Planar Transformer PCB Winding Layout for Higher Power Density

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Solution Overview

Problem

The existing power supply modules for communication devices face challenges in increasing output power while maintaining or reducing the module's size, resulting in low power density due to inefficient use of space.

Innovation Solution

The proposed solution involves a planar transformer design with a sub-transformer that includes a magnetic core with a hole and PCB windings, where the first winding is disposed around the magnetic core, and a part of it is located in the hole, allowing for improved space utilization and increased power density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the magnetic core height is increased to improve transformer performance, then the magnetic core protrudes from the PCB windings, but space above the semiconductor device is wasted and power density decreases

Engineering Contradiction:

Improvetransformer performanceVSAvoidpower density

Core Design Contradiction:

PowerVSQuantity of substance

Solution Approach 1:

The first winding is disposed around at least a part of the magnetic core, with a portion of the first winding located inside the hole of the magnetic core. This nesting arrangement allows the winding to occupy the internal space of the magnetic core, eliminating wasted space above the semiconductor device while maintaining the required magnetic coupling, thereby improving power density without compromising transformer performance.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If the magnetic core protrudes from the PCB windings to ensure proper magnetic coupling, then transformer performance is maintained, but space utilization is reduced

Engineering Contradiction:

Improvemagnetic couplingVSAvoidspace utilization

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The first winding is nested around and inside the magnetic core structure, with portions of the winding occupying the hole space. This ensures proper magnetic coupling between the winding and core while utilizing the internal volume of the magnetic core, thereby maintaining reliability without increasing the external dimensions of the transformer.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The winding transitions from a purely planar arrangement on the PCB to a three-dimensional configuration that extends into the hole of the magnetic core. This dimensional change allows the winding to access internal space that would otherwise be unused, improving space utilization while maintaining magnetic coupling through the core structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Length of stationary object

If the PCB windings are made thinner to reduce module height, then space above the semiconductor device is wasted, but the module size constraint is met

Engineering Contradiction:

Improvemodule heightVSAvoidpower density

Core Design Contradiction:

Length of stationary objectVSQuantity of substance

Solution Approach 1:

Inventive Principle:

Principle #7Nested doll (Nesting)

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 design enhances power density by eliminating wasted space and improving space utilization within the planar transformer, thereby increasing the efficiency and performance of the power module.

Implementation Method 1

a first winding and a second winding, the first winding is disposed around at least a part of the magnetic core

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250157721A1Planar transformer, power module, and power supply module

Publication Date: 2025.05.15 HUAWEI TECH CO LTD

AI summary

The disclosure includes a planar transformer including a magnetic core, where a hole is formed on a surface of the magnetic core, and a PCB winding, where the PCB winding includes a first winding and a second winding. The first winding is disposed around at least a part of the magnetic core, a part of the first winding is disposed on the surface of the magnetic core, the magnetic core and the part of the first winding disposed on the surface of the magnetic core are disposed in a stacked manner, a part of the first winding is located in the hole, and the second winding is disposed on the magnetic core, where the first winding is one of a primary winding and a secondary winding, and the second winding is the other of the primary winding and the secondary winding. In this disclosure, power density of the planar transformer can be increased.