Level Shifter Bias Circuit for Wide Voltage Domain Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current level shifters face challenges in expanding the voltage shift range to accommodate circuits operating in different voltage domains, which limits their effectiveness in applications requiring varied voltage levels.
Innovation Solution
The proposed level shifter incorporates a buffer circuit and two shift circuits with voltage divider circuits to provide inner biases to transistors, allowing for increased voltage shift range by operating in both positive and negative voltage domains, and utilizing a deep N-well N-type transistor to manage PN junction voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional level shifter is used, then the circuit can operate with different voltage requirements, but the voltage shift range is limited
Solution Approach 1:
The level shifter is divided into multiple independent shift circuits (first shift circuit and second shift circuit), each handling different voltage domains. This segmentation allows each circuit to be optimized for specific voltage ranges, expanding the overall voltage shift range while maintaining reliable operation in each domain
Solution Approach 2:
A buffer circuit is introduced as an intermediary between the input signal and the shift circuits. The buffer circuit provides isolated driving capability, ensuring that the expanded voltage shift range does not compromise the accuracy of switch operation by preventing direct loading effects
2Adaptability or versatility
If the voltage shift range is expanded to cover both positive and negative voltage domains, then adaptability increases, but circuit complexity increases
Solution Approach 1:
The shift circuits are designed with universal functionality to handle both positive and negative voltage domains using the same basic circuit topology. This multi-functionality allows the circuit to cover expanded voltage ranges without proportionally increasing complexity, as the same circuit structure serves multiple voltage domains
Solution Approach 2:
The circuit utilizes parameter changes in transistor threshold voltages and bias conditions to adapt to different voltage domains. By changing operating parameters rather than fundamentally altering circuit structure, the circuit achieves wide voltage domain coverage with controlled complexity
3Reliability
If deep N-well N-type transistors are used to manage PN junction voltages, then switch operation accuracy improves, but manufacturing complexity increases
Solution Approach 1:
Deep N-well structures are applied locally only to N-type transistors that require precise voltage management, rather than to all transistors in the circuit. This localized application maintains high switch operation accuracy where needed while minimizing the impact on overall manufacturing complexity and process steps
Data Source
AI summary
A level shifter includes a buffer circuit, a first shift circuit, and a second shift circuit. The buffer circuit provides a first signal and a first inverted signal to the first shift circuit, such that the first shift circuit provides a second signal and a second inverted signal to the second shift circuit. The second shift circuit generates a plurality of output signals according to the second signal and the second inverted signal. The first shift circuit includes a plurality of first stacking transistors and a first voltage divider circuit. The first voltage divider circuit is electrically coupled between a first system high voltage terminal and a system low voltage terminal. The first voltage divider circuit is configured to provide a first inner bias to gate terminals of the first stacking transistors.