Parallel Transistor Device with Wide Bandgap Protection

Solution Overview

Problem

Transistor devices face inefficiencies under partial and full load conditions, and lack robustness against overvoltages, particularly in high voltage applications where they need to switch between full and partial loads, with silicon-based IGBTs and MOSFETs having drawbacks in efficiency and overvoltage tolerance.

Innovation Solution

A transistor device comprising a first transistor coupled with a second transistor in parallel, where the second transistor is made from wide bandgap semiconductor material like silicon carbide, designed to have a lower breakdown voltage than the first transistor within a specified operating range, providing overvoltage protection and improved efficiency across varying loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If IGBTs are used for high currents, then current handling capability is improved, but efficiency under partial load deteriorates

Engineering Contradiction:

Improvecurrent handling capabilityVSAvoidefficiency under partial load

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent implements dynamic load sharing between two transistor types (IGBT and MOSFET) based on operating conditions. The transistors are connected in parallel with different breakdown voltages, allowing the device to automatically optimize which transistor carries the load current depending on whether full load or partial load conditions exist, thereby maintaining high efficiency across varying load conditions while preserving high current capability

Inventive Principle:

Principle #15Dynamics

2Loss of energy

If MOSFETs are used, then efficiency under partial load is improved, but efficiency under full load and chip area deteriorate

Engineering Contradiction:

Improveefficiency under partial loadVSAvoidefficiency under full load

Core Design Contradiction:

Loss of energyVSPower

Solution Approach 1:

The patent implements dynamic load sharing between two transistor types (IGBT and MOSFET) based on operating conditions. The transistors are connected in parallel with different breakdown voltages, allowing the device to automatically optimize which transistor carries the load current depending on whether full load or partial load conditions exist, thereby maintaining high efficiency across varying load conditions while preserving high current capability

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If silicon-based transistors are used, then manufacturing cost is reduced, but overvoltage robustness deteriorates

Engineering Contradiction:

Improvemanufacturing costVSAvoidovervoltage robustness

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a second transistor with higher breakdown voltage as a protective element in parallel with the primary transistor. This second transistor acts as an intermediary safety mechanism that becomes conductive during overvoltage events, clamping the voltage and protecting the primary transistor from damage while allowing the use of cost-effective silicon-based materials

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10404250B2Transistor device

Publication Date: 2019.09.03 INFINEON TECHNOLOGIES AG

AI summary

Transistor devices are described that include a first transistor and a second transistor coupled in parallel between a first terminal and a second terminal. The second transistor is based on a wide bandgap semiconductor material. The second transistor has a breakthrough voltage lower than a breakthrough voltage of the first transistor over a predetermined operating range. The predetermined operating range comprises at least an operating range for which the transistor device is specified.