875results about "Low frequency amplifiers" patented technology

An example apparatus includes: class D amplifier circuitry having a first input, a second input, a third input, and an output, the first input of the class D amplifier circuitry coupled to the output of the class D amplifier circuitry; and class AB amplifier circuitry having a first input, a second input, a third input, and an output, the first input of the class AB amplifier circuitry coupled to the first input of the class D amplifier circuitry and the output of the class D amplifier circuitry, the second and third inputs of the class AB amplifier circuitry coupled to the second and third inputs of the class D amplifier circuitry, and the output of the class AB amplifier circuitry.

The embodiment of the invention provides a closed-loop control method for power driving and protection, and the method comprises the steps: constructing a voltage feedback type circuit through a high-speed operational amplifier, and forming a closed-loop gain structure through a feedback network of the voltage feedback type circuit; the load current of the output end of the voltage feedback type circuit is monitored in real time, and when the load current exceeds a first set threshold value, a protection mechanism is triggered to turn off the output stage; the power-on surge current is limited through the soft start control circuit; phase information of a load reflection coefficient is obtained, an inductance / capacitance combination of the variable dynamic impedance matching network is selected according to phase information table look-up, inductance / capacitance parameters are switched through a relay, and the transmission standing-wave ratio between the power amplifier and a load is optimized; monitoring the temperature of the radiating fin of the power tube, and dynamically adjusting the resistance value of the feedback network; and performing cooperative control of short-circuit protection, over-temperature protection and surge suppression according to the priority. According to the embodiment of the invention, the performance bottleneck in a load fluctuation scene is broken through.

A class D amplifier circuit receives an analog audio signal with a first reference voltage as its center level, and outputs an output pulse signal having a duty cycle that corresponds to the analog audio signal. A bias circuit generates a second reference voltage having a voltage level obtained as a division of the first reference voltage and the power supply voltage. A periodic voltage generating circuit of the class D amplifier circuit generates a periodic voltage having a triangle waveform or otherwise a sawtooth waveform having an amplitude that corresponds to the second reference voltage.

An example apparatus includes: current source circuitry having a first terminal, a second terminal, a third terminal, and a fourth terminal; current sink circuitry having a first terminal, a second terminal, a third terminal, and a fourth terminal; common mode voltage circuitry having a first terminal and a second terminal, the first terminal of the common mode voltage circuitry coupled to the first terminal of the current source circuitry and the first terminal of the current sink circuitry, the second terminal of the common mode voltage circuitry coupled to the second terminal of the current source circuitry and the second terminal of the current sink circuitry; idle current source circuitry having a terminal coupled to the third terminal of the current source circuitry; and feedback current source circuitry having a terminal coupled to the fourth terminal of the current source circuitry.

There is provided mechanisms for operating a DPD for a non-linear electronic device. A method is performed by a DPD controller. The method comprises receiving an input signal destined to be input to the non-linear electronic device. The method comprises selecting a basis function that represent non-linear input-output characteristics of the non-linear electronic device. The basis function is defined by kernels of a pruned Volterra series, and comprises higher-than-order-1 polynomial terms, polynomial cross-terms, memory cross-terms, and common tap delays shared by all polynomial terms. The method comprises obtaining an output signal by subjecting the input signal to a linearization function defined by the basis function. The method comprises providing the output signal as input to the non-linear electronic device.

The invention discloses a parallel constant-voltage digital audio power amplifier and a broadcasting system. Comprising a line input module, a line output module, a first analog-to-digital conversion circuit, a second analog-to-digital conversion circuit, a third analog-to-digital conversion circuit, a digital signal processor, a single-chip microcomputer, a digital-to-analog conversion circuit, an error comparator, a modulator, an integrating circuit, a pulse width modulation input half-bridge output stage, and a first carrier frequency selection and gain adjustment module. A second carrier frequency selection and gain adjustment module, a first LC filter, a high-frequency compensation network, a communication bus and a power switch. The technical problems that an existing multi-channel parallel digital constant-voltage power amplifier is only limited to power amplifier channels in the same power amplifier, the parallel connection mode only uses the first channel as a main power amplifier and only uses the other channels as slave power amplifiers, and certain limitation exists are solved.

