US 10,483,993 B1 · Residue amplifier

Abstract

A pipelined analog-to-digital converter (ADC) and a residue amplifier used in the ADC. An ADC includes a capacitive digital-to-analog converter (CDAC), a residue amplifier, and a switched capacitor circuit. The residue amplifier is coupled to the CDAC. The residue amplifier includes a first complementary transistor pair and a first tail current circuit. The first complementary transistor pair is coupled to a first output of the CDAC, and includes a high-side transistor and a low-side transistor. The first tail current circuit is coupled to the high side transistor. The switched capacitor circuit is coupled to inputs of the CDAC and to the first tail current circuit. The switched capacitor circuit is configured to generate a voltage to bias the first tail current circuit with compensation for common mode voltage at the inputs of the CDAC.

Claims20

Dependent claims

An analog-to-digital converter (ADC), comprising:

a capacitive digital-to-analog converter (CDAC);
a residue amplifier coupled to the CDAC, and comprising:
a first complementary transistor pair coupled to a first output of the CDAC, and comprising:
a high-side transistor;
and
a low-side transistor;
and
a first tail current circuit coupled to the high side transistor;
a switched capacitor circuit coupled to inputs of the CDAC and the first tail current circuit, and configured to:
generate a voltage to bias the first tail current circuit;
and
compensate for common mode voltage at the inputs of the CDAC.

9 more elements

A residue amplifier, comprising:

a preamplifier, comprising:
a first transistor;
a second transistor comprising:
a first terminal coupled to a first terminal of the first transistor;
and
a second terminal coupled to a second terminal of the first transistor;
a third transistor comprising a first terminal coupled to a third terminal of the first transistor;
a fourth transistor comprising:
a first terminal coupled to a second terminal of the third transistor;
a second terminal coupled to a third terminal of the third transistor;
and
a third terminal coupled to a third terminal of the second transistor;
a first tail current circuit coupled to the first terminal of the third transistor and the third terminal of the first transistor;
and
a switched capacitor circuit comprising a hold capacitor, wherein a top plate of the hold capacitor is coupled to a terminal of the first tail current circuit.

12 more elements

A residue amplifier, comprising:

a preamplifier comprising:
a first input terminal for connection to a first output of a capacitive digital-to-analog converter (CDAC);
a second input terminal for connection to a second output of the CDAC;
a first complementary transistor pair coupled to the first input terminal;
a second complementary transistor pair coupled to the second input terminal;
a first tail current circuit coupled to, and configured to provide a first bias current to, the first complementary transistor pair and the second complementary transistor pair;
a second tail current circuit coupled to, and configured to provide a second bias current to, the first complementary transistor pair and the second complementary transistor pair;
and
a switched capacitor circuit coupled to the first tail current circuit and the second tail current circuit, and configured to provide to the first tail current circuit and the second tail current circuit a bias voltage that is a function of top plate common mode voltage provided to the CDAC and common mode voltage of input signal provided to the CDAC for digitization.

6 more elements

Dependencies are inferred from the claim text.

Residue amplifier

Life of this patent

Residue amplifier

Life of this patent

Abstract

Claims20