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Introduction to Thermal Analysis in Electronic System Design
Thermal analysis is a crucial aspect of designing reliable electronic systems, especially for high-power devices. Effective heat removal mechanisms, such as PCB substrates, heat sinks, and fans, are essential to maintain performance and prevent failure. This analysis is typically performed by mechanical engineers or specialized third-party companies that simulate heat and airflow. Accurate thermal analysis requires detailed information about component placement on the PCB, actual power dissipation, and the materials and geometry of the PCB.
The Importance of Accurate Power Ratings
Traditionally, thermal analysts conduct calculations using the absolute maximum power ratings from component datasheets. However, the actual power consumed is often significantly lower than these maximum ratings. This discrepancy can lead to the overdesign of heat removal mechanisms, resulting in unnecessary costs and inefficiencies.
BQR Solutions for Component Stress Analysis
BQR offers advanced software and professional services for component stress analysis through circuit stress simulation. Our solutions empower engineers to achieve precise calculations and documentation of actual stress values (power, current, and voltage) in electronic components.
Key Features of BQR's Software
Semi-Automatic Assignments: Stresses can be easily assigned to components using the BQR E-CAD plug-in on the schematic.
Automated Stress Simulation: Component stress is calculated using our unique CircuitHawk simulator.
Benefits of Using BQR for Stress Analysis
Early Detection of Design Errors: Identify and resolve potential issues before layout.
Optimal Thermal Design: Exact stress calculations save space and reduce costs.
Improved MTBF Calculations: Using precise stress data yields higher MTBF (Mean Time Between Failures) values.
Real-World Examples of Success
Example 1: Impact of Accurate Power Dissipation
For IC U2a, a junction temperature (Tj) of 137.1°C was calculated based on the absolute maximum power rating of 6.12W. This result led the mechanical engineer to plan for additional cooling, such as adding a fan. However, after using the actual power dissipation data from the CircuitHawk™ simulation (see IC U2 in Fig. 1), Tj was found to be 95°C, indicating that natural cooling was sufficient. Additionally, the failure rate decreased from 6.129 to 0.804 failures per million hours, showing a reduction by a factor of 7.6.
Example 2: MTBF Calculations
The MTBF of an actual board was calculated using both the Parts Stress Method and the Parts Count Method. The MTBF calculated with actual stress was found to be approximately 1.5 times higher than that calculated using the 50% stress method.
Conclusion
Utilizing actual power dissipation data significantly reduces the unnecessary use of costly cooling elements and results in a much higher MTBF.
BQR's software solutions help engineers optimize thermal design, improve reliability, and reduce costs. Contact us for more information on our services.