Sensor amplifier arrangement and method for amplification of a sensor signal
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.
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.