PCB Package Structure With Hot-Melt Short-Circuit Protection
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Solution Overview
Problem
In chip packaging, when a short circuit occurs during power-on, it generates a large current that can cause the printed circuit board (PCB) to overheat and catch fire, leading to significant losses as all components on the PCB are scrapped.
Innovation Solution
A package structure with a protection structure made of a hot-melt material, such as zinc or cadmium, is integrated inside the dielectric layer of the PCB, which self-blows when a short circuit occurs, preventing excessive temperature buildup and potential fires by having a lower melting point than the PCB's cabling layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a protection structure with low melting point material is integrated inside the dielectric layer, then the PCB is protected from carbonization and fire when chip short-circuits, but the device complexity increases due to the integrated protection structure
Solution Approach 1:
The protection structure is merged with the PCB by integrating it inside the dielectric layer, combining the protective function with the existing PCB structure rather than adding separate external protection components
Solution Approach 2:
The protection structure utilizes parameter changes (melting point difference) between the hot-melt material and the PCB materials to achieve automatic protection when temperature exceeds the melting point during short-circuit conditions
2Reliability
If the protection structure is made of hot-melt material with lower melting point than the cabling layers, then the protection structure blows first to prevent cable overheating, but the manufacturing precision requirements increase for material selection and integration
Solution Approach 1:
The protection mechanism relies on parameter changes, specifically the melting point difference between the hot-melt material (260°C to 450°C) and the PCB cabling layers, to ensure the protection structure blows first during short-circuit conditions
Solution Approach 2:
The protection structure uses inexpensive hot-melt materials (zinc, cadmium, tin-antimony, tin-lead, lead-antimony, aluminum-magnesium, or aluminum-antimony) that are designed to be consumed (blown) during fault conditions
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
This solution effectively reduces losses by preventing the PCB from carbonizing or catching fire, while maintaining normal operation during non-short-circuit conditions, and does not require additional space or components like fuse tubes, thus improving design efficiency and reducing costs.
Implementation Method 1
The protection structure is made of a hot-melt material, and a melting point of the hot-melt material used by the protection structure is lower than melting points of the first cabling layer or the second cabling layer
Implementation Method 2
When the chip is short-circuited, currents at the protection structure, the first cabling layer or the second cabling layer, and the chip are increased. A temperature of a cable used to carry the current and a temperature of the protection structure rise due to the increase in the currents
Data Source
Figure 1~3
Figure 4
AI summary
This application relates to the field of chip packaging technologies, and specifically, to a package structure and an electronic device. The package structure includes a protection structure, a circuit board, and a chip. The circuit board includes a first cabling layer, a dielectric layer, and a second cabling layer that are laminated. The protection structure is disposed inside the dielectric layer. The protection structure is configured to electrically connect the first cabling layer to the second cabling layer. When the chip is packaged on the circuit board, the chip is electrically connected to the first cabling layer or the second cabling layer. In a process of powering on the chip, a current needs to flow through a protection structure to the chip electrically connected to the first cabling layer or the second cabling layer. When the chip is short-circuited, the current is increased. A temperature of a cable used to carry the current and a temperature of the protection structure rise due to the increase in the current. The protection structure is made of a hot-melt material, and a melting point of the hot-melt material is lower than a melting point of the first cabling layer or the second cabling layer through which the current flows. Therefore, the protection structure blows first. This can prevent the temperature of the cable from being excessively high, and therefore prevent a PCB from being carbonized or catching fire, thereby reducing a loss.