Sigma-delta analogue-to-digital converter with gmC-VDAC

Patent metadata

Field	Value
Publication number	US-12176925-B2
Application number	US-202017755229-A
Country	US
Kind code	B2
Filing date	Oct 23, 2020
Priority date	Oct 25, 2019
Publication date	Dec 24, 2024
Grant date	Dec 24, 2024

Abstract

The present invention relates to a sigma-delta analogue-to-digital converter. The sigma-delta analogue-to-digital converter comprises a transconductance stage having first, second and third terminals. A capacitor is connected in parallel at the third terminal. Further, the sigma-delta analogue-to-digital converter comprises a quantiser at the third terminal of the transconductance stage with feedback by a voltage digital-to-analogue converter for feeding back a feedback signal to one of the terminals of the transconductance stage.

First claim

The invention claimed is:

1. A sigma-delta analogue-to-digital converter comprising:
a transconductance stage comprising a first terminal, a second terminal, a third terminal and a capacitor connected in parallel at the third terminal; and
a quantiser at the third terminal of the transconductance stage with a feedback by a voltage digital-to-analogue converter for feeding back a feedback signal to one of the terminals of the transconductance stage;
wherein the first terminal is configured as a non-inverting input and the second terminal is configured as an inverting input, and wherein the non-inverting input is configured to receive an analogue input voltage signal and the inverting input is connected to the digital-to-analogue converter;
wherein the transconductance stage is configured as a single-ended transconductance stage with a first switching element and a second switching element; and
wherein the first switching element and the second switching element are connected to a power source by a terminal via a voltage node and to the third terminal of the transconductance stage by a further terminal in each case via a summing element, and the first switching element is switched via the input voltage signal and the second switching element is switched via the feedback signal at a respective control terminal.

2. The converter according to claim 1 , wherein a maximum modulation level of the transconductance stage corresponds to a difference between the received input voltage signal and the feedback signal.

3. The converter according to claim 1 , wherein in the feedback a low-pass filter is connected between the quantiser and the digital-to-analogue converter.

4. A sigma-delta analog-to-digital converter according to claim 1 for processing audio signals in communication systems, in particular in mobile communication systems.

5. A sigma-delta analogue-to-digital converter comprising:
a transconductance stage comprising a first terminal, a second terminal, a third terminal and a capacitor connected in parallel at the third terminal; and
a quantiser at the third terminal of the transconductance stage with a feedback by a voltage digital-to-analogue converter for feeding back a feedback signal to one of the terminals of the transconductance stage;
wherein the first terminal is configured as a non-inverting input and the second terminal is configured as an inverting input, and wherein the non-inverting input is configured to receive an analoque input voltage signal and the inverting input is connected to the digital-to-analogue converter:
wherein the transconductance stage is configured as a differential transconductance stage having a first differential pair input combination comprising a first switching element and a second switching element interconnected in each case via a first terminal, and a second differential pair combination comprising a third switching element and a fourth switching element interconnected in each case via a first terminal.

6. The converter according to claim 5 , wherein the first differential pair input combination is connected via a voltage node and the second differential pair input combination is connected via a voltage node to a power source, respectively, and wherein the further terminals of the first switching element and the third switching element have a common node and further terminals of the second switching element and the fourth switching element have a common node, and wherein the common nodes are each connected to the third terminal of the transconductance stage via a summing element, and the first switching element and the fourth switching element are switched via the input voltage signal and the second switching element and the third switching element are switched via the feedback signal at a respective control terminal.

7. The converter according to claim 5 , wherein the first differential pair input combination is connected via a voltage node and the second differential pair input combination is connected via a voltage node to a fifth switching element, respectively, and wherein further terminals of the first switching element and the third switching element have a common node and further terminals of the second switching element and the fourth switching element have a common node, and wherein the common nodes are each connected to the third terminal of the transconductance stage via a summing element, and the first switching element and the fourth switching element are switched via the input voltage signal, and the second switching element and the third switching element are switched via the feedback signal at a respective control terminal.

8. The converter according to claim 7 , wherein the first differential pair input combination between the voltage node and the fifth switching element and the second differential pair input combination between the voltage node and the fifth switching element each comprise a sixth switching element.

9. The converter according to claim 8 , wherein the sixth switching element of the first and the second differential pair input combination are switched by an output signal of the fifth switching element, amplified by an amplifier.

10. The converter according to claim 9 , wherein the first switching element and the second switching element are switched via the input voltage signal and the third switching element and the fourth switching element are switched via the feedback signal.

11. A sigma-delta analog-to-digital converter according to claim 5 for processing audio signals in communication systems, in particular in mobile communication systems.

12. The converter according to claim 5 , wherein a maximum modulation level of the transconductance stage corresponds to a difference between the received input voltage signal and the feedback signal.

13. The converter according to claim 5 , wherein in the feedback a low-pass filter is connected between the quantiser and the digital-to-analogue converter.

Assignees

• Univ Berlin Tech

Inventors

• Gerfers Friedel
• Runge Marcel

Classifications

• H03M3/494 Primary

  Sampling or signal conditioning arrangements specially adapted for delta-sigma type analogue/digital conversion systems · CPC title

• H03F3/45475

  using IC blocks as the active amplifying circuit · CPC title

• H03F3/45183

  Long tailed pairs (H03F3/4521, H03F3/45237 take precedence) · CPC title

• H03M3/358 Primary

  of non-linear distortion, e.g. instability (avoiding instability by structural design H03M3/44) · CPC title

• H03F2203/45138

  Two or more differential amplifiers in IC-block form are combined, e.g. measuring amplifiers · CPC title