Offset Cancellation in Incremental ∆Σ ADCs

The offset cancellation in incremental Delta-Sigma (IDS) ADCs has to be treated differently compared to the cancellation in their freerunning counterparts. In the state of the art (SoA), there exists a lack of theory about this topic. Therefore, in this paper offset propagation and cancellation in I-DS ADCs is analysed. Thereby the idea of fractal sequences to cancel the offset is revised and extended to a more general description to cancel the offset at the output of the I-DS ADC. The derived theory is further explained and backed up by simulations for an exemplary modulator architecture. The intention is to give a deeper understanding on the offset propagation and cancellation in I-DS ADCs and close this gap in the SoA.