This application relates to methods and apparatus for switched mode drivers. A BTL driver has a switch network operable in different switch states, wherein, in each switch state, each of first and second output nodes is connected to a respective one of a first switching voltage, a second switching voltage or an intermediate switching voltage between the first and second switching voltages which is provided by a driver capacitance. A controller is configured to control the switch network to operate in a sequence of switch states to generate a differential drive signal based on an input signal. The controller is configured such that operation of driver switch network in said sequence of switch states to generate said differential drive signal provides voltage regulation of the intermediate voltage provided by said driver capacitance.

An integrated circuit (IC), comprising: a first gain stage configured to apply a first gain to a first signal to generate a first amplified signal; a first converter configured to convert the first signal to a first output signal; a first output pin for outputting the first output signal; gain update circuitry configured to: output a first internal gain control signal to the first gain stage to update the first gain of the first gain stage, subsequently output a first external gain control signal to a second output pin of the IC, wherein output of the first external gain control signal is delayed relative to output of the first internal gain control signal by a first predetermined delay, the first predetermined delay to compensate for signal chain delay between the first gain stage and the first output pin.

An audio amplifier includes a loop filter, at least one high pass filter (HPF) circuit, a pulse width modulation (PWM) generator, and a power stage. The loop filter is arranged to receive an audio signal and a feedback signal, and includes a first amplifier and a second amplifier, wherein the first amplifier has a first output node, and is arranged to process the audio signal and the feedback signal; the second amplifier has a first input node, and is arranged to receive a first amplifier input and a second amplifier input; and the first amplifier input is obtained from a signal path coupled between the first output node and the first input node. The at least one HPF circuit is coupled between the first amplifier and the second amplifier, and is arranged generate and output the second amplifier input according to an amplifier output of the first amplifier.

A voltage generation circuit includes a voltage input terminal, a voltage output terminal, a first resistor having a first terminal electrically connected to the voltage input terminal, a second resistor having a third terminal electrically connected to the second terminal and a fourth terminal electrically connected to a ground potential, a first capacitor having a first capacitive terminal electrically connected to the voltage input terminal, a third resistor having a fifth terminal electrically connected to a second capacitive terminal, a fourth resistor having a seventh terminal electrically connected to a sixth terminal, and a first operational amplifier having a first inverting input terminal electrically connected to the sixth terminal, a first non-inverting input terminal electrically connected to the second terminal, and a first output terminal electrically connected to the voltage output terminal and an eighth terminal.

A system may include a Class-D stage comprising a first high-side switch coupled between a supply voltage and a first output terminal of the Class-D stage, a second high-side switch coupled between the supply voltage and a second output terminal of the Class-D stage, a first low-side switch coupled between a ground voltage and the first output terminal, and a second low-side switch coupled between the ground voltage and the second output terminal. The system may also include current sensing circuitry comprising a plurality of sensors, each sensor configured to sense a current associated with a respective one of the first high-side switch, second high-side switch, first low-side switch, and second low-side switch. The system may also include short-circuit detection circuitry configured to determine a presence and a location of a short circuit in the Class-D stage based on the sensed currents.

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.

The invention belongs to the technical field of integrated circuits, and particularly discloses a numerical control programmable gain amplifier chip, which adopts an SIP (Session Initiation Protocol) packaged operational amplifier, a digital potentiometer, an input end Vin and an output end Vout, and is characterized in that an alternating current signal is input from the Vin end and is connected to an inverted input end of the operational amplifier through a capacitor C1 and an input resistor R1; a positive power supply pin of the operational amplifier is connected with a power supply positive electrode VDD, a negative power supply pin is grounded, and a VDD / 2 direct current bias voltage is obtained by an in-phase input end through a precision resistance voltage dividing network and is accessed after low-pass filtering; the high end of the digital potentiometer is connected with the Vout end, the low end is connected with the inverting input end of the operational amplifier, and a feedback path is formed through a sliding end. The digital potentiometer and the operational amplifier are integrated, high integration and modularization of the programmable gain amplification circuit are achieved, and the problems that in a traditional discrete scheme, due to analog switch conduction resistance, gain precision is insufficient, reliability of a multi-element system is lowered, and the circuit size is large are solved.

