Sigma-delta analogue to digital converter

Patent metadata

Field	Value
Publication number	US-12418302-B2
Application number	US-202318455291-A
Country	US
Kind code	B2
Filing date	Aug 24, 2023
Priority date	Sep 2, 2022
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

A sigma-delta ADC comprising: a first-input-resistor connected in series between a first-input-terminal and a first-feedback-node; a second-input-resistor connected in series between a second-input-terminal and a second-feedback-node; a third-input-resistor connected in series between a third-input-terminal and a third-feedback-node; a first-multiplexer-switch connected in series between the first-feedback-node and a first-amplifier-second-input-terminal; a second-multiplexer-switch connected in series between the second-feedback-node and a first-amplifier-first-input-terminal; a third-multiplexer-switch connected in series between the third-feedback-node and the first-amplifier-second-input-terminal; a first-feedback-current-source having a first terminal and second terminal, wherein the second terminal is connected to a reference-terminal; a second-feedback-current-source having a first terminal and second terminal, wherein the second terminal is connected to the reference-terminal; a first-feedback-selection-switch connected in series between the first-feedback-node and the first terminal of the first-feedback-current-source; a second-feedback-selection-switch connected in series between the second-feedback-node and the first terminal of the second-feedback-current-source; and a third-feedback-selection-switch connected in series between the third-feedback-node and the first terminal of the first-feedback-current-source.

First claim

The invention claimed is:

1. A sigma-delta ADC comprising:
a first-input-terminal configured to receive a first-analogue-input-signal;
a second-input-terminal configured to receive a second-analogue-input-signal;
a third-input-terminal configured to receive a third-analogue-input-signal;
a reference-terminal;
a first-amplifier-stage comprising:
a first-amplifier-first-input-terminal;
a first-amplifier-second-input-terminal;

a first-input-resistor connected in series between the first-input-terminal and a first-feedback-node;
a second-input-resistor connected in series between the second-input-terminal and a second-feedback-node;
a third-input-resistor connected in series between the third-input-terminal and a third-feedback-node;
a first-multiplexer-switch connected in series between the first-feedback-node and the first-amplifier-second-input-terminal;
a second-multiplexer-switch connected in series between the second-feedback-node and the first-amplifier-first-input-terminal;
a third-multiplexer-switch connected in series between the third-feedback-node and the first-amplifier-second-input-terminal;
a first-feedback-current-source having a first terminal and second terminal, wherein the second terminal is connected to the reference-terminal;
a second-feedback-current-source having a first terminal and second terminal, wherein the second terminal is connected to the reference-terminal;
a first-feedback-selection-switch connected in series between the first-feedback-node and the first terminal of the first-feedback-current-source;
a second-feedback-selection-switch connected in series between the second-feedback-node and the first terminal of the second-feedback-current-source; and
a third-feedback-selection-switch connected in series between the third-feedback-node and the first terminal of the first-feedback-current-source.

2. The sigma-delta ADC of claim 1 , further including one or more:
even-input-terminals each configured to receive a respective even-analogue-input-signal;
even-input-resistors, each connected in series between a respective one of the even-input-terminals and a respective even-feedback-node;
even-multiplexer-switches, each connected in series between a respective one of the even-feedback-nodes and the first-amplifier-second-input-terminal; and
even-feedback-selection-switches, each connected in series between a respective one of the even-feedback-nodes and the first terminal of the first-feedback-current-source.

3. The sigma-delta ADC of claim 2 , further including one or more:
odd-input-terminals each configured to receive a respective odd-analogue-input-signal;
odd-input-resistors, each connected in series between a respective one of the odd-input-terminals and a respective odd-feedback-node;
odd-multiplexer-switches, each connected in series between a respective one of the odd-feedback-nodes and the first-amplifier-first-input-terminal; and
odd-feedback-selection-switches, each connected in series between a respective one of the odd-feedback-nodes and the first terminal of the second-feedback-current-source.

4. The sigma-delta ADC of claim 1 , further including one or more:
odd-input-terminals each configured to receive a respective odd-analogue-input-signal;
odd-input-resistors, each connected in series between a respective one of the odd-input-terminals and a respective odd-feedback-node;
odd-multiplexer-switches, each connected in series between a respective one of the odd-feedback-nodes and the first-amplifier-first-input-terminal; and
odd-feedback-selection-switches, each connected in series between a respective one of the odd-feedback-nodes and the first terminal of the second-feedback-current-source.

