How to test power loss of MOS transistor?

In order to solve the problem of MOS transistor heating, it is necessary to accurately determine whether it is caused by the above reasons, and more importantly, to correctly test the power loss of the switching transistor in order to identify the problem and find the key points for improvement. So we can use an oscilloscope to observe the waveform of the switch diode, to determine whether the driving frequency is too high, and to test the magnitude of the G-pole driving voltage, the Id current passing through the drain source, and directly test the power loss of the switch diode.

There are four working states of MOS transistors: turn-on process, conduction state, turn off process, and turn off state.

The main losses of MOS transistors are switching losses, conduction losses, cutoff losses, and energy losses. Switching losses are often greater than the latter, with a small portion of energy reflected in the "conducting state", while the losses in the "closing state" are very small and almost negligible.