Surface Mount Power Module with Metal Leadframe

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Solution Overview

Problem

Current power management systems, such as FunctionPAK ®< DC/DC converters and current control modules, face limitations including parasitic resistance, inductance, limited current carrying capacity, decreased efficiency, and poor thermal performance due to thin copper layers and encapsulation in low thermal conductivity materials, which impact reliability and efficiency.

Innovation Solution

A complete power management system is implemented using a surface mount package with a driver/controller, MOSFET transistor, and passive components connected to a metal leadframe, employing metal clip bonding and an exposed metal bottom for improved thermal and electrical performance, replacing traditional multilayer PCBs and BGA connections with a copper leadframe for reduced parasitic effects and enhanced heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional multilayer PCBs with thin copper layers are used, then assembly is simplified, but current carrying capacity and thermal performance deteriorate

Engineering Contradiction:

Improveassembly simplicityVSAvoidcurrent carrying capacity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the copper layer thickness parameter from thin (traditional PCB) to thick (2-10 mils), directly improving current carrying capacity and thermal performance while maintaining PCB assembly simplicity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure with copper-clad laminate combining thick copper layers with high thermal conductivity core materials, achieving both high current capacity and thermal performance

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If traditional encapsulation materials are used, then manufacturing is simplified, but thermal conductivity deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidthermal conductivity

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The patent replaces traditional epoxy encapsulation with composite materials containing metal particles or ceramic fillers, achieving high thermal conductivity (5-10 W/mK) while maintaining manufacturing compatibility

Inventive Principle:

Principle #40Composite materials

3Reliability

If BGA connections are used, then electrical connectivity is improved, but parasitic inductance and resistance increase

Engineering Contradiction:

Improveelectrical connectivityVSAvoidparasitic effects

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the power delivery network into multiple thick copper power planes and ground planes, reducing current density and parasitic effects in each individual connection path

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from point-to-point BGA connections to planar power/ground plane structures, eliminating via inductance and reducing parasitic effects by distributing connections across two-dimensional planes

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Use of energy by moving object

If DC/DC converters are placed right alongside semiconductor devices, then power delivery efficiency is improved, but system complexity increases

Engineering Contradiction:

Improvepower delivery efficiencyVSAvoidsystem complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges the DC/DC converter, power MOSFETs, and passive components into a single integrated power module, reducing system complexity while maintaining efficient power delivery to semiconductor devices

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 configuration results in higher current ratings, reduced parasitic effects, increased efficiency, lower thermal resistance, and a smaller footprint, enhancing the reliability and performance of DC-DC converters while simplifying assembly and reducing costs.

Implementation Method 1

employing metal clip bonding and an exposed metal bottom for improved thermal and electrical performance, replacing traditional multilayer PCBs and BGA connections with a copper leadframe for reduced parasitic effects and enhanced heat dissipation

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

replacing traditional multilayer PCBs and BGA connections with a copper leadframe for reduced parasitic effects

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP1900022B1Complete power management system implemented in a single surface mount package

Publication Date: 2015.10.07 VISHAY SILICONIX LLC

Figure 1A
Figure 1B
Figure 1C~2A

AI summary

A complete power management system implemented in a single surface mount package. The system may be drawn to a DC to DC converter system and includes, in a leadless surface mount package, a driver/controller, a MOSFET transistor, passive components (e.g., inductor, capacitor, resistor), and optionally a diode. The MOSFET transistor may be replaced with an insulated gate bipolar transistor, IGBT in various embodiments. The system may also be a power management system, a smart power module or a motion control system. The passive components may be connected between the leadframe connections. The active components may be coupled to the leadframe using metal clip bonding techniques. In one embodiment, an exposed metal bottom may act as an effective heat sink.