Differential Transistor Drive Circuit for Common-Mode Interference

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Solution Overview

Problem

Conventional drive circuits for transistors with two control terminals and two load terminals require expensive potential barriers, such as transformers, to manage induced voltages in connecting lines, leading to high costs and complexity.

Innovation Solution

A drive circuit comprising a differential amplifier arrangement and a driver circuit that generates a drive voltage between the two control terminals, using a first and second output node, and a first and second input node, which suppresses common-mode interference from parasitic inductances, eliminating the need for a potential barrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a potential barrier such as a transformer is used to manage induced voltages in connecting lines, then the transistor can be driven reliably despite induced voltages, but the cost and device complexity increase significantly

Engineering Contradiction:

Improvetransistor drive reliabilityVSAvoiddrive circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the expensive transformer component from the drive circuit by using a different approach - connecting the inverting input of the differential amplifier directly to the first control terminal, thereby removing the need for galvanic isolation while maintaining reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a differential amplifier arrangement as an intermediary that processes the input signal and generates the drive signal, using operational amplifiers to handle the voltage differences caused by parasitic inductances without requiring a transformer

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a potential barrier such as a transformer is used to manage induced voltages, then induced voltages are suppressed, but the manufacturing cost increases

Engineering Contradiction:

Improveinduced voltagesVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive transformer with cheaper operational amplifiers and resistive elements that can effectively suppress induced voltages, reducing manufacturing costs while maintaining the ability to handle harmful induced voltages

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The differential amplifier arrangement acts as an intermediary that suppresses induced voltages through its circuit configuration, providing the same protective function as a transformer but at lower cost

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a differential amplifier arrangement is used to generate the drive signal, then common-mode interference is suppressed and the need for a potential barrier is eliminated, but the circuit complexity increases

Engineering Contradiction:

Improvecircuit structureVSAvoidcommon-mode interference

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful common-mode interference into a manageable signal by using the differential amplifier to detect and reject it, transforming the problem into a solution where the interference is automatically suppressed through the differential configuration

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

The solution provides a cost-effective and reliable drive circuit that effectively suppresses induced voltages, reducing the need for expensive components and enhancing the reliability of transistor operation.

Implementation Method 1

The differential amplifier arrangement connected to the first input node, the second input node and the second output node is designed to generate a drive signal based on the input signal

Methodology Applied

Scientific EffectCommon-mode interference suppression:

Data Source

PatentUS10608628B2Drive circuit for a transistor component

Publication Date: 2020.03.31 INFINEON TECH AUSTRIA AG

AI summary

A drive circuit for a transistor component is described. The drive circuit comprises: an output, which is designed to be connected to a drive input of a transistor component and which has a first output node and a second output node; an input, which is designed to receive an input signal, which is referred to a reference potential, and which has a first input node and a second input node; a differential amplifier arrangement, which is connected to the first input node, the second input node, and the second output node, and which is designed to generate a drive signal based on the input signal; and a driver circuit, which is designed to receive the drive signal and to generate a drive voltage between the first and second output node based on the drive signal.