Thermal Analysis Consulting and Training
TMLLC is a single person LLC. Mike Jouppi is a mechanical engineer that has been a thermal analyst since 1982. Specialties are in modeling thermal systems and electronics. TMLLC would like to work with companies that wish to improve their understanding of conductor current carrying capacity in printed circuit applications.
Involvement as a team member for spacecraft projects has been with the development of the system level models and detailed electronics modeling, thermal vacuum test environment models, correlation of the models to test results, boundary condition calculations for payloads, documentation and validation/verification reports.
Electronics thermal management is an area of expertise. A significant amount of time and effort were given to understanding and improving the industry standard for determining conductor current carrying capacity in printed circuits, IPC-2152.
Thermal Management Training
Lunch and Learn
Learn the origin of the conductor sizing charts published in IPC-2221, IPC-D-275, Mil-Std-275 and others before those. Get a look at the original data that went in to the old charts and compare with data used to create the charts in IPC-2152. This knowledge gives you the information you can use to help determine when technology specific design tools make sense for conductor heating design issues, such as traces, parallel traces, vias, microvias, and odd shaped geometries.
Technology Specific Design Tools
IPC-2152 is one step toward managing current carrying capacity problems commonly seen during the printed circuit board design process. The next step is to develop design tools that are specific to the technology that is being developed. We use our "trace heating database tool" as a starting point for the development of Technology Specific Design Tools.
The "trace heating database tool" is a copy of the latest trace heating data used to create IPC-2152 and more. The Trace Heating Database Tool was developed to manage data for sizing traces, vias, microvias, and other geometries.
The value of this information is that it provides a foundation for conductor thermal modeling. The key is to have a process that will help determine the temperature of a conductor anywhere on your board when you apply current to it.
Many people make design decisions based on the IPC-2221 or Mil-Std-275 charts without understanding the origin of the data used to create them. The hard part is knowing the difference between a trace temperature calculated using IPC-2221, Mil-Std-275 or IPC-2152 versus traces in your hardware under your contractual worst case conditions. I say the best solution is to create your own charts and design tools. That way you can take into account your components, copper layers, various mounting configurations, vaccum, high/low altitude or anything that would impact the actual temperature of the conductor, trace, via, etc.
Real data is hard to come by, it takes a long time to collect. Every design cycle has some common issues, such as high current pulses, wagon wheel vs. current, narrow traces through connector pins, and more. The design charts in IPC-2152 or others do not apply to these problems, so why not create your own charts for your technology.
We can work through the temperature rise of any conductor at both steady state and transient conditions.
Thermal Management LLC has a process to help your team develop technology specific design tools to evaluate current applied to conductors in your own designs.
Electronics Thermal Management Plan
The details make a difference. What is in your thermal management plan? Follow your process from system level down to your final documentation.
What do your designers use for sizing electrical conductors?
Do your PCB designers and electrical engineers understand the parallel conductor rule?
Do your design guidelines match your technology?
Would you like your design guidelines to match your technology?
Do you know how to evaluate your conductor sizing guidelines?
How do you handle current in vias, microvias, wagon wheels and odd shaped geometries?
TMLLC has a process to evaluate and help bring answers to these questions.
Electronics Thermal Management Training
IPC-2152 with TRM Training
Lunch and Learn Training (Customized)
Electronics Thermal Management (Customized)
Customized: Depending on the needs of a group, a lunch and learn can be developed to focus on specific needs or areas of interest.
PCB Thermal Management
A component database is important for maintaining quality and accountability for the thermal calculations that are done in your thermal analysis. It should be easy to use and easy to add new components. If you don't have a component database, I can help you get started.
Calculating the Case-to-board thermal resistance. Understanding the various component thermal resistance values is important so that you use the correct value in the appropriate application.
What is in the Component Database that gets used in your thermal analysis?
The old Mil-Std and old IPC trace sizing charts were developed in the mid 1950's, using phenolic boards and a mix of variables that impact conductor temperature rise. IPC-2152 was published in 2009 and represents conductor heating with control over many variables, such as board material and thickness, known board thermal conductivity in the x, y and z axis, known board thermal properties, such as specific heat and density, and known convective and radiation environments.
Thermal Management LLC
Cordwood Construction Electronics