364results about "Audio amplifier" patented technology

A circuit comprises a first half-bridge power stage including a first set of switches and a second half-bridge power stage including a second set of switches. The circuit further comprises a first power source and a second power source that are coupled to the first and second half-bridge power stages for supplying a first direct current (DC) voltage and a second DC voltage, respectively. The circuit further comprises an output interface coupled to the first and second half-bridge power stages and configured to couple to a speaker load. The first and second half-bridge power stages are configured to generate a five-level differential signal for driving the speaker load. Each set of switches includes a respective first subset of switches configured to operate at a first voltage level and a respective second subset of switches configured to operate at a second voltage level.

A method includes determining whether an audio signal processed in a class-D amplifier is clipping. Responsive to clipping of the audio signal, a speaker voltage is estimated as a ratio of a power supply voltage of the class-D amplifier to a resistance of a speaker driven by the class-D amplifier. An amplitude of the audio signal is controlled based on the speaker voltage.

Provided are an audio playing module and an audio processing circuit thereof, and an electronic device, which belong to the technical field of electronics. In the audio processing circuit, by adding a feedback control circuit between a power circuit and an audio amplifier, the feedback control circuit can control, according to a change in the amplitude of an audio signal received by the audio amplifier, the power circuit to adjust a power supply voltage provided for the audio amplifier. Thus, when the amplitude of the audio signal changes, an appropriate power supply voltage can be matched for the audio amplifier by means of the feedback control circuit, thereby solving the problem of the audio playing module generating whistling when the amplitude of the audio signal changes, and thus optimizing the sound quality of played sounds.

Signal processing circuitry configured to receive an input signal and to output a processed output signal, wherein the signal processing circuitry is configured to: receive an indication of a temporal location of a transient in the input signal; and provide, in the processed output signal, a masking signal bridging the temporal location of the transient to mask the transient.

This application relates to sensing of signals with a common-mode variation. Embodiments describe a switching driver circuit with a modulator configured to control modulation of an output node between different switching voltages and a current sensor configured to sense a voltage drop across a sense resistor connected in series with the output node. The current sensor performs sensing during a first time window that occurs at regular intervals and the modulator avoids any transition in switching voltage at the first output node during the first time window. Embodiments also describe a sensing circuit for sensing a differential voltage with a common-mode variation which has a first sensing portion implemented to provide a floating voltage domain and a second sensing portion implemented to provide a static voltage domain. At least one switched capacitor provides a boundary between the voltage domains and is switched to transfer charge between the voltage domains.

The invention relates to a low-power-consumption high-performance D-type power amplifier modulation method and circuit and a D-type audio power amplifier, and the method comprises the steps: separating a pair of BD mode modulated signals outputted by a PWM modulation module in the D-type audio power amplifier circuit into a common mode component and a differential mode component, and outputting the common mode component and the differential mode component; feeding back the common-mode component and the differential-mode component to a differential input end through a common-mode feedback link and a differential-mode feedback link respectively; wherein the common-mode component and the common-mode feedback link are completely arranged in the chip; the differential mode component and the differential mode feedback link are realized by a power MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) integrated inside the chip or an external power MOSFET; and outputting the differential mode component to a to-be-driven object through the power output stage. According to the method, after two feedback links are separated, in a zero-input mute state, no common-mode signal is sent to an output stage for amplification, and power consumption is not caused at the output stage, so that the overall efficiency is greatly improved; and meanwhile, static bottom noise is almost eliminated.

A lavalier microphone has improved dynamic range. The lavalier microphone incorporates a pair of microphone transducer elements into the same housing or attached housings, with one of the microphone transducer elements being more sensitive to acoustic input than the other. The voltage signals from the respective transducer elements are processed and combined, resulting in a digital output audio signal with improved signal to noise both at lower and higher input acoustic levels.

An audio amplifier that implements current mode control without the use of an explicit or separate current mode sensor is disclosed. The audio amplifier may include a pair of feedback loops that provide current from a node located before an inductor of an output filter and current from a node located after the inductor of the output filter to an integrator circuit. The integrator circuit may be formed from existing circuitry of the audio amplifier controller. Thus, current mode control can be implemented without a separate current mode sensor. Further, the audio amplifier can be implemented as a half bridge or as a full bridge design without increasing the number of operational amplifiers compared to the half bridge.

