Two stage analog-to-digital conversion with second stage offset correction

An analog to digital converter circuit, comprising:

• a stage for developing a set of bits from received analog signals, the stage including two residue amplifiers for amplifying the received analog signals corresponding to respective differences between an analog input signal and threshold values directly above and below, respectively, the analog input signal;
• and
• wherein the analog to digital converter circuit further comprises:
• means for reversing the received analog signals,
• offset detection means coupled to the stage for retrieving offset data representative of offset errors and detecting the offset data from the residue amplifiers, and
• offset correction means coupled to receive the offset data for correcting the offset errors corresponding to the detected offset data from the residue amplifiers.

For use with an analog to digital converter that converts an analog input signal to a digital output signal, a circuit arrangement comprising:

• a chopper circuit to chop received residue signals corresponding to respective differences between the analog input signal and threshold values directly above and below, respectively, the analog input signal;
• amplifiers to amplify the respective chopped residue signals;
• ana analog to digital converter circuit to convert the analog output of the amplifiers into a digital signal;
• and
• a residue processing circuit to retrieve offset data representative of offset errors in the amplified residue signals and to provide a feedback control signal to the amplifiers to correct for the offset errors.