Randy Slone's multislope VI limiter

[michaelkiwanuka]

Here is another document that might help.

 

[michaelkiwanuka]

...I need an enormous heatsink...

I don't see why you think you need a very large heatsink given the low power MOSFETs you're using.

 

[michaelkiwanuka]

I've this pdf about heatsink dimensioning that I've got from ST, I could use this formulas?

The simplest way is to assume your amplifier dissipates maximum power when it is delivering a third of its output power to the load. So if you designed afor a maximum power output of 100W, then assume worst case amplifier dissipation of 2/3 of 100W, which is roughly 67W.

Divide this figure by the number of ouput devices and thus determine the maximum dissipation of each output device. You then use this to determine the thermal resistance of your heatsink.

Alternatively, just use LTSpice to determine average power dissipation of each device when delivering 1/3 output power.

 

[AndrewT]

Thanks Ian for looking that up.
post37 takes one to the correct page.
In the appendix are the two Eather articles named Part1 and Part2.
The appendix1 may also be useful.

Download Bensen's spreadsheet.
Or go to Jan Didden's webpage for an alternative method.