Patent ID: 8456347
Filing Date: 2013-06-04
Classification: H03M

Abstract:
1. A parallel successive-approximation analog-to-digital converter for generating a digital output signal based on an analog input signal, comprising: a reference-voltage generation unit having a plurality of output terminals, wherein the reference-voltage generation unit is arranged to generate a unique reference-voltage on each of its output terminals, and each reference voltage and corresponding output terminal correspond to a unique digital number in a range [X a plurality of sub analog-to-digital converters arranged for successive-approximation operation in a time-interleaved manner; a reference-voltage selection unit operatively connected to the reference-voltage generation unit for selecting a reference voltage generated by the reference-voltage generation unit based on a digital number X wherein the reference-voltage selection unit has a first and a second output terminal operatively connected to the comparator arrangement of the respective sub analog-to-digital converter and includes a first switch layer comprising a plurality of switch groups, wherein each switch group comprises a plurality of switch devices, each switch device in a switch group being operatively connected to a unique one of the output terminals of the reference-voltage generation unit by a first terminal of the switch device and to a common node of the switch group by a second terminal of the switch device, and, for each X in the range [X a second switch layer comprising, for each switch group in the first switch layer, a switch device operatively connected between the common node of the switch group and the first output terminal of the reference-voltage selection unit and a switch device operatively connected between the common node of the switch group and the second output terminal of the reference-voltage selection unit; and wherein the parallel successive-approximation analog-to-digital converter comprises a control unit arranged to generate control signals for the switch devices in the reference-voltage selection unit based on the digital number X a first selected switch device in the first switch layer that is connected to the output terminal of the reference-voltage generation unit that corresponds to X the switch device in the second switch layer that is connected between the common node of the switch group to which the first selected switch device belongs and the first output terminal; a second selected switch device in the first switch layer that is connected to the output terminal of the reference-voltage generation unit that corresponds to Xmax+Xmin−X the switch device in the second switch layer that is connected between the common node of the switch group to which the second selected switch device belongs and the second output terminal; and wherein the control unit includes a first encoder to receive the digital number Xsa and output a first control signal to close both the first selected switch device in the first switch layer that is connected to the output terminal of the reference-voltage generation unit that corresponds to Xsa and the second selected switch device in the first switch layer in the first switch layer that is connected to the output terminal of the reference-voltage generation unit that corresponds to Xmax+Xmin−Xsa; and a second encoder to receive most significant bits of the digital number Xsa and output a second control signal to close both the switch device in the second switch layer that is connected between the common node of the switch group to which the first selected switch device belongs and the first output terminal and the switch device in the second switch layer that is connected between the common node of the switch group to which the second selected switch device belongs and the second output terminal.