Source Driver Digital-Analog Converter for Stable Initialization Voltage
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Solution Overview
Problem
Display devices face issues with reference voltage stability due to increased bonding resistance between the printed circuit board and the source driver, and between the source driver and the display panel, especially in high-temperature and humid environments, leading to mura defects and varying reference voltages across source drivers.
Innovation Solution
A source driver with a digital-analog converter that generates an initialization voltage in an analog format, using a voltage divider and a digital-analog converter switch unit with N-type and P-type transistors, ensures consistent reference voltage delivery across multiple source drivers, independent of bonding resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reference voltage is provided via printed circuit board and source driver in analog form, then the reference voltage can be delivered to the display panel, but the magnitude of the reference voltage changes due to bonding resistance and self-resistance of power lines
Solution Approach 1:
The patent replaces the analog reference voltage transmission system with a digital signal transmission system. Instead of transmitting the reference voltage directly through analog power lines (which are affected by resistance), the system transmits digital data representing the reference voltage level through data lines. The actual reference voltage is then generated locally at the source driver based on this digital data, eliminating the harmful effects of bonding resistance and self-resistance on voltage magnitude.
Solution Approach 2:
The patent introduces a digital-analog converter (DAC) as an intermediary component. The DAC receives digital reference voltage data from the data driver and converts it into the corresponding analog reference voltage locally at the source driver. This intermediary conversion process ensures that the reference voltage is generated after transmission, bypassing the resistance issues that affect direct analog transmission.
2Area of stationary object
If display panel size is increased requiring more source drivers, then the display area is expanded, but reference voltage magnitudes differ between source drivers causing mura defects
Solution Approach 1:
The patent segments the reference voltage generation process into individual source drivers. Each source driver independently generates its own reference voltage based on digital data received from the data driver, rather than relying on a centralized analog reference voltage source. This segmentation ensures that each source driver has precise control over its reference voltage magnitude, eliminating variations between drivers even as the display panel size increases.
Solution Approach 2:
The patent changes the state of reference voltage transmission from direct analog voltage to digital data representation. By transmitting digital parameters (data values) instead of analog voltage directly, the system enables precise control and consistent reproduction of reference voltage magnitudes across multiple source drivers, preventing mura defects caused by voltage variations.
3Reliability
If digital-analog converter is added to generate initialization voltage, then reference voltage consistency is improved, but device complexity increases
Solution Approach 1:
The digital-analog converter serves as an intermediary that bridges the digital data transmission system and the analog voltage generation system. While it adds a component to the source driver structure, it enables the system to maintain reference voltage consistency by converting digital reference voltage data into precise analog voltages locally at each driver, ensuring uniform performance across the display.
Data Source
AI summary
A display device includes: a display panel including a plurality of pixels; a source driver for outputting a target initialization voltage in an analog format to the pixels through sensing lines; and a timing controller for providing the source driver with a data control signal including packet information associated with the target initialization voltage. The packet information is in a digital format. The source driver includes a digital-analog converter which generates the target initialization voltage in the analog format, based on the packet information.