This is what I'm going to try:
First Iĉm going to try and replace the resistor with a higher value and higher power handlig capabilities. probably 3k4 6W since that what i have lying arround.
The next thing I'm going to try is to use the values from the HP UHU board which also includes an inductor. I wont be needing an inductor capable of handeling 20A, probably 5 A is sufficient. This will however require heavier modifications of the PCB.
My biggest concern when increasing the voltage is that the turn-off time on the transistors gets higher that than the delay and turn on time. This will cause severe power loss in the output stage. Guess i just have to try and see what happens.
regards
chris |