Electronics Protection - Winter 2015 - (Page 10)

Feature Slashing Printed Circuit Board Design Cycle Time Using Real-Time PCB Thermal Analysis Tools Benjamin Cook, Cradle North America, Inc. Electronic devices are getting smaller, yet they are more powerful. More and more electronic components are being packed onto PCBs, which generate more heat and makes heat management critical. Overheating will not only affect the chips and processors on the PCB, but also adjacent components and the overall system. Sealed electronic devices have also become more prevalent, which reduces the impact of forced convection cooling. Today, thermal management of electronic devices depends primarily on the ability of the PCB to dissipate heat. This means that the goal is to properly arrange the electronic components and create efficient conduction paths that move heat from the heat sources to lower temperature thermal sinks. To fully capture the time saving benefits of the computational tools it requires understanding both the technical objectives and the work flow processes. The bottlenecks must be identified for the process as a whole and the solutions identified that alleviate these bottlenecks. A common characteristic of all product design processes is that maximum design flexibility occurs during the early stages of the process. As the product proceeds deeper into the process, changes to the design are more difficult and more costly to make. At the same time, tools with limited capabilities, or tools that only address the primary function of the product, are used early in the design process. More sophisticated tools are used and detailed analyses performed after the product details are better defined. This suggests that more upfront analysis capabilities can be beneficial if the tools are simple to use and deliver fast results. In the PCB design process, the electrical designers traditionally identify their best PCB concept based on electrical performance before the mechanical designers perform their thermal analysis. When thermal deficiencies are identified by the mechanical designers, the design must go back to the electrical designers for another design iteration. This can be very time consuming. In addition, identifying thermal deficiencies so late in the process makes it more difficult to find solutions. The process works this way because most electrical designers know little about fluid dy- Figure 1. Preview mode shows the PCB geometry and namics and heat transfer. For this reason electrical designers may temperature distribution in 3D. not understand the intricacies of traditional thermal analysis, but they can look at temperature predictions for various conceptual designs and easily identify the most promising concept. The motivation behind PICLS was to eliminate unnecessary PCB redesign work by creating a fast, easy-to-use PCB thermal analysis tool that electrical designers can use during concept development. Moving preliminary thermal analysis forward in the design process is one way to dramatically impact the design cycle time. PICLS permits the electrical designer to immediately address thermal management issues very early in the design phase when they have the most design flexibility. However, to be successful, PICLS must be easy and intuitive for the electrical designers to use. By achieving these objectives, PICLS will reduce the likelihood of project delays caused by thermal management issues. In addition, it can increase the reliability of the design. Cradle worked with their customers to survey electrical designers who had little experience with Computer Aided Engineering (CAE) tools. Together they identified six critical requirements for PICLS that would make the tool effective and usable by electrical designers. * Minimize fluid/thermal knowledge needed by electrical designers to use PICLS * Include pertinent PCB design attributes * Produce accurate results * Use 2D interface * Produce fast results so design decisions can be made immediately * Output results as a report or seamlessly export to CFD software Some of the desired attributes for PICLS are completely different than the attributes of conventional Computational Fluid Dynamics (CFD) software. CFD is predominantly 3D. It can be complicated and difficult to master depending on the complexity of the models. CFD models can contain millions of elements and take anywhere from minutes to days to determine the solution. 10 Winter 2016 * www.ElectronicsProtectionMagazine.com http://www.ElectronicsProtectionMagazine.com

Table of Contents for the Digital Edition of Electronics Protection - Winter 2015

Electronics Protection - Winter 2015
Editor's Choice
Thick Print Copper Technology Increases Thermal Reliability
Slashing Printed Circuit Board Design Cycle Time Using Real-Time PCB Thermal Analysis Tools
Thermal Management of Electronic Devices Utilizing LHS Materials
Industry News
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Electronics Protection - Winter 2015