Display Panel Driver CMOS Stages for Low-Power Voltage Output
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Solution Overview
Problem
Conventional display device drivers require bootstrapping operations to achieve desired voltage levels, leading to increased power consumption due to the use of a single type of transistor in each stage.
Innovation Solution
Implementing a driver stage with complementary metal-oxide-semiconductor (CMOS) transistors, specifically combining p-type (PMOS) and n-type (NMOS) transistors in series, where the active regions of PMOS and NMOS transistors are made of different materials, such as polycrystalline silicon and oxide semiconductor, respectively, to eliminate the need for bootstrapping operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single type of transistor (PMOS) is used in each driver stage, then the device complexity is reduced, but power consumption increases due to the need for bootstrapping operations
Solution Approach 1:
The patent combines both PMOS and NMOS transistors in each driver stage to form a CMOS configuration. This merging of transistor types eliminates the need for bootstrapping operations, thereby reducing power consumption while maintaining the driver functionality. The complementary nature of PMOS and NMOS transistors allows for efficient voltage level generation without additional bootstrapping circuitry.
2Ease of operation
If PMOS transistors are used to output low voltage levels, then the voltage level output capability is achieved, but power consumption increases due to bootstrapping requirements
Solution Approach 1:
The patent changes the voltage level parameters by utilizing the complementary characteristics of both PMOS and NMOS transistors. The NMOS transistor, with its lower threshold voltage, can directly output low voltage levels without requiring bootstrapping operations. This parameter change in voltage generation approach eliminates the power-consuming bootstrapping mechanism while maintaining the ability to output both high and low voltage levels.
3Reliability
If different materials are used for PMOS and NMOS active regions, then transistor performance is optimized, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by using different materials for PMOS and NMOS active regions specifically where each transistor type is located. The PMOS active region uses one material optimized for p-type transistor performance, while the NMOS active region uses a different material optimized for n-type transistor performance. This localized material differentiation optimizes transistor performance in each region without requiring complete redesign of the entire manufacturing process.
Solution Approach 2:
The patent employs composite materials strategy by combining different semiconductor materials for PMOS and NMOS active regions. This composite approach allows each transistor type to operate with its optimal material characteristics, improving overall driver performance. The manufacturing process is designed to accommodate these different materials through sequential deposition and processing steps.
Data Source
AI summary
A driver is disposed in a display panel, and includes a plurality of stages. At least one stage of the plurality of stages includes an input circuit which transfers an input signal to a first node in response to at least one of a clock signal and an inverted clock signal, and inverters which generate an output signal based on a voltage of the first node. At least one of the inverters includes a p-type metal-oxide-semiconductor (“PMOS”) transistor and an n-type metal-oxide-semiconductor (“NMOS”) transistor connected in series between a line transferring a relatively high gate voltage and a line transferring a relatively low gate voltage. A first active region of the PMOS transistor includes a material different from a material of a second active region of the NMOS transistor.