Single-Sided Direct-Cooled Power Module With Low-Inductance Leads
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Solution Overview
Problem
Existing power modules face challenges due to high stray inductance caused by narrow contact areas between DC voltage lead frame connections and the power module substrate, as well as short creepage distances between signal pins.
Innovation Solution
A power module design featuring a substrate with electrically insulating and conductive regions, where high-side and low-side power switches are strategically positioned and connected through conductive regions, and power leads are coupled to the substrate via conductive spacers to reduce inductance and enhance creepage distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If narrow contact area between DC voltage lead frame connections and power module substrate is used, then device complexity is reduced, but stray inductance increases due to low current flow and high electrical resistance
Solution Approach 1:
The patent merges multiple contact areas into a single wide contact area between the DC voltage lead frame connection and the power module substrate. This consolidation increases the effective contact surface area, reducing electrical resistance and stray inductance while maintaining structural simplicity. The wide contact area design allows higher current flow capacity without requiring multiple separate connection points.
2Ease of manufacture
If signal pins are attached to side of molded body, then ease of manufacture is improved, but creepage distance between signal pins becomes short
Solution Approach 1:
The patent transitions signal pin attachment from a two-dimensional side surface configuration to a three-dimensional arrangement where pins are attached to the top surface of the molded body. This dimensional change allows signal pins to be positioned farther apart, increasing creepage distance while maintaining ease of manufacture through standard top-surface mounting processes.
3Reliability
If wide contact area is used between power leads and substrate, then stray inductance is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates alignment features directly into the wide contact area structure, where the lead frame connection includes built-in mechanical alignment elements that self-align with corresponding features on the substrate. This self-aligning mechanism ensures precise positioning of the wide contact area without requiring additional external alignment procedures or fixtures, thereby reducing stray inductance while maintaining manufacturing feasibility.
Data Source
AI summary
A power module includes a substrate that includes an electrically insulating layer. A first electrically conducting region, a second electrically conducting region, and a third electrically conducting region are each disposed on the electrically insulative layer. The electrically conducting regions are electrically isolated from each other. A plurality of high-side power switches is disposed on and electrically coupled to the first electrically conducting region. A plurality of first connectors is coupled between the plurality of high-side power switches and the second electrically conductive region. A plurality of low-side power switches is disposed on and electrically coupled to the second electrically conductive region. A plurality of second connectors is coupled between the plurality of low-side power switches and the third electrically conductive region. A power lead is coupled to the first electrically conductive region via a spacer.