High-Voltage Packaged Device Leadframe Segmentation
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Solution Overview
Problem
Conventional packaged devices face challenges in operating at high voltages without experiencing voltage breakdown due to arcing, induction, and flashover, as they often lack sufficient creepage and clearance distances between leads.
Innovation Solution
The design of high-voltage packaged devices with a first lead exposed from one end of the molded housing and second and third leads from the opposite end, without a fourth lead electrically connected to the first lead, allows for extended creepage and clearance distances, using a leadframe and molded housing configuration that includes insulating material between leads to prevent electrical connections between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaged devices use standard lead configurations with leads exposed from the same end, then device complexity is reduced and ease of manufacture is improved, but creepage and clearance distances are insufficient leading to voltage breakdown at high operating voltages
Solution Approach 1:
The leadframe is segmented into distinct groups: leads exposed from a first end and leads exposed from a second end. This segmentation physically separates high-voltage and low-voltage leads into different spatial zones, automatically increasing creepage and clearance distances without requiring additional insulating components or complex routing.
Solution Approach 2:
The patent transitions from a two-dimensional lead arrangement (all leads at one end) to a three-dimensional configuration utilizing both ends of the packaged device. By exposing leads from opposite ends along the longitudinal axis, the design exploits the third dimension (length of the package) to maximize electrical isolation distances.
2Volume of stationary object
If leads are positioned closer together to reduce package size, then volume of the packaged device is reduced, but creepage and clearance distances decrease causing voltage breakdown
Solution Approach 1:
Instead of increasing lateral spacing between leads (which would increase package footprint), the design utilizes the longitudinal dimension by placing leads at opposite ends of the package. This allows minimal lateral spacing while maintaining adequate creepage and clearance distances along the length of the package, optimizing overall volume efficiency.
3Adaptability or versatility
If a fourth lead electrically connected to the first lead is added and exposed from the second end, then electrical connectivity is improved, but creepage and clearance distances between the first lead and other leads are reduced
Solution Approach 1:
The harmful element (the fourth lead that would compromise creepage distance) is completely removed from the design. Instead of trying to insulate or route it carefully, the patent extracts this problematic lead from the configuration entirely, maintaining electrical connectivity through alternative means that do not compromise high-voltage isolation.
Data Source
AI summary
Packaged devices and methods for making and using the same are described. The packaged devices contain one or more circuit components, such as a die, that is attached to a leadframe having a first lead, a second lead, and a third lead (although, higher lead counts may be employed in some implementations). A portion of the circuit component and the leadframe are encapsulated in a molded housing so that the first lead is exposed from a first end of the housing while the second and third leads are exposed from a second end of the housing. In some configurations, the packaged device does not contain a fourth lead that is both electrically connected to the first lead and that is exposed from the second end of the molded housing. In other configurations, an area extending from the second lead to the third lead in the molded housing comprises an insulating material having a substantially uniform conductivity. Thus, the packaged devices have relatively large creepage and clearance distances between the first lead and the second and third leads. As a result, the packaged devices are able to operate at relatively high operating voltages without experiencing voltage breakdown. Other embodiments are described.