Stmicroelectronics S.r.l.

Texas Instruments Corporation

Alberto Danioni

Germano Nicollini

Giulio Ricotti

Sergio Pernici

Andrea Barbieri

Paolo Invernizzi

Alessandro Morcelli

Edoardo Marino

Federica Barbieri

A charge amplifier circuit is provided. The charge amplifier circuit is couplable to a transducer that generates an electrical charge that varies with an external stimulus. The charge amplifier circuit includes an amplification stage having an input node, couplable to the transducer, and an output node. The amplification stage biases the input node at a first direct current (DC) voltage. The charge amplifier circuit includes a feedback circuit, which includes a feedback capacitor, electrically coupled between the input and output nodes of the amplification stage. The feedback circuit includes a resistor electrically coupled to the input node, and a level-shifter circuit, electrically coupled between the resistor and the output node. The level-shifter circuit biases the output node at a second DC voltage and as a function of a difference between the second DC voltage and a reference voltage.

Charge amplifier circuit with a high output dynamic range for a microelectromechanical sensor

In at least one embodiment, an interface electronic circuit for a capacitive acoustic transducer having a sensing capacitor is provided. The interface electronic circuit includes an amplifier, a voltage regulator, a common-mode control circuit, and a reference generator. The amplifier has an input coupled to an electrode of the sensing capacitor. The voltage regulator is configured to receive a regulator reference voltage, generate a regulated voltage based on the regulator reference voltage, and supply the regulated voltage to a supply input of the amplifier. The common-mode control circuit controls a common-mode voltage present on the input of the amplifier based on a common-mode reference voltage. The reference generator receives a supply voltage and generates the regulator reference voltage and the common-mode reference voltage with respective values that are variable as a function of the supply voltage.

Interface electronic circuit for a microelectromechanical acoustic transducer and corresponding method

A MEMS acoustic transducer device has a capacitive microelectromechanical sensing structure and a biasing circuit. The biasing circuit includes a voltage-boosting circuit that supplies a boosted voltage on an output terminal, and a high-impedance insulating circuit element set between the output terminal and a terminal of the sensing structure, which defines a first high-impedance node associated with the insulating circuit element. The biasing circuit has: a pre-charge stage that generates a first pre-charge voltage on a first output thereof, as a function of, and distinct from, the boosted voltage; and a first switch element set between the first output and the first high-impedance node. The first switch element is operable for selectively connecting the first high-impedance node to the first output, during a phase of start-up of the biasing circuit, for biasing the first high-impedance node to the first pre-charge voltage.

Biasing circuit for a MEMS acoustic transducer with reduced start-up time

An amplifier configuration including first and second amplifier inputs and a bias input adapted to receive a common mode signal indicative of a common mode input voltage. First and second amplifier input stage sections, each having first and second inputs coupled to respective ones of the first and second amplifier inputs, are provided. Operating mode circuitry switches the amplifier configuration between first and second operating modes in response to the common mode signal, where in the first operating mode the first and second amplifier input stage sections are active and inactive, respectfully and where in the second operating mode the first and second amplifier input stage sections are inactive and active, respectfully. The active first and second amplifier input stage sections are capable of operating with common mode voltages in excess of the upper and lower power supply rails, respectively.

Current sense amplifier having bipolar common mode input range

A signal-processing circuit has a first and a second input, which receive a first and a second differential signal, a third input, which receives a common-mode signal, the first and second differential signals having an equal and substantially opposite trend with respect to the common-mode signal, and a first output supplying a first processed signal, equivalent to the first differential signal rectified with respect to the common-mode signal, and satisfying throughout its course a first relation of comparison with the common-mode signal. The processing circuit is provided with first formation means for formation of the first processed signal, which operate on the basis of the first differential signal, and second formation means for formation of the first processed signal, which operate on the basis of the second differential signal; the first and second formation means co-operate in the formation of the first processed signal.

Signal-processing circuit, in particular operating as a rectifier and peak detector, with active elements and differential inputs

A driving device is provided for driving at least one power transistor of a voltage converter that includes a piezoelectric transformer. The power transistor has a first non-drivable terminal coupled to an input voltage and to the input of the piezoelectric transformer. The converter includes an inductor coupled between the input voltage and the piezoelectric transformer, and a resistor coupled between a second non-drivable terminal of the power transistor and ground. The driving device is coupled to the drivable terminal of the power transistor, to the input of the piezoelectric transformer, and to the second non-drivable terminal of the power transistor so as to detect a first voltage value and a second current value. The driving device is adapted to cause the turning on of the power transistor if the first voltage value is equal to a third prefixed voltage value, and to cause the turning off of the power transistor if the second current value is equal to a fourth prefixed current value.

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Pavia, Italy

Alberto Danioni