Opto-coupler for smps feedback with base connection?

[grizedale]

hello,

Do you know what is the purpose of the base connection in this opto-coupler?

Can i somehow use it to speed up the opto-coupler, giving a faster transient response to the smps?

https://www.farnell.com/datasheets/72450.pdf

 

[FvM]

For analog applications, there are two options to speed up an opto-coupler
- use it in current source mode, e.g. a cascode circuit or another means that creates a low (AC) load impedance, to overcome miller capacitance.
- use it as a photo diode. In this case, you'll need the base terminal.

Did you check, if the opto coupler pole is actually creating problems in your design?