Converter In-Rush Thermistors etc, UPDATE -4

BFL13 wrote:
Ok I got my five-minute degree in that one now :) so what would my "Desired in-rush current limit " be? They use 30A

You guys had my voltage up to 170v same as theirs, so if I knew what I-limit is, I get R?

they did energy using their 5000uf but mine is 2400uf and they got a fairly low J, so I am ignoring the J for now since I am good for that with having to meet the current anyway..

And the converter spec is for 13a input draw 15a circuit required so we know that.

so what is my desired in rush current limit?

Inrush current limit, don't know offhand.

However, remember to consider the max ambient temp and use the derating info in the lesson for that, since you want it to function properly after a 5 minute or so shutdown and restart. I'd go for a 10C internal rise during operation and figure it will take a long time for the inside the case (and NTC thermistor) to come back to the 25C or so "normal" ambient. Or, you could use a thermocouple and actually measure the internal rise of the converter. And if you are considering operating it in the summertime in the 90-100F, use that as the ambient and add 10C to that.

A slightly higher than minumum resistance at "normal" ambient is ok as long as the thermistor can handle the max inrush energy and max load current with some margin. Rather have lower than max inrush current at low ambient and no more than max inrush current at high ambient and after a short (10 minute?) shutdown than exceed inrush current under these conditions and risk eventual diode failure.

And if your going to use this in the winter, also do a calculation for inrush power and max thermistor power disspation at low ambient (0F???).