MOSFET transient calculation

[Techman_7]

If a MOSFET is operated at different current levels and pulse widths (say 5ms, 15ms, 50ms etc. with only conduction loss), how to determine the Pd and Tj ?

 

[KlausST]

Hi,

first of all it depends on frequency.

then calculate the average power dissipation. According V x I (as always)
then calculate the temperature rise
and add it to your ambient temperature


All as usual, nothing special (unless you missed to tell us) ...

--> thus you ill find many hundreds of application notes, examples, web sites, online calculators ... and so on.

It not even depends whether it´s a MOSFET, IGBT, triac, LED, resistor, diode, lamp, soldering iron, ... it all follows the same ruels of electronics and physics.

Klaus

 

[FvM]

Most exact junction temperature for arbitrary pulse load can be calculated with thermal model, if available, in a simulator. Dynamic thermal resistance curves in datasheet gives at least an idea.