# Mosfet coss modeling **URL:** https://forum.plexim.com/t/mosfet-coss-modeling/2761 **Category:** General **Tags:** mosfet, plecs **Created:** [December 17, 2025, 2:19pm UTC](https://forum.plexim.com/t/mosfet-coss-modeling/2761 "2025-12-17T14:19:07Z") **Posts on this page:** 1 **Showing post:** 4
### Author: ![Munadir\_Ahmed](https://dub1.discourse-cdn.com/flex006/user_avatar/forum.plexim.com/munadir_ahmed/32/1540_2.png) [@Munadir\_Ahmed](https://forum.plexim.com/u/Munadir_Ahmed) #### Post date: [December 18, 2025, 8:31pm UTC](https://forum.plexim.com/t/mosfet-coss-modeling/2761/4 "2025-12-18T20:31:22Z")
Please see my responses below: _Firstly, If I work without Coss capacitances […] this circumstances._ You are absolutely right, without modeling the resonating capacitor you will not be able to observe the ZVS functionality. _Second option , connecting a paralell coss […] then stabilize._ Hard to tell what is going on without a PLECS model. What I will say is if you don’t achieve ZVS and turn on the FET you are effectively shorting a capacitor (Coss) across a very small resistor (Rdson). For example, if your Rdson is 1mOhm and you have 1V then the instantaneous current would be 1000A with a decay defined by the Rdson\*Coss time constant. _This is my full bridge structure […] to error like the image below_ Please see the following description of the error you are experiencing: [What does the error message "state/source dependence" mean? | Plexim](https://www.plexim.com/support/solutions/166) _I wonder that Why mosfet […] thermal charasteristic in this situtaion_ A potential solution might be the one I proposed in this comment on that thread I had sent you earlier: [Soft switching implementation in a DAB converter - #7 by Munadir\_Ahmed](https://forum.plexim.com/t/soft-switching-implementation-in-a-dab-converter/2666/7) . Effectively having a single configuration to model both ZVS and thermals may not be a feasible option. --- _[View the full topic](https://forum.plexim.com/t/mosfet-coss-modeling/2761)._