Level Shifter Dynamic Threshold Adjustment
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Solution Overview
Problem
Existing level shifters fail to adjust the threshold voltage of an input voltage signal in response to changes in power supply voltage, leading to potential misoperation during voltage drops, such as those in in-vehicle batteries.
Innovation Solution
A level shifter design incorporating a power supply system current source with transistors and resistors that regulate current flow, allowing the threshold voltage of the input voltage signal to change with power supply voltage variations, and including an electrostatic protection component to prevent breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the threshold voltage is kept constant in existing level shifters, then the circuit structure is simple, but misoperation occurs during voltage drops as the input voltage signal may not reach the threshold voltage
Solution Approach 1:
The patent implements dynamic threshold voltage adjustment by introducing a power supply system current source that automatically modifies the threshold voltage in response to power supply voltage changes. The current source circuit includes transistors and resistors configured to sense power supply voltage variations and accordingly adjust the threshold voltage level, ensuring reliable operation under varying voltage conditions while maintaining circuit simplicity
Solution Approach 2:
The patent changes the threshold voltage parameter dynamically based on power supply voltage conditions. The power supply system current source modifies the threshold voltage parameter in response to power supply voltage changes, allowing the level shifter to adapt to voltage drops and prevent misoperation. This parameter change approach resolves the contradiction by making the threshold voltage flexible rather than fixed
2Reliability
If the threshold voltage is changed in accordance with voltage changes, then operational reliability is improved, but the circuit complexity increases
Solution Approach 1:
The power supply system current source is designed to automatically adjust the threshold voltage without external intervention. The circuit self-senses power supply voltage changes and self-adjusts the threshold voltage accordingly through its internal transistor and resistor configuration, eliminating the need for complex external control circuits while improving reliability
Solution Approach 2:
The power supply system current source serves multiple functions: it provides current to the level shifting operation and simultaneously adjusts the threshold voltage based on power supply conditions. This multi-functionality reduces overall circuit complexity by combining what could be separate circuits into a single integrated component
Data Source
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AI summary
A level shifter that includes: a power supply system current source; a second transistor having a third main electrode that is connected to an input voltage signal terminal, a fourth main electrode that is connected to an output voltage signal terminal, and a second control electrode that is connected to a third power supply voltage having a voltage that is lower than a first power supply voltage and higher than a second power supply voltage; a second resistor; and a third transistor having a fifth main electrode that is connected to the second end of the second resistor, a sixth main electrode that is connected to the second power supply voltage, and a third control electrode that is connected to a first control electrode of a first transistor of the power supply system current source.