The invention discloses an audio power amplifier starting-up sonic boom suppression method based on a sound masking effect, and belongs to the technical field of power amplifiers, and the method comprises the following steps: S1, presetting a voltage reference value for audio detection; s2, correspondingly outputting a suppression signal or a working signal according to the comparison between the input voltage value and the voltage reference value; s3, generating a PWM signal, and connecting the PWM signal to a switch module through an AND gate and a buffer; s4, when the suppression signal is generated, it is judged that the audio input signal has sonic boom at the moment, and the output end of the power amplifier does not generate an impact signal; and when the working signal is generated, the output end of the power amplifier generates an impact signal containing a suppression effect. According to the invention, through input signal threshold detection, the composite sound superposed with the preset switch music signal is generated, and the method has the advantages of solving the bottleneck of response lag during shock-wave suppression of the D-type power amplifier and promoting the D-type power amplifier to be miniaturized.

The invention discloses a final-stage voltage tracking anti-clipping circuit for an audio power amplifier, and relates to the technical field of power amplifiers, and the circuit comprises a voltage division circuit which is used for receiving final-stage voltage from target power amplifier equipment and generating a combined voltage signal; the audio attenuation module is used for receiving an audio input signal and a final-stage voltage, and judging whether amplitude limiting modulation is carried out on the audio input signal or not to complete power amplifier output by judging whether a starting signal is received or not; and the starting judgment module is used for receiving the combined voltage signal and the first output signal, and comparing the combined voltage signal with the first output signal to generate a starting signal. According to the invention, the collected final-stage voltage of the target power amplifier is set as the dynamic amplitude limiting threshold, so that an over-high signal can be effectively suppressed to a safe range quickly when the power supply drops instantaneously, and the effects of avoiding hearing deterioration caused by power amplifier signal waveform truncation and avoiding potential safety hazards caused by amplitude limiting and topping to the loudspeaker are achieved.

Provided is a differential amplifier comprising: a first differential amplification circuit that has a first input terminal, a second input terminal, a first output terminal and a second output terminal which respectively output a first output signal and a second output signal; an RC filter that filters the first output signal and the second output signal and outputs them; a second differential amplification circuit that has a third input terminal and a fourth input terminal to which the first output signal and the second output signal filtered by the RC filter are respectively input and a third output terminal which outputs a third output signal; and a third amplification circuit that has a fifth input terminal to which the third output signal is input and a fourth output terminal which outputs a fourth output signal according to the third output signal.

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.

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.

The present disclosure discloses a duty cycle signal processing circuit and method, and an audio signal processing device. The duty cycle signal processing circuit includes an amplitude detector and an operation unit, where the amplitude detector is configured to detect a first amplitude of an audio signal, generate a second amplitude, and send the second amplitude to the operation unit; and the operation unit is configured to obtain a power supply voltage, and perform operation processing on the second amplitude and the power supply voltage, to obtain a duty cycle control signal that matches at least one parameter of the second amplitude and the power supply voltage. In the present disclosure, conversion efficiency of a corresponding power amplifier unit can be improved.

The invention provides an intelligent audio power amplifier system and a working method thereof. The working method comprises the steps that a dynamic noise suppression module enables an input signal after reverse noise injection to enter a distortion compensation module; a distortion compensation signal is synthesized by using a distortion compensation module; the life cycle parameter self-calibration module calibrates parameters and inputs the parameters to the dynamic noise suppression module and the distortion compensation module; the dynamic noise suppression module is based on an intelligent learning method and adopts a frequency band channel network, a time sequence channel network and a fusion layer; the life cycle parameter self-calibration module provides the temperature and the working time for the dynamic noise suppression module to optimize the time domain channel network and provides the temperature and the working time for the distortion compensation module to update the predistortion coefficient of the dynamic nonlinear distortion model; the output of the dynamic noise suppression module is provided for the distortion compensation module; and the output of the distortion compensation module is fed back to the dynamic noise suppression module. The problems of high-frequency noise interference, nonlinear distortion degradation and insufficient long-term stability are solved at the same time.

