Patent ID: 7502059

Claim:
An asymmetric comparator for use in a pixel sampling circuit, comprising: a differential transistor pair of a first conductivity type, wherein the gate of a first transistor of said differential pair is connected at an input of said comparator to receive a pixel image signal and the gate of a second transistor of said differential pair is connected to receive a ground voltage potential, said gate of said first transistor of said differential pair providing a first switching threshold for said comparator; said first of said transistors of said differential pair having a conduction characteristic different from that of said second transistor of said differential pair; a pair of cross-coupled transistors of a second conductivity type for use as current sources, each of said pair of cross-coupled transistors of said second conductivity type being serially connected with a respective one of said differential pair of transistors of said first conductivity type, the gates of said pair of cross-coupled transistors being disconnected from each other; and an output terminal coupled to a node serially interconnecting said first transistor of said differential pair to a gate of a first of the pair of cross-coupled transistors.