Isolated Wide-Voltage Level Shifting Circuit for Low-Leakage Logic Transfer
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Solution Overview
Problem
Integrated circuits with multiple power supply domains face challenges in transmitting logic signals between voltage domains with different voltage levels, leading to potential damage and performance issues due to voltage mismatches, which existing level shifting circuits struggle to address effectively.
Innovation Solution
The proposed system includes an input circuit, a power circuit, and an output driver configured to shift voltage levels between power domains, using an inverting circuit and power latch to generate appropriate voltage levels and reduce leakage by isolating from the ground signal when necessary, with the option to employ ultra-low voltage threshold MOSFETs for efficient operation across wide voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a level shifting circuit is used to transmit logic signals between voltage domains with different voltage levels, then signal transmission between power domains is enabled, but voltage mismatches may cause potential damage and performance issues
Solution Approach 1:
The patent introduces an intermediary level shifting circuit between voltage domains with different levels. The circuit includes voltage level detection units that detect the voltage level of input signals, and corresponding output units that generate output signals at appropriate voltage levels. This intermediary structure enables safe signal transmission between power domains while preventing voltage mismatches from causing damage.
Solution Approach 2:
The patent dynamically changes the output voltage level parameter based on the detected input voltage level. When a high voltage level is detected, the circuit outputs a high voltage signal; when a low voltage level is detected, it outputs a low voltage signal. This parameter adaptation ensures reliable signal transmission while protecting circuits from voltage incompatibility.
2Adaptability or versatility
If existing level shifting circuits are used to handle wide voltage differences, then voltage level conversion is achieved, but leakage current increases and performance degrades
Solution Approach 1:
The patent employs ultra-low voltage threshold MOSFETs in the level shifting circuit. These special transistors maintain effective switching at very low voltage levels, enabling the circuit to handle wide voltage differences while minimizing leakage current. The low threshold voltage characteristic of these MOSFETs prevents excessive current flow during voltage conversion operations.
Solution Approach 2:
The circuit dynamically adjusts its operation based on the voltage level differences encountered. The voltage detection mechanism enables the circuit to adapt its switching behavior and transistor operation modes according to the specific voltage conditions, optimizing performance and minimizing energy loss across different operating scenarios.
3Adaptability or versatility
If voltage regulators are used to generate power signals of varying voltage levels, then multiple power domains can be created, but circuit complexity increases
Solution Approach 1:
The level shifting circuit is segmented into distinct functional units: voltage level detection units and corresponding output units. Each detection unit is paired with its dedicated output unit, creating modular building blocks that can be independently designed and analyzed. This segmentation simplifies the overall circuit structure while maintaining the capability to handle multiple voltage domains.
Solution Approach 2:
The voltage level detection units automatically detect the input voltage level and trigger the appropriate output unit without requiring external control signals or complex management logic. This self-service mechanism reduces circuit complexity by eliminating the need for additional control circuits while maintaining flexible operation across multiple power domains.
Data Source
AI summary
In an embodiment, an apparatus includes an input circuit coupled to a first power supply with a first voltage level, a power circuit coupled to a second power supply with a second voltage level, and an output driver. The input circuit may receive an input signal, and generate an inverted signal dependent upon the input signal. The power circuit may generate a power signal in response to first values of the input and the inverted signals, wherein a voltage level of the power signal may be dependent upon the second voltage level. The power circuit may also generate a third voltage level on the power signal in response to second values of the input and the inverted signals. The output driver may generate an output signal dependent upon the input signal. The output signal may transition between the voltage level of the power signal and the ground reference level.