TI and Würth Elektronik LED RoadTest+ - Thermal Mania - 6/10

31 Dec 2015

While I am working on the PCB of my Smart Headlight circuit design, I got the sparkling idea about thermal protection for Würth Elektronik's LEDs. Würth Elektronik's LEDs has thermal pad contact on their high bright LEDs to control heat dissipation, I have seen some post from other Road testers too, but, my idea is to use single mid sized heatsink for all the LEDs. More or less 76 LEDs in total. I can't provide numerous heatsinks for that much volume of LEDs and in small size of circuit board...

So here is my approach...

It's not finished or the actual full circuit design, It's just the experiment deign to show you guys how I am going to use single heatsink for my LEDs. The curved or swirled traces will be on the centre of my circuit board, the outer most edges of the swirl trace will be connected to thermal pad of LEDs as I shown in the example PCB design. All the LED thermal pad traces will be well layered and connected to swirl traces, the centre most of swirl trace will be connected to single heatsink, either on the trace layer side of the circuit board or the backside. In this way I can reduce heat of numerous LEDs and connected to single heatsink, as well save space in circuit board...

So I am asking Würth Elektronik and other experts here to comment on this approach... As I am doing this as experiment with my little idea. Awaiting for your inputs

FYI: This is not actual PCB design with resistors,LEDS, etc, etc, it's just an example to show my idea, hope you people get my point here...

Top Comments

DAB over 10 years ago in reply to gpolder

I agree with Gerrit.

If you are worried about heat, add some actual heat sinks to the board and use a larger block of solid copper to ensure that the energy gets evenly dissipated.

DAB
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tonyboubady over 10 years ago in reply to gpolder

Ah! ok thanks, maybe I am trying to over doing it in the name of aesthetic and as well I thought the heat will dissipate faster in swirl trace, won't it cool down a bit more?... but yes, as you said maybe i will leave the traces as solid and still make it looks good...I am still about to design the PCB, so good input, thanks.
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gpolder over 10 years ago

Hi Antony,

whats the reason for the swirled traces?
The larger the coper area the faster the heat is dissipated.
I would say just use a solid coper area, which is as large as possible added to a heatsink.
Look for instance to the example Würth sent me in post: LED Road Test - LED PCB issues - Blog 3 - Dec 5, where four LEDs are connected to one heatsink.
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tonyboubady over 10 years ago in reply to DAB

True, I accept your point here... But I hope the LED thermal pad won't produce any voltage other than heat...
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DAB over 10 years ago in reply to tonyboubady

Hi Antony,

What I worry about is the generation of various modulated EMI waves, which could interfere with other electronic devices in the vehicle.
You might want to consider shielding the LED container and maybe adding some ferrite cores to the power and signal lines.

DAB
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