APPLICATION NOTE
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Figure 13: Switch Loss in Hard Switching Condition
Another type of loss in MOSFET is conduction loss or loss in switch when it is conducting. As high voltage
MOSFETs devices have high RDS, this loss can also be significant. This is also known as the Ohmic
loss.
You can use simulation to accurately estimate losses in power devices and tune gate resistance and
other circuit parameters to optimize the design.
In figure 14, the topmost waveform plot is average switch power loss; the middle waveform is
instantaneous switch power loss, and the bottom waveform is switch current and voltage waveforms.
Average switch power loss is integration of instantaneous power loss over time. This can be performed
using integration S function in PSpice.
Similar approach can be adopted for estimation of power loss in other devices.
