A second-order non-feedback ΔΣ modulator for D/A conversion

This paper describes a novel second-order noise-shaping ΔΣ modulator without the global feedback found in a conventional ΔΣ modulator. The proposed topology allows a pipelined clocking scheme which leads to increased speed-potential and thus higher oversampling ratios compared to conventional topologies. The maximum clock-frequency will now be limited only by the delay through one single accumulator regardless of modulator order which represents a huge saving compared to the conventional modulator. Theoretical analysis and system-level simulations for a second-order converter are presented.