Molded Transformer Power Converter Package With Fewer Cure Steps

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional planar laminate transformer assembly processes involve multiple mount and cure steps, leading to significant risks of die attach epoxy bleed-out (EBO) issues, which contaminate leads and cause non-stick wirebond and delamination problems.

Innovation Solution

The integration of a molded transformer with a leadframe and supports, using a laminate substrate with embedded coils and magnetic mold material, reduces the number of mount and cure processes by employing a magnetic mold compound that encapsulates the laminate substrate, eliminating two of the three conventional processes and enhancing isolation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multiple mount and cure processes are used for conventional planar laminate transformer assembly, then the transformer can be assembled with separate magnetic sheets and laminate substrate, but the risk of die attach epoxy bleed-out problems increases significantly

Engineering Contradiction:

Improvetransformer assembly processVSAvoidepoxy bleed-out risk

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent combines the magnetic sheets and laminate substrate into a single molded transformer component. The magnetic mold compound encapsulates the laminate substrate containing the coils, integrating multiple separate parts (top magnetic sheet, bottom magnetic sheet, and laminate substrate) into one unified structure that is molded as a single piece and then attached to the leadframe in one operation.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If conventional separate mount processes are used for magnetic sheets and laminate substrate, then each component can be attached independently, but the number of mount and cure steps increases to three separate processes

Engineering Contradiction:

Improvecomponent attachment flexibilityVSAvoidnumber of mount and cure steps

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the attachment of top magnetic sheet, bottom magnetic sheet, and laminate substrate into a single molding operation. The magnetic mold compound is molded to encapsulate the laminate substrate and form the complete transformer assembly, which is then attached to the leadframe in one mount and cure step, reducing the process from three separate operations to one.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If die attach epoxy is applied multiple times for separate component mounting, then each component can be securely attached, but the contamination of leads and die pad surface increases

Engineering Contradiction:

Improvecomponent attachment strengthVSAvoidepoxy contamination

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent combines multiple epoxy application steps into a single die attach operation. The molded transformer assembly is attached to the leadframe using one application of die attach epoxy, eliminating the repeated epoxy applications that cause bleed-out contamination. The single attachment step secures the entire transformer assembly without contaminating the leads or die pad surface.

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 approach significantly reduces partial discharge yield loss, improves reliability, and increases power conversion efficiency to 90% by simplifying the integration process and reducing material costs, while maintaining compatibility with existing manufacturing infrastructure.

Implementation Method 1

The magnetic mold material comprises magnetic particles and a second dielectric material

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

The laminate substrate includes a first coil and a second coil and a dielectric material

Methodology Applied

Scientific EffectDielectric: Dielectric

Implementation Method 3

Transformers are used in a variety of applications to step-up and/or step-down voltages while providing galvanic isolation between an input and an output

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11870341B2Isolated power converter package with molded transformer

Publication Date: 2024.01.09 TEXAS INSTRUMENTS INC

AI summary

An isolated power converter package includes a leadframe including a first and second die pad, first and second supports connected to first leads, second leads. A first semiconductor die is on the first die pad and a second semiconductor die is on the second die pad. The molded transformer includes a top and bottom side magnetic sheet each having a magnetic mold material including magnetic particles in a second dielectric material on respective sides of a laminate substrate including a dielectric material and a first coil and a second coil that each include a coil contact. Edges of the laminate substrate are on the supports. Bond wires are between the first die bond pads and the second leads, between the second die bond pads and the second leads, between the first die bond pads and coil contacts, and between the second die bond pads and the coil contacts.