Intermediate Voltage Source for Gate Oxide Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuit design faces challenges in balancing maximum stress voltages for transistor devices with rail-to-rail voltage requirements, often necessitating compromises between device size and voltage capabilities, particularly when gate oxide voltages are limiting.
Innovation Solution
An electronic circuit design featuring a first and second circuit leg with reference current circuits and transistors forming current mirrors, generating a stable intermediate voltage node that balances rail-to-rail voltage requirements while protecting gate oxides by using longer channel length transistors and capacitors to stabilize voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rail-to-rail voltages are increased to meet voltage requirements, then voltage capability is improved, but gate oxide stress voltage is exceeded causing device damage
Solution Approach 1:
The patent introduces an intermediate voltage source that generates a mid-rail voltage (approximately halfway between VDD and VSS) to serve as a protected reference voltage for circuit nodes. This intermediary voltage allows the circuit to interface with full rail-to-rail signals while maintaining gate oxide voltages within safe limits, effectively mediating between the high-voltage external environment and the low-voltage internal transistor requirements
Solution Approach 2:
The voltage domain is segmented into multiple levels: the full rail-to-rail voltage range (VDD to VSS) for external signaling, and an intermediate mid-rail voltage domain for internal circuit operation. This segmentation allows different parts of the circuit to operate at appropriate voltage levels, with the intermediate source creating a protected voltage domain that prevents gate oxide stress while maintaining compatibility with external full-swing signals
2Area of stationary object
If device size is reduced to improve integration, then area is reduced, but maximum gate oxide stress voltage capability decreases
Solution Approach 1:
The patent applies local quality by providing different voltage environments to different parts of the circuit. Small transistors with low voltage capability operate in the protected intermediate voltage domain, while the overall circuit can still interface with full rail-to-rail voltages through level shifting. This allows compact device sizing without compromising the voltage capability of the overall system
3Adaptability or versatility
If multiple voltage domains and level shifters are implemented to meet both voltage requirements, then voltage compatibility is improved, but circuit complexity increases
Solution Approach 1:
The intermediate voltage source is designed to serve multiple functions simultaneously: it acts as a reference voltage for level shifting, provides a protected voltage domain for gate oxide protection, serves as an output driver voltage, and enables bidirectional signal translation between full-swing and reduced-swing domains. This multi-functionality reduces the need for separate dedicated circuits for each function
Data Source
AI summary
An electronic circuit. The electronic circuit includes a first circuit leg coupled to a first supply voltage node and a second supply voltage node. The first circuit leg includes a first reference current circuit configured to produce a first reference current and a second reference current circuit configured to produce a second reference current. The electronic circuit further includes a second circuit leg coupled in parallel with the first circuit leg. The second circuit leg includes a first transistor coupled to form a current mirror with the first reference current circuit and a second transistor coupled to form a current mirror with the second reference current circuit. The source terminals of each of the first and second transistors are coupled together to form a third supply voltage node.