MOS Level Shifter Architecture for High-Voltage Logic Signals
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Solution Overview
Problem
Level shifters and logic circuits implemented with MOS transistors face challenges when handling full voltage ranges, as the MOS transistors' breakdown voltage is often smaller than the required range, leading to inefficiencies and potential damage.
Innovation Solution
Designs of level shifters and high voltage logic circuits using MOS transistors with reduced voltage ranges, where the driver circuit and latch operate within non-overlapping or partially overlapping voltage ranges, allowing the MOS transistors to handle digital input and output signals without exceeding their breakdown voltage, and incorporating inverters and transistors to generate and manage differential signals across various voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If MOS transistors are used to implement level shifters and logic circuits with small size and low power dissipation, then device size and power consumption are reduced, but the transistors cannot handle the full voltage range as the voltage may exceed their breakdown voltage
Solution Approach 1:
The voltage range is segmented into multiple non-overlapping or partially overlapping voltage ranges, each handled by separate MOS transistor circuits operating at different voltage levels. This allows the system to achieve the full voltage range capability without requiring any single transistor to withstand the complete voltage span, thus preventing breakdown while maintaining low power dissipation.
Solution Approach 2:
Level shifters are introduced as intermediary circuits between different voltage domains. These level shifters translate signals from one voltage range to another, enabling MOS transistors to operate within their safe breakdown voltage limits while still facilitating communication across the full voltage range required by the system.
2Reliability
If MOS transistors operate within reduced voltage ranges below their breakdown voltage, then transistor reliability is improved, but the ability to handle the full voltage range is compromised
Solution Approach 1:
The level shifter architecture provides multi-functionality by enabling the same MOS transistor circuit to effectively handle multiple voltage ranges through the level shifting mechanism. The system achieves universality in voltage range handling without compromising transistor reliability, as each transistor operates only within its safe voltage range while the level shifters bridge the gaps between ranges.
Data Source
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AI summary
Level shifters and high voltage logic circuits implemented with MOS transistors having a low breakdown voltage relative to the voltage swing of the input (Vinp, Vinn) and output (Voutp, Voutn) signals are described. In an exemplary design, a level shifter (102) includes a driver circuit (110) and a latch (140). The driver circuit receives an input signal having a first voltage range and provides a drive signal having a second voltage range. The first and second voltage ranges may cover positive and negative voltages or different ranges of positive voltages. The latch (140) receives the drive signal and provides an output signal having the second voltage range. The driver circuit may generate a control signal (Vcrtlp, Vctrln) having a full voltage range based on the input signal and may then generate the drive signal based on the control signal. The level shifter (102) may be used to implement a high voltage logic circuit.