Sensor amplifier arrangement and method for amplification of a sensor signal

Patent metadata

Field	Value
Publication number	US-9300259-B2
Application number	US-201213438975-A
Country	US
Kind code	B2
Filing date	Apr 4, 2012
Priority date	Apr 4, 2012
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A sensor amplifier arrangement includes an amplifier having a signal input to receive a sensor signal and a signal output to provide an amplified sensor signal, and a feedback path that couples the signal output to the signal input and provides a feedback current that is an attenuated signal of the amplified sensor signal and is inverted with respect to the sensor signal.

First claim

The invention claimed is:

1. A sensor amplifier arrangement comprising:
an amplifier having a signal input to receive a sensor signal and a signal output to provide an amplified sensor signal, and
a feedback path that couples the signal output to the signal input and comprises
an anti-parallel circuit of diodes,
an offset signal source, and
an adder comprising:
a first input coupled to the signal output,
a second input coupled to the offset signal source, and
an output coupled to the signal input via the anti-parallel circuit of diodes, wherein the feedback path comprises a feedback amplifier coupling the signal output to the first input of the adder.

2. The sensor amplifier arrangement according to claim 1 , wherein the feedback path provides a bootstrapping loop between the signal output and the signal input.

3. The sensor amplifier arrangement according to claim 1 , wherein the gain of the feedback amplifier is controlled by a control signal.

4. The sensor amplifier arrangement according to claim 1 , wherein the amplifier comprises an input transistor which is a field-effect transistor and comprises a control terminal connected to the signal input of the amplifier.

5. The sensor amplifier arrangement according to claim 1 , wherein the offset signal source is a voltage source.

6. The sensor amplifier arrangement according to claim 1 , wherein the feedback path obtains a low pass characteristic.

7. The sensor amplifier arrangement according to claim 1 , wherein the sensor amplifier arrangement comprises a sensor that is a microphone coupled to the signal input of the amplifier.

8. The sensor amplifier arrangement according to claim 7 , wherein the sensor amplifier arrangement comprises a biasing voltage source coupled to the sensor such that an electrode of the sensor is coupled to the signal input of the amplifier and a further electrode of the sensor is coupled to the biasing voltage source.

9. The sensor amplifier arrangement according to claim 1 , wherein the feedback amplifier is an operational amplifier.

10. The sensor amplifier arrangement according to claim 1 , wherein the feedback amplifier is an operational transconductance amplifier.

11. The sensor amplifier arrangement according to claim 1 , wherein the feedback path comprises a filter.

12. The sensor amplifier arrangement according to claim 11 , wherein the filter is coupled between the output of the feedback amplifier and the first input of the adder.

13. A method of amplifying a sensor signal comprising:
receiving a sensor signal at a signal input of an amplifier,
amplifying the sensor signal and providing an amplified sensor signal at a signal output of the amplifier, and
feeding back a feedback current by a feedback path that couples the signal output to the signal input and comprises:
an anti-parallel circuit of diodes,
an offset signal source, and
an adder comprising a first input coupled to the signal output, a second input coupled to the offset signal source, and an output coupled to the signal input via the anti-parallel circuit of diodes,

wherein the offset signal source is implemented as a voltage source and the adder is a summing circuit that sums up voltages at the first and the second inputs.

14. A sensor amplifier arrangement comprising:
an amplifier having a signal input to receive a sensor signal and a signal output to provide an amplified sensor signal, and
a feedback path that couples the signal output to the signal input, obtains a low pass characteristic and comprises
an anti-parallel circuit of diodes,
an offset signal source, and
an adder comprising:
a first input coupled to the signal output,
a second input coupled to the offset signal source, and
an output coupled to the signal input via the anti-parallel circuit of diodes.

15. A sensor amplifier arrangement comprising:
an amplifier having a signal input to receive a sensor signal and a signal output to provide an amplified sensor signal, and
a feedback path that couples the signal output to the signal input and comprises
an anti-parallel circuit of diodes,
an offset signal source which is a voltage source, and
an adder comprising:
a first input coupled to the signal output,
a second input coupled to the offset signal source, and
an output coupled to the signal input via the anti-parallel circuit of diodes,

wherein the adder is a summing circuit that sums up voltages at the first and second inputs.

16. The sensor amplifier arrangement according to claim 13 , wherein the feedback path comprises a feedback amplifier coupling the signal output to the first input of the adder.

17. The sensor amplifier arrangement according to claim 13 , wherein the feedback path obtains a low pass characteristic.

Assignees

• Fröhlich Thomas
• Steiner Matthias
• Ams Ag

Inventors

• Fröhlich Thomas
• Steiner Matthias

Classifications

• H03F1/34

  Negative-feedback-circuit arrangements with or without positive feedback (H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence {; for rejection of common mode signals H03F3/45479}) · CPC title

• H04R2430/01

  Aspects of volume control, not necessarily automatic, in sound systems · CPC title

• H03F3/187 Primary

  in integrated circuits · CPC title

• H03F2200/213

  A variable capacitor being added in the input circuit, e.g. base, gate, of an amplifier stage · CPC title

• H03F3/04

  with semiconductor devices only · CPC title