- Is this how it's done in real designs?
The example shown starting at 10:00 is normally how it is done but as the video shows, how it is implemented is important.
- I've run across the phrase "op amps with or-ed outputs". Does anyone have a link for an explanation of how that's done?
For operational amplifiers it means that the outputs are connected using diodes so either operational amplifier can reduce the drive to the pass transistors lowing the output voltage or current. Since neither operational amplifier can provide drive to the pass transistor through the diodes in this configuration, a separate circuit provides current to drive the pass transistor and either operational amplifier reduces that current through the diodes as needed.
This is not the only good implementation of this idea however. Another way is to have one operational amplifier provide limited drive current while the second reduces that current as required. This avoids having to use a third circuit to provide the drive current.