An A/D converter that supports multi-mode and that can minimize power
consumption is provided. A hybrid A/D converter comprises: hybrid stages
composed of 1.5-bit A/D converter for pipeline use that convert analogue
input signals into digital signals; 1/1.5-bit D/A converters that switch
between pipeline use and delta-sigma modulation use according to the mode
in use; analogue adders that subtract output of the 1/1.5 D/A converters
from the analogue input signals; and analogue operation circuits that
receive as input the output of the analogue adders and function as
amplifiers in pipeline mode and as integrators in delta-sigma mode.