Embedded-Logic Level Shifter for Low-Voltage Signal Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits face challenges in managing power consumption, particularly as supply voltage levels are reduced to conserve energy, leading to inaccurate signal transmission between voltage domains due to asymmetrical level shifter circuits when one domain is powered down.
Innovation Solution
The implementation of a level shifter circuit with a shift stage that embeds transistors for logic operations and includes dummy transistors to enhance symmetry, ensuring consistent electrical properties for both rising and falling transitions, thereby maintaining accurate signal transmission even when the supply voltage is powered down.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the supply voltage is reduced to lower power consumption, then power consumption decreases, but signal transmission accuracy deteriorates due to asymmetrical level shifter behavior when voltage domains are powered down
Solution Approach 1:
The patent intentionally introduces asymmetry through dummy transistors to compensate for the inherent asymmetry in level shifter circuits. The dummy transistors are configured to match the electrical characteristics of the functional transistors, creating a symmetrical overall structure that ensures consistent signal transmission during both active and powered-down states of voltage domains
Solution Approach 2:
The patent modifies the electrical parameters of the level shifter circuit by adding dummy transistors with specific sizing and configuration. These dummy transistors are designed to match the on-resistance and other electrical characteristics of the functional transistors, thereby changing the overall parameter balance of the circuit to achieve symmetry in signal transmission behavior
2Reliability
If dummy transistors are added to improve circuit symmetry, then signal transmission accuracy improves, but device complexity increases
Solution Approach 1:
The level shifter circuit is segmented into functional transistor components and dummy transistor components. This segmentation allows the dummy transistors to be independently designed and configured to match specific electrical characteristics of the functional transistors, making the complexity management more systematic and targeted rather than requiring complete circuit redesign
Solution Approach 2:
The dummy transistors are created as copies of the functional transistors, replicating their electrical characteristics such as on-resistance, gate capacitance, and physical dimensions. This copying approach ensures that the dummy transistors provide the necessary symmetry without requiring complex custom designs, thereby limiting the increase in device complexity
Data Source
AI summary
In one embodiment, a level shifter circuit may include a shift stage that also embeds transistors that implement a logic operation on two or more inputs to the level shifter. At least one of the inputs may be sourced from circuitry that is powered by a different power supply than the level shifter and circuitry that receives the level shifter output. Additionally, the level shifter includes one or more dummy transistors that match transistors the perform the logic operation, to improve symmetry of the level shifter circuit. In some embodiments, certain design and layout rules may be applied to the level shifter circuit to limit variation in the symmetry over various manufacturing variations.