Method and apparatus for reducing noise in analog-to-digital converter devices

An analog-to-digital converter apparatus having a plurality of stages;

• each respective stage of said plurality of stages comprising:
• (a) a residue amplifier having a first amplifier unit and a second amplifier unit;
• each of said first amplifier unit and said second amplifier unit having a first input locus, a second input locus and an output locus;
• said first and second amplifier units cooperating in receiving a differential input data signal at said first input loci of said first and second amplifier units;
• (b) a DC level setting signal unit coupled with said second input loci of said first and second amplifier units;
• said DC level setting signal unit providing a DC level setting current in a first current direction to said second input loci;
• and
• (c) a counter-current signal generating unit coupled with said second input loci via a single coupling locus common with said second input loci;
• said counter-current signal generating unit providing a control current signal to said second input loci in a second current direction opposite to said first current direction;
• said control current signal providing a DC level control for each of said first and second amplifier units.

A method for reducing noise in input signals to a residue amplifier in an analog-to-digital converter apparatus;

• the residue amplifier having a first amplifier unit and a second amplifier unit;
• each of said first amplifier unit and said second amplifier unit having a first input locus, a second input locus and an output locus;
• said first and second amplifier units cooperating in receiving a differential input data signal at said first input loci of said first and second amplifier units;
• a DC level setting signal unit coupled with said second input loci of said first and second amplifier units provides a DC level setting current in a first current direction to said second input loci;
• the method comprising the steps of:
• (a) providing a counter-current signal generating unit coupled with said second input loci via a single coupling locus common with said second input loci;
• and
• (b) operating said countercurrent signal generating unit to provide a control current signal to said second input loci in a second current direction opposite to said first current direction to establish a DC level control for each of said first and second amplifier units.