Fet's with thermal shutdown

I've built analog computers to calculate mosfet junction temperature in real time, for shutdown. That lets me use a fast/giant fet that doesn't self-protect.

At lower powers, there are some cool self-protecting SSRs.

Den onsdag den 31. maj 2017 kl. 19.15.16 UTC+2 skrev George Herold:

We've used quite a few VND-something for driving 24V solenoid valves

Maybe the VNP10N07? I'm ordering some of those.

George H.

I've got too many projects, and not enough time to think about each one.

In this case it works as designed, but I realized (during testing) that if the out put gets shorted or some low resistance, then the Fet is going to consume ~10 Watts... That's a pretty big heat sink I think... (ambient air)

George H.

VND7NV04 I think, so similar but a bit lower voltage and current

Thanks Lasse, "Protected Mosfet" (or fully protected or self protected) seems to be the right search term. I'm so addicted to Digikey it's hard for me to find parts without it. :^)

George H.

George Herold:

Herold:

similar) 0.5A current but with a thermal shut down. (something like the bipolar lm395)

valves

Infineon make them - BSP78 is about right for you (SOT223) or maybe BTS134D in TO252. The problem with these devices (and many others) is that the shut down current is very high so they don't current limit when shorted unless your power supply is very beefy. If possible I like to monitor the voltage across the device and switch it off before it gets hot enough to do so itself. But to do this you need reasonably fast voltage monitoring which may be a problem for you.

MK

Thanks Michael, I've ordered the infineon BTS133BKSA1. I also found the web page for ST-micro that lists their offerings. (I had to search starting with automotive products.)

I'm not so much interested in the current limit, but the thermal shutdown. I think they all claim to shut down near 165 C which strikes me as kinda high, but I'll see.

George H.