circuit that compares grayscale values and switches to a low-brightness mode if values exceed a high-brightness reference, using a digital-to-analog converting circuit to output low-brightness analog voltage to prevent excessive current and abnormal light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high driving current is supplied to control pixel brightness at high levels, then pixel brightness is improved, but heat generation and risk of burning lines or devices increases
Solution Approach 1:
The control circuit performs preliminary detection of grayscale values before the driving current is applied to the pixel. When an abnormal grayscale value exceeding the reference threshold is detected, the control circuit preemptively clamps the grayscale value to prevent excessive driving current from being supplied, thereby avoiding heat generation and potential burning of lines or devices before the harmful effect can occur.
Solution Approach 2:
The control circuit continuously monitors the grayscale values of pixel data and compares them against a predetermined reference threshold. This feedback mechanism enables real-time detection of abnormal grayscale values and automatic adjustment by clamping exceeded values, ensuring that the driving current remains within safe limits while maintaining normal operation when grayscale values are within the acceptable range.
2Productivity
If pixel data with abnormal grayscale value is processed normally, then image data processing speed is maintained, but afterimage and image noise visibility occur
Solution Approach 1:
The control circuit performs preliminary detection and correction of abnormal grayscale values in the pixel data before the data is processed further and displayed. By clamping grayscale values that exceed the reference threshold in advance, the control circuit prevents abnormal brightness and subsequent afterimage effects, while maintaining normal processing speed for all other pixels without requiring complex post-processing operations.
Data Source
AI summary
The present embodiment relates to a technology for driving a display device, and provides a technology in which a pixel driving device determines whether or not an overcurrent flows through a driving voltage line, and, if it is determined that an overcurrent flows therethrough, controls pixel data or an analog voltage output to a pixel so as to reduce a driving current.