# Thermal Analysis of SMPS

#### sunil0790

Joined Feb 11, 2013
14
I built a simple 100W LED driver, I noticed the ambient temperature of the driver is increasing upto 80deg C after a few hours time. The MOSFET and Transformer are reaching up to 100deg. I am not sure if the temperature rise is within the acceptable range or not!
Can someone help?

#### Dodgydave

Joined Jun 22, 2012
9,940

#### Janis59

Joined Aug 21, 2017
1,330
If mosfet outside is ca 100C then inside is ca 180C. Sure unpardoned.
Driver 80C outside is ca inside 140 C what is just on the sharp boarder between to be or not to be that is the question. If it would be the 60C it may be just brilliant.

#### ebp

Joined Feb 8, 2018
2,332
It really depends on the devices and how the supply is assembled.

80°C at the surface of the FET is probably OK. Again it depends on the device - what kind of package it is in. If the actual FET die in the package is at 100°C it will be just fine.

100°C is quite hot for a transformer but may be OK. It depends a lot on where the heat is being produced.

#### sunil0790

Joined Feb 11, 2013
14