RL on class d h bridge

[franticDIY]

Hi,
i've found an old inverter schematic with an inductor and resistor on high mosfets' drain as figure below



I try to reproduce it without RL circuit and mosfets become hot (80° over ambient) for conduction and switching losses as in my calculations.

Then i tried to mount the RL circuit and temperature rise on mosfets was very low (30° over ambient).

I did not understand how this circuit (RL red circle in figure) acts and how you can calculate component values.

Could you help me? I don't found anything (tutorial or application note on this subject).

This RL also allow me to increase switching frequency...

Parameters:
Fswitching=50Khz
Pout=150Wrms

 

[DUG]

The RL could be there to mask problems with dead time. (time between one fet off and the other fet on)

More information would be needed for a more complete answer.

(I could also be completely wrong, too)

🙂