Switching loss calculator
Choose the switching-loss model your datasheet can support.
No single switching-loss equation is best for every datasheet. PowerFET Lab offers four input methods so the estimate can follow the evidence you actually have.
Four supported methods
- Rise/fall time: a triangular voltage-current overlap approximation for first-pass hard-switching estimates.
- Eon/Eoff: preferred when manufacturer test conditions resemble the real operating point.
- Qgd/gate current: estimates Miller transition time from available gate charge and drive current.
- Manual watts: accepts a measured or externally simulated switching-loss value.
Basic hard-switching estimate
Esw ≈ ½ · VDS · ID · (tr + tf)
Psw = Esw · fs · Nevents
This approximation omits nonlinear capacitance, common-source inductance, reverse recovery, gate-loop ringing, dynamic RDS(on), and soft-switching effects unless they are modeled separately.
Do not mix test conditions casually
Scaling Eon/Eoff linearly is only a screening assumption. Compare the datasheet voltage, current, temperature, gate resistance, and commutation loop with the intended converter.