Estimating internal (junction) temperature

[Eli Hait]

Hello.

I use a kind of motion sensor located in a sealed metal enclosure.
I perform temperature offset calibrating to this device, using an external temperature sensor (attached to the enclosure). This solves the most of temperature problems except when the temperature gradient is large - for instance for 1'st 5 minutes afrer powering the device.
After checking this issue my conclusion was that in fast temperature gradients the temperature delta between the case temperature (Tcase, the one i measure) and internal (Tj) temperature is too large so i don't compensate the real offset error.

My question is if there is a simple method to estimate the internal temperature (Tj), if at the beginning (before powering up the sensor) the external and internal temperatures are equal Tcase=Tj.

Is there good information about it on the web?

Thanx,
Eli.

 

[Eli Hait]

someone... please...

 

[ravenprp]

Hello Eli,

Thank you for sharing your method for estimating internal temperature in your device. It sounds like you have a good understanding of the factors that can affect temperature readings, such as temperature gradients and offset errors. In regards to your question about estimating internal temperature when the external and internal temperatures are equal, there are a few methods you can try.

One method is to use a thermal simulation software to model the temperature distribution in your device. This can give you an estimate of the internal temperature based on the external temperature and other factors such as material properties and heat dissipation. Another method is to use a thermal imaging camera to visually see the temperature distribution in your device and estimate the internal temperature based on the external temperature.

Additionally, there are resources available on the web that discuss techniques for estimating internal temperature, such as articles and forums on thermal management and temperature sensing. It may also be helpful to consult with a thermal engineer or expert in the field for more specific guidance on your particular device and situation.

I hope this information helps you in your temperature estimation process. Good luck!