Cross-coupled folding circuit and analog-to-digital converter provided with such a folding circuit

摘要

A cross coupled folding circuit comprises a reference voltage circuit to supply m reference voltages, an amplifier circuit to provide control signals, in response to an input signal and to the reference voltages and 2ⁿ-I three times cross coupled folding circuits, each of which comprising three differential transistor pairs, said differential transistors pairs being controlled by said control signals and active in a voltage range around a respective one of said reference voltages, with m=3(2''-1). In cascade with said 2ⁿ-I folding circuits, there are differential transistor pairs in n-1 successive steps 2^n-1, 2^n-2, 2^o. To obtain complete folding, switching circuits are provided, cooperating with the transistor pairs in the last ₂n-2 steps of the cascade configuration, to supply the respective control signals to those transistors of the respective differential transistor pairs that provide complete folding.