Analog-to-digital converters and pipeline analog-to-digital converters

A pipeline analog-to-digital converter comprising a plurality of pipeline circuit stages coupled in series, wherein each of the pipeline circuit stages comprises a sub analog-to-digital converter circuit and a multiplying digital-to-analog converter, and the sub analog-to-digital converter circuit comprises:

• a sampling-voltage providing circuit providing a group of first comparison voltages and a group of second comparison voltages;
• a first comparison circuit, coupled to the sampling-voltage providing circuit, for performing a first comparison operation to an analog-signal input quantity according to the group of first comparison voltages to generate a first comparison digital quantity;
• a second comparison circuit, coupled to the sampling-voltage providing circuit and the first comparison circuit, for selecting second comparison voltages among the group of second comparison voltages according to the first comparison digital quantity and performing a second comparison operation to the analog-signal input quantity according to the selected second comparison voltages to generate a second comparison digital quantity;
• and
• an encoder circuit, coupled to the first comparison circuit and the second comparison circuit, for encoding the first comparison digital quantity and the second comparison digital quantity and generating a digital quantity corresponding to the analog-signal input quantity.