US 2006/0049973 A1Published application

Pipelined A/D converter and method for correcting output of the same

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsShiro Dosho, Takashi Morie

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Abstract

Analog inputs to a controllable stage can be switched by an input selecting section, while digital inputs to a D/A converter in the controllable stage can also be switched. An error calculation section calculates an error in the output of the pipelined A/D converter caused by an error in the analog output of the controllable stage, based on the output of the pipelined A/D converter produced when the controllable stage is in a given input state, and an expected value thereof. A correction value generation section generates a correction value for correcting the output of the pipelined A/D converter, based on the calculated error. An output correction section corrects the output of a digital calculation section based on the generated correction value.

Claims5

Dependent claims

A pipelined A/D converter, which includes a plurality of cascade-connected stages and a digital calculation section for sequentially shifting digital outputs of the respective stages and adding resultant shifted digital values together, and

in which one or more of the stages are controllable stages, each of which includes:
an A/D converter for converting an analog input to the controllable stage to digital form and outputting a first digital signal as the digital output;
a D/A converter for converting a digital input to analog form;
a selecting device for selecting, as the digital input to the D/A converter, either the first digital signal output from the A/D converter or a supplied second digital signal;
and
a summing amplifier circuit for adding the analog input and an analog output of the D/A converter together and amplifying a resultant value,
the pipelined A/D converter comprising:
an input selecting section for determining whether or not a normal input signal is supplied as the analog input to the controllable stage;
an error calculation section for calculating an error in an output of the digital calculation section caused by an error in an analog output of the controllable stage;
a correction value generation section for generating a correction value for correcting the output of the digital calculation section, based on the error calculated by the error calculation section;
and
an output correction section for correcting the output of the digital calculation section based on the correction value generated by the correction value generation section,
wherein in a state in which the normal input signal is not supplied as the analog input to the controllable stage, the error calculation section calculates the error based on an output of the pipelined A/D converter produced when the second digital signal is supplied to the D/A converter in the controllable stage and based on an expected value for that output of the pipelined A/D converter.

10 more elements

A method for correcting an output of a pipelined A/D converter which includes a plurality of cascade-connected stages and a digital calculation section for sequentially shifting digital outputs of the respective stages and adding resultant shifted digital values together, and

in which at least one of the stages is a controllable stage that includes:
an A/D converter for converting an analog input to the controllable stage to digital form and outputting a first digital signal as the digital output;
a D/A converter for converting a digital input to analog form;
a selecting device for selecting, as the digital input to the D/A converter, either the first digital signal output from the A/D converter or a supplied second digital signal;
and
a summing amplifier circuit for adding the analog input and an analog output of the D/A converter together and amplifying a resultant value,
the method comprising:
a first input selecting step of selecting the second digital signal as the digital input to the D/A converter in the controllable stage, in a state in which a normal input signal is not supplied as the analog input to the controllable stage;
an error calculation step of calculating an error in an output of the digital calculation section caused by an error in an analog output of the controllable stage, based on an output of the pipelined A/D converter and an expected value thereof, after the first input selecting step has been performed;
a correction value generation step of generating a correction value for correcting the output of the digital calculation section, based on the error calculated in the error calculation step;
a second input selecting step of selecting the normal input signal as the analog input to the controllable stage, and selecting the first digital signal as the digital input to the D/A converter in the controllable stage;
and
an output correction step of correcting the output of the digital calculation section based on the correction value generated in the correction value generation step, after the second input selecting step has been performed.

10 more elements

Dependencies are inferred from the claim text.