Apparatus and techniques for adaptively adjusting an input current limit of a boost converter that supplies power to a load, such as an amplifier. An exemplary circuit for supplying power generally includes a boost converter having an output coupled to the load, and logic configured to adaptively adjust the input current limit of the boost converter and apply the input current limit to the boost converter based on an estimated output power of the boost converter. One exemplary method for supplying power generally includes converting an input voltage to an output voltage by a boost converter to power a load for the boost converter, adaptively adjusting the input current limit of the boost converter based on the estimated output power of the boost converter, and applying the input current limit to the boost converter during conversion.

An example apparatus includes class D amplifier circuitry (130) having a first input, a second input, a third input, and an output, the first input of the class D amplifier circuitry (130) being coupled to the output of the class D amplifier circuitry (130); and class AB amplifier circuitry (140) having a first input, a second input, a third input, and an output, the first input of the class AB amplifier circuitry (140) being coupled to the first input of the class D amplifier circuitry (130) and the output of the class D amplifier circuitry (130), the second and third inputs of the class AB amplifier circuitry (140) are coupled to the second and third inputs of the class D amplifier circuitry (130) and the output of the class AB amplifier circuitry (140).

The present invention is in the field of underlying electronic circuits, in particular audio amplifiers, more particularly class D amplifiers, such as for digital audio converters and digital amplifier controllers, chips comprising said audio amplifiers, and devices comprising said audio amplifiers or said chips.

A class D amplifier including a pulse width modulation (PWM) control loop, an H-bridge driver, a PWM controller having a PWM pulse generator to generate PWM pulses supplied to the H-bridge driver in response to an ADC value output by an analog-to-digital converter of the PWM control loop, and a comparator. The comparator is configured to trigger a cutoff of a PWM pulse generated by the PWM pulse generator during a respective loop cycle of the PWM control loop and to trigger generation of at least one counter PWM pulse with an opposite polarity in the respective loop cycle such that a net pulse energy of the cutoff PWM pulse and of the at least one generated counter PWM pulse corresponds to a pulse energy representing the ADC value provided by the analog-to-digital converter of the PWM control loop during the respective loop cycle.

A class-D amplifier includes an output driver stage and a current sensing circuit connected. The current sensing circuit includes: an operational amplifier having a positive input terminal and a negative input terminal; a positive input replica transistor, where a source of the positive input replica transistor is connected to the positive input terminal, a drain and a gate of the positive input replica transistor is connected to the drain and the gate of a first n-type output transistor, respectively; and a negative input replica transistor, where a source of the negative input replica transistor is connected to the negative input terminal, a drain and a gate of the negative input replica transistor is connected to the drain and the gate of the second n-type output transistor, respectively.

This application relates to methods and apparatus for controlling a switching driver to drive a load with a drive signal based on an input signal. A controller is configured to control modulation of at least one driver output node between selected switching voltages of a set of at least four different switching voltages to generate the drive signal. The output node is modulated according to a switching pattern and the controller is configured such that, for a given level of drive signal, the controller can selectively operate with a plurality of different switching patterns and selects an appropriate switching pattern to control at least one parameter of the switching driver other than the drive voltage.

A differential delta-sigma-modulator has an integrator (49) including a pair of single-ended amplifiers (46, 47). The differential delta-sigma-modulator comprises a sample clock (50) driving a first switchable capacitor configuration (31) and a second switchable capacitor configuration (32) at a predetermined switching cycle. The second switchable capacitor configuration (32) is adapted for sampling respective outputs from the pair of single-ended amplifiers (46, 47) on a pair of output sampling capacitors (C3, C5) in the first part of the switching cycle (P1), and charging a common mode capacitor (C4) with the average voltage of the voltage sampled by the pair of output sampling capacitors (C3, C5) in the second part of the switching cycle (P2). The voltage across the common mode capacitor (C4) represents the common mode voltage for the integrator (49).

