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After reading those

Interpreting Maximum Power of a MOSFET from the datasheet

How to interpret Vgs(th) min/max in a MOSFET datasheet?

https://www.infineon.com/dgdl/Infineon-ApplicationNote_Linear_Mode_Operation_Safe_Operation_Diagram_MOSFETs-AN-v01_00-EN.pdf?fileId=db3a30433e30e4bf013e3646e9381200

enter image description here what i understand :

clarify coniditons :

fet calculation :

1)Vgs min :

from zero thermal coeffcient , from gaph : Ids , Vgs , to prevent thermal runaway

2)Vgs max : from datasheet Vgss

3)Vds max : From Safe operating Area graph , before thermal instability line, and keep in mind power limit .


project calculation :

1) first model my load , to know its impedance , resistance 2) calculate Vds = Vbattery - Load Voltage drop , Vd = Vb , Vs = Vd-Vds

( stated in pdf that Vds depends on voltage drop of load )

3) controlling Vg so it can be variable or constant , connect it to ground so it becomes zero

4) calculate Id ,from Id , Vds graph at known Vgs

Does these steps are correct , fully understood or i miss something ?


i want to know in Ids ( Vds graph )

is linear region , when Vds before V pinch ? and this region correspond to Rds on limit in SOA graph ?

also does saturation region corresponds to package limited ?

if these are correct what does max power limit corresponds to in Ids Vds graph ?

enter image description here

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  • \$\begingroup\$ Where did you find schematic with load and supply on wrong sides \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Feb 18 '20 at 14:47
  • \$\begingroup\$ @TonyStewartSunnyskyguyEE75 sorry i dont understand what do u mean \$\endgroup\$ – Ahmed elmenshawie Feb 18 '20 at 15:28
  • \$\begingroup\$ Swap supply and load if you want correct polarity. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Feb 19 '20 at 1:54
  • \$\begingroup\$ infineon.com/dgdl/… \$\endgroup\$ – Ahmed elmenshawie Feb 19 '20 at 10:44
  • \$\begingroup\$ @TonyStewartSunnyskyguyEE75 please read this , u will find they use it the same way like im using , also i have already tested and simulated it and works fine , actually im asking about sizing and doing calculations \$\endgroup\$ – Ahmed elmenshawie Feb 19 '20 at 10:45

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