Power Transistor Avalanche Shutdown for Inductive Voltage Spikes

Solution Overview

Problem

Switching off power transistor circuits in electronic circuits with parasitic inductances can cause voltage increases due to stored energy, which is not efficiently managed by existing clamping circuits that add cost and complexity.

Innovation Solution

Operating power transistors in Avalanche mode to dissipate stored energy within the transistors, eliminating the need for additional clamping circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a clamping circuit is connected in parallel with the power transistor circuit to clamp voltage and dissipate stored energy, then voltage protection is improved, but device complexity and cost increase

Engineering Contradiction:

Improvevoltage protectionVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The power transistor itself is made to dissipate the stored energy from parasitic inductances through Avalanche mode operation. The transistor's inherent Avalanche capability allows it to act as its own protection mechanism, eliminating the need for external clamping circuits and achieving self-protection functionality.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The protection function previously requiring a separate clamping circuit is extracted and integrated directly into the power transistor through Avalanche mode operation. This removes the need for additional protection components while maintaining voltage protection capability.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If a clamping circuit is connected in parallel with the power transistor circuit to clamp voltage and dissipate stored energy, then voltage protection is improved, but cost increases

Engineering Contradiction:

Improvevoltage protectionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The power transistor itself is made to dissipate the stored energy from parasitic inductances through Avalanche mode operation. The transistor's inherent Avalanche capability allows it to act as its own protection mechanism, eliminating the need for external clamping circuits and achieving self-protection functionality.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The protection function previously requiring a separate clamping circuit is extracted and integrated directly into the power transistor through Avalanche mode operation. This removes the need for additional protection components while maintaining voltage protection capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If the power transistor circuit is switched off in circuits with parasitic inductances, then switching function is achieved, but voltage across the transistor increases due to stored energy

Engineering Contradiction:

Improveswitching functionVSAvoidvoltage increase

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The harmful voltage spike caused by parasitic inductances during switching off is converted into a beneficial Avalanche breakdown phenomenon. By intentionally allowing the voltage to rise and trigger Avalanche mode, the stored energy is safely dissipated through the transistor's inherent Avalanche capability rather than damaging the device or requiring external protection circuits.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Effectively manages energy dissipation without additional hardware, reducing circuit complexity and cost while ensuring safe operation of power transistors.

Implementation Method 1

operating at least one power transistor included in the power transistor circuit in an Avalanche mode so that at least a portion of energy stored in the electronic circuit before switching off the power transistor circuit is dissipated in the at least one power transistor

Methodology Applied

Scientific EffectAvalanche mode: Avalanche Breakdown

Data Source

PatentUS20250226820A1Method for operating a power transistor circuit

Publication Date: 2025.07.10 INFINEON TECH AUSTRIA AG

AI summary

A method is disclosed. The method includes switching off a power transistor circuit in an electronic circuit. The electronic circuit includes a power source and a load circuit. The power transistor circuit is connected between the power source and the load circuit. Switching off the power transistor circuit includes operating at least one power transistor included in the power transistor circuit in an Avalanche mode so that at least a portion of energy stored in the electronic circuit before switching off the power transistor circuit is dissipated in the at least one power transistor.