Stmicroelectronics S.r.l.

Sgs-thomson Microelectronics S.r.l.

St-ericsson Sa

Sgs-thomson Microelectronics S.p.a.

Sergio Pernici

Germano Nicollini

Andrea Barbieri

Pierangelo Confalonieri

Riccardo Martignone

Edoardo Marino

Federica Barbieri

Sebastiano Conti

Daniel Senderowicz

Angelo Nagari

Carlo Pinna

Silvia Adorno

Federico Guanziroli

Alberto Danioni

Federico Garibaldi

Jan R E Thimansson

Robert Nilsson

Fabio Stevenazzi

Jan Thimansson

A fully balanced differential difference amplifier includes a first differential input stage that receives an input voltage and a second differential input stage that receives a common-mode voltage. A first resistive-degeneration group is coupled to the first differential input and a second resistive-degeneration group is coupled to the second differential input. A differential output stage generates an output voltage. A first switch is coupled in parallel to the first resistive-degeneration group and a second switch is coupled in parallel with the second resistive-degeneration group. The first and second switches are driven into the closed state when the voltage input assumes a first value such that said first input stage operates in the linear region, and are driven into the open state when the voltage input assumes a second value, higher than the first value, such that the first input stage operates in a non-linear region.

FBDDA amplifier and device including the FBDDA amplifier

A MEMS acoustic transducer has: a detection structure, which generates an electrical detection quantity as a function of a detected acoustic signal; and an electronic interface circuit, which is operatively coupled to the detection structure and generates an electrical output quantity as a function of the electrical detection quantity. The detection structure has a first micromechanical structure of a capacitive type and a second micromechanical structure of a capacitive type, each including a membrane that faces and is capacitively coupled to a rigid electrode and defines a respective first detection capacitor and second detection capacitor; the electronic interface circuit defines an electrical connection in series of the first detection capacitor and second detection capacitor between a biasing line and a reference line, and further has a first single-output amplifier and a second single-output amplifier, which are coupled to a respective one of the first detection capacitor and the second detection capacitor and have a respective first output terminal and second output terminal, between which the electrical output quantity is present.

Differential-type MEMS acoustic transducer

A FBDDA amplifier comprising: a first differential input stage, which receives an input voltage; a second differential input stage, which receives a common-mode voltage; a first resistive-degeneration group coupled to the first differential input; a second resistive-degeneration group coupled to the second differential input; a differential output stage, generating an output voltage; a first switch coupled in parallel to the first resistive-degeneration group; and a second switch coupled in parallel to the second resistive-degeneration group. The first and second switches are driven into the closed state when the voltage input assumes a first value such that said first input stage operates in the linear region, and are driven into the open state when the voltage input assumes a second value, higher than the first value, such that the first input stage operates in a non-linear region.

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

The invention relates to a circuit () for use with a loudspeaker () having a first differential input terminal (t) and a second differential input terminal (t), the circuit () comprising: a differential power amplifier () having a first differential output terminal (t) operatively connected to the first differential input terminal (t) of the loudspeaker () and a second differential output terminal (t) operatively connected to the second differential input terminal (t) of the loudspeaker ();&#x2014;a first resistor (RS) disposed between the first differential output terminal (t) of the differential power amplifier () and the first differential input terminal (t) of the loudspeaker (); a second resistor (RS) disposed between the second differential output terminal (t) of the differential power amplifier () and the second differential input terminal (t) of the loudspeaker (). The circuit () further comprises: a first resistive module (RR, RR) arranged to generate on a respective output terminal (t) a first control voltage (VIN), the first resistive module (RR, RR) having a first input terminal (t) connected to the first differential output terminal (t) of the power amplifier () and a second input terminal (t) connected to the second differential input terminal (t) of the loudspeaker (), a second resistive module (RR, RR) arranged to generate on a respective output terminal (t) a second control voltage (VIP), the second resistive module (RR, RR) having a first input terminal (t) connected to the second differential output terminal (t) of the power amplifier () and a second input terminal (t) connected to the first differential input terminal (t) of the loudspeaker (). The loudspeaker circuit () being arranged to control the differential power amplifier () on the basis of the first control voltage (VIN) and the second control voltage (VIP).

Circuit for use with a loudspeaker for portable equipments

An integrated circuit for processing audio and voice signals in a telephone is disclosed. The integrated circuit comprises an audio output port having a first and a second output terminal for connection to a first and a second input terminal, respectively, of a speaker. The integrated circuit further comprises an audio input port having a first and a second input terminal for connection to a first and a second output terminal of an audio input source. The integrated circuit also comprises at least one audio output path and one audio input path. Moreover, the integrated circuit comprises a test impedance, such as a resistor, (RT) for measuring an electrical impedance of the speaker.

