A continuous-time level-crossing ADC with 1-bit DAC and 3-input comparator

A novel continuous-time level-crossing analog-to-digital converter (LC-ADC) for biomedical application is proposed. Lower power consumption and less design complexity with respect to the conventional designs are achieved due to 1) replacing the n-bit digital-to-analog converter (DAC) with a 1-bit DAC; 2) introducing a 3-input comparator and switching off the idle branches in the following stages when possible; 3) utilizing the opposite polarity of the differential input signals and fixing the comparison window with only one reference level; 4) splitting the level-crossing detections. Designed to be implemented in 0.18 µm CMOS technology, the proposed ADC achieves 8 bits of resolution with much lower power consumption than conventional LC-ADCs.