Transformer-Isolated Semiconductor Switch Driving for Fast Switching

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Solution Overview

Problem

Existing semiconductor switch driving technologies face challenges in achieving fast switching times and efficient energy transmission while ensuring galvanic isolation and minimizing component count, particularly in bidirectional current applications like electric motor drives.

Innovation Solution

A method and device utilizing a transformer-based bridge circuit to transmit control signals and power to the load circuit, eliminating the need for additional galvanic isolation components and enabling quick switching with a threshold value signal, and incorporating a semiconductor protection circuit for overcurrent detection without additional shunt resistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a transformer-based bridge circuit is used to transmit control signals and power, then switching delay time is reduced and component count is minimized, but galvanic isolation and energy transmission efficiency must be maintained

Engineering Contradiction:
Improveswitching delay timeVSAvoidgalvanic isolation
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The transformer serves multiple functions simultaneously: it provides galvanic isolation between control and load circuits, transmits control signals, and supplies power to the load circuit. This multi-functionality reduces component count while maintaining reliability and reducing switching delay time.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The transformer acts as an intermediary device that couples the control circuit and load circuit magnetically rather than electrically. This intermediary approach enables both galvanic isolation and efficient signal/power transmission, resolving the contradiction between isolation reliability and switching speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If additional galvanic isolation components are added to ensure isolation, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvegalvanic isolationVSAvoidcomponent count
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The transformer is designed to perform both galvanic isolation and signal/power transmission functions simultaneously. By making the transformer multi-functional, the patent eliminates the need for separate isolation components, thereby reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of galvanic isolation, signal transmission, and power supply into a single transformer component. This consolidation reduces the total number of components and simplifies the overall device structure while ensuring reliable galvanic isolation.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a protection circuit with additional shunt resistors is used for overcurrent detection, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveovercurrent detectionVSAvoidcomponent count
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the overcurrent detection function from a separate protection circuit with shunt resistors and integrates it into the existing current path of the load circuit. By utilizing the existing current flow through the load, the system achieves accurate overcurrent detection without adding shunt resistors or increasing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The load circuit itself serves the dual purpose of consuming power and providing the current path for overcurrent detection. The existing current flow through the load is utilized for protection purposes, eliminating the need for additional detection components and making the system self-sufficient.

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

This solution achieves short switching delay times, efficient energy transmission, and compact design with reduced components, ensuring safe operation by preventing undefined switching states and protecting against overcurrent and overvoltage.

Implementation Method 1

a primary signal is generated at a primary winding of the transformer on the output side... The primary signal is then transmitted with the transformer as a secondary signal to the load circuit which is galvanically isolated from the control circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3491738B1Method and device for controlling a semiconductor switch
Publication Date: 2022.12.14 ELLENBERGER & POENSGEN GMBH
  • EP3491738B1 patent drawingFigure 1
  • EP3491738B1 patent drawingFigure 2
  • EP3491738B1 patent drawingFigure 2

AI summary

The invention relates to a method for controlling an electronic semiconductor switch (14, 16) connected in a load current circuit (2), said semiconductor switch being connected between an input terminal (10) routed to a source (6) and an output terminal (12) of the load current circuit (2) routed to a load (4), with a control circuit (18), which is connected to a supply voltage (UV) and has a bridge circuit (28) connected on the primary side to a transformer (20) and to the supply voltage (UV), and with a load circuit (22) connected to the transformer (20) on the secondary side, said load circuit having a driver circuit (38) for the semiconductor switch (14, 16), wherein a threshold value signal (S, Sa, Sb) is routed to the bridge circuit (28) on the control side, the bridge circuit (28) generates a primary signal (A), which is transmitted to the load circuit (22) that is galvanically separated from the control circuit (18) as a secondary signal (B), and wherein the secondary signal (B) is fed to the driver circuit (38), which generates a control signal (G) for the semiconductor switch (14, 16).