Power Semiconductor Package Self-Cutoff for PCB Overcurrent Heat
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Solution Overview
Problem
Power semiconductor devices in electronic assemblies are prone to overheating due to overcurrents, which can cause damage to printed circuit boards and lead to 'board burning', as existing technologies lack effective overcurrent protection mechanisms.
Innovation Solution
A package structure incorporating a power semiconductor device, a wire, and a shape memory object that deforms at a preset temperature to cut off or reduce current, utilizing the shape memory object's high resistivity to concentrate heat and break the wire, thereby preventing overheating and protecting the circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power semiconductor device is soldered on a printed circuit board in an SMT secondary package manner, then the device can supply power to the board, but when an overcurrent occurs, a large amount of heat is generated causing damage to the printed circuit board
Solution Approach 1:
A shape memory object is introduced as an intermediary element between the power semiconductor device and the printed circuit board. This shape memory object serves as a mediator that detects temperature changes caused by overcurrent and triggers a protective mechanism by deforming to cut off the wire, thereby preventing direct heat damage to the printed circuit board while maintaining normal power supply functionality
Solution Approach 2:
The harmful heat generated by overcurrent is converted into a beneficial protective signal. The shape memory object utilizes the temperature rise from overcurrent as a trigger mechanism - the heat that would otherwise damage the board instead activates the shape memory effect, causing the object to deform and cut off the wire, thereby converting the harmful thermal energy into a useful protection signal
2Device complexity
If no overcurrent protection mechanism is implemented, then the device structure remains simple, but the printed circuit board is vulnerable to damage from overcurrent
Solution Approach 1:
The shape memory object provides self-service protection without requiring external control systems or complex protection circuits. The object automatically detects temperature changes through its inherent shape memory properties and autonomously deforms to cut off the wire when overcurrent occurs, enabling the system to protect itself using the thermal energy already present in the failure mode
Solution Approach 2:
The protection mechanism relies on changing the physical state of the shape memory object based on temperature parameter changes. When the temperature reaches a critical threshold due to overcurrent, the shape memory object undergoes a phase transformation that causes it to deform and cut off the wire, providing protection through a simple parameter-based trigger rather than complex control logic
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the risk of damage to printed circuit boards by cutting off current when an overcurrent occurs, implementing an overcurrent self-protection capability and prolonging the service life of the board.
Implementation Method 1
the shape memory object is configured to deform when temperature of the shape memory object is not less than preset temperature
Implementation Method 2
the power semiconductor device generates heat when an overcurrent occurs in the power semiconductor device
Implementation Method 3
The heat generated by the power semiconductor device when an overcurrent occurs in the power semiconductor device is conducted to the shape memory object
Data Source
AI summary
A package structure and an electronic apparatus includes a power semiconductor device, a wire, and a shape memory object. The wire is electrically connected to the power semiconductor device, the shape memory object is in contact with the wire, and the shape memory object is configured to deform when temperature of the shape memory object is not less than preset temperature, to enable a current in the wire to be cut off or reduced. In this way, impact of high temperature generated by the power semiconductor device when an overcurrent occurs in the power semiconductor device on the printed circuit board is reduced, a possibility that a printed circuit board is damaged is greatly reduced, and an overcurrent self-protection capability of the package structure is implemented.