Current-Steering Level Shifter for Limited Voltage Differentials
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional level-shifters for system-on-chip (SoC) designs with multiple voltage domains face significant performance and area overheads due to their large size and high leakage currents, especially when dealing with limited voltage differentials, making them inefficient for low-power operation.
Innovation Solution
A compact current-steering level-shifter (CSLS) design that steers current between two input power supply rails using a single N-well and seven transistors, reducing area overhead and leakage currents, while supporting both low-to-high and high-to-low voltage signal conversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional level-shifters are used to interface multiple voltage domains, then voltage level conversion is achieved, but area overhead and leakage currents increase significantly
Solution Approach 1:
The patent changes the operating parameters of the level-shifter by using a compact current-steering topology with seven transistors instead of conventional large-sized level-shifters. This parameter change in circuit topology and transistor count directly reduces the area overhead while maintaining the voltage level conversion function across multiple voltage domains.
Solution Approach 2:
The patent extracts and eliminates the excessive leakage current paths present in conventional level-shifters by implementing a current-steering mechanism that directs current flow through optimized paths. This extraction of harmful current paths reduces overall leakage while preserving the essential voltage conversion capability.
2Reliability
If conventional level-shifters are used to interface multiple voltage domains, then voltage level conversion is achieved, but leakage currents increase significantly
Solution Approach 1:
The patent converts the potentially harmful leakage current into a useful steering current by implementing controlled current paths through the seven-transistor topology. The current that would otherwise be wasted as leakage is redirected through the current-steering mechanism to perform useful work in voltage level conversion, thereby converting harm into benefit.
Solution Approach 2:
The patent introduces intermediate current-steering transistors that act as mediators between the different voltage domains. These intermediary transistors control and regulate the current flow, preventing direct leakage paths while enabling controlled current transfer between voltage domains, thus reducing overall leakage current.
3Use of energy by moving object
If the number of voltage domains is increased for power optimization, then power consumption is reduced, but the number of level-shifters increases resulting in performance and area overheads
Solution Approach 1:
The patent creates a universal compact level-shifter design that can be reused across multiple voltage domain interfaces. The seven-transistor current-steering topology serves as a multi-functional building block that can interface any two voltage domains, eliminating the need for different specialized level-shifters for each voltage domain interface, thus reducing total area overhead.
Solution Approach 2:
The patent segments the voltage domain interface function into compact, modular current-steering units that can be independently instantiated. Each unit is a self-contained seven-transistor module that can be replicated and placed at different voltage domain interfaces, allowing systematic reduction of area overhead through modular design and efficient placement.
Data Source
AI summary
Described is a level-shifter that can save area between voltage domains with limited voltage differential, and further save power by steering current between two power supply rails. The level-shifter comprises: an input to receive a first signal between a first reference rail and a second reference rail; an output to provide a second signal the first reference rail and a third reference rail, wherein in a voltage level of the third reference rail is higher than a voltage level of the second reference rail, and wherein a voltage level of the first reference is lower than the voltage level of the second reference rail and the third reference rail; and a circuitry coupled to the input and the output, wherein the circuitry is to steer current from the third reference rail to the second reference rail.