Patent ID: 7764101
Filing Date: 2010-07-27
Classification: H03K

Abstract:
1. A Schmitt trigger, comprising: a number A of first PMOS transistors having the drains and sources thereof serially connected and coupled between a voltage source and an output end, and having gates thereof coupled to an input end; a number B of first NMOS transistors having the drains and sources thereof serially connected and coupled between the output end and ground, and having gates thereof coupled to the input end; a number C of second PMOS transistors functioning as feedback transistors, each of which is coupled between ground and a node between the drain and the source of the first PMOS transistors and has the gate thereof coupled to the output end; and a number D of second NMOS transistors functioning as feedback transistors, each of which is coupled between the voltage source and a node between the drain and the source of the first NMOS transistors and has the gate thereof coupled to the output end; wherein A is greater than 2 and greater than C, and B is greater than 2 and greater than D.