Hi Alberto One thing that I've seen on some switchers is something that watches to see if the transformer/coil core saturates. It is a simple coil that picks up the stray magnetic fields when the coil is overloaded( that often causes the blowout current in the switching transistor ). One has this detection circuit clamp the gate voltage to the switching transistor when it see excess leakage flux. It works better than a simple current detect because it self compensates for the cores temperature. If there is a current overload, it will keep the circuit detect the condition. Dwight