Level Shifter Bypass Circuit for Low-Voltage Leakage Control
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Solution Overview
Problem
Existing level shifters face challenges in achieving efficient and fast level shifting across a wide range of supply voltages, particularly around-threshold or near-threshold to super-threshold regions, due to issues like high standby leakage, asymmetric delays, and impractical transistor sizing, making them unsuitable for dynamic voltage scaling applications.
Innovation Solution
A circuit arrangement with a level shifting stage coupled to reference voltages and a bypass circuit element in parallel to the load, allowing current to flow through upon external voltage application, which enables efficient level shifting and reduces standby leakage by bypassing the load, thus improving performance across various voltage regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transistor sizes are increased to enable operation at around-threshold voltages, then the level shifter can operate at lower voltages, but the transistor area and device complexity increase significantly
Solution Approach 1:
The patent introduces a bypass circuit element as an intermediary component that provides an alternative current path when the level shifter operates at around-threshold voltages. This bypass element compensates for the weak pull-down current without requiring excessive enlargement of the main transistors, thus resolving the contradiction between voltage adaptability and device complexity
Solution Approach 2:
The bypass circuit element is dynamically controlled based on the operating voltage region. It is activated when operating at around-threshold voltages and deactivated when operating at super-threshold voltages, allowing the circuit to adapt its structure dynamically to maintain optimal performance across different voltage regions without permanent complexity
2Adaptability or versatility
If current mirror configuration is used to achieve level shifting at lower supply voltages, then voltage adaptability improves, but standby leakage power consumption increases
Solution Approach 1:
The bypass circuit element operates periodically based on the operating conditions - it is activated only when needed at around-threshold voltages and deactivated when not needed at super-threshold voltages. This periodic activation pattern eliminates continuous standby leakage while maintaining voltage adaptability across different operating regions
3Use of energy by moving object
If transistors are operated in sub-threshold region to reduce power consumption, then energy efficiency improves, but the pull-down current becomes too weak to overcome pull-up current
Solution Approach 1:
The bypass circuit element serves as a mediator that compensates for the insufficient pull-down current of sub-threshold transistors. It provides additional pull-down capability when needed without requiring the main transistors to operate in the strong inversion region, thus maintaining both low power consumption and reliable level shifting function
Solution Approach 2:
The patent changes the effective pull-down strength by activating the bypass circuit element, which modifies the electrical parameters of the pull-down path. This allows the transistors to maintain sub-threshold operation for low power while the bypass element dynamically adjusts the overall pull-down current to ensure reliable level shifting
Data Source
AI summary
In various embodiments, a circuit arrangement may be provided. The circuit arrangement may include a level shifting stage configured to be coupled to a first reference voltage, the level shifting stage having an output node. The circuit arrangement may further include a first input electrode in electrical connection with the level shifting stage. The circuit arrangement may also include a second input electrode in electrical connection with the level shifting stage. The circuit arrangement may further include a load having a first end and a second end, the first end coupled to the level shifting stage and the second end for coupling to a second reference voltage. In addition, the circuit arrangement may include a bypass circuit element connected in parallel to the load. The bypass circuit element may be configured to allow current to flow through upon application of an external voltage for bypassing the load.