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Date: Wed, 29 May 2024 11:53:29 -0400
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Subject: Re: Optocoupler datasheets
Newsgroups: sci.electronics.design
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 <v37hur$16nlg$2@dont-email.me>
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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.