Certain aspects of the present disclosure are generally directed to circuitry and techniques for voltage-to-current conversion. For example, certain aspects provide a circuit for signal amplification including a first amplifier; a first transistor, