Sensor amplifier arrangement and method of amplifying a sensor signal

Patent metadata

Field	Value
Publication number	US-10211792-B2
Application number	US-201715689760-A
Country	US
Kind code	B2
Filing date	Aug 29, 2017
Priority date	Apr 4, 2012
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

A sensor amplifier arrangement includes an amplifier having a signal input to receive a sensor signal and a signal output, and a feedback path that couples the signal output to the signal input, wherein the feedback path includes an anti-parallel circuit of diodes, and a voltage divider including a first and a second divider resistor and a voltage divider tap between the first and the second divider resistor, wherein the voltage divider couples the signal output to a reference potential terminal, and the voltage divider tap is coupled to the anti-parallel circuit of diodes and the anti-parallel circuit of diodes is coupled to the signal input.

First claim

What is claimed is:

1. A sensor amplifier arrangement comprising:
an amplifier having a signal input to receive a sensor signal and a signal output, and
a feedback path that couples the signal output to the signal input,
wherein the feedback path comprises
an anti-parallel circuit of diodes, and
a transconductance amplifier having an input coupled to the signal output and an output coupled to the anti-parallel circuit of diodes, and
wherein the anti-parallel circuit of diodes is coupled to the signal input and the sensor amplifier arrangement comprises a sensor that is a capacitive sensor and is coupled to the signal input.

2. The sensor amplifier arrangement according to claim 1 , wherein the sensor amplifier arrangement comprises a biasing voltage source coupled to the signal input via the sensor.

3. The sensor amplifier arrangement according to claim 1 , wherein the transconductance amplifier comprises
an input stage connected to the input of the transconductance amplifier, and
a current mirror that couples the input stage to the output of the transconductance amplifier.

4. The sensor amplifier arrangement according to claim 3 , wherein the input stage is configured to generate an intermediate current, and
the current mirror is configured to reduce the intermediate current by a current reduction factor and to generate an output current.

5. The sensor amplifier arrangement according to claim 1 , wherein the feedback path comprises an integration capacitor having a first terminal coupled to the output of the transconductance amplifier.

6. The sensor amplifier arrangement according to claim 1 , wherein the anti-parallel circuit of diodes comprises a first diode that is a bipolar diode and a second diode that is a further bipolar diode.

7. The sensor amplifier arrangement according to claim 1 , wherein the anti-parallel circuit of diodes comprises a first and a second diode,
the first diode is a field-effect transistor having a first terminal connected to a first terminal of the first diode,
a second terminal, and
a control terminal connected to the second terminal of the field-effect transistor and to a second terminal of the first diode, and
wherein the second diode is a further field-effect transistor having a first terminal connected to a first terminal of the second diode,
a second terminal, and
a control terminal connected to the second terminal of the further field-effect transistor and to a second terminal of the second diode.

8. A sensor amplifier arrangement comprising:
an amplifier having a signal input to receive a sensor signal, a further signal input, a signal output and a further output,
a regulator having an input connected to the further output of the amplifier and an output coupled to the further signal input of the amplifier,
a capacitive sensor coupled to the signal input of the amplifier, and
an additional capacitor that couples the further signal input of the amplifier to the capacitive sensor.

9. The sensor amplifier arrangement according to claim 8 , wherein the sensor amplifier arrangement comprises a biasing voltage source coupled to a node between the capacitive sensor and the additional capacitor.

10. The sensor amplifier arrangement according to claim 8 , wherein the sensor amplifier arrangement comprises a regulator reference source coupled to a further input of the regulator.

11. The sensor amplifier arrangement according to claim 8 , wherein the amplifier is configured to generate a common mode signal at the further output.

12. A sensor amplifier arrangement comprising:
an amplifier having a signal input to receive a sensor signal and a signal output,
a regulator having an input coupled to an output side of the amplifier,
a capacitive sensor having a first electrode coupled to the signal input of the amplifier, and
an additional capacitor coupled to an output of the regulator and a second electrode of the capacitive sensor.

13. The sensor amplifier arrangement according to claim 12 ,
wherein the amplifier comprises a further input coupled to the second electrode of the capacitive sensor.

14. The sensor amplifier arrangement according to claim 12 ,
wherein the sensor amplifier arrangement comprises a biasing voltage source coupled to the second electrode of the capacitive sensor.

15. The sensor amplifier arrangement according to claim 12 ,
wherein the sensor amplifier arrangement comprises a regulator reference source coupled to a further input of the regulator.

16. The sensor amplifier arrangement according to claim 12 ,
wherein the amplifier is configured to generate a common mode signal applied to the input of the regulator.

17. A sensor amplifier arrangement comprising:
an amplifier having a signal input to receive a sensor signal and a signal output, and
a feedback path that couples the signal output to the signal input,
wherein the feedback path comprises
an anti-parallel circuit of diodes, and
a transconductance amplifier having an input coupled to the signal output and an output coupled to the anti-parallel circuit of diodes, and
wherein the anti-parallel circuit of diodes is coupled to the signal input and the sensor amplifier arrangement comprises a biasing voltage source coupled to the signal input via the sensor.

Assignees

• Ams Ag

Inventors

• Fröhlich Thomas
• Steiner Matthias

Classifications

• H03F3/04

  with semiconductor devices only · CPC title

• H03F3/187 Primary

  in integrated circuits · CPC title

• H03F2200/129

  there being a feedback over the complete amplifier · CPC title

• H03F2200/213

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

• H03F2200/126

  A diode being coupled in a feedback path of an amplifier stage, e.g. active or passive diode · CPC title