Patent ID: 8207879
Filing Date: 2012-06-26
Classification: H03M

Abstract:
1. An analog-to-digital converter, comprising: a first switch circuit that receives an external analog signal from outside, outputs the analog signal in reverse phase during a first interval, and outputs the analog signal in positive phase during a second interval; a first integrator that receives and integrates the analog signal with cross-coupling by integrating an output of the first switch circuit during the first interval and sampling the output of the first switch circuit during the second interval; a second switch circuit that outputs an output of the first integrator during the first interval and outputs a common mode output potential of the first integrator during the second interval; a second integrator that samples an output of the second switch circuit during the first interval and integrates the output of the second switch circuit during the second interval; a quantizer that single-bit-quantizes an output of the second integrator to provide the output of the second integrator as a digital signal output; and a digital-to-analog converter that receives an output of the quantizer and provides the output of the quantizer as an analog signal output, each of the first and second integrators receiving and integrating an output of the digital-to-analog converter with cross-coupling, the first integrator including: a fully-differential first operational amplifier that differentially amplifies each signal input to a pair of first input terminals and outputs to a pair of first output terminals; the second integrator includes: each of the first and second integrators being a switched-capacitor fully-differential integrator, and a closed circuit being formed and a common mode feedback being provided during the first and second intervals.