How to reduce heat in order to avoid Thermal shutdown in TOP267
Hello there,
We have designed a 24v/5A SMPS using ETD29 Transformer but when it is packed in an ABS body and is made to run at 4Amp it is going into thermal shutdown after 30min please suggest method to reduce heat, we will not be able to increase heatsinks as we do not have enough space on the PCB
Comments
Hello there,
Thank you for such a quick reply, the Heat Sink we are using is of U type with a total Surface area of 4200 sq mm used with TOP267EG and the same site is also used with the Output Diode, since we have a size issue inside the body, so we have placed a cooling fan inside. Sharing the schematic as well as the Gerber files, please go through the layout and let us know what is the best we can get using this layout
warm Regards
| Attachment | Size |
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| Cam File (332.59 KB) | 332.59 KB |
Hi Oki,
The heatsink is too small for the design. This may cause the thermal issue. Do you have data or temperature values of the IC and for each component that surrounded the TopSwitch before the failure? You can provide us the data if there are other way to improve the thermal.
However, the only solution that I could think now is to increase the area size of the heatsink you are using in the board. With your current heatsink, even you add a fan or airflow, this may not help a lot since you need a direct contact from the IC to transfer the internal heat outside through the heatsink which should be greater than 13736mm^2 size.
Regards,
PI-Nanoe
Hi Oki,
We are dealing >100W design, the only way to improve the thermal would be increasing the size of the heatsink for EG package if you like to see a noticeable changes. Other changes would be layout and optimizing transformer design if possible, however, this is just nominal change.
What is the size of the heatsink? I tried to replicate this using PIExpert and the minimum heatsink size area should be 13736mm^2. As much as possible the heatsink greater than the recommended.
Regards,
PI-Nanoe