which MOSFETs would dissipate less power in this circuit

Thread Starter


Joined Nov 25, 2018
The Vds is well bellow the parts maximum value and Vds current is not enough to cause large power dissipation by simply going off I^2R but LTSPICE calculates power using Vds *Id * *Vgs * Igs.

What MOSFET parameters has the most important role in determining power dissipation in this sort of circuit?



Joined Jun 4, 2014
Your gate waveform is very slow rise and fall so the MOSFET will spend a long time partly on, and so will dissipate lots of power. Reducing the rise and fall times will dramatically reduce the power needed.


Joined May 20, 2015
Not so simple. Now the transistor dissipates approximately 100 watts. And the surge voltage on the drain is 180 V with an admissible drain voltage of 200 V. At smaller fronts, the surge will be greater. If now the transistor melts, then in your case the transistor will break through the voltage surge.


Joined Jun 4, 2014
Then, depending on your application, you can catch the spike with a diode, a zener diode, or a combination of diode, capacitor, and resistor.