A method for use with an acoustic system (referred to as a plant in control theory) (125) including a loudspeaker set (120), the method comprising obtaining an input audio sample (r n ) and a measured current (m n-d ) drawn by the loudspeaker set, and for a current time step, using a state space model of the loudspeaker set to generate a state vector (x n ) and a model-based estimated current (y n ), generating a predicted current (y n ) for a next time step based on the state vector (x e,n+1 ), generating a replacement audio sample (u n ) based on the state vector (x L,n ) for the current time step, generating a feedback signal (f n-d ) that contributes to the generation of the state vector (x n-d ) for a next time step based on the measured current (m n+1 ) and a time-aligned model-based estimated current (y n ), and generating an output audio sample (u n ) for the current time step, wherein when the predicted current (y e,n+1 ) is higher in amplitude than a threshold (I max ), the output audio sample (u n ) is either the input audio sample (r n ) or the replacement audio sample (u L,n ) for the current time step.

An audio signal processing method, and an audio signal processing device for executing the audio signal processing method includes, obtaining an audio signal and compressing the audio signal to generate a first compressed signal; calculating a duration for which a power value of the first compressed signal equals a first power threshold; determining whether the duration exceeds a first time threshold; when the duration exceeds the first time threshold, compressing the first compressed signal to generate a second compressed signal, and amplifying and outputting the second compressed signal.

A valve amplifier (105, 305) comprising an output transformer (110, 310) and a capacitor (210, 410) connected in parallel with a secondary winding (205, 405) of the output transformer (110, 310) Systems (100, 300), methods, and valve amplifier accessories (325, 500, 600) are also provided.

In some examples, a circuit include a class-D amplifier configured to receive an input signal and provide a drive signal based on and responsive to the input signal for driving an output device. The circuit also includes a current sensing circuit coupled to the class-D amplifier and configured to provide voltage signals representative of current flow through the class-D amplifier. The circuit also includes a current measurement circuit coupled to the current sensing circuit and configured to provide a first and second voltage difference signals derived from the voltage signals. The circuit also includes a current summing circuit coupled to the current measurement circuit and configured to determine a first current signal representative of the first voltage difference signal, determine a second current signal representative of the second voltage difference signal, and combine the first and second current signals to form a current sum signal. The circuit also includes a converter circuit coupled to the current summing circuit and configured to convert the current sum signal to a voltage representation.

A method for operating a speaker, in particular a dynamic-speaker, in which a useful signal for producing sound by the speaker is linearized. According to the disclosure, the useful signal is filtered depending on frequency and only a filtered portion of the useful signal is linearized. Advantageously, the useful signal is filtered by a high-pass filter and / or a low-pass filter. In one embodiment, only a portion of the useful signal that is output by the low-pass filter is linearized.

An apparatus comprising; an amplifier (308) having an amplifier input and an amplifier output; a power stage (PSI) having a power stage input and a power stage output, the power stage input coupled to the amplifier output; and an overcurrent protection circuit (402, 404) coupled to the power stage, the overcurrent protection circuit having an overcurrent threshold control input coupled to the amplifier.

Provided are feedforward amplifier circuit, audio amplifier and audio playing device, including: a main amplifier circuit, an adder circuit, a sub-amplifier circuit and a subtractor circuit, wherein the main amplifier circuit adds distortion to a first input signal to output a distorted signal, and inputs the distorted signal to the adder circuit and the subtractor circuit for performing feedforward correction; the sub-amplifier circuit amplifies a second input signal and serves as a positive input of the subtractor, so that a signal gain output by the subtractor is equal to a signal gain of the main amplifier; the subtractor circuit, with the distorted signal as a negative input, reversely amplifies the distorted signal and afterwards performs feedforward; and the adder circuit superimposes the distorted signal output by the main amplifier circuit and the reversely amplified distorted signal output by the subtractor, so as to output a distortion-free signal.

