1214results 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 signal amplifier includes a driver and a network of switches forming a power converter coupled to a H-bridge circuit. The power converter has a flying capacitor and an inductor. The H-bridge circuit receives a converted voltage from the power converter and applies an output modulated voltage to a load, for instance a loudspeaker. The driver drives the network of switches in a neutral state, a first state and a second state. In the neutral state no voltage is applied to the load. In the first state, an input voltage supply and the inductor are serially coupled, and the flying capacitor is coupled in parallel with the serially coupled input voltage supply and inductor. In the second state, the flying capacitor is coupled in series with at least one of the input voltage supply and the inductor. The signal amplifier may be a multi-level class D or class H amplifier.

In various embodiments, a sound modification application selectively modifies one or more sounds included in one or more audio signals. In operation, the sound modification application determines classifications associated with multiple sounds included in one or more audio signals. The sound modification application selects a first frequency sub-band of a first sound included in the multiple sounds based on a first classification associated with the first sound. The sound modification application then modifies the first frequency sub-band of the first sound, without modifying at least a second frequency sub-band of the first sound, to generate a modified audio signal.

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.

In an audio amplifier circuit, a power supply terminal receives a power supply voltage. A voltage source generates an internal power supply voltage obtained by multiplying the power supply voltage by a first gain and a bias voltage obtained by multiplying the power supply voltage by a second gain. An input gain circuit amplifies an analog audio signal with reference to the bias voltage. The input gain circuit has an input stage and a gain stage. A phase compensation capacitor is connected to the gain stage. A withstand voltage protection circuit clamps an output voltage of the gain stage to a predetermined clamp voltage.

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.

The present disclosure is directed to low noise amplifiers built as a monolithic millimeter or microwave integrated circuit (MMIC) that includes an amplification stage with two or more field effect transistors (FETS) connected in a parallel configuration. An amplifier may include two, three, or more amplification stages. Amplifiers consistent with the present disclosure may operate at frequencies in the range of 3 gigahertz (GHz) to 9 GHz. Each transistor or amplification stage may include their own series feedback element. A second amplification stage may include two parallel transistors, with one having a series feedback element and a feedback shunt spanning the second stage. A third stage may include a single transistor. Each of the transistors connected in a parallel configuration may be tuned to a different corner frequency in order to improve metrics of noise figure, gain, input return loss, and output return loss not possible with conventional amplifier designs.

Embodiments described herein relate to methods and apparatus for outputting a haptic signal to a haptic transducer. A method for triggering a haptic signal being output to a haptic transducer comprises receiving an audio signal for output through an audio output transducer; determining whether the audio signal comprises a haptic trigger based on an indication of a rate of change of an amplitude of the audio signal, and responsive to determining that the audio signal comprises a haptic trigger, triggering the haptic signal to be output to the haptic transducer.

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 cascaded switched power converter provides a wide voltage conversion ratio and improved efficiency ins systems such as power supplies and amplifiers. A switched-capacitor charge pump circuit is operated by one or more first clock signals and is coupled in cascade with an inductor-based power supply circuit according to one or more second clock signals. A control circuit that generates clock signals so that the one or more second clock signals have a phase offset with respect to the one or more first clock signals that is set to adjust a conversion ratio of the cascaded combination of the switched-capacitor charge pump circuit and the inductor-based power supply circuit. The inductor of the inductor-based power supply circuit may be an inductive load, such as a speaker, and the phase offset may be modulated according to an audio signal to provide audio amplification.

The utility model discloses a power amplifier circuit and electronic equipment. The power amplifier circuit comprises a power supply module; the power supply end of the power amplification module is connected with the power supply module, and the output end is connected with an external loudspeaker; the signal detection module is connected with the output end of the power amplification module and the power supply module; wherein the signal detection module is configured to detect an audio signal of the output end of the power amplification module, and the power supply module is configured to provide a first voltage signal for the power amplification module when the signal detection module does not detect the audio signal and provide a second voltage signal for the power amplification module when the signal detection module detects the audio signal. A second voltage signal is provided for the power amplification module, and the voltage value of the second voltage signal is larger than that of the first voltage signal. Through the mode, the power supply voltage can be reduced when the power amplification module has no audio output, the circuit energy consumption is reduced, the heating is reduced, and the service life of the power amplifier is further prolonged.

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.

According to an aspect of an embodiment, thermal management system for an audio amplifier system may include a heatsink and an active thermal management system. The heatsink may be coupled to an enclosure housing the audio amplifier system and an amplifier of the audio amplifier system. The heatsink may be configured to passively dissipate heat generated in the amplifier to the enclosure and provide structural support for the enclosure. The active thermal management system may include a temperature sensor configured to generate temperature data, a fan configured to provide air to the audio amplifier system to lower temperature measured using the temperature sensor and an embedded computing device configured to obtain the temperature data from the temperature sensor and control the fan based on the temperature data.

A method for providing an analog output signal includes (a) amplifying a digital first internal signal using a first Class-D amplifier to generate a digital first output signal, (b) filtering the digital first output signal to generate an analog first output signal, (c) providing the analog first output signal to a first load, (d) sensing the analog first output signal to generate an analog first feedback signal, (e) converting the analog first feedback signal to a digital first feedback signal, and (f) configuring the first Class-D amplifier for an impedance of the first load by generating the digital first internal signal at least partially based on the digital first feedback signal.

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.

Provided in the present application are an audio system and a terminal device, which can be applied to the technical field of audio. In the audio system of the present application, a second audio power amplifier is added to a first audio power amplifier, wherein the first audio power amplifier is a common audio power amplifier, the second audio power amplifier is a high-power audio power amplifier, such that the sound effect of a terminal device can be improved by means of the second audio power amplifier. In addition, an audio processor in the audio system can dynamically adjust, on the basis of a volume level, a battery charge level or a battery temperature, audio streams input into the first audio power amplifier and the second audio power amplifier, and can dynamically adjust an input voltage of the second audio power amplifier on the basis of the volume level, the battery charge level or the battery temperature, such that the power consumption of the terminal device can be reduced while the sound effect of the terminal device is improved.

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.

The invention provides an audio system and terminal equipment, which can be applied to the technical field of audio. In the audio system, the second audio power amplifier is added on the basis of the first audio power amplifier, the first audio power amplifier is a common audio power amplifier, the second audio power amplifier is a high-power audio power amplifier, and the sound effect of the terminal equipment can be improved through the second audio power amplifier. Besides, an audio processor in the audio system can dynamically adjust audio streams input to the first audio power amplifier and the second audio power amplifier according to the volume level, the battery electric quantity or the battery temperature, and can dynamically adjust the input voltage of the second audio power amplifier according to the volume level, the battery electric quantity or the battery temperature. While the sound effect of the terminal equipment is improved, the power consumption of the terminal equipment can be reduced.

This application relates to methods and apparatus for current monitoring in switched mode drivers. A switching driver has an output stage with a network of switches for switching an output node between different switching voltages and a modulator for controlling a duty-cycle of the switching output stage based on the input signal, where the modulator generates a modulator signal based on the input signal. A current monitor is configured to receive a first current signal indicative of a sensed first driver current and to determine and / or limit a second driver current using the first current signal and the modulator signal. One of the first driver current and the second driver current is an output current to the load and the other of the first driver current and the second driver current is an input current from a power supply.

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.