MULTI-LEVEL QUANTIZER DELTA SIGMA MODULATOR WITH CURRENT MODE DEM AND DEM DECISION LOGIC

摘要

A multilevel quantizer (14) is provided in combination with dynamic element matching DEM (20) circuitry in a multibit sigma-delta modulator (10). The DEM circuitry is implemented in a divided manner as two major component parts: at least one current mode DEM switch matrix (20B)(SM), and an associated DEM decision logic block that implements the DEM control algorithm (20A) and that controls the SM. The DEM decision logic block is removed from the delay sensitive sigma-delta feedback loop, while the DEM SM remains within the feedback loop. Also described is a convenient and efficient technique to implement the DEM SM, using current steering logic within the multibit quantizer. In this case one or more DEM switching matrices may be provided within the quantizer for reordering the N-1 digital output bits of the N-level quantizer.