Decay of charge current into fet gate?

[treez]

Hello,

In the top table of page 7 of the HV9911 datasheet it says "t = 2.3 *Rgate * Cgs"

this refers to the diagam at the bottom of page 6.

Where does the "2.3" come from?


HV9911 DATASHEET
**broken link removed**

 

[chuckey]

When a RC circuit discharges, the current flows exponentialy, i.e. at T0 = I, @Trc = .63 X I..... @T (5 X RC) ~ 0. 2.3 is just a number where the charging current is a small fraction of the initial current - probablely 10%. Search WIKIPEDIA for the formula.
Frank

 

[treez]

Search WIKIPEDIA for the formula

i know the formula, it's i(t) = I (e^(-t/RC)).

However, i dont know where "0.23" came from

 

[chuckey]

2.3 = e^.1
Frank