terkio wrote: ↑Thu Aug 08, 2019 9:21 am
There is a catch in the Deboo integrator, differential or single.
It is sensitive to resistor mismatch.
This can be important or not, depending of the application.
When in need for near perfect integrators, one needs capacitors with very high insulation resistors. Using a Deboo configuration, the unavoidable resistor mismatch results in an additional parasitic resistor across the capacitor of a positive or negative high resistance.
I've been looking at servo performance in a preamp that has to correct large offset voltages and the more I experiment with the differential DeBoo the more I agree with terkio.
With large offsets to correct there is also a gain error due to resistor mis-match.
I was able to minimize it with resistor selection but the differential DeBoo requires ratio-matching 4 resistors to each other in addition to matching another pair of feedback resistors for 6 total.
In the situation where I've used the differential DeBoo it had small offsets to correct and worked well with 1% resistors.
For the input-capacitorless mic preamp, which may have large offsets to correct, I need to use a floating conventional integrator as a servo.