MOSFET equation

[Electronics4you]

Hi there,

I'm doing a large mechatronic project and need to do some MOSFET calculations, so I can do a theoretically/practical analysis. I found the equation for Drain-Source current, but can't figure out where to get the values from. Does someone know where to find the first four values for e.a. the MOSFET IRFZ34N?

Equation link:
https://en.wikipedia.org/wiki/MOSFET

 

[ljcox]

The first 4 are constants so I would look at the data sheet and extract Id, Vgs, Vth & Vds from the tables and graphs and calculate k

where k = u C W/L

 

[Roff]

You won't find Cox, W, or L on any power MOSFET datasheet (or anywhere else except in the engineering department at the factory). Do your analysis using the data in the datasheet. As a practical matter, that equation is useless, except to engineers who design transistors.

EDIT: Len posted while I was composing. I suppose you could work backwards to get k, but I doubt it would be helpful in your analysis.

 

[OutToLunch]

what sort of theoretical/practical analysis are you performing? Power loss calculation?

 

[Analog]

I would use the MOSFET curves given on the data sheet.