It occurred to me while writing the next OTA article (It's All Done with Mirrors) that a favorite theory of mine is made possible by the OTA.
The OTA has the property that it can only drive so much current, and no more. That current is specified by the bias current. What comes out of the output pin is +/- Ibias max.
So - if you drive the input with a carefully scaled input voltage so that you don't overload the inputs, and also scale the output currents, you could select the max diode current on a pair of clipping diodes from the output pin to Vref. That would guarantee that you could never get beyond whatever point in the forward voltage/current characteristic you like.
I'll have to so some simulation to see what kind of clipping can be wrung out of that.
That's an interesting concept. What chip would it use? A CA3080?
Sounds like it will be an interesting article. 8)