Methods, systems, and computer program products are presented herein for rendering synchronous audio using audio rendering devices. A networked audio rendering device may include a first wireless communications module, a second wireless communications module, a microcontroller, at least one speaker driver, and at least one digital audio amplifier. Audio data may be received by a first wireless communications module. Timecode data may be received by a second wireless communications module operating at a sub-GHz ISM band. The audio data may be received by a microcontroller. The audio data is processed by the microcontroller to generate output audio signals based on the timecode data. The output audio signals may be amplified by at least one digital audio amplifier. At least one speaker driver may be driven, by the at least one digital audio amplifier, to render an audio output.

A switching circuit outputs a modulated signal. A low-pass filter circuit receives the modulated signal and applies low-pass filtering processing at a low-pass cut-off frequency to generate a demodulated signal to a load impedance. A replicating circuit receives the modulated signal and applies a replica of the low-pass filtering processing of the low-pass filter circuit to generate a reference signal. A signal processing circuit applies signal processing to the demodulated signal and the reference signal to generate at least one indicator signal which is indicative of a variation of the low-pass cut-off frequency.

This application relates to modulator circuits (401, 501) for driving switching output stages (102) in a class-D amplifier system (400) or the like. The switching output stage (102) has an output node (105) and high-side and low-side switches (104H, 104L) for selectively connecting the output node to respective high-side and low-side voltages (VH, VL) and is configured to be operable in a continuous conduction mode of operation, in which there is always an output current flowing throughout a switching cycle and also in a discontinuous conduction mode of operation where there is a period in each switching cycle where there is no output current. The modulator circuit comprises a compensator (407, 408) operable to apply compensation, in the discontinuous conduction mode of operation, to at least partly compensate for a non-linearity when operating in the discontinuous conduction mode.

Distortion correction for audio amplifiers can be implemented in an audio driver that includes an audio amplifier configured to operate in a high output resistance (HOR) mode with an HOR driver or a zero output resistance (ZOR) mode with a ZOR driver. The audio amplifier includes an output node coupled to both of the HOR driver and the ZOR driver, such that the output node is subject to an effect of the ZOR driver in a disabled state when the audio amplifier is operating in the HOR mode. The audio driver further includes a control system configured to correct for the effect of the disabled ZOR driver by adjusting an input signal.

The present disclosure relates to an amplifier device for amplifying an input signal Sx at a device input X to an output signal Sy at a device output Y, for driving a loudspeaker or comparable reactive load, comprises a self-oscillating Class D power amplifier stage with transfer function KA(s). The amplifier stage includes a comparator, a power stage, and a second-order low-pass output filter comprising an inductor and a capacitor. A time delay unit provides a delay determined by one or more of the comparator, the power stage, and a first feedback filter. The output signal Sy is fed back to the comparator via the first feedback path to establish oscillation and provide basic low-frequency feedback. A correction stage is provided, comprising a second feedback path that feeds the output signal Sy, via a scaling resistor, to a virtual ground input of a transimpedance amplifier.

An audio amplifier circuit is provided. The circuit comprises a reference PWM unit for generating a reference PWM signal based on the audio signal to be rendered, and a driving PWM unit for generating a driving PWM signal for driving the speaker based on the correction signal. The correction signal depends on the audio signal to be rendered. The circuit also includes an oscillator for adjusting an oscillator frequency according to the error signal. The error signal depends on the reference PWM signal and the drive PWM signal. The circuit also includes a counter to determine a cumulative counter value based on an oscillator period of the oscillator. The circuit also includes a digital loop filter to generate a correction signal for determining a corrected signal based on the cumulative counter value.

An apparatus may include a set of terminals, a first switch circuit, and a second switch circuit. The set of terminals can include a power supply terminal, a reference terminal, and an intermediate voltage terminal. The first switch circuit, which can include a first set of control inputs and a positive drive terminal, is configured to, responsive to a first set of control signals applied to the first set of control inputs, selectively couple a first terminal of the set of terminals to the positive drive terminal. The second switch circuit, which can include a second set of control inputs and a negative drive terminal, is configured to, responsive to a second set of control signals applied to the second set of control inputs, selectively couple either the first terminal or a second terminal of the set of terminals to the negative drive terminal.