If the turn-on/turn-off voltage (Von+ Voff) of our Power Supply DUT is 400V and 0.5V respectively+ can TDSPWR3 measure the power characteristic curve on V(0.5V) due to the oscilloscope vertical scale issue?

If the turn-on/turn-off voltage (Von+ Voff) of our Power Supply DUT is 400V and 0.5V respectively+ can TDSPWR3 measure the power characteristic curve on V(0.5V) due to the oscilloscope vertical scale issue?

Yes. TDSPWR3 is the only tool which can make measurement at this condition. In this situation, in switching loss measurement user need to select "User" in user interface. Then enter the RDS On value. then while calculating Power loss at a switching device the To and Toff loss are calculated using measured V & I. For total loss, PWR3 computes the conductions loss using measured I and entered RDSon value using I2R formula. then it offers Ton+, Toff, conduction loss gives the total loss.