Dynamic offset cancellation in sigma-delta converter

摘要

A sigma-delta converter, analog-to-digital conversion system, and an Integrated Circuit (IC) chip are disclosed that include a main sigma-delta modulator and an auxiliary sigma-delta modulator. The auxiliary sigma-delta modulator is electrically matched with the main sigma-delta modulator and is configured to generate an output that is incorporated into a feedback loop of the main sigma-delta modulator to enable the main sigma-delta modulator to adjust an offset signal applied at a main analog channel.

主权项

1. A sigma-delta converter, comprising:
a main sigma-delta circuit comprising:
an input configured to receive an analog input signal from an analog input circuit;a filter configured to filter out at least one frequency band from the analog input signal thereby resulting in a filtered analog signal;a quantizer configured to receive the filtered analog signal from the filter and generate a main circuit digital output signal; anda feedback loop including at least one digital-to-analog converter that generates an analog feedback signal for the main sigma-delta circuit, wherein the at least one digital-to-analog converter generates the analog feedback signal based on the main circuit digital output signal and an analog input reference signal received from the analog input circuit; and an auxiliary sigma-delta circuit that is electrically matched to the main sigma-delta circuit, wherein the auxiliary sigma-delta circuit is configured to receive the analog input reference signal from the analog input circuit and generate an auxiliary circuit digital output that is incorporated into the feedback loop of the main sigma-delta circuit thereby enabling the main sigma-delta circuit to apply an offset signal that is capable of dynamically changing.