US 6,650,267 B2 · Analog to digital converter

Abstract

The output of each cell in an A-D converter on an IC chip is dependent upon the relative values of an input voltage and an individual one of progressive fractions of a reference voltage respectively introduced to the branches in a differential amplifier. To minimize output errors from cell mismatches, first and second sets of averaging impedances, preferably resistors, are respectively connected between the output terminals in the first branches, and the output terminals in the second branches, in successive pairs of cells. The impedances have relatively low values, particularly compared to the impedances of current sources connected to the branch output terminals. First and second resistive strips on the chip may be tapped at progressive positions to respectively define the impedances in the first and second sets.

Claims28

Dependent claims

A method for converting analog signals to digital signals comprising:

introducing an analog input voltage to a plurality of cells;
introducing a reference voltage to the plurality of cells;
receiving the analog input voltage on a first input terminal of each of the plurality of cells;
receiving the reference voltage on a second input terminal of each of the plurality of cells;
providing an output signal across a first and second output terminal of each of the plurality of cells;
coupling a first set of impedance elements to the respective first and second output terminals of each of the plurality of cells;
and
coupling a subset of a second set of impedance elements between the respective first output terminals of adjacent cells and coupling the remainder of the second set of impedance elements between the respective second output terminals of adjacent cells, wherein the second set of impedance elements provide relatively small impedance values compared with the first set of impedance elements.

5 more elements

A method for converting analog signals to digital signals comprising:

introducing an analog input voltage to a plurality of differential amplifiers;
introducing a reference voltage to the plurality of differential amplifiers;
receiving the analog input voltage on a first input terminal of each of the plurality of differential amplifiers;
receiving the reference voltage on a second input terminal of each of the plurality of differential amplifiers;
providing an output signal across a first and second output terminal of each of the plurality of differential amplifiers;
coupling a first set of impedance elements to the respective first and second output terminals of each of the plurality of differential amplifiers;
and
coupling a subset of a second set of impedance elements between the respective first output terminals of adjacent differential amplifiers and coupling the remainder of the second set of impedance elements between the respective second output terminals of adjacent differential amplifiers, wherein the second set of impedance elements provide relatively small impedance values compared with the first set of impedance elements.

5 more elements

Dependencies are inferred from the claim text.

Analog to digital converter

Life of this patent

Analog to digital converter

Life of this patent

Abstract

Claims28