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#1 Feb 24, 2021
Attila Várhelyi
Last seen: 6 months 2 weeks ago
Joined: 2021-02-24 14:09

Calculating average power loss via S() and PowerDissipation_mW() function



I am redirected to this forum from TI.

I would like to calculate and draw the average power from loggeg/recorded instantaous W(t) function.

The used simulation parameters are:



log start=3.0ms

W(t) {3.0-3.9ms}


1. How could I define avarage power dissipation with S(x) function? What is the syntax for it?

Take a look to chapter here, Switching Losses in MOFFETs (top picture):

Single Switch Forward Converter | PSpice


PSpice manual only talkes about integral, but average power is area under W(t).


2. Could you tell me what does PowerDissipation_mW() mean?

A manual does not define it well, and I get very false values somtimes.

I don't understand the definition of this, and I can not get the same result to compare S(x).


PSpice Advanced Analy sis User Guide (


PowerDissipation_mW: "Total power dissipation in milli-watts during the final period of time (can be used to calculate total power dissipation, if the first waveform is the integral of V(load)"

V(load)? Integral of V(load)? Maybe this is typo here and means W(load)?

What is the meaning of final period?

The function waits constant as Periode, so any equations like time-3.9m, or 1/Period(x) and so on can not be used.



Sun, 2021-05-16 06:47
Last seen: 2 weeks 6 days ago
Joined: 2016-05-10 23:49

To calculate power dissipation in mosfet - one should multiply appropriate voltage and current waveform and simply take average using avg function. If your simulation has only steady state region you will get resonable result or one can use option in x axis setting dialog to use data in restricted range to select only time range of intrest from full simulation 

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