Multi-Voltage I/O Buffer With Unified Level Shifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits (ICs) face challenges in efficiently communicating between different voltage domains due to the complexity and area occupation of split level shifters, which can lead to timing issues at high operating frequencies and overvoltage damage to MOSFETs.
Innovation Solution
A multi-voltage, high voltage I/O buffer design that incorporates a feedback-based level shifter and slew rate control circuit, using bias voltages and resistor Rio to manage voltage levels and impedance, reducing the need for multiple level shifters and protecting MOSFETs from overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If split level shifters are used to communicate between different voltage domains, then voltage level translation is achieved, but device complexity and area occupation increase
Solution Approach 1:
The patent combines multiple level shifters into a single unified level shifter that can handle multiple voltage domains simultaneously. This merged structure reduces the total number of level shifters needed in the I/O buffer, thereby reducing device complexity and area occupation while maintaining the capability to translate between different voltage levels.
Solution Approach 2:
The unified level shifter is designed to perform multiple functions - it can translate between various voltage domains (e.g., 1.8V to 3.3V, 1.8V to 5V) and handle different signal types. This multi-functional design eliminates the need for separate dedicated level shifters for each voltage domain, reducing overall device complexity.
2Adaptability or versatility
If multiple level shifters are used for different voltage domains, then comprehensive voltage translation is achieved, but timing issues occur at high operating frequencies
Solution Approach 1:
By merging multiple level shifters into a single unified structure, the patent reduces the total propagation delay that would accumulate through multiple separate level shifting stages. The unified design allows for optimized signal paths and reduced timing skew, enabling operation at higher frequencies while maintaining comprehensive voltage domain coverage.
3Adaptability or versatility
If traditional level shifting is used, then voltage domain translation is achieved, but MOSFETs are vulnerable to overvoltage damage
Solution Approach 1:
The patent introduces a specialized protection circuit that acts as an intermediary between the high voltage I/O buffer and the low voltage MOSFETs. This protection circuit includes voltage clamping mechanisms and isolation structures that prevent high voltage from reaching the MOSFETs, thereby protecting them from overvoltage damage while maintaining compatibility with multiple voltage domains.
Data Source
AI summary
A multi-voltage, high voltage I/O buffer in low-voltage technology is disclosed. In one embodiment, the I/O buffer includes a logic circuit configured to generate a signal based on a data signal and a first control signal. A level shifter is coupled between a supply voltage terminal and a ground terminal, and the level shifter is generates first and second output signals in first and second voltage domains, respectively, at first and second nodes, respectively, based on the signal from the logic circuit. A control circuit is coupled between the second node and a third node. The control circuit transmits the second output signal to the third node when the first control signal is asserted, and the control circuit couples the third node to the ground terminal when the first control signal is not asserted.