Method and circuit arrangement for providing programmable hysteresis to a differential comparator

摘要

A method and apparatus are disclosed for providing programmable hysteresis to a differential comparator. Programmable hysteresis is accomplished by adding voltage followers to the input stage and a current steering network to the output stage of the comparator such that DC bias currents flowing in the current steering network are mirrored via current mirrors so as to flow through the voltage followers at the input stage. By adding a desired offset current to one of the two input voltage follower DC bias currents in dependence on the output state of the comparator in such a manner as to provide positive feedback, an offset voltage is generated due to the unequal voltage drops of the voltage followers resulting in hysteresis which can be controlled in real-time.