hi,

I do not know, maybe next idea is crazy. I have no time to test it with real hardware, anyway here is the schematic for usage with AC input:



Here are:
- voltage stabilizer;
- voltage level detector.

The idea is the usage of good and big capacitor. I think that such capacitor may accumulate enough power to make life of upper transistor easy (I mean its power dissipation).
But perhaps I am wrong... Any suggestions?

Regards,
Oleg