This high-side P-channel FET circuit that seems to work to switch 9V from 5V micro:
The FET is a digital-drive type.
- Does opto U1 (LTV-817S) require a minimum current on the output side to stay turned on? The datasheet has a parameter Ic (collector current) with minimum value 2.5 mA, does that mean it must have at least this much current to stay on, or what?
- Will the C1/R3 combination work ok to limit in-rush to the (capacitive) load when the FET turns on. I looked for how to do this and found the advice to add C1 to slow the turn-on of the FET. I guess it make sense to control the rate of change of turn-on signal for FET, but I didn't find much guidance in datasheet to determine what filter time constant to use.
I ask because I would like to use larger R2-R3 if possible to save current when FET is on, and also be more sure of how to control in-rush.