Flexible Printed Circuit Board Strain Absorption for Power Semiconductor Heat Sink
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Solution Overview
Problem
Rigid printed circuit boards in power supply apparatuses can cause strain on power semiconductor devices due to dimensional errors and assembly inaccuracies, leading to inadequate heat dissipation and potential device breakdown, especially during transportation or movement.
Innovation Solution
A multi-layered printed circuit board with a flexible portion formed by thinning the insulating substrate near the connection points of semiconductor devices, eliminating the need for separate flexible boards and allowing strain absorption, thus maintaining component contact with the heat sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid printed circuit boards are used for control and driver boards, then structural stability is improved, but dimensional errors and assembly inaccuracies cause strain on power semiconductor devices, leading to detachment from heat sink and potential breakdown
Solution Approach 1:
The patent applies this principle by making the insulating substrate of the printed circuit board flexible in specific regions (where semiconductor devices are mounted) while maintaining rigidity in other regions. This flexible portion absorbs dimensional errors and assembly inaccuracies, preventing strain on the power semiconductor devices and their connections to the heat sink, thus resolving the contradiction between structural stability and device reliability.
Solution Approach 2:
The patent divides the printed circuit board into different regions with different mechanical properties: rigid portions for structural support and flexible portions for strain absorption. This segmentation allows the board to simultaneously provide structural stability while accommodating assembly variations without damaging the semiconductor devices.
2Reliability
If separate flexible boards are used to connect power semiconductor devices to driver board and driver board to control board, then strain on components is reduced, but device complexity and space requirements increase, impeding downsizing
Solution Approach 1:
The patent merges the function of separate flexible connection boards into the printed circuit board itself by creating flexible portions directly within the PCB structure. This integration eliminates the need for additional flexible boards while maintaining the strain-absorption function, thus reducing device complexity and space requirements while still protecting against strain.
Solution Approach 2:
The printed circuit board is designed to serve multiple functions: it provides structural support, electrical connections, and strain absorption through its flexible portions. This multi-functionality eliminates the need for separate flexible connection boards, reducing overall device complexity while maintaining reliability.
Data Source
AI summary
A printed circuit board (120) includes an insulating substrate (120a) on which conductive films (120b) are formed. Semiconductor devices (8) disposed external to the printed circuit board (120) have their leads (24a, 24b, 24c) connected to the conductive films. A flexible portion (30) is formed in the insulating substrate (120a) at a location near the location where the leads (24a, 24b, 24c) are connected to the conductive films (120b).