Two-Stage Level Shifter for High-Frequency Low-Voltage Signals

Solution Overview

Problem

Conventional level shifter circuits fail to efficiently handle high frequency and low voltage input signals due to increased response time and require larger transistor sizes to enhance current, leading to increased circuit area and power consumption.

Innovation Solution

A level shifter circuit comprising a first voltage adjusting circuit and a second voltage adjusting circuit, where the first circuit adjusts the input signal to a middle voltage range and the second circuit further adjusts the differential signals to a larger output voltage range, utilizing current sources and transistors to enhance driving capability and reduce circuit area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the width of the NMOS transistor is enlarged to increase the conducting current and response speed, then the response time is reduced, but the circuit area becomes too large

Engineering Contradiction:

Improveresponse speedVSAvoidcircuit area

Core Design Contradiction:

SpeedVSArea of stationary object

Solution Approach 1:

The level shifter is divided into two independent stages: a first level shifter handling voltage level conversion and a second level shifter handling differential signal conversion. Each stage uses appropriately sized transistors optimized for its specific function, avoiding the need for oversized transistors in a single-stage design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A differential signal generation circuit is introduced as an intermediary between the input signal and the second level shifter. This intermediate stage converts the single-ended input signal to differential signals, enabling the second level shifter to operate efficiently with smaller transistors while maintaining fast response speed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If the width of the NMOS transistor is enlarged to increase the conducting current, then the response time is reduced, but the power consumption increases

Engineering Contradiction:

Improveresponse speedVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The level shifter is divided into two independent stages: a first level shifter handling voltage level conversion and a second level shifter handling differential signal conversion. Each stage uses appropriately sized transistors optimized for its specific function, avoiding the need for oversized transistors in a single-stage design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A differential signal generation circuit is introduced as an intermediary between the input signal and the second level shifter. This intermediate stage converts the single-ended input signal to differential signals, enabling the second level shifter to operate efficiently with smaller transistors while maintaining fast response speed.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the conventional level shifter is used for high frequency input signals, then the circuit structure is simple, but the response time exceeds the signal period causing level shifting failure

Engineering Contradiction:

Improvecircuit structureVSAvoidresponse time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The level shifter is divided into two independent stages: a first level shifter handling voltage level conversion and a second level shifter handling differential signal conversion. Each stage uses appropriately sized transistors optimized for its specific function, avoiding the need for oversized transistors in a single-stage design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A differential signal generation circuit is introduced as an intermediary between the input signal and the second level shifter. This intermediate stage converts the single-ended input signal to differential signals, enabling the second level shifter to operate efficiently with smaller transistors while maintaining fast response speed.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7808296B2Image display system

Publication Date: 2010.10.05 INNOLUX CORP

AI summary

An image display system is provided. The image display system includes a level shifter including a first voltage adjusting circuit and a second voltage adjusting circuit. The first voltage adjusting circuit adjusting the voltage of an input signal, includes a small signal input terminal receiving the input signal and a differential output terminal outputting a pair of differential signals. The available voltage ranges of the differential signals are larger than that of the input signal. The second voltage adjusting circuit, coupled to the first voltage adjusting circuit, includes a first input terminal and a second input terminal respectively receiving the pair of differential signals. The second adjusting circuit adjusts the voltage of the differential signals and generates an output signal. The available voltage range of the output signal is larger than that of the differential signals.