Buffer amplifier used in medical implants

Hey guys, i'm new here so if i'm posting in the wrong area please let me know!

Recently at university I've had a guest lecturer that works at Cochlear developing medical implant for the hearing impaired, the guest lecturer mentioned and drew an example diagram of a buffer amplifier with 10v rail to ground supply and an input voltage between 1-10v which would mean an ideal output of 1-10v since its a buffer, the guest lecturer also mentioned about additional voltages added with Vin such that if Vin = 1v(min), an additional 0.5v would be added to it hence Vin = 1.5v... or Vin of 10v(max) = 10v + 0.5v = 10.5v ranging between 1.5v-10.5v!? Unfortunately I was unable to ask after the lecture but this has been bugging me since I have no idea why this would be useful to have additional voltage at the input in that kind of implementation?

If anyone knows please shed some light!

They are called "Saturation Voltage"

Lower saturation voltage = negative supply + 1.5

and Upper saturation voltage = Positive supply - 1.5

In your case it is 8.5V so that the max opamp output voltage could be 8.5V

The voltage ranges are just for example purpose only, now a days the opamps are there with very low drop in voltage.

Venkadesh_M said:

They are called "Saturation Voltage"

Lower saturation voltage = negative supply + 1.5

and Upper saturation voltage = Positive supply - 1.5

In your case it is 8.5V so that the max opamp output voltage could be 8.5V

The voltage ranges are just for example purpose only, now a days the opamps are there with very low drop in voltage.

Click to expand...

Thanks, that makes a lot of sense.
But how is that practical? and why would they need that in medical implants?

thanks!

not only in medical implants in every place, if you use opamp the saturation will limit the output voltage.