Self-Bootstrapping Regenerative Diode Reducing Forward Voltage Drop

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Solution Overview

Problem

Conventional diodes, such as Schottky barrier diodes, suffer from high energy losses due to large forward voltage drops, and synchronous rectifiers, while more efficient, require complex circuitry and additional signal processing, increasing cost and reducing reliability.

Innovation Solution

A regenerative diode structure combining MOSFETs and regenerative building blocks (RBBs) with carefully managed gate oxide thickness and dopant concentration, allowing for automatic switching between ON and OFF states without the need for additional control signals, reducing forward voltage drop and leakage current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If Schottky barrier diodes are used for rectification, then the device is simple to use, but the forward voltage drop is large causing high energy loss

Engineering Contradiction:
Improveease of useVSAvoidenergy loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent implements positive feedback by connecting the drain of one MOSFET to the gate of the other MOSFET, and vice versa. This feedback mechanism causes the MOSFETs to automatically switch between ON and OFF states based on their drain-source voltage, eliminating the need for external control signals while achieving low voltage drop operation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The regenerative diode structure is self-controlling through its internal feedback connections. Each MOSFET's gate voltage is automatically generated from the other MOSFET's drain voltage, allowing the device to self-regulate its switching without external controllers or sensors, thus maintaining simplicity while improving efficiency

Inventive Principle:
Principle #25Self-service

2Loss of energy

If synchronous rectification with MOSFETs is used, then the voltage drop is reduced improving efficiency, but the circuit implementation becomes more complicated

Engineering Contradiction:
Improveenergy lossVSAvoidcircuit complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent uses feedback connections where each MOSFET's drain is connected to the other MOSFET's gate. This automatic feedback mechanism eliminates the need for external controllers, sensors, and complex gate drive circuits, reducing device complexity while maintaining the low voltage drop benefits of synchronous rectification

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent extracts and eliminates the complex control circuitry (controllers, sensors, signal processing) from the synchronous rectification system by using only two cross-connected MOSFETs with inherent feedback, retaining only the essential switching function while removing unnecessary complexity

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If synchronous rectification is used, then efficiency is improved, but additional signal processing increases cost and reduces reliability

Engineering Contradiction:
Improveenergy lossVSAvoidreliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent removes all additional signal processing components (controllers, sensors) from the synchronous rectification circuit, leaving only the two cross-connected MOSFETs. This extraction eliminates potential failure points while maintaining efficiency through the inherent feedback mechanism

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The regenerative diode structure is self-controlling through its internal feedback connections. Each MOSFET's gate voltage is automatically generated from the other MOSFET's drain voltage, allowing the device to self-regulate its switching without external controllers or sensors, thus maintaining simplicity while improving efficiency

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The regenerative diode achieves improved efficiency and reduced overhead circuitry compared to Schottky diodes and synchronous rectifiers, with simpler fabrication and easier integration, while maintaining high frequency operation and reliability.

Implementation Method 1

depleted of charge carriers by a potential applied to a gate

Methodology Applied
Scientific EffectDepletion:

Implementation Method 2

Self-bootstrapping field effect diode structures and methods

Methodology Applied
Scientific EffectField effect:

Data Source

PatentEP2384518B1Self-bootstrapping field effect diode structures and methods
Publication Date: 2019.09.04 STMICROELECTRONICS NV
  • EP2384518B1 patent drawingFigure 1A~1B
  • EP2384518B1 patent drawingFigure 2
  • EP2384518B1 patent drawingFigure 3

AI summary

A two terminal device which can be used for the rectification of the current. Internally it has a regenerative coupling between MOS gates of opposite type and probe regions. This regenerative coupling allows to achieve performance better than that of ideal diode.