Estimate where MOSFET power loss actually goes.
A useful MOSFET loss estimate separates the mechanisms instead of hiding them behind one efficiency number. PowerFET Lab calculates each contribution per device and closes a first-pass thermal loop using temperature-adjusted on-resistance.
Loss terms included
The calculator can also include Coss/Eoss, reverse-recovery charge, diode conduction during dead time, and user-entered passive losses. Switching loss can be entered by transition time, measured Eon/Eoff, Qgd with gate current, or manual watts.
Data that matters most
Use RDS(on) at the actual gate voltage and temperature, not only the headline 25 °C value. Match switching-energy data to bus voltage, current, gate resistance, driver voltage, and junction temperature. Treat Coss as nonlinear when voltage spans a wide range and prefer Eoss curves when available.
Thermal accuracy depends on the real heat path. A single steady-state Rθ value does not reproduce short pulses, interface spreading, copper area, airflow, or neighboring heat sources.
Interpretation limit
This is a screening model. Verify candidate devices against absolute maximum ratings, SOA, transient thermal impedance, measured switching waveforms, and hardware temperature before production release.