46results about "Audio amplifier" patented technology

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.

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.

An audio input circuit includes a single-ended signal input circuit, a differential signal input circuit, a first amplifier circuit, and a second amplifier circuit. The single-ended signal input circuit is enabled by switches in a single-ended mode to output a single-ended audio signal to the first amplifier circuit. The differential signal input circuit is enabled by switches in a differential mode to output a differential audio signal to the first amplifier circuit. The first amplifier circuit outputs an inverted audio output signal to the second amplifier circuit according to signals it received. The second amplifier circuit outputs a non-inverted audio output signal according to signals it received. In the single-ended and differential modes, the signals inputted to non-inverting inputs of the first and second amplifier circuits are DC signals to stabilize the on-resistance linearity of the switches and prevent the deterioration of the audio input circuit's total harmonic distortion.

This application relates to methods and apparatus for clipping prevention. A driver apparatus for driving a load with an output signal has a switching driver with a switch network and a modulator configured to control the switch network to switch output nodes between different switching voltages with a controlled duty-cycle. A quantizer controller receives a quantizer input signal based on an input signal and a feedback signal and controls the duty-cycle of the switch network. A clipping prevention controller is configured to control a gain applied to the input signal so as to provide limiting of the input signal to avoid clipping, wherein the clipping prevention controller is configured to dynamically control at least one limiting threshold used to determine when to apply limiting of the input signal based on an indication of said quantizer input signal.

An amplifier having one or more channels where each channel includes a two half bridges (a master and slave sub-channel). The sub-channels can be connected either in parallel or in a full-bridge configuration via internal switches that route signals to a pair of speaker jacks. One switch in the amplifier has a first position that selectively connects the outputs of the master and slave sub-channel to the same input of the speaker load so that the two sub-channels will drive the speaker load in parallel and a second position where the output of the slave sub-channel is connected to another input of the speaker load so that the master sub-channel and the slave sub-channel will drive the speaker load in a Full-bridge configuration. A second switch has a first position that connects a second input of the speaker load to ground or reference potential of the sub-channels when the speaker load is to be driven in parallel and a second position that is a No-connect position that is used when the speaker load is driven in the Full-bridge configuration and a ground potential is not to be connected to the speaker.

This application relates to methods and apparatus for power limiting for amplifiers. An amplifier is configured to receive an input supply voltage and to draw, in use, an amplifier input current resulting in an amplifier input power. A power limiter is configured to monitor an indication of the amplifier input power, determine a first signal limit based on said indication of the amplifier input power and a pre-set limit and apply regulation to the input signal to provide a regulated input signal for input to the amplifier that does not exceed the first signal limit.

An integrated circuit (IC) 100 includes a first transducer driver 102 and a second transducer driver 104, for respectively driving first and second transducers 114, 116, and boost converter circuitry

A sensor component is disclosed including a transducer and an electrical circuit disposed in a housing. The electrical circuit includes a bias voltage source coupled to a first electrode of the transducer. A non-inverting amplifier stage is coupled to a second electrode of the transducer. An inverting amplifier stage is coupled to an output of the non-inverting amplifier stage. A negative feedback path is located between an output of the inverting amplifier stage and the first electrode of the transducer. An electrical output signal of the transducer can be attenuated by applying an attenuation signal, based on a filtered electrical signal, to the first electrode via the negative feedback path.

A method for use in an audio system including a plurality of amplifier channels of a corresponding audio channel. Each of the amplifier channels receives a respective input audio signal and is powered by the same power supply. The method includes obtaining (810) a value of an indicator, the indicator representing an energy reserve of the power supply, and for each of the amplifier channels, determining (830) a gain to be applied to the respective input audio signal by an attenuation function and a clipping level to be applied to the output of the attenuation function by a clipping function, wherein when the value of the indicator is below a threshold, the gain decreases over time, when the value of the indicator is above the threshold, the gain increases over time to a maximum value, the threshold represents a nominal energy level at which the power supply is in a nominal operating state, and the clipping level is determined as a monotonic function of the value of the indicator.

An amplifier power attenuator utilizes an amplified audio feedback signal from an audio amplifier (which is driving a loudspeaker), along with a user-set impedance and a maximum voltage set-point reflective of the operational parameters of the loudspeaker, to attenuate an audio signal prior to amplification thereby preventing damage to the loudspeaker. The impedance of a variable impedance optocoupler is changed to adjust the attenuation of the audio signal to one of a plurality of predetermined attenuation levels responsive to an error between a voltage level of the feedback signal and the maximum voltage set-point. The error is reflected in a counter value having a linear or non-linear relationship with the error dependent upon a magnitude of the error; the counter value is assessed against a plurality of target values associated with respective ones of the predetermined attenuation levels to identify the attenuation to be applied to the audio signal.

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.

Systems and methods improve power efficiency in a communication system by examining a digital signal to determine if a threshold corresponding to an increase in power requirements is likely to be exceeded. The signal is encoded with information indicative of the likely change and transmitted to a driver that, after extracting the information, uses the information to instruct an amplifier to increase power output to accommodate the increase in power requirements. Once the threshold is no longer exceeded, the driver circuit advantageously reduces the power output to conserve energy. In various embodiments, the amplifier can improve power efficiency by switching from a low power circuit configuration to a high circuit configuration.

