Intelligent Power Module Creepage Distance via Isolation Lead
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Solution Overview
Problem
Conventional molded intelligent power modules (IPMs) for motor driving face challenges in compact size and reliability, particularly with the integration of multiple driving ICs and high voltage applications, where the distance between leads is insufficient for effective creepage and electrical current capability.
Innovation Solution
The IPM design incorporates multiple MOSFETs attached to die paddles, a single IC attached to a tie bar, and a molding encapsulation that encloses these components, with strategically placed isolation leads increasing the creepage distance between power and other leads, enhancing electrical current capability and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple driving ICs are integrated in conventional IPM design, then the driving capability is improved, but the package size increases and reliability decreases
Solution Approach 1:
The patent combines multiple driving functions into a single integrated circuit that directly attaches to the tie bar. This single IC integrates the functions of multiple conventional driving ICs, reducing the number of separate components while maintaining the required driving capability for multiple MOSFETs. The consolidation improves reliability by reducing the number of attachment points and potential failure sources.
Solution Approach 2:
The single driving IC is designed to perform multiple driving functions simultaneously, controlling multiple MOSFETs (first through fourth MOSFETs) attached to different die paddles. This multi-functional IC replaces what would traditionally require multiple separate ICs, achieving both compactness and maintained driving capability.
2Volume of moving object
If lead distance is reduced for compactness, then package size decreases, but creepage distance for high voltage application becomes insufficient
Solution Approach 1:
The patent introduces an isolation lead as an intermediary element between the power lead and other leads. This isolation lead acts as a mediator that provides the necessary creepage distance for high voltage applications while allowing the overall package to remain compact. The isolation lead strategically increases the electrical clearance without requiring proportional increases in the entire package dimensions.
3Adaptability or versatility
If dual-in-line package is used, then multiple ICs can be mounted, but system design time increases and reliability decreases
Solution Approach 1:
Instead of using multiple separate ICs in a dual-in-line configuration, the patent inverts the approach by using a single integrated IC that provides the functionality of multiple ICs. This inversion simplifies the packaging approach, reduces design complexity, and decreases system design time while maintaining the capability to drive multiple MOSFETs through a unified interface.
Data Source
AI summary
An intelligent power module (IPM) has a first, second, third and fourth die paddles, a first, second, third, fourth, fifth and sixth metal-oxide-semiconductor field-effect transistors (MOSFETs), a tie bar, an IC, a plurality of leads and a molding encapsulation. The first MOSFET is attached to the first die paddle. The second MOSFET is attached to the second die paddle. The third MOSFET is attached to the third die paddle. The fourth, fifth and sixth MOSFETs are attached to the fourth die paddle. The IC is attached to the tie bar. The molding encapsulation encloses the first, second, third and fourth die paddles, the first, second, third, fourth, fifth and sixth MOSFETs, the tie bar and the IC. The IPM is a small-outline package. It reduces system design time and improves reliability. The IC includes boost diodes. It reduces a package size of the IPM.