TPS55332-Q1: thermal shutdown

Hello Andrew,

The thermal shutdown temperature needs to be above the operating temperature to make sure that the device is able to operate at the maximum allowed temperature. This is a protection feature that makes sure that the device does not break down immediately when it overheats, it does not guarantee that it does not get damaged when you operate it permanently there.

Hi Brigitte,

Thanks for your reply. I suspected that that was the case.

In my application this boost converter will operate from a large battery which could conceivably left heavily discharged for a long time. This would have the boost converter running at a low input voltage, high input current state for a long time resulting in greater losses and possibly leading to over temperature on the converter. From what you say, I can't rely on the built-in thermal shutdown to handle this over heating if I want long term reliability. I would be better off adding an external thermal protection to shut down the converter before it exceeded its maximum operating junction temperature. Do you agree?

Regards,

Andrew

Hello Andrew,

If you know the minimum input voltage at which the converter still operates, I would recommend doing a test in the lab with the maximum load that could happen and check the temperature you achieve in this test case. If you are below 150C, I think relying on the internal thermal protection is good enough as the overheating only happens if something goes heavily wrong.

If your system can for long periods of time run above the abs max temperature rating, adding a heatsink or limiting the output current would be my first choice, but you could as well add a temperature sensor to turn off the device. heatsink or current sensor would be my first choice as I do not want to have anything running for a long time at such high temperatures.