BGA Terminal Layout for High-Current Switch Heat Reduction
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Solution Overview
Problem
Conventional switching power supply units face challenges in minimizing heat generation and power loss due to high current flowing through ball terminals in grid array structures, leading to potential terminal melting and reduced conversion efficiency.
Innovation Solution
A semiconductor device with a built-in switch circuit and drive circuit utilizing a grid array terminal structure, where multiple terminals are connected in parallel to reduce current flow through each terminal, and interposing terminals with minimal current flow are added between nearest neighbors to distribute heat, with all terminals located at the outermost positions for enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple bonding wires are parallelly connected to reduce voltage drop, then power loss is reduced, but it becomes difficult to implement in BGA structure with small ball terminals
Solution Approach 1:
The invention divides the single high-current terminal into multiple smaller ball terminals connected in parallel. Each ball terminal carries a fraction of the total switching current, reducing the current density and Joule heat at each terminal while maintaining the same total current capacity. This segmentation allows the use of standard small ball terminals in BGA structures without exceeding their current withstand limits.
2Loss of energy
If ball terminal size is increased to reduce contact resistance, then power loss is reduced, but terminal density in BGA structure decreases
Solution Approach 1:
Instead of using one large ball terminal, the invention uses multiple small ball terminals in parallel. The total cross-sectional area of all ball terminals combined provides sufficient current carrying capacity and low contact resistance, while each individual terminal remains small enough to maintain high terminal density in the BGA grid array structure.
Solution Approach 2:
Multiple ball terminals are electrically connected in parallel to function as a single equivalent terminal with lower contact resistance and higher current capacity. The combined effect of multiple small terminals achieves the same electrical performance as a large terminal would provide, while preserving the space efficiency of small terminals.
3Power
If high switching current flows through single ball terminal, then switching power supply performance is improved, but terminal melts due to excessive heat generation
Solution Approach 1:
The high switching current is divided and distributed through multiple ball terminals in parallel. Each terminal carries only a fraction of the total current (e.g., Io/n for n terminals), which significantly reduces the Joule heat generation at each terminal according to the formula P=I²R. This prevents terminal melting while maintaining the required total power switching capability.
Solution Approach 2:
The invention converts the potentially harmful high current density at a single terminal into a beneficial distributed current distribution across multiple terminals. The heat generation problem is transformed into an advantage by using the parallel configuration to dissipate heat more effectively across multiple contact points, improving both reliability and thermal management.
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 configuration reduces Joule heat and power loss, preventing terminal melting and improving conversion efficiency by distributing heat and reducing contact resistance, while allowing thicker external wiring for better heat radiation.
Implementation Method 1
The ball terminal connected to a transistor switch generates heat determined by the contact resistance thereof and the current Io. As a consequence, these ball terminals connected to a transistor switch are in jeopardy of being melt down by heat.
Data Source
AI summary
A semiconductor device has pluralities of grid array terminals forming a grid array structure, e.g. a BGA structure, in which the output end of a built-in switch circuit is connected to multiple terminals of the grid array structure, thereby reducing the current that flows through each of the multiple terminals below a permissible level and minimizing the heat due to contact resistances of the multiple terminals in contact with the IC socket of the semiconductor device. Each pair of nearest neighbors of the multiple terminals is interposed by at least one further array terminal. The multiple terminals are all located at the outermost peripheral terminal positions of the grid array structure. Thus, the heat generated in the respective multiple terminals connected to the switch circuit is reduced, thereby minimizing the possibility of hazardous melting of the terminals.