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Unique mechanized PCB/Thermal/Electrical Technique

TEMProducts

I etched my first PCB when I was 13 years old. I made it using transfer sheets and the junky Clad from RadioShack. It was all I knew at the time. Needless to say I found printed circuits to be fascinating.

 

Today I’m 24 years old and I’ve made many PCBs along the way. As my capabilities as an engineer grew, my understanding of PCBs became more complex. Traces are microscopic. Vias connect multiple layers. The circuitry is dense with activity.

 

The modern circuit board is a marvel; functioning not only to transfer electrical power and signals, but also to transfer thermal energy, and provide mechanical structure.

 

In April of 2011 I founded TEM Products Incorporated and began inventing miniature electronics hardware. After over two years and several successful product launches I reminisce to some of my first boards. I’m excited for what the future holds as I’m convinced I’ve reached a new plateau in the PCB realm.

 

Don’t take my word for it. Look at these pictures! image

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Pictured above is my invention – PowerPeg Thermal Connector, and several attached coolers. PowerPeg is a system of interchangeable parts for thermal management. PowerPeg integrates with CAD libraries to provide drag and drop connection, and the standardized thermal output means the designer can choose from a selection of attachable heat sinks.

 

I’m writing this post about a design I recently completed. It’s an integrated Stepper Motor controller based on the DRV8818 from Texas Instruments. With active cooling the device operates safely at 3.5 amps peak.

 


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PowerPeg is an excellent alternative to ground plane heat sinking, because the PCB doesn’t heat up. The components can be placed close together. I took advantage of this in the design for StepperStack. It’s compact, robust, economical, beautiful, and the on-board firmware macros make it very useful for motion control.

 

The stepper circuit can be noisy, and the on-board MCU has some analog functions which can be sensitive. One of the biggest challenges I faced in this design was maintaining circuit ground.

 

PowerPeg came to the rescue again as an electrical connection. The DRV8818 has a bottom-facing thermal pad which is connected to circuit ground. This means PowerPeg became a very low resistance ground bus, and it’s bolted directly into the heatsink. The heatsink covers one entire side of the PCB acting as a really good shield.

 

But that’s not all…. The heatsink used in StepperStack is one of our standard products (GP-43-A). It is a precision-machined heatsink plated with a durable nickel coating. The nickel coating provides excellent electrical connectivity.

 

In one area of the PCB I ran into a problem where a high-current path was isolated, and I had no way of properly grounding the chip.

 

Eureka! Spring-loaded contacts from Mill-Max Mfg. Corp. to the rescue. I should take this opportunity as a “machined pin enthusiast” of sorts to complement Mill-Max. They make really beautiful connectors.

 

So what I ended up doing was using the heatsink as an effective 3rd layer of the PCB. The image below shows the current path through the heatsink.

 


image

 

 

Here is what the spring contacts look like.

 


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Here is the assembled unit.

 


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More information and parts sourcing can be found here.

 

www.tem-products.com/stepperstack

 

 

 

As the company grows I imagine more clever designs and components being added to the portfolio. I’m hoping element14 community appreciates the concept as much as I do.

 

For example - I’m dreaming of a SUPER TINY freon-based refrigeration unit which can be installed directly onto the PCB.  It’s been 3 years and I’ve spent every dollar I have, so that project won’t be possible on our budget until TEM Products gains some traction!

 

Feel free to contact me if you’re interested or have a design question.

 

Thanks.

  • Hi Dean,

     

    It's really great all the ideas you're providing for the possibilities with the device. I know one equipment manufacturer that for a while had an edge on performance to a major extent because they had better cooling than their competitors so their hardware could run at higher speeds more often - yet your product can be used for solving other design challenges too.

    The stepper boards look fantastic. If/when I ever get round to experimenting with my linear motion components, I'm going to use your boards because they are nice parts you're using there, including the TI driver and your heatsink. I'm interested to use the spring contacts design against the heatsink too - superb animated demo you have above.