Schmitt trigger circuit with near rail-to-rail hysteresis

Schmitt trigger with rail-to-rail or near rail-to-rail hysteresis. In some embodiments, a method includes switching an output of a Schmitt trigger from a first logic state to a second state in response to an input meeting a threshold, where the threshold is applied to a first transistor of a first doping type and the input is applied to a second transistor of the first doping type, the first and second transistors operably coupled to each other through a current mirror of a second doping type. The first doping type may be an n-type, the second doping type may be a p-type, and the threshold may be a rising threshold having a value within 10% of a supply voltage. Alternatively, the first doping type may be a p-type, the second doping type may be an n-type, and the threshold may be a falling threshold having a value within 10% of ground.