The audio amplifier includes a variable gain amplifier receiving the input audio signal and providing the output signal, whereby the output signal corresponds to the input signal amplified by a limiter gain. The audio amplifier further includes a limiter gain calculation unit, thus the input signal is amplified by the limiter gain. A control unit receives a signal representative of the input signal and is configured to estimate, based on a mathematical model, the input current or the total output current of the audio amplifier thus providing an estimated current signal corresponding to (and resulting from) the output signal, whereby the limiter gain calculation unit is configured to calculate, dependent on the estimation, the limiter gain such that the actual input current or the total output current of the audio amplifier does not exceed a threshold current value.

To prevent temperature rise of an amplifier. An AV amplifier 1 that amplifies an audio signal includes a PWM modulator 5 that controls dynamic range of the audio signal to not more than a setting value, and a microcomputer 2 sets the setting value based on consumption current. The microcomputer 2 sets the setting value to a predetermined value (35 dB) in case that state that consumption current is not less than a predetermined threshold (4.9 A or 3.6 A) continues for a predetermined time (2 minutes or 7.5 minutes).

Range to a human speaker is determined using a laser-based time of flight (ToF) system, with the range then being used to adjust the gain of a microphone receiving the speaker's voice. If desired, an acoustic-based Direction of Arrival (DoA) system uses acoustic information to determine the direction of incoming sound, such as a person talking, and the direction of the sound is then used to focus the area of laser illumination.

A circuit includes: a signal processing unit which is configured to perform signal processing; an amplifying unit which is configured to amplify a signal output from the signal processing unit; a first power supplying path which is extended from a battery to the signal processing unit; a second power supplying path which is branched from the first power supplying path, and which is extended to the amplifying unit; a power limiting unit which is provided in the second power supplying path, and which is configured to limit power flowing in the second power supplying path; and a capacitor which is connected to the second power supplying path, and which is configured to supplement power to be supplied to the amplifying unit.

The present invention relates in one aspect to a class D audio amplifier with improved output driver topology supporting multi-level output signals such as 3-level, 4-level or 5-level pulse width or pulse density modulated output signals for application to a loudspeaker load. The present class D audio amplifiers are particularly well-suited for high-volume consumer audio applications and solutions.

The present disclosure provides an amplifier for vehicle, vehicle including the amplifier, and method for controlling the amplifier for vehicle, which uses a 48 volt (V) battery voltage and adjusts speaker output according to variable audio signals, thereby minimizing the size of the amplifier, reducing conversion loss of a Direct Current (DC)-to-DC converter, and increasing output efficiency. In accordance with one aspect of the present disclosure, An amplifier for vehicle includes a first input port for receiving a first voltage; a second input port for receiving a second voltage lower than the first voltage; at least one power Integrated Chip (power IC) connected to a speaker for using a voltage received from the first input port; and a controller for controlling the power IC using a voltage received from the second input port.

A driving apparatus includes a power amplifier that supplies a driving signal to a vibrator, a current detector that outputs a detection signal corresponding to a driving current of the vibrator, and a driving controller that positively feedback a signal based on the detection signal to the power amplifier. The driving controller includes an A/D converter that A/D converts the detection signal, a first processing section that applies a gain compensation and compressor processes to an output digital signal of the A/D converter, a second processing section that performs a process of adding a digital signal corresponding to an input signal of the driving apparatus to an output digital signal of the first processing section, and a D/A converter that D/A converts an output digital signal of the second processing section to produce an analog signal supplied to the power amplifier.

Amplifying a signal includes outputting an output signal from a Class D amplifier configured to operate as a current driver to a load, such as a loudspeaker, the output of the Class D amplifier controlled by a feedback loop, and, in the feedback loop: performing analog filtering using an active analog filter on an error signal that is based on the output of the Class D amplifier and a reference signal, digitizing a filtered output of the analog filter to produce a sequence of digital values, performing digital filtering on the sequence of digital values to produce a sequence of filtered digital values, and generating a pulse signal to control the output of the Class D amplifier based on the sequence of filtered digital values. The digital filter reduces a destabilizing effect of the loudspeaker's inductance. Associated circuits, systems, modules and electronic devices are disclosed.

Embodiments of the disclosure may include a method and apparatus for improving the efficiency and extending the operation time between recharges or replacement batteries of a portable audio delivery system. The audio delivery system may include a processor, an audio processing device, a speaker, and a rechargeable power source. The audio delivery system is generally configured to generate and/or receive an audio input signal and efficiently deliver an amplified, high quality audio output signal to a user. In some embodiments of the disclosure, the audio processing device of the audio delivery system may include a switch mode power supply (SMPS), a signal delay element, an envelope detector, and a switching signal amplifier.

This application relates to amplifier circuitry for amplifying a signal from a MEMS transducer. A super source follower circuit (40) is provided which includes a feedback path from its output node (N.sub.out) to a control bias node (BC) in order to provide a preamplifier signal gain that may be greater than unity. A first transistor (M1) is configured to have its gate node connected to an input node (N.sub.IN) for receiving the input signal (V.sub.IN) and its drain node connected to an input node (X) of an output stage (A). The source node of the first transistor is connected to the output node (N.sub.OUT). A current source (I2) is configured to deliver a current to the drain node of the first transistor (M1), wherein the current source (I2) is controlled by a bias control voltage (V.sub.BC) at the bias control node (BC). A feedback impedance network (Z1) comprising a first port connected to the output node (N.sub.OUT) and a second port connected to the bias control node (BC) is provided.