Power Semiconductor Pin Housing With Insulating Ring Isolation
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Solution Overview
Problem
Power semiconductor devices face challenges due to carbonization of packaging materials in contact with metal pins under high currents or voltages, necessitating complex creepage considerations in design.
Innovation Solution
Incorporation of insulating rings made of non-carbonizable materials, such as molten glass or ceramic, within the plastic housing to prevent contact and creepage issues, combined with metal pins inserted through aligned through holes in the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal pins are used in direct contact with packaging materials, then electrical connection is achieved, but carbonization occurs under high currents or voltages
Solution Approach 1:
An insulating ring made of non-carbonizable material is introduced as an intermediary component between the metal pin and the plastic housing. This ring prevents direct contact between the metal pin and the plastic material, eliminating the carbonization problem while maintaining electrical connection through the metal pin to the internal electrode seat structure
Solution Approach 2:
The packaging structure uses composite materials: the plastic housing provides insulation and structural support, while the insulating ring made of non-carbonizable material (such as ceramic or glass-filled polymer) provides high-temperature resistance and electrical isolation at the metal pin interface, combining the advantages of different materials to solve both connection and carbonization issues
2Reliability
If creepage distance is increased to prevent carbonization, then safety is improved, but device complexity and design difficulty increase
Solution Approach 1:
The insulating ring acts as a mediator that provides electrical isolation and creepage protection without requiring complex design calculations. The ring's material properties (non-carbonizable, insulating) inherently ensure adequate creepage distance, simplifying the design process while maintaining safety
Solution Approach 2:
Instead of increasing creepage distance throughout the entire packaging structure, the insulating ring provides localized creepage protection only where needed - at the metal pin interface with the housing. This targeted approach maintains simplicity while ensuring safety at the critical location
3Reliability
If insulating rings are added to prevent carbonization, then reliability under high voltage is improved, but manufacturing complexity increases
Solution Approach 1:
The insulating ring is integrated into the housing structure such that it is embedded in the plastic housing and forms a unified component. This merging of the ring and housing reduces assembly steps and simplifies manufacturing, while still providing the necessary insulation and creepage protection for high voltage applications
Data Source
AI summary
A power semiconductor device includes a mounting base; a power chip fixed on the mounting base; a bond wire electrically connecting the power chip to a circuit pattern on the mounting base; a columnar electrode seat disposed on the mounting base; a plastic housing encapsulating an upper surface of the mounting base, the power chip, the bond wire, and the columnar electrode seat. The plastic housing includes a through hole aligned with the columnar electrode seat (e.g. pin holders). An insulating ring is embedded on the surface of the plastic housing and surrounds the through hole. A metal pin is inserted into the through hole and fixed on the columnar electrode seat. The insulating ring and the plastic housing are made of different materials.