Estimation of chip temperature via NTC

Nico

Hello,

I have another question regarding the Wolfspeed Modules CAB320M17XM3.

We did some tests with the module and are so far happy with the performance. However, one question regarding the temperature measurement came up. The NTC is sitting next to the low-side MOSFETs. So, naturally there is a temperature difference that can be measured, when the current direction is reversed (for example in a DCDC converter, where in the boost direction the low-side MOSEFT is the active device and in the buck-direction the high-side MOSFET is the active device). Now we are looking for more information on the temperature difference between the two sides.

Additionally, we are interested in understanding the measured temperature by the NTC vs. the actual junction temperature. Do you have a value or a thermal network that you could share, that we could implement in the temperature measurements?

Thanks in advance for your help!

Best regards,

Nico

Forum_Moderator

Thank you for your post, it has been approved and we will respond as soon as possible.

ShamarChristian

Hi Nico,

Thank you for the question. We have recently released a thermal app note detailing the performance of the NTC and the implications of trying to measure the junction temperature using the NTC. It is much more thermally coupled with the case than it is the junction; so thermal events and interfaces taking place at the case such as cold plate flow rate and TIM quality, affect the sensitivity and accuracy of the NTC reading.

You can find details of this in Section 4 of the App Note pasted below.

PRD-08376: Thermal Characterization Methods and Applications | Wolfspeed

Regards,

TBhatia

Hi, I hope that this answered your question. I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.