Flexible Circuits Replace Twisted Wires in Power Modules

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Solution Overview

Problem

The use of twisted wires in power modules is labor-intensive and prone to variations in wire length, leading to increased manufacturing costs and process control challenges.

Innovation Solution

The implementation of flexible circuits with parallel conductive traces that connect I/O contacts to terminal leads, replacing twisted wire pairs, and integrating gate protection devices, gate resistors, and gate drivers directly onto the flex circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If twisted wires are used to connect I/O contacts to terminal leads, then flexibility and ease of routing are improved, but manufacturing complexity and labor intensity increase

Engineering Contradiction:

Improveease of routingVSAvoidmanufacturing complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges multiple separate wire connections into a single flexible circuit board that provides both signal and power connections. The FPCB integrates multiple conductive traces that replace several individual twisted wire pairs, reducing assembly complexity while maintaining routing flexibility.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical twisting and manual soldering of individual wires with a pre-fabricated flexible circuit board that uses standardized mounting and connection methods. The FPCB substitutes complex manual wire manipulation with a standardized electronic component approach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If twisted wire pairs are used for connections, then inductive coupling effects are reduced, but variations in wire length between modules increase

Engineering Contradiction:

Improveinductive couplingVSAvoidwire length consistency

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent combines multiple signal paths into the rigid structure of the FPCB where trace lengths are precisely controlled during manufacturing. This eliminates the variability inherent in manual wire cutting and assembly while maintaining electromagnetic coupling benefits through controlled trace routing.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical state of the connection medium from flexible wires with variable lengths to a rigid FPCB with precisely controlled trace geometries. The trace lengths, widths, and spacing are controlled parameters during FPCB fabrication, ensuring consistency across all modules.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If manual soldering of wire pairs is performed, then connection flexibility is maintained, but manufacturing time and cost increase

Engineering Contradiction:

Improveconnection flexibilityVSAvoidmanufacturing speed

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent performs the connection preparation in advance during FPCB manufacturing. All conductive traces, pads, and mounting holes are pre-configured before the FPCB is installed in the module, eliminating time-consuming on-site wire cutting, twisting, and soldering operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual soldering operations with automated FPCB mounting processes. The FPCB is designed with standardized mounting features that enable rapid attachment to the module substrate, substituting skilled manual labor with automated assembly equipment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8154874B2Use of flexible circuits in a power module for forming connections to power devices

Publication Date: 2012.04.10 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

A power module includes a power switching device and a flexible circuit with first and second traces electrically connected to the switching device, the first and second traces serving as an input signal carrier and an output signal carrier for the switching device.