Re: Optocoupler datasheets

On 5/29/2024 11:34 AM, Don Y wrote:

On 5/29/2024 8:15 AM, bitrex wrote:

Any suggestions for how to approach methodically/mathematically selecting drive current would be appreciated, thank you! ("Don't bother" a valid option)

 One thing you can try (depending on what's on the other side of the device
and whether or not you want linear operation) is to drive it with a pulsed,
higher current source and filter on the isolated side.  (assuming total power
is what's driving your design)
 

Right, that's a good idea.
Situations where they're just left on for DC most of the time and trying to get minimal forward current by optimizing a resistor value seem hopeless.
Could wrap a DC feedback loop around it which would only make sense in the situations where you have a lot more power available on the secondary side for some reason, hard to think of a use case.
Logic-output couplers seem somewhat better specified in the sense they explicit state the relatively high minimum forward currents or all bets are off.