A circuit (35) for detecting electrical short circuits in a full-bridge class-D amplifier that comprises: a first branch (HP, LP) comprising a first high-side switch (HP) and a first low-side switch (LP); and a second branch (HM, LM) comprising a second high-side switch (HM) and a second low-side switch (LM). The circuit (35) comprising: a measuring unit configured to provide a first measure of a first operating characteristic of the high-side switch (HP; HM) comprised in one of the first branch (HP, LP) and the second branch (HM, LM) of the full-bridge class-D amplifier, and a second measure of a second operating characteristic of the low-side switch (LM; LP) comprised in the other of the first branch (HP, LP) and the second branch (HM, LM) of the full-bridge class-D amplifier; a checking unit configured to receive from the measuring unit the first measure and the second measure and to provide an unbalance signal indicative of the presence of unbalance between said first measure and said second measure; and a detection unit configured to receive from the checking unit said unbalance signal and to detect the presence of an electrical short circuit in response to said unbalance signal indicating the presence of unbalance between said first measure and said second measure.

A driver (300, 400) for driving a transducer has nodes for connection to high-side and low-side voltage supplies, an output node (301) and nodes (N1-N4) for connecting first and second capacitors (C1,

An apparatus includes an audio amplifier having a terminal and voltage estimator circuitry having a temperature input and an output. The voltage estimator circuitry is configured to generate a value at the output of the voltage estimator circuitry based on a temperature value at the temperature input of the voltage estimator circuitry. A boost converter has a first terminal, a second terminal, and a third terminal. The first terminal is coupled to an input voltage terminal. The second terminal of the boost converter is coupled to the terminal of the audio amplifier. The third terminal of the boost converter is coupled to the output of the voltage estimator circuitry. The boost converter is configured to generate a voltage at the second terminal of the boost converter based on the value.

A sensor component is disclosed comprising a transducer and an electrical circuit arranged in a single package. The electrical circuit includes a bias voltage coupled to a first electrode of the transducer. A non-inverting amplifier stage is coupled to a second electrode of the transducer. An inverting amplifier stage is coupled to an output of the non-inverting amplifier stage. A negative feedback path is located between an output of the inverting amplifier stage and the first electrode of the transducer. An electrical output signal of the transducer can be attenuated by applying an attenuation signal, based on a filtered electrical signal, to the first electrode via the negative feedback path.

A startup circuit for a bandgap reference source can include a first transistor coupled to a supply source and configured to provide a current to a reference resistance when the bandgap reference source is turned on, to thereby provide a reference voltage at a first node between the first transistor and the reference resistance, a second transistor coupled to the supply source to provide a second node therebetween, the second transistor having a gate coupled to the first node, such that the second transistor is off and a startup voltage at the second node is up when the reference voltage is at or below a threshold voltage, and the second transistor is on and the startup voltage at the second node is down when the reference voltage exceeds the threshold voltage, and a third transistor implemented between the supply source and a startup node of a bandgap core, the third transistor having a gate coupled to the second node such that the third transistor turns on to inject a startup current to the startup node when the startup voltage is up, and turns off when the startup voltage is down.

An integrated resistive element adapted to be configured as an integrated sensing unit and electronic apparatus including the same. The integrated resistive element in an embodiment includes a plurality of resistive segments disposed in or on a well formed in a substrate. The plurality of resistive segments are arranged in an array or a matrix and are configured for being electrically coupled in series with each other between a first terminal and a second terminal of the integrated resistive element. The integrated resistive element in an embodiment further includes a sensing terminal disposed between a first portion of the plurality of resistive segments and a second portion of the plurality of resistive segments and for being electrically coupled to the first portion and the second portion of the plurality of resistive segments.

An amplifier system may include at least one alternating current (AC) input source, a first DC-DC converter configured to convert the AC voltage to a first rail voltage, a second DC-DC converter configured convert the AC voltage to a second rail voltage, and a Class D amplifier configured to receive the first rail voltage on a first positive rail from the first DC-DC converter and the second rail voltage on a second negative rail from the second DC-DC converter to reduce rail pumping of the first and second voltage rails.

In an embodiment, a device includes: a transistor having a first terminal and a control terminal; continuous operating loss (COL) fit circuitry (715, 735) having an input and an output; current sense circuitry (720, 740) having a first input, a second input, and an output, the first input of the current sense circuitry (720, 740) coupled to the first terminal of the transistor and the input of the COL fit circuitry (715, 735), the second input of the current sense circuitry (720. 740) coupled to the control terminal of the transistor; and comparator circuitry (725, 745) having a first input and a second input, the first input of the comparator circuitiy (725, 745) coupled to the output of the COL fit circuitry (715, 735), the second input of the comparator circuitry (725, 745) coupled of the output of the current sense circuitry (720, 740).

Control of an electrostatic sound transducer including a microelectronic component. A control circuit including a differential amplifier is provided, wherein, at a central terminal of the sound transducer, a bias voltage is provided relative to the common mode voltage of the differential amplifier. The supply voltage of the differential amplifier is adjusted on the basis of the maximum signal amplitude of the input signal.

