Incremental ∆Σ ADCs without Periodic Reset

The theory of incremental Delta-Sigma (I-DS) converters relies on memoryless operation between consecutive Nyquist samples. This is achieved by resetting the analog loop-filter and digital reconstruction filter every Nyquist period. It is shown that the use of reconstruction filters with negligible first-sample weights opens the possibility of removing the periodic reset from the analog loop filter of incremental Delta-Sigma modulator (I-DSM) while maintaining memoryless operation. The periodic reset can further be removed from reconstruction filters whose impulse response is inherently finite. Combining the two features enables free-running Delta-Sigma (DS) converters to be used in time-domain multiplexing applications and without inter-channel interference.