This page is used to estimate the turn on and turn off time for a PowerMos.

Driver	What type of driver used, select the best match for your actual driver
Vswitch (Vsw)	Open loop drain voltage
Iswitch (Isw)	Closed loop drain current
Fswitch	PowerMos switching frequence
On percent	Part of switch cycle driver output is pulling high
Vgdrive	Gate driver supply voltage
Igdrive	Gate driver current
Rgdrive	Gate resistor, excluding any internal driver resistance
Qgs	Gate charge before PowerMos start conducting
Qgd	Gate charge required to change output voltage from Vswitch to 0
Qg	Total gate charge including safety overdrive
Vgsth	Voltage where PowerMos start conducting
Vt	Voltage where Qgd charges, this value must be estimated from the curves i.e. "Typical Output Characteristics", it is the lowest gate voltage that can turn on the PowerMos at the desired current.
Vg	Gate voltage for Qg, Qg is scaled for other gate voltages

Total turn on time	Time from drives goes high to Vg has reached Vgdriver
Turn on time	Time from Vg reaches Vgsth to Qgd is charged
Total turn off time	Time from drives goes low to Vg has reached 0
Turn off time	Time from Vg reaches Vt until Vg is down to Vgsth
PowerMos power	Estimated power lost in PowerMos (Turn-On on-state Turn-Off)
Gate resistor power	Power lost in gate resistor (Turn-On Turn-Off)
Gate driver power	Power lost in driver (Turn-On Turn-Off)
Scaled Qg	Qg is scaled according to high voltage on gate

The turn on/off is in 3 parts
First part goes linear from 0 to Vt requiring Qgs, when Vgs reaches Vgsth the MOS starts conducting
Second part is when charging Qgd, Vgs is assumed to be constant (this assumption is only valid for constant current loads)
Third part is when charging up to Qg, MOS is supposed to be fully on
Qg is scaled according to actual Vg used
The switching loss is calculated as U*I/4 while partial conduction, this gives a too high value for most circuits
The on state loss is calculated as I*Rds while on

It is possible to make external tables with driver specifications, for more information email me.

MiscEl: PowerMos