Thin-Oxide Level Shifter Circuit Without Gate-Oxide Overstress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuit designs face challenges in interfacing circuit blocks with different voltage requirements, as existing level shifter technologies often limit switching speed and frequency due to the use of thick-oxide transistors, which are slower than thin-oxide transistors.
Innovation Solution
A level shifter circuit utilizing thin-oxide transistors, including a source follower transistor and complementary inverter circuits, to generate a high-speed output signal by shifting voltage levels between different supply voltages without overstressing the gate oxide, enabling faster data rates up to 13 Gbps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick-oxide transistors are used in level shifters, then transistor reliability is improved, but switching speed and frequency are reduced
Solution Approach 1:
The patent changes the oxide thickness parameter of the transistor from thick to thin, which fundamentally alters the switching speed characteristic. Thin-oxide transistors enable faster charge and discharge of the gate capacitance, achieving 13 Gbps data rates while the circuit design ensures reliability through controlled voltage levels that prevent oxide breakdown.
2Speed
If thin-oxide transistors are used in level shifters, then switching speed is improved, but transistor reliability deteriorates due to gate oxide stress
Solution Approach 1:
The patent ensures that voltage levels throughout the circuit remain within safe operating ranges for thin-oxide transistors. By carefully designing the level shifter to maintain equipotential conditions and prevent voltage excursions beyond the thin oxide's breakdown threshold, the circuit achieves high-speed operation without compromising transistor reliability.
Solution Approach 2:
The level shifter circuit acts as an intermediary between different voltage domains, controlling signal transitions to prevent direct exposure of thin-oxide transistors to excessive voltage stress. The circuit mediates voltage levels to enable fast switching while protecting the thin oxide layer from breakdown.
3Adaptability or versatility
If multiple independent supply voltages are used, then voltage level shifting capability is improved, but device complexity increases
Solution Approach 1:
The level shifter circuit is designed to operate with a single supply voltage while achieving level shifting functionality. The circuit uses the single supply voltage to generate both the high and low voltage levels needed for interfacing between different voltage domains, eliminating the need for multiple independent supply voltages and reducing overall system complexity.
Data Source
AI summary
A level shifter circuit includes an input circuit, an inverter, a pull-up circuit, and a pull-down circuit. The input circuit generates a pull-up signal in response to an input signal using charge from a supply voltage. The inverter inverts the input signal to generate a pull-down signal. The inverter comprises complementary transistors that receive charge from the supply voltage. The pull-up circuit pulls a level shifted output signal of the level shifter circuit to the supply voltage in response to the pull-up signal. The pull-down circuit pulls the level shifted output signal to a low voltage in response to the pull-down signal.