Differential-type MEMS acoustic transducer

An electronic device, comprising:

• a package including a MEMS acoustic transducer, the MEMS acoustic transducer including, a detection structure configured to generate an electrical detection quantity as a function of a detected acoustic signal, the detection structure including a first micromechanical structure of a capacitive type and a second micromechanical structure of a capacitive type, each of the first and second micromechanical structures including a membrane which faces and is capacitively coupled to a rigid electrode, the first and second micromechanical structures defining a first detection capacitor and second detection capacitor, respectively;
• and an electronic interface circuit including a biasing line and a reference line, the first detection capacitor and second detection capacitor connected in series between the biasing line and reference line, the membrane of the first detection capacitor being directly connected to the membrane of the second detection capacitors, and the electronic interface circuit configured to generate an electrical output quantity as a function of the electrical detection quantity, the electronic interface circuit further including a first single-output amplifier and a second single-output amplifier coupled to the first detection capacitor and second detection capacitor, respectively, and having a first output terminal and a second output terminal, respectively, configured to generate the electrical output quantity between the first and second output terminals;
• a processor coupled to the MEMS acoustic transducer;
• an input/output interface coupled to the processor;
• and a memory coupled to the processor.

A method, comprising:

• sensing a change in capacitance of a first detection capacitor responsive to acoustic waves incident upon a first membrane plate of the first detection capacitor, the first detection capacitor further including a first back plate coupled to a biasing line;
• sensing a change in capacitance of a second detection capacitor responsive to acoustic waves incident upon a second membrane plate of the second detection capacitor, the second detection capacitor further including a second back plate coupled to a reference line, and the first and second detection capacitors being coupled in series between the biasing line and the reference line and each of the first and second membrane plates being directly electrically coupled to a common node;
• buffering a first voltage developed on the first back plate of the first detection capacitor to generate a first output voltage, the first output voltage varying as a function of the capacitance of the first detection capacitor;
• buffering a second voltage developed on the second back plate of the second detection capacitor to generate a second output voltage, the second output voltage varying as a function of the capacitance of the second detection capacitor and the second output voltage being in phase opposition to the first output voltage;
• and
• sensing a differential voltage of the first and second output voltages to generate a differential output signal indicative of the magnitude of the incident acoustic waves.