Display Driver Pre-Emphasis Circuit for Faster Gray-Scale Voltage Switching
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Solution Overview
Problem
High-resolution and large-scale display devices face challenges in rapidly converting output voltage without increasing the quiescent current of the amplifier, leading to abnormal image quality and increased temperature in source driver ICs.
Innovation Solution
A pre-emphasis circuit that includes a first latch, second latch, decoder, gamma voltage supplier, and amplifier input pre-emphasis module, which determines whether to pre-emphasize gray-scale voltage based on designated bits of input data, allowing for rapid voltage conversion without increasing quiescent current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the quiescent current of the amplifier is increased to increase the conversion rate, then the voltage conversion speed is improved, but the temperature of the IC increases
Solution Approach 1:
The patent applies preliminary action by detecting the input data pattern before the amplifier conversion and pre-adjusting the gray-scale voltage accordingly. The pre-emphasis module checks if the input data indicates a need for rapid conversion (e.g., transitioning from dark to bright regions) and pre-adjusts the voltage to match the target gray level, enabling the amplifier to complete conversion faster without requiring increased quiescent current, thus avoiding temperature rise.
2Measurement precision
If the resolution of the display screen is increased, then the image quality is improved, but the driving time required for each pixel becomes shorter
Solution Approach 1:
The pre-emphasis module performs preliminary detection of input data patterns that indicate rapid gray-level transitions (common in high-resolution displays with fine detail). When such patterns are detected, the system pre-adjusts the gray-scale voltage to the target level before the amplifier conversion, compensating for the reduced pixel driving time and ensuring accurate voltage conversion despite the shorter available time window.
Solution Approach 2:
The patent dynamically changes the operating parameters of the gray-scale voltage supply based on the detected input data patterns. When rapid conversion is needed (indicated by specific bit patterns in the input data), the pre-emphasis module adjusts the voltage parameter to accelerate the conversion process, allowing the system to maintain accurate voltage conversion for high-resolution displays even with reduced pixel driving time.
3Area of stationary object
If the screen size is increased, then the display area is improved, but the capacitance of the screen increases
Solution Approach 1:
The pre-emphasis module detects patterns in the input data that indicate large gray-level transitions, which are more common in larger screens with higher capacitance. When such patterns are detected, the system pre-adjusts the gray-scale voltage to the target level before amplifier conversion, compensating for the increased capacitance effect and enabling faster voltage conversion without requiring proportionally higher current that would cause excessive temperature rise.
Data Source
AI summary
The present disclosure provides a pre-emphasis circuit, method and display device, and belongs to a field of display driving. The pre-emphasis circuit according to the disclosure can determine whether to output a pre-emphasis voltage corresponding to grayscale of current input data via an input terminal of an amplifier according to data input to a data terminal by adding an amplifier input pre-emphasis module. Rapid conversion of output voltage can be realized without increasing the quiescent current of the amplifier, while the stability of temperature of the IC is ensured.