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HEAT SINK DESIGN

Posted by: viveksharmakallur on

Hi

I want design heat for my power supply

Input 85-265V AC'
Output 12V 10A 120watt Power Supply

Support need to design Heat sink for TOP271EG
Please share the heat sink design calculations

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Submitted by PI-Jedidiah on 11/07/2018

Hi viveksharmakallur,
(Tamb - Tjunction[TOP271EG])=Pdiss*(Rth[ic]+Rth[heatsink]). Tamb is the maximum allowed ambient temperature in your design like 40degC. Tjunction is your goal for the maximum temperature you want TOP271EG to have (example is you want it to be at 100DegC). Pdiss is the computed or measured power dissipation in TopSwitch while Rth = 2degC/watt. The only variable left is Rth of the heatsink. You may refer to websites like shown below that has heatsink with Rth equivalent.
http://www.aavid.com/product-group/extrusions/search
Regards,
Jedidiah

Submitted by viveksharmakallur on 11/07/2018

Please share exact part number suitable for TOP271EG from aavid

Submitted by PI-Jedidiah on 11/09/2018

Hi viveksharmakallur,
I only gave reference/sample website as an example for heatsink with Rth parameter. For exact heatsink suitable for TOP271EG, we need to check the mechanical dimension of the vendors that can suite or device. Also, you need to compute what's suitable for your specs. It will depend on your maximum allowable temperature, and on the size of heatsink allowed on your design.
Regards,
Jedidiah