Planar Transformer Integration for Isolation Amplifier Height Reduction

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Solution Overview

Problem

Existing isolation amplifiers with transformers face challenges in miniaturization, cost-effectiveness, and meeting high requirements for air and creepage distances, particularly when using SMD assembly technology, as they often result in excessive height or are not suitable for large-scale production.

Innovation Solution

A transformer design featuring interconnected conventionally wound toroidal cores with planar short-circuit windings on a substrate, allowing for SMD mounting and integration into narrow insulating housings, with conductor tracks and insulation ensuring compliance with EX standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a transformer is mounted on a circuit board using SMD assembly technology with a carrier plate, then the transformer can be easily assembled, but the overall height from the circuit board becomes excessive

Engineering Contradiction:
Improveease of assemblyVSAvoidoverall height
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The patent merges the transformer component with the circuit board by integrating the windings directly onto the board's conductor tracks, eliminating the need for a separate carrier plate. This combination reduces the overall height while maintaining SMD assembly capability, as the transformer components are mounted directly on the board surface without additional supporting structures.

Inventive Principle:
Principle #5Merging (Combining)

2Volume of moving object

If the transformer is miniaturized to reduce installation space, then the space requirements are reduced, but the air and creepage distances required by EX standards may not be met

Engineering Contradiction:
Improvetransformer sizeVSAvoidcompliance with EX standards
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating distinct isolation regions on the circuit board with different conductor track arrangements. Primary and secondary windings are positioned in separate zones with controlled conductor track spacing, ensuring that local air and creepage distances meet EX standards while allowing overall miniaturization of the transformer component.

Inventive Principle:
Principle #3Local quality

3Reliability

If conventional transformers are used with toroidal cores and carrier plates, then the transformation function is achieved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvetransformation functionVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential transformation function from the conventional transformer structure, retaining only the necessary elements (windings and magnetic core) while eliminating the carrier plate and complex mounting structures. This extraction simplifies the device to a flat, integrated component that maintains transformation functionality with reduced structural complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If the transformer is designed for SMD assembly, then productivity is improved, but the design constraints and manufacturing precision requirements increase

Engineering Contradiction:
Improveassembly speedVSAvoidmounting precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent designs the circuit board conductor tracks to serve multiple functions: they act as both the mechanical mounting structure for the windings and the electrical connection paths. This multi-functionality simplifies the assembly process, as the same structures provide both mechanical support and electrical connectivity, reducing the need for separate precision-aligned components while maintaining SMD assembly productivity.

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

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 enables a miniaturized, cost-effective transformer that meets high safety standards and can be easily integrated into isolation amplifiers using SMD assembly, reducing overall height and improving coupling efficiency while maintaining intrinsic safety requirements.

Implementation Method 1

The galvanic isolation is carried out, for example, by inductive passive components, which have the property of being able to transmit electrical energy. An important passive component in electrical engineering is the transformer.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP1922738B1transformer
Publication Date: 2014.08.27 PHOENIX CONTACT GMBH & CO KG
  • EP1922738B1 patent drawingFigure 1
  • EP1922738B1 patent drawingFigure 2
  • EP1922738B1 patent drawingFigure 3

AI summary

The present invention relates generally to the field of interface technology. Electronic components, for example modular converters for measuring technology, control technology and control engineering, in particular isolation amplifiers, are known in the field of interface technology. Such isolation amplifiers can be used to galvanically separate, convert, amplify and filter standard signals and to adapt analogue signals. The isolation amplifiers are galvanically separated one from the other in the input, output and supply circuits. According to the invention, for separation purposes a separate component of a transformer is integrated into a printed-circuit board of an isolation amplifier using SMD mounting technology, the transformer containing a combination of inductive components, consisting of a magnetic core and winding and a substrate with internal printed conductors which form planar cage windings.