A hysteresis comparator for level-crossing ADC

Sensors are used to collect the natural signals, including rarely change signals. Level-crossing ADC (LC-ADC) employs the idea of irregular sampling, which is adapted to convert the sparse signals. The comparator is an important block of the converter and hysteresis is useful for removing erroneous sampling due to noise. Two hysteresis comparators are presented, one is used in the detection of the signal down and the other is used in the detection of the signal up. The comparators have been implemented in 0.18μm CMOS technology, the area is 940.7μm
²
and 864.5μm
²
respectively, and the propagation delay for the low-to-high transition is 9.5ns and the propagation delay for the high-to-low transition is 10.5ns with the common mode input voltage is 800mV.