The invention discloses an audio driving circuit and audio driving equipment. The audio driving circuit comprises an input amplification module, a filtering amplification module, a PWM (Pulse Width Modulation) driving module, a feedback loop and a frequency equalization module. And the feedback loop is used for generating a feedback signal based on the driving signal, performing feedforward control on the feedback signal based on the input signal, and suppressing PWM residual aliasing distortion in the feedback signal. The frequency equalization module is used for adjusting the phase of the first amplification signal based on the input signal. Input signals can be gained through the input amplification module, and feedback control can be achieved based on feedback signals. Meanwhile, the frequency equalization module can reduce the phase difference between the first amplification signal and the input signal, and the suppression effect on PWM residual aliasing distortion is improved.

A Class-D audio amplifier includes a triangular wave generator, a wave reshaping device and a pulse-width modulator. The triangular wave generator generates a first triangular wave. The wave reshaping device generates a second triangular wave by reshaping the first triangular wave. The pulse-width modulator modulates a pair of differential audio input waves with the second triangular wave instead of the first triangular wave to reduce a switching loss of the Class-D audio amplifier.

In an embodiment, a device includes: phase frequency detector (PFD) circuitry having an input and an output; an oscillator having an input and an output, the input of the oscillator coupled to the output of the PFD circuitry; clock divider circuitry having a first input, a second input, and an output, the first input of the clock divider circuitry coupled to the output of the oscillator, the output of the clock divider circuitry coupled to the input of the PFD circuitry; and a controller having an output coupled to the second input of the clock divider circuitry.

The invention provides a multi-phase pulse width modulation method and related equipment for reducing harmonic waves for a class-D power amplifier, and relates to the field of radio and television, and the method comprises the steps: sampling an original audio signal at a preset sampling rate, and obtaining a sine wave audio signal; generating a plurality of triangular wave signals corresponding to the sine wave audio signal according to a preset frequency multiple; performing amplitude comparison on the sampling signal and each triangular wave signal to obtain a pulse width modulation signal corresponding to each triangular wave signal; superposing the plurality of pulse width modulation signals to obtain a superposed signal; and inputting the superposed signal into a D-type power amplifier to obtain a power amplifier output signal after harmonic wave reduction. By implementing the method, the performance requirement on a post-stage low-pass filter can be reduced, so that the harmonic distortion of the output signal is suppressed on the premise of not increasing the cost and complexity of the filter.

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.

The utility model discloses a discharge detection device for a dry-type transformer, and the device comprises a sound collection module which is used for collecting sound signals generated during the discharge of the dry-type transformer; the audio pre-amplification module is connected with the sound collection module and is used for carrying out primary amplification on the sound signal to obtain a first sound signal; the frequency selection module is connected with the audio pre-amplification module and is used for screening the frequency of the first sound signal to obtain a second sound signal; the audio amplification module is connected with the frequency selection module and is used for carrying out secondary amplification on the second sound signal to obtain a third sound signal; and the audio output module is connected with the audio amplification module and is used for outputting the third sound signal. According to the utility model, the sound collection module is arranged to collect sound during operation of the transformer, the audio pre-amplification module and the audio amplification module are adopted to amplify the sound to a frequency band which can be heard by people, the sound is output through the audio output module, and an operator hears the sound to judge the discharge condition of the transformer.

The present invention relates to a high-performance audio amplifier (102) intended to control at least one loudspeaker (R44), the amplifier comprising a preamplifier stage (301) receiving an input signal (S1), a power amplifier stage (302) connected to the preamplifier stage (301), and a negative feedback loop delivering an image of an output signal (3) to the preamplifier stage (301), the power amplifier stage (302) comprising two power supply circuits (155a, 155b), the two power supply circuits comprising MOSFET transistors (M1, M2). The present invention is characterized in that it comprises: a subcircuit for assisting charging, a subcircuit for assisting discharging of the MOSFET transistors (M1, M2), and a voltage shifting subcircuit.

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.