Stacked DC/DC Converter Package with Integrated Controller

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Solution Overview

Problem

Existing power converter devices have a large footprint and require complex and time-consuming clip connections, leading to increased fabrication costs and higher failure rates, making them unsuitable for compact electronic devices.

Innovation Solution

A power converter package design featuring a high side and low side field effect transistor mounted on a shared lead frame with a conductive clip for electrical coupling, along with a controller positioned above the clip, and an interposer element to reorient the gate contact, reducing the footprint and simplifying manufacturing by eliminating the need for two clips.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a planar die arrangement with multiple clips is used to connect FETs and controller, then reliable electrical connections are achieved, but the footprint area increases significantly

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidpackage footprint

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent transitions from a planar two-dimensional arrangement to a three-dimensional stacked configuration. The controller is positioned vertically above the FETs on the lead frame, utilizing the Z-dimension to reduce the horizontal footprint. This vertical stacking allows electrical connections to be maintained through vertical vias and conductive paths rather than requiring extended planar clip connections, directly resolving the contradiction between connection reliability and footprint reduction.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If two separate clips are used to connect HS FET and LS FET, then proper electrical connections are established, but the number of components and alignment complexity increases

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidnumber of clips and alignment steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent consolidates the function of two separate clips into a single integrated clip structure. This single clip simultaneously connects both the high-side FET and low-side FET to the lead frame, reducing the component count from two clips to one. The merged clip design simplifies the assembly process by eliminating the need for separate alignment operations for each clip, directly addressing the contradiction between connection reliability and device complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If a single clip connects both FETs to the lead frame, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvenumber of clipsVSAvoidclip alignment precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The single clip is designed with self-aligning features that enable it to automatically position itself relative to the FETs and lead frame during assembly. The clip geometry includes built-in alignment references and compliance elements that compensate for minor dimensional variations, reducing the stringency of external alignment precision requirements. This self-service mechanism allows the simplified single-clip design to achieve proper connections without imposing excessive manufacturing precision demands.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8679896B2DC/DC converter power module package incorporating a stacked controller and construction methodology

Publication Date: 2014.03.25 NAT SEMICON CORP

AI summary

Methods and systems are described for enabling the efficient fabrication of small form factor power converters and also the small form factor power converter devices.