Multi-Stage Level Shifter Without High-Voltage Transistors

Solution Overview

Problem

Conventional level shifters require high-voltage transistors to convert low-voltage signals into high-voltage signals, leading to increased chip area occupation and fabrication difficulties due to the need for transistors with VGS voltages of 6 V or more.

Innovation Solution

A level shifter design utilizing multiple medium-voltage transistor units, each converting the signal into a higher voltage range without requiring high-voltage transistors, with each transistor's gate-source voltage difference limited to 6 V or less, allowing for efficient signal conversion from 0 V to 1.5 V to 5 V to 10 V.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-voltage transistors are used to convert low-voltage signals into high-voltage signals, then the signal conversion function is achieved, but the chip area occupied increases substantially

Engineering Contradiction:

Improvesignal conversion capabilityVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The level shifter is divided into multiple stage units (first-level, second-level, third-level shifter units), where each stage converts the voltage to an intermediate level. This segmentation allows the use of medium-voltage transistors instead of high-voltage transistors, reducing the chip area required for each transistor while achieving the overall high-voltage conversion function.

Inventive Principle:

Principle #1Segmentation

2Reliability

If high-voltage transistors with VGS of 6 V or more are used, then high-voltage signal conversion is achieved, but fabrication becomes difficult

Engineering Contradiction:

Improvehigh-voltage signal conversionVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the voltage parameter constraints by ensuring that the gate-source voltage (VGS) of each medium-voltage transistor in every stage remains equal to or less than 6 V. This parameter control allows the use of standard fabrication processes that do not support high-voltage transistors, making the device easier to manufacture while still achieving high-voltage signal conversion through multiple stages.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If multiple level shifter units are connected in series to convert low-voltage to high-voltage signals, then the voltage conversion range is extended, but the chip area occupied increases

Engineering Contradiction:

Improvevoltage conversion rangeVSAvoidchip area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The level shifter is divided into multiple stage units (first-level, second-level, third-level shifter units), where each stage converts the voltage to an intermediate level. This segmentation allows the use of medium-voltage transistors instead of high-voltage transistors, reducing the chip area required for each transistor while achieving the overall high-voltage conversion function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the voltage parameter constraints by ensuring that the gate-source voltage (VGS) of each medium-voltage transistor in every stage remains equal to or less than 6 V. This parameter control allows the use of standard fabrication processes that do not support high-voltage transistors, making the device easier to manufacture while still achieving high-voltage signal conversion through multiple stages.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8710897B2Level shifter and method of using the same

Publication Date: 2014.04.29 MAGNACHIP SEMICON LTD

AI summary

A level shifter and a method of operating a level shifter are provided. The level shifter includes a first-level shifter unit configured to convert an external input signal into a signal in a preset first-voltage range using a plurality of transistors and output the converted signal and a second-level shifter unit configured to convert the signal output from the first-level shifter unit into a signal in a preset second-voltage range using a plurality of transistors and output the converted signal.