Display Driver IC Gamma Voltage Buffering for Slew Rate
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Solution Overview
Problem
Current display driver integrated circuits (DDIs) face challenges in efficiently amplifying and buffering gamma voltages for display panels, leading to decreased slew rates and performance, particularly due to increased parasitic resistances and capacitances in gamma lines.
Innovation Solution
The proposed solution involves a display driver IC with a gamma block that generates and amplifies gamma voltages, and buffer blocks that adjust and buffer these voltages, reducing the load on source channels and improving slew rates by distributing source channels into groups with interposed buffer blocks to manage parasitic resistances and capacitances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If source channels are directly connected to gamma lines without buffer blocks, then device complexity is reduced, but slew rate and recovery speed deteriorate due to increased parasitic resistances and capacitances
Solution Approach 1:
Buffer blocks are introduced as intermediary components between gamma lines and source channels. These buffer blocks compensate for parasitic resistances and capacitances by providing strong drive capability and low output impedance, thereby maintaining high slew rates and recovery speeds without requiring direct long connections.
Solution Approach 2:
Source channels are divided into multiple groups (first source channels and second source channels) and distributed to different buffer blocks. This segmentation reduces the length of gamma lines each buffer block must drive, minimizing parasitic effects and allowing each buffer block to serve a localized region efficiently.
2Adaptability or versatility
If gamma lines are made longer to reach more source channels, then adaptability is improved, but parasitic resistances and capacitances increase leading to performance deterioration
Solution Approach 1:
The display panel's source channels are segmented into multiple groups distributed across different buffer blocks. Each buffer block serves a specific region, which allows gamma lines to remain short and minimize parasitic effects while still covering the entire display area through the distributed architecture.
Solution Approach 2:
Buffer blocks act as intermediaries that extend the effective reach of gamma lines without actually increasing their physical length. The buffer blocks provide strong drive capability that can compensate for parasitic effects, allowing gamma lines to be shorter while maintaining adaptability to serve multiple source channel groups.
3Speed
If buffer blocks are added to improve slew rate, then speed is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Multiple buffer blocks are merged into a single integrated circuit structure that can be manufactured using standard semiconductor fabrication processes. The buffer blocks are designed with standardized interfaces and control mechanisms, allowing them to be manufactured together with source channels and gamma voltage generation circuits in a unified process flow.
Data Source
AI summary
An electronic device includes a first source group and a second source group, each of which includes a plurality of source channels, and a gamma block that receives first to 2i-th initial voltages (i being an integer of 1 or more), outputs first to 2i-th intermediate voltages by amplifying the first to i-th initial voltages, and outputs first to i-th gamma voltages to the first source group by buffering the first to 2i-th intermediate voltages, and a first buffer block that receives the first to 2i-th intermediate voltages from the gamma block and buffers the first to 2i-th intermediate voltages so as to be output to the second source group, and the gamma block may include a first resistor string including a plurality of resistors connected between nodes from which the first to i-th gamma voltages are output.