Stmicroelectronics S.r.l.

Stmicroelectronics (shenzhen) R&d Co. Ltd.

Giovanni Gonano

Edoardo Botti

Pietro Mario Adduci

Marco Raimondi

Hong Wu Lin

Francesco Stilgenbauer

Paolo Cacciagrano

Flavio Polloni

An embodiment apparatus comprises a switching-type output power stage, a modulator circuit configured for carrying out a pulse-width modulation and converting an electrical input signal into an input signal pulsed between two electrical levels, having a mean value proportional to the amplitude of the input signal, and a circuit arrangement for controlling saturation of an output signal supplied by the switching-type output power stage. The circuit arrangement comprises a pulse-remodulator circuit, between the output of the modulator circuit and the input of the switching-type output power stage, that is configured for supplying, as a driving signal to the switching-type output power stage, a respective modulated signal pulsed between two electrical levels, measuring a pulse width as pulse time interval elapsing between two consecutive pulsed-signal edges of the pulsed input signal, and, if the measurement indicates that the latter is below a given minimum value, remodulating the pulsed input signal.

Electronic apparatus comprising a switching-type output stage, corresponding circuit arrangement and method

A digital audio playback circuit includes a noise shaping circuit configured to receive an input digital audio signal, and a digital to analog converter (DAC) configured to convert the input digital audio signal to a pre-amplified output analog audio signal according to a gain ramp defined by a gain control signal. A muting circuit is configured to compare input digital audio signal to a threshold and assert a mute control signal when the input digital audio signal is below the threshold. An analog gain control ramp circuit is configured to generate the gain control signal in response to the mute control signal to cause the gain ramp to ramp down. An amplifier is configured to amplify the pre-amplified output analog audio signal for playback by an audio playback device.

Noise shaper fader

An embodiment pulse-width modulation (PWM) modulator circuit comprises a first half-bridge stage having a first output node and a second half-bridge stage having a second output node. The first output node and the second output node are configured to have an electrical load coupled therebetween to apply thereto a PWM-modulated output signal. The circuit comprises a differential stage having input nodes configured to receive an input signal applied between the input nodes and produce a differential control signal for the first half-bridge stage and the second half-bridge stage. A current comparator is arranged intermediate the differential stage and the first and second half-bridge stages. The current comparator is configured to produce a PWM-modulated drive signal to drive the half-bridge stages as a function of the input signal applied between the input nodes in the differential stage.

Modulator circuit, corresponding device and method

In an embodiment, a method for shaping a PWM signal includes: receiving an input PWM signal; generating an output PWM signal based on the input PWM signal by: when the input PWM signal transitions with a first edge of the input PWM signal, transitioning the output PWM signal with a first edge of the output PWM signal; and when the input PWM signal transitions with a second edge before the first edge of the output PWM signal transitions, delaying a second edge of the output PWM signal based on the first edge of the output PWM signal.

PWM driving circuit and method

A switching circuit includes a switching circuit stage configured to supply a load via filter networks. Control circuitry is provided to control alternate switching sequences of transistors in the half-bridges of the switching circuit stage. A current flow line is provided between the output nodes of the half-bridges including an inductance between two switches. First and second capacitances are coupled with the output nodes of the half-bridges. The control circuitry switches first and second switches to the conductive state at intervals in the alternate switching sequences of the transistors in the half-bridges between switching the first pair of transistors to a non-conductive state and switching the second pair of transistors to a conductive state.

Switching circuit, corresponding device and method

A bi-directional switch circuit includes first and second transistors having their control electrodes coupled at a first common node and the current paths coupled at a second common node in an anti-series arrangement. First and second electrical paths coupled between the first common node and the first and second transistors, respectively, include first and second switches switchable between a conductive state and a non-conductive state. A third electrical path between the first and second common nodes includes a third switch switchable between a conductive state and a non-conductive state. The third switch is coupled with the first and second switches by a logical network configured to switch the third switch to the conductive state with the first and second switches switched to the non-conductive state, and to the non-conductive state with either one of the first and second switches switched to the conductive state.

Switch circuit, corresponding device and method

A method can be used to measure a load driven by a switching amplifier having a differential input, an LC output demodulator filter and a feedback network between the amplifier output and the differential input. The amplifier is AC driven in a differential and in a common mode by applying a common. The feedback network provides feedback towards the differential input from downstream the LC demodulator filter by computing the impedance of the load as a function of the differential mode output current and the common mode output current. The feedback network provides feedback towards the differential input from upstream the LC demodulator filter by measuring the impedance value of the inductor of the LC demodulator filter, and computing the impedance of the load as a function of the differential mode output current, the common mode output current and the impedance value of the inductor of the LC demodulator filter.

Method for load measurement in switching amplifiers, corresponding device and amplifier

The present invention relates to a method and a circuit for testing a tweeter. The tweeter is part of a loudspeaker system. The method includes the steps of: applying a high-frequency voltage signal to one terminal of the tweeter, whereby the high-frequency voltage signal is generated by first electronic means. The method also includes applying a constant voltage signal to the other terminal of the tweeter, whereby the constant voltage signal is generated by second electronic means. The method includes measuring a current (I) that flows through the tweeter into the second electronic means and determining a connect/disconnect state of the tweeter from the value of the current.

Method and circuit for testing an audio high-frequency loudspeaker being part of a loudspeaker system

An electronic circuit is disclosed for driving a switching amplifier. The electronic circuit is configured for generating, when operating in a switch-on mode, a driving signal for driving the switching amplifier. The driving signal carries a plurality of pulses having: an pulse width increasing between contiguous pulses of the plurality of pulses according to a step value having modulus equal to two and odd values; a polarity alternating between the contiguous pulses.

Electronic circuit for driving a switching amplifier

The present invention relates to a method and a circuit for testing a tweeter, said tweeter being part of a loudspeaker system, wherein the method includes the steps of: applying a high-frequency voltage signal to one terminal of said tweeter, said high-frequency voltage signal being generated by first electronic means; applying a constant voltage signal to the other terminal of said tweeter, said constant voltage signal being generated by second electronic means; measuring a current Ithat flows through said tweeter into said second electronic means; determining a connect/disconnect state of said tweeter from the value of said current.

A method for testing the operating conditions of an electric network, including at least one operating state, including the steps of providing a voltage signal (v(t)) to a network load and measuring the instantaneous current signal (i(t)) circulating in the load, delaying the instantaneous current signal (i(t)) to generate an instantaneous current signal delayed ((i(t+&#x3c4;)) by a predetermined amount of time (&#x3c4;), the predetermined amount of time (&#x3c4;) being a function of the operating state of said load, the method including the steps of calculating, within a predetermined measurement time (Tm), an admittance ratio (G(&#x3c4;)) between the mean of the product of the voltage signal (v(t)) and the delayed instantaneous current signal (i(t+&#x3c4;)), and the mean of the square of the voltage signal (v(t)), and to compare the value of the admittance ratio (G(&#x3c4;)) with a range of predetermined values (Gmin,Gmax) to determine the operating state of the electric network.

Method and apparatus for testing the operating conditions of an electric network

A process and apparatus for generating an output signal whose frequency varies according to a modulation scheme, the process including the steps of providing a dither generator for receiving a first input signal representative of a clock frequency and for generating, according to the modulation scheme, a dithered output signal representative of the first signal at a dithered frequency; providing a DSP for receiving the following input signals: the signal at the dithered frequency and a second signal representative of a clock frequency, the DSP adapted to generate a processed output signal representative of the maximum frequency of the second signal; wherein the modulation scheme has a periodic ultrasonic modulating wave.

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Padua, Italy

Giovanni Gonano