PCB Planar Transformer for Multi-Output Gate Driver Isolation

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Solution Overview

Problem

Conventional ferrite-core transformers occupy significant space and are costly, posing challenges in automotive applications where space is restricted and high-profile designs are not feasible.

Innovation Solution

The use of planar transformers with flat, thin PCB windings and the omission of ferrite cores, allowing for a single primary winding to power multiple secondary windings, along with electromagnetic shielding to manage fringing fields, reduces both space and material costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional ferrite-core transformers are used, then power transfer efficiency is maintained, but space occupation and cost increase significantly

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidspace occupation
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The patent removes the ferrite core from the transformer structure, retaining only the planar windings on the PCB. This extraction eliminates the bulky core component while maintaining acceptable power transfer efficiency through optimized winding designs and electromagnetic coupling between primary and secondary coils

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The transformer transitions from a three-dimensional ferrite-core structure to a two-dimensional planar configuration on the PCB. The windings are arranged in different layers of the PCB, creating vertical electromagnetic coupling while maintaining a flat profile that significantly reduces space occupation in the horizontal plane

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If conventional ferrite-core transformers are used, then power transfer efficiency is maintained, but manufacturing cost increases

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidmanufacturing cost
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

By removing the ferrite core and associated assembly processes, the patent simplifies manufacturing to PCB fabrication techniques only. This eliminates costly core materials, winding insulation materials, and complex assembly steps while maintaining acceptable efficiency through optimized copper trace designs

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The transformer structure is replicated using standard PCB manufacturing processes where copper traces on different layers serve as windings. This copying approach using established PCB fabrication techniques replaces expensive custom transformer manufacturing with scalable, cost-effective board production

Inventive Principle:
Principle #26Copying

3Reliability

If multiple isolated power supplies are provided for each semiconductor switch, then gate driver isolation is achieved, but space requirement increases significantly

Engineering Contradiction:
Improvegate driver isolationVSAvoidspace requirement
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent designs the planar transformer with a single primary winding that can simultaneously drive multiple secondary windings, each providing isolated power to different gate drivers. This multi-functional configuration allows one transformer to replace what would traditionally require multiple separate transformers, reducing overall space while maintaining isolation for each output

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

Solution Approach 2:

Multiple isolated power outputs are combined into a single planar transformer structure on the PCB. The primary and secondary windings are arranged in different layers with optimized coupling, merging multiple power conversion functions into one integrated component that provides both isolation and space efficiency

Inventive Principle:
Principle #5Merging (Combining)

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 enables compact, cost-effective multiple-output isolated power supplies, reducing the number of PCB layers and associated costs, while maintaining efficiency and magnetic coupling.

Implementation Method 1

Power conversion for the isolated power supplies may occur through use of transformers to transfer power from a power source to a load

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

one or more ferrite materials, the one or more ferrite materials providing a shield for electromagnetic interference for the planar transformer

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP4462456A1Systems and methods for multiple-output isolated power supply for gate-driver circuit
Publication Date: 2024.11.13 BORGWARNER US TECHNOLOGIES LLC
  • EP4462456A1 patent drawingFigure 1
  • EP4462456A1 patent drawingFigure 2
  • EP4462456A1 patent drawingFigure 3

AI summary

A planar transformer includes: a first primary coil in a first layer of a printed circuit board (PCB); a first secondary coil in one or more second layers in the PCB; and a second secondary coil in the one or more second layers.