Bidirectional Power Switch with Segmented Semiconductor Components

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Solution Overview

Problem

Existing bidirectional power switches face challenges in being controllable in both the closed and open states, with triacs being inexpensive but limited in control, and MOS or bipolar transistor-based switches being expensive and requiring complex circuitry.

Innovation Solution

A bidirectional power switch comprising three semiconductor components of alternating conductivity types, where the first and second components are formed in separate chips and the third in a distinct chip, with a control terminal allowing for efficient switching between states by applying a control current, enhancing the gain and voltage withstand while maintaining a reasonable semiconductor surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If triacs are used for bidirectional power switching, then cost is reduced, but control capability in the closed state is lost

Engineering Contradiction:
ImprovecostVSAvoidcontrol capability
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent divides the bidirectional power switch into three separate semiconductor components (first, second, and third components) with alternating conductivity types. These components are connected in series between the supply terminals, with each component having specific doping levels and geometric dimensions. This segmentation allows independent optimization of each component's characteristics while achieving overall bidirectional control capability that triacs cannot provide.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If MOS or bipolar transistor-based switches are used for bidirectional control, then control capability in both states is achieved, but cost increases and circuitry complexity increases

Engineering Contradiction:
Improvebidirectional control capabilityVSAvoidcircuitry complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating asymmetric doping levels within specific regions of the semiconductor components. The second regions of the first and second components have doping levels between 7×10^15 and 7×10^17 atoms/cm³, while the second region of the third component has a doping level between 7×10^15 and 7×10^17 atoms/cm³. This localized variation in doping quality enables bidirectional control functionality while maintaining relative simplicity in the overall device structure and control circuitry.

Inventive Principle:
Principle #3Local quality

3Strength

If the semiconductor surface area is increased to improve voltage withstand, then voltage withstand is improved, but device size and cost increase

Engineering Contradiction:
Improvevoltage withstandVSAvoidsemiconductor surface area
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The patent employs asymmetry in the geometric dimensions and doping levels of the three semiconductor components. The first component has a first geometric dimension and first doping level, the second component has a second geometric dimension and second doping level, and the third component has a third geometric dimension and third doping level. This asymmetric design allows optimization of voltage withstand characteristics without requiring uniform increases in semiconductor surface area across all components, thereby controlling device size and cost.

Inventive Principle:
Principle #4Asymmetry

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 solution provides a significant increase in gain beyond theoretical limits, allowing for efficient control of the switch in both states with improved voltage withstand and reduced control current intensity, while maintaining a reasonable semiconductor surface area and cost.

Implementation Method 1

the first, second and third regions of the first component are respectively of the P, N and P type

Methodology Applied
Scientific EffectDoping: Dopants

Data Source

PatentEP3091572B1Bidirectional power switch
Publication Date: 2019.10.30 STMICROELECTRONICS (TOURS) SAS
  • EP3091572B1 patent drawingFigure 1~3

AI summary

The invention relates to a switch (200) comprising three components (1001, 1002, 1003) each comprising: a stack of three semiconductor regions (102, 104, 106) of alternating types; and a control region (108) of the opposite type to that of the first region (102), in which: the first regions (102) of the first and second components are of the same type and the first regions (102) of the first and third components are of opposite types; the first region (102) of the first component is connected to the control regions (108) of the second and third components; the first regions (102) of the second and third components are connected to a terminal (A1); the third (106) regions of the first, second and third components are connected to a terminal (A2); and the control region (108) of the first component is connected to a terminal (G).