Thin-Oxide Level Shifter Circuit for High-Bandwidth Voltage Translation
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Solution Overview
Problem
Current level shifter circuits face performance limitations at high frequencies due to the use of thick gate oxide transistors, which result in higher power consumption and lower bandwidth, as they need to be sized larger to drive current effectively, leading to increased capacitive loading and reduced performance.
Innovation Solution
Implementing a level shifter circuit with a thin gate oxide transistor at the input of the output stage, coupled with a thick gate oxide transistor, and biasing the gate node to a reference voltage to manage voltage stress and prevent overstress on the thin gate oxide transistor, allowing for high-frequency operation while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick gate oxide transistors are used in the level shifter circuit, then device reliability and voltage stress tolerance are improved, but bandwidth and power consumption are worsened due to larger transistor sizing requirements
Solution Approach 1:
The patent applies different gate oxide thicknesses to different stages of the level shifter circuit. Specifically, the input stage uses thin gate oxide transistors for high-speed operation, while the output stage uses thick gate oxide transistors for high voltage tolerance. This local differentiation allows each stage to be optimized for its specific functional requirements, resolving the contradiction between speed and reliability.
2Power
If thick gate oxide transistors are sized larger to drive required load current, then current driving capability is improved, but capacitive loading increases and bandwidth decreases
Solution Approach 1:
The patent uses thin gate oxide transistors in the input stage where high-speed operation is critical, eliminating the need for large transistor sizes. The thin gate oxide provides lower capacitance and faster switching, while still achieving the required current driving capability through optimized device geometry and circuit configuration specific to the input stage requirements.
3Reliability
If thick gate oxide transistors are used, then voltage stress tolerance is improved, but power consumption increases due to larger transistor sizes
Solution Approach 1:
The patent confines thick gate oxide transistors to the output stage where high voltage tolerance is required for driving the load at elevated voltage levels. The input stage uses thin gate oxide transistors that consume less power due to smaller device sizes. This spatial separation of thick and thin gate oxide devices optimizes the overall power consumption while maintaining necessary voltage stress tolerance in the output stage.
4Power
If larger sized transistors are used to compensate for thick gate oxide limitations, then current capability is improved, but chip area increases
Solution Approach 1:
The patent uses thin gate oxide transistors in the input stage which provide higher current capability per unit area compared to thick gate oxide transistors. This allows the circuit to achieve the required current driving capability with smaller transistor sizes, thereby reducing the overall chip area occupied by the level shifter circuit while maintaining necessary performance.
Data Source
AI summary
A level shifting circuit with a thin gate transistor connected to the input of the output stage is presented. The level shifting circuit has an input stage that receives an input that is at first voltage. A transistor with a thin gate oxide has one terminal connected to the input stage and another terminal coupled to an input of the output stage. The output stage of the level shifting circuit is implemented with thick gate oxide transistors.