A method and apparatus are provided for reducing reaction forces in loudspeakers. The method includes providing, from a power source (312) connected to a loudspeaker (304), a current to the loudspeaker. The method also includes measuring, using a current sense resistance (308) connected in series to the loudspeaker, the current through the loudspeaker. The method further includes providing, using a voltage-controlled source (310) connected in series to the loudspeaker, a current substantially proportional to the measured current through the loudspeaker to an actuator (306), wherein the actuator is connected in series to the loudspeaker.

Embodiments of the present disclosure provide a diaphragm and an audio device. The diaphragm comprises: at least one insulating film, a plurality of conductive films, and a plurality of connecting pieces. The insulating film is provided with a magnetic pole corresponding area. Each of the conductive films is connected at least to one insulating film, the plurality of conductive films is arranged with an interval, and the magnetic pole corresponding regions are respectively arranged on the two sides of each conductive film. The plurality of conductive films is connected in series by means of the plurality of connecting pieces to form an energized circuit. According to the technical solution provided in the embodiments of the present disclosure, the at least one insulating film is connected with the plurality of conductive films arranged with an interval, and the magnetic pole corresponding regions are respectively arranged on the two sides of each conductive film, such that a conductive film having a relatively large area can be located in a relatively strong magnetic field, each conductive film also emits low-frequency sound that meets user's needs, and the conductive film can cover the high, medium and low frequency spectrum.

An exemplary audio enhancement system substantially eliminates latency by returning audio input signals in amplified form directly in the analog domain to the source, thereby reducing signal degradation and removing redundancy from digital and analog audio transmission and processing architectures.

This application relates to switching drivers which receive a supply voltage that can vary in use. An output stage switches a driver output node between switching voltages with a controlled duty-cycle and is operable in different driver modes in which the switching voltages are different in the different driver modes. A capacitive voltage generator is operable to generate a switching voltage used in one of the driver modes. The switching driver is operable a first regime, in which a capacitor of the voltage generator is biased to a capacitor voltage with a magnitude greater than the input supply voltage, or a second regime, where the biasing of the capacitor is different, such that the capacitor voltage magnitude has a ratio to the input supply voltage with a lower value than in the first regime. The regime is controlled based on the magnitude of the supply voltage and / or the capacitor voltage.

A class-D amplifier includes a loop filter configured to receive first and second feedback signals, to receive first and second input signals through first and second resistors respectively, and to filter the first and second input signals and the first and second feedback signals to generate first and second filtered signals; a triangle wave generator configured to generate a triangle wave according to first and second reference voltages; first and second comparators configured to compare the first and second filtered signals with the triangle wave respectively to generate the first and second pulse width modulation (PWM) signals, respectively; first and second driver circuits configured to generate first and second output signals according to the first and second PWM signals, respectively; and a reference voltage generation circuit configured to generate the first and second reference voltages according to a control signal.

A load driver and an audio amplifier are provided. The load driver comprises an output stage and a control module. The control module is connected to the output stage; and the control module is configured to control the output stage so that an output node of the output stage outputs a load drive signal, a rising edge of the load drive signal has a plurality of segments, and a rising slope of a previous segment among the plurality of segments of the rising edge is larger than a rising slope of a next segment.

A full-bridge class-D amplifier includes: a first branch with a first high-side switch and a first low-side switch coupled at a first output node in series between a supply voltage and ground; and a second branch with a second high-side switch and a second low-side switch coupled at a second output node in series between the supply voltage ground. A circuit for detecting electrical short circuits in the amplifier includes: a measuring circuit configured to provide a first measure of high-side switch operation in one of the branches and a second measure of low-side switch operation in the other of the branches; a checking circuit configured to determine an imbalance between the first and second measures to generate an imbalance signal; and a detection circuit configured to presence of an electrical short circuit in response to the imbalance signal.

An integrated resistive element suitable for configuration as an integrated sensing unit and an electronic device thereof. The integrated resistive element can include a plurality of resistive segments including a first portion disposed in or on a first well region formed in a substrate and a second portion disposed in or on a second well region formed on a substrate. The second portion is configured to be electrically coupled between a first terminal of the integrated resistive element and a sensing terminal. The first portion is configured to be electrically coupled between the sensing terminal and a second terminal of the integrated resistive element.

An amplifier includes an amplification section for amplifying a musical tone signal input from an electric musical instrument. A speaker is connected to the amplifier. The amplifier includes a storage section storing a characteristic adjustment value which is a value for adjusting an output impedance characteristic or an input impedance characteristic of the amplifier according to a characteristic of the speaker; an inspection signal output section outputting a predetermined inspection signal to the speaker via the amplification section; an observation section observing a resulting inspection signal output to the speaker by the inspection signal output section; an analysis section analyzing the characteristic of the speaker based on the resulting inspection signal observed by the observation section; and an adjustment value storage section storing, in the storage section, the characteristic adjustment value corresponding to the characteristic of the speaker analyzed by the analysis section in association with the speaker.