As electronic devices continue to shrink in size, thermal PCB board design becomes increasingly crucial. The compact nature of these devices results in higher temperatures of components, which in turn reduces the system’s reliability. Therefore, this paper employs ANSYS finite element software to analyze the temperature distribution of key components on the printed circuit board (PCB) based on heat transfer principles. By identifying high-temperature and low-temperature areas of the PCB during operation, a more effective layout can be determined. Through the analysis of a sample PCB with different layouts, a more optimal layout can be achieved by reducing temperatures and enhancing system reliability.
Introduction
The continuous miniaturization of electronic equipment makes the layout of the PCB board more and more compact. However, the unreasonable PCB board layout seriously affects the heat transfer path of the electronic components on the board, which leads to a decrease in the reliability of the electronic components due to temperature increase. This ultimately results in a significant reduction in system reliability. The temperature rise problem of the PCB board has become a critical issue, with reports indicating that 55% of failure factors in electronic equipment are attributed to temperatures surpassing specified values. Even a decrease of 1°C can substantially reduce the failure rate of electronic equipment. For example, in civil aviation, a 1°C reduction can lead to a 4% decrease in failure rate. Therefore, thermal design to control temperature rise is imperative for ensuring the stability and reliability of electronic components on the PCB board. The main source of heat on the PCB is power dissipation components such as transformers, high-power transistors, and high-power resistors. To improve stability and reliability, it is essential to understand the power consumption of key components and the temperature distribution on the board for a rational layout.
When conducting thermal simulations, finite element analysis is commonly used to solve heat transport and fluid flow equations. This paper adopts finite element analysis, known for its accuracy in solving complex geometries and allowing for mesh refinement in areas of particular interest. Mesh refinement is crucial for accurately capturing temperature distribution and heat dissipation.
Basic heat transfer principle and ANSYS finite element thermal simulation process
In this study, the geometric model is created using ANSYS software, with the solid model constructed using bottom-up and top-down methods. Due to the complex structure of electronic components, the solid model is simplified for efficient mesh division and result accuracy. SOLID87 10-node elements, suitable for irregular-shaped elements, are selected for mesh division.
Finite element solution of temperature field
Example analysis of two-dimensional temperature field
Layout 1: Chip1 and Chip2 placed side by side with Chip3 positioned next to Chip1. Temperature recorded at 101.5°C and 92.7°C.
Layout 2: Chip1 and Chip2 placed side by side on one side, with Chip3 placed on the other side of the PCB. Temperature recorded at 90°C and 70.7°C.
Comparative analysis
Comparison of the simulated temperature fields shows a significant reduction in temperature for Layout 2 (approximately 10∽20℃), which is crucial for electronic thermal reliability and equipment failure rate reduction. The distribution of power dissipation components affects temperature distribution, emphasizing the importance of a strategic layout to avoid irregular temperature fields. Convective heat transfer coefficients vary for different components, requiring adjustments for accurate results. Correct boundary conditions during modeling are essential for reliable simulations.
Example analysis of 3D temperature field
Three chips on the PCB with parameters identical to 2.
Conclusion and Analysis
The three-dimensional temperature field simulation may seem less ideal than the two-dimensional simulation, but the results are accurate as they reflect component die location temperatures. The complexity of 3D models requires detailed material and structure considerations for accuracy. While 3D simulation provides more information, 2D simulation can quickly approximate temperature distribution. Practical applications should consider the specific needs of the PCB board to choose between these two methods.
Introduction
The continuous miniaturization of electronic equipment makes the layout of the PCB board more and more compact. However, the unreasonable PCB board layout seriously affects the heat transfer path of the electronic components on the board, which leads to a decrease in the reliability of the electronic components due to temperature increase. This ultimately results in a significant reduction in system reliability. The temperature rise problem of the PCB board has become a critical issue, with reports indicating that 55% of failure factors in electronic equipment are attributed to temperatures surpassing specified values. Even a decrease of 1°C can substantially reduce the failure rate of electronic equipment. For example, in civil aviation, a 1°C reduction can lead to a 4% decrease in failure rate. Therefore, thermal design to control temperature rise is imperative for ensuring the stability and reliability of electronic components on the PCB board. The main source of heat on the PCB is power dissipation components such as transformers, high-power transistors, and high-power resistors. To improve stability and reliability, it is essential to understand the power consumption of key components and the temperature distribution on the board for a rational layout.
When conducting thermal simulations, finite element analysis is commonly used to solve heat transport and fluid flow equations. This paper adopts finite element analysis, known for its accuracy in solving complex geometries and allowing for mesh refinement in areas of particular interest. Mesh refinement is crucial for accurately capturing temperature distribution and heat dissipation.
Basic heat transfer principle and ANSYS finite element thermal simulation process
In this study, the geometric model is created using ANSYS software, with the solid model constructed using bottom-up and top-down methods. Due to the complex structure of electronic components, the solid model is simplified for efficient mesh division and result accuracy. SOLID87 10-node elements, suitable for irregular-shaped elements, are selected for mesh division.
Finite element solution of temperature field
Example analysis of two-dimensional temperature field
Layout 1: Chip1 and Chip2 placed side by side with Chip3 positioned next to Chip1. Temperature recorded at 101.5°C and 92.7°C.
Layout 2: Chip1 and Chip2 placed side by side on one side, with Chip3 placed on the other side of the PCB. Temperature recorded at 90°C and 70.7°C.
Comparative analysis
Comparison of the simulated temperature fields shows a significant reduction in temperature for Layout 2 (approximately 10∽20℃), which is crucial for electronic thermal reliability and equipment failure rate reduction. The distribution of power dissipation components affects temperature distribution, emphasizing the importance of a strategic layout to avoid irregular temperature fields. Convective heat transfer coefficients vary for different components, requiring adjustments for accurate results. Correct boundary conditions during modeling are essential for reliable simulations.
Example analysis of 3D temperature field
Three chips on the PCB with parameters identical to 2.
Conclusion and Analysis
The three-dimensional temperature field simulation may seem less ideal than the two-dimensional simulation, but the results are accurate as they reflect component die location temperatures. The complexity of 3D models requires detailed material and structure considerations for accuracy. While 3D simulation provides more information, 2D simulation can quickly approximate temperature distribution. Practical applications should consider the specific needs of the PCB board to choose between these two methods.
