Analog-digital converter having multiple feedback, and communication device including the analog-digital converter

A device, comprising:

• a capacitor digital-analog converter including a plurality of switches driven by a digital code and a plurality of capacitors respectively connected to the plurality of switches, wherein the capacitor digital-analog converter is configured to generate a residue voltage based on an analog input voltage and a voltage corresponding to the digital code;
• first through Kth feedback capacitors each storing the residue voltage;
• an integrator configured to generate an integral signal by integrating the residue voltage;
• and
• first through Kth comparators configured to respectively generate first through Kth comparison signals from the integral signal,
• wherein the first through Kth comparison signals are respectively fed back to the first through Kth feedback capacitors, and
• wherein a capacitance of each of the first through Kth feedback capacitors is in inverse proportion to K, wherein K is an integer of at least 2.

An analog-digital converter, comprising:

• a capacitor digital-analog converter, including a plurality of switches driven by a digital code and a plurality of capacitors respectively connected to the plurality of switches, wherein the capacitor digital-analog converter is configured to generate a residue voltage based on an analog input voltage and a voltage corresponding to the digital code;
• a feedback capacitor storing the residue voltage;
• an integrator configured to generate an integral signal by integrating the residue voltage;
• a comparator configured to generate a comparison signal from the integral signal;
• a feedback switch connected to the feedback capacitor in series, and connected to a ground voltage terminal or a reference voltage terminal to which a reference voltage is applied, in response to a digital control signal corresponding to the comparison signal;
• and
• a digital logic circuitry configured to receive the comparison signal, and generate a digital output signal from the comparison signal,
• wherein the device operates at a Nyquist frequency with respect to the analog input voltage.

The device of claim 26, further comprising:

• a first integral capacitor connected between a first output terminal of the integrator and a ground voltage terminal;
• a first reset switch connected across the first integral capacitor in parallel;
• a second integral capacitor connected between a second output terminal of the integrator and the ground voltage terminal;
• and
• a second reset switch connected across the second integral capacitor in parallel.