5. The sigma-delta ADC of claim 1 , wherein:
the first-multiplexer-switch is connected in series between the first-feedback-node and an even-amplifier-connection-node;
the second-multiplexer-switch is connected in series between the second-feedback-node and an odd-amplifier-connection-node;
a third-multiplexer-switch connected in series between the third-feedback-node and the even-amplifier-connection-node;

the sigma-delta ADC further comprising:
a first-even-amplifier-connection-switch connected in series between the even-amplifier-connection-node and the first-amplifier-second-input-terminal;
a second-even-amplifier-connection-switch connected in series between the even-amplifier-connection-node and the first-amplifier-first-input-terminal;
a first-odd-amplifier-connection-switch connected in series between the odd-amplifier-connection-node and the first-amplifier-first-input-terminal; and
a second-odd-amplifier-connection-switch connected in series between the odd-amplifier-connection-node and the first-amplifier-second-input-terminal.

6. The sigma-delta ADC of claim 5 , wherein:
the first-feedback-selection-switch is connected in series between the first-feedback-node and an even-current-source-connection-node;
the second-feedback-selection-switch is connected in series between the second-feedback-node and an odd-current-source-connection-node;
a third-feedback-selection-switch connected in series between the third-feedback-node and the even-current-source-connection-node;

the sigma-delta ADC further comprising:
a first-even-current-source-connection-switch connected in series between the even-current-source-connection-node and the first-feedback-current-source;
a second-even-current-source-connection-switch connected in series between the even-current-source-connection-node and the second-feedback-current-source;
a first-odd-current-source-connection-switch connected in series between the odd-current-source-connection-node and the second-feedback-current-source; and
a second-odd-current-source-connection-switch connected in series between the odd-current-source-connection-node and the first-feedback-current-source.

7. The sigma-delta ADC of claim 6 , further comprising:
a first-feedback-switch connected in series between: i) the first-feedback-current-source; and ii) each of the first-even-current-source-connection-switch and the second-odd-current-source-connection-switch, such that the first-feedback-switch can selectively disconnect the first-feedback-current-source from the even-current-source-connection-node and the odd-current-source-connection-node; and
a second-feedback-switch connected in series between: i) the second-feedback-current-source; and ii) each of the second-even-current-source-connection-switch and the first-odd-current-source-connection-switch, such that the second-feedback-switch can selectively disconnect the second-feedback-current-source from the even-current-source-connection-node and the odd-current-source-connection-node.

8. The sigma-delta ADC of claim 5 , further including one or more:
even-input-terminals each configured to receive a respective even-analogue-input-signal;
even-input-resistors, each connected in series between a respective one of the even-input-terminals and a respective even-feedback-node;
even-multiplexer-switches, each connected in series between a respective one of the even-feedback-nodes and the first-amplifier-second-input-terminal; and
even-feedback-selection-switches, each connected in series between a respective one of the even-feedback-nodes and the first terminal of the first-feedback-current-source.

9. The sigma-delta ADC of claim 5 , further including one or more:
odd-input-terminals each configured to receive a respective odd-analogue-input-signal;
odd-input-resistors, each connected in series between a respective one of the odd-input-terminals and a respective odd-feedback-node;
odd-multiplexer-switches, each connected in series between a respect

Assignees

• Nxp Usa Inc

Inventors

• Cassagnes Thierry Dominique Yves
• D'Esposito Francesco
• Sandrez Pascal
• Tico Olivier
• Brule Simon

Classifications

• H03M3/458 Primary

  Analogue/digital converters using delta-sigma modulation as an intermediate step · CPC title

• H03M1/183

  the feedback signal controlling the gain of an amplifier or attenuator preceding the analogue/digital converter · CPC title

• H03M3/39

  Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators (of digital delta-sigma modulators H03M7/3004) · CPC title

• H03M3/464

  Details of the digital/analogue conversion in the feedback path · CPC title

• H03M1/123 Primary

  Simultaneous, i.e. using one converter per channel but with common control or reference circuits for multiple converters · CPC title