Sensor component with improved overload and interference immunity performance
A sensor component is disclosed including a transducer and an electrical circuit disposed in a housing. The electrical circuit includes a bias voltage source coupled to a first electrode of the transducer. A non-inverting amplifier stage is coupled to a second electrode of the transducer. An inverting amplifier stage is coupled to an output of the non-inverting amplifier stage. A negative feedback path is located between an output of the inverting amplifier stage and the first electrode of the transducer. An electrical output signal of the transducer can be attenuated by applying an attenuation signal, based on a filtered electrical signal, to the first electrode via the negative feedback path.
1 . A sensor component comprising:
a transducer disposed in a housing;
an electrical circuit disposed in the housing and electrically coupled to the transducer and to an electrical interface on an exterior of the housing, the electrical circuit comprising:
a bias voltage source coupled to a first electrode of the transducer;
a non-inverting amplifier stage having an input coupled to a second electrode of the transducer;
an inverting amplifier stage coupled to an output of the non-inverting amplifier stage;
a negative feedback path between an output of the inverting amplifier stage and the first electrode of the transducer;
a filter configured to filter an electrical signal of the electrical circuit,
wherein an electrical output signal of the transducer is attenuated by an attenuation signal applied to the first electrode via the negative feedback path, the attenuation signal based on the filtered electrical signal.
2 . The sensor component of claim 1 , wherein the filter is a bandpass filter located between the non-inverting amplifier stage and the inverting amplifier stage.
3 . The sensor component of claim 2 further comprising a signal detector between the bandpass filter and the inverting amplifier stage, and an attenuation signal actuator that applies the attenuation signal to the transducer based on a signal detected by the signal detector.
4 . The sensor component of claim 2 , wherein the filter is a bandpass filter having a low frequency cutoff not more than 300 Hz and a high frequency cutoff not less than 4 KHz.
5 . The sensor component of claim 2 , wherein the filter is a bandpass filter having a low frequency cutoff between 20 Hz and 200 Hz and a high frequency cutoff between 4 KHz and 20 KHz.
6 . The sensor component of claim 2 , wherein the inverting amplifier stage comprises an inverting amplifier coupled to a driver, and the negative feedback path is between an output of the driver and the transducer.
7 . The sensor component of claim 6 further comprising a signal detector at an input of the inverting amplifier stage, and an attenuation signal actuator that applies the attenuation signal based on a signal detected by the signal detector.
8 . The sensor component of claim 1 , the filter is a bandstop filter between the output of the inverting amplifier stage and the transducer, wherein the attenuation signal predominantly attenuates signals from the transducer at frequencies outside a rejected band of the bandstop filter.
9 . The sensor component of claim 8 , wherein the bandstop filter has a low frequency cutoff not more than 300 Hz and a high frequency cutoff not less than 4 KHz.
10 . A sensor component comprising:
a microelectromechanical systems (MEMS) transducer disposed over a sound port in a housing;
an electrical circuit disposed in the housing and electrically coupled to the MEMS transducer and to an electrical interface on an exterior of the housing, the electrical circuit comprising:
a bias voltage source coupled to a first electrode of the MEMS transducer;
a non-inverting amplifier stage having an input coupled to a second electrode of the MEMS transducer, the input having an impedance greater than 100 TΩ;
an inverting amplifier stage having an input coupled to an output of the non-inverting amplifier stage;
a negative feedback path between an output of the inverting amplifier stage and the first electrode of the MEMS transducer;
a filter configured to filter an electrical signal of the electrical circuit,
wherein an electrical output signal of the MEMS transducer is attenuated by an attenuation signal applied to the first electrode via the negative feedback path, the attenuation signal based on the filtered electrical signal.
11 . The sensor component of claim 10 , wherein the filter is a bandpass filter located between the output of the non-inverting amplifier stage and the input of the inverting amplifier stage.
12 . The sensor component of claim 11 is an acoustic sensor, wherein the bandpass filter has a low frequency cutoff not more than 300 Hz and a high frequency cutoff not less than 4 KHz.
13 . The sensor component of claim 11 , wherein the bandpass filter has a low frequency cutoff between 20 Hz and 200 Hz and a high frequency cutoff between 4 KHz and 20 KHz.
14 . The sensor component of claim 12 further comprising a signal detector at the input of the inverting amplifier stage, and an attenuation signal actuator that applies the attenuation signal to the MEMS transducer based on a signal detected by the signal detector.
15 . The sensor component of claim 12 , wherein the inverting amplifier stage comprises an inverting amplifier coupled to a driver, and the negative feedback path is located between an output of the driver and the MEMS transducer.
16 . The sensor component of claim 15 further comprising a signal detector at the input of the inverting amplifier stage, and an attenuation signal actuator that applies the attenuation signal to the MEMS transducer when a signal level detected by the signal detector reaches a threshold.
17 . The sensor component of claim 10 , the filter is a bandstop filter located between the output of the inverting amplifier stage and the MEMS transducer, wherein the attenuation signal predominantly attenuates signals from the transducer at frequencies outside a rejected band of the bandstop filter.
18 . The sensor component of claim 17 is an acoustic sensor, wherein the bandstop filter has a low frequency cutoff between 20 Hz and 200 Hz and a high frequency cutoff between 4 KHz and 20 KHz.
19 . The sensor component of claim 17 is an acoustic sensor, wherein the bandstop filter has a low frequency cutoff not more than 300 Hz and a high frequency cutoff not less than 4 KHz.