Speaker impedance measurement

An integrated circuit includes a substrate of semiconductive material, a first circuit environment made from the substrate which includes an output terminal and a first pair of power supply terminals for receiving a first power supply voltage applicable between the terminals. The integrated circuit also includes a second circuit environment made from the semiconductor substrate which includes an input terminal electrically coupled to the output terminal and also includes a second pair of power supply terminals for receiving a second power supply voltage applicable between the second pair of terminals of said second pair. The circuit further includes a device providing protection from electrostatic discharges which includes an integrated resistive device coupled between the input and output terminals.

Integrated circuit with device for protection against electrostatic discharges

An operational amplifier having a first amplification stage with an input terminal to receive a signal to be amplified, and a first output terminal, and a second amplification stage having a first input terminal connected to the first output terminal, and an output terminal to provide the amplified signal. The first and second amplification stages define, between the input terminal and the output terminal, a signal transfer function having first and second poles. The amplifier further includes a decoupling stage having a further input terminal connected to the first stage input terminal, and a further output terminal connected to the second stage output terminal. The decoupling stage is so arranged as to introduce at least one zero in the operational amplifier transfer function.

Operational transconductance amplifier having two amplification stages

A single-ended or differential single-stage, or multi-stage sigma-delta analog-to-digital converter includes at least one switched-capacitor integrator comprising a switched-capacitor network receiving as input a signal to be sampled, and an amplifier coupled in cascade to the switched-capacitor network. A circuit is coupled to the amplifier for feeding an analog dither signal to a virtual ground of the amplifier.

Method of adding a dither signal in output to the last integrator of a sigma-delta converter and relative sigma-delta converter

A single-loop differential switched-capacitor sigma-delta converter has a three stage double-sampling architecture with reduced current consumption. The converter is stable for large input dynamics, which makes it suitable for RF applications. The three-stage multi-bit double-sampled architecture has a single-loop architecture in which all integrators are included in a same feedback loop. This has been made possible based upon the type of integrators that are connected in cascade. Functioning of the converter is less sensitive to nonlinearities of the operational amplifiers of the integrators.

Single-loop switched-capacitor analog-to-digital sigma-delta converter

A processing unit with balanced outputs transfers a received digital signal to an amplification unit with balanced inputs and outputs. A control unit enables or disables the processing and amplification units in response to a power up/power down signal. To prevent disturbances due to power up/power down transients from appearing in a speaker connected between the outputs of the amplification unit, switches are provided between the outputs of the processing unit and the inputs of the amplification unit. A delay circuit generates according to a predetermined timing program enabling/disabling control signals for the processing and amplification units, and generates control signals for the switches.

Receiving section of a telephone

A telephone receiving section having a final stage, an electroacoustic transducer having a first terminal connected to the ground of the circuit, a unit for controlling switching on/off, a source of a reference voltage, a switch that can adopt a first position or a second position in order to connect the second terminal of the transducer selectively, via a capacitor, to a reference-voltage terminal of the reference voltage source or to an output terminal of the final stage, respectively, and control means that respond to signals of the unit for controlling switching on/off in order to activate or to deactivate the final stage and the reference-voltage source and to operate the switch in accordance with a predetermined time program. The receiving section operates with the same immunity to disturbances as a fully balanced structure, even though the transducer is not connected between two balanced outputs.

Receiving section of a telephone with suppression of interference upon switching on/off

It is described a circuit generating a stable reference voltage with respect to temperature, which circuit is connected between first and second voltage references and comprises at least one current generating circuit adapted to inject a reference current into a resistive element connected between a base terminal of a bipolar transistor and an additional voltage reference. The bipolar transistor is connected between the first and second voltage references and to an output terminal of the generator circuit whereat the stable reference voltage with respect to temperature is. The generator circuit further comprises at least another resistive element, feedback connected between the output terminal of the generator circuit and the base terminal of the bipolar transistor to enable injecting additional current, having reverse dependence on temperature from the reference current, into the resistive element.

Circuit generating a stable reference voltage with respect to temperature, particularly for CMOS processes

A receiver portion of a telephone includes a differential amplifier stage with a single output, an electroacoustic transducer connected between the output, via a capacitor and ground and a unit for controlling switching on/off, connected to the differential stage for the activation or deactivation thereof. To prevent annoying noises in the transducer upon switching on and off, the differential stage includes an operational amplifier having a first capacitor and a second capacitor in series with the inverting and the non-inverting input terminals. A third capacitor is connected between the inverting input and the output of the operational amplifier. A fourth capacitor is connected between the non-inverting input and a first reference-voltage terminal. A first switching capacitor is alternatively connectable between a second and a third reference-voltage terminal, or between the first input and the output of the operational amplifier. A second switching capacitor is alternatively connectable between a fourth and a fifth reference-voltage terminal, or between the second input of the operational amplifier and the fifth reference-voltage terminal.

Growing community of inventors

Bergamo, Italy

Sergio Pernici