I want to design a comparator with hysteresis using a folded cascode type. As I have to design different types of comparators with different hysteresis I need to know where to connect the possitive feedback to..
Or would you suggest using a different type of comparaor?
The reason why I want to choose this architecture: I want to use it in a auto zero environment. As I have an auto zero opamp available and the architecture is a folded cascode one.. I wanted to resuse as much as possible.
The positive feedback can be as inside and outside of the comparator.
The internal positive feedback can be made in loading of the first cascade of the comparator.
for high speed comparator, there are three stages:
1) Input Stage (in your case, folded amplifier)
2) Decision Stage (hysterisis with latch)
3) Output stage (CSDA Complementary Self Biased Differential Amp.)
Ofcourse, follow third stage with two inverters as buffers to give you clean digital output. Read P Ellen's stuff on his website www.aicdesign.org. thanks.