Comparator-Based Switched-Capacitor Delta-Sigma Modulation

In order to eliminate the use of operational amplifiers (opamps) in sampled-data systems and thus avoid several delicate tradeoffs in-volved with their design, a new class of switched-capacitor circuits based on comparators was reported. The novelty of this comparator-based switched-capacitor (CBSC) design method is the detection of a virtual ground condition rather than forcing it through feedback as in the case of opamp-based systems. In this paper, the previously reported CBSC circuit was extended to a differential configuration. As an application, first- and second-order low-power lowpass discrete-time ∆Σ modulators with CBSC gain stages were designed and their performance evaluated