Patent ID: 7394421
Filing Date: 2008-07-01
Classification: H03M

Abstract:
1. An analogue-to-digital converter having differential inputs and a parallel structure, comprising at least one network of N series resistors with value r and one network of N comparators wherein: the series resistor network receives a reference voltage and is traversed by a fixed current I the row i, i varying from 1 to N, comparator comprises: a dual differential amplifier with four inputs, two inputs receiving a differential voltage to be converted, said differential voltage provided by a sample-and-hold module, a third input being connected to a row i resistor of the network, and a fourth input being connected to an N-i row resistor of the network, the dual differential amplifier supplying a voltage representing a difference of the form (VS−VSN)−(N−2 wherein the resistor network is supplied by a variable reference voltage originating from a servoloop circuit which locks the voltage level of the middle of the resistor network at a voltage equal to the common mode voltage (VS−VSN)/2 present at the output of the sample-and-hold module, said servoloop circuit comprising an amplifier having an input connected to a mid-point of the resistor network.