Source Driver Level Shift Circuit for Smaller Display Driver Chips
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Solution Overview
Problem
Existing source drivers for display devices face increased chip size due to the use of high voltage elements, which are necessary for processing high voltage logic signals and source signals, leading to larger circuit sizes and higher costs.
Innovation Solution
A level shift circuit utilizing only middle voltage elements to process high voltage logic signals, incorporating a first and second level shifter and an output circuit with pull-up and pull-down elements operating in different voltage ranges to generate logic signals that can swing across a high voltage range, thereby reducing the need for high voltage elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage elements are used to process high voltage logic signals, then the logic signal can be processed correctly, but the chip size increases
Solution Approach 1:
The patent changes the voltage parameter of the logic signal by introducing a level shift circuit that converts high voltage logic signals to middle voltage logic signals. This allows middle voltage elements to process signals that originally required high voltage elements, thereby reducing chip size while maintaining processing capability
Solution Approach 2:
The level shift circuit acts as an intermediary between the high voltage logic signal source and the middle voltage elements. It transforms the incompatible high voltage signals into compatible middle voltage signals, enabling middle voltage elements to function in place of high voltage elements
2Ease of operation
If high voltage elements are used in the level shift circuit, then high voltage logic signals can be processed, but the chip size and product cost increase
Solution Approach 1:
The level shift circuit changes the voltage parameter from high voltage to middle voltage, allowing middle voltage elements to handle high voltage logic signals. This eliminates the need for high voltage elements in the level shift circuit, reducing chip size and cost
3Reliability
If high voltage elements are used throughout the circuit, then high voltage signals can be processed, but manufacturing cost increases due to high voltage mask layers
Solution Approach 1:
By changing the voltage parameter through the level shift circuit, middle voltage elements can process high voltage signals. This eliminates the need for expensive high voltage mask layers in the manufacturing process, reducing production costs while maintaining high voltage signal handling capability
Data Source
AI summary
The present disclosure discloses a source driver including a level shift circuit. The source driver may include a level shift circuit outputting second and third logic signals by shifting a level of a first logic signal and a multiplexer transferring a first or second source signal to a first or second pad in response to the second and third logic signals. The level shift circuit may include a first level shifter outputting first and second input signals by shifting the level of the first logic signal, a second level shifter outputting third and fourth input signals by shifting the level of the first logic signal, and an output circuit outputting the second logic signal in response to the second and fourth input signals and outputting the third logic signal in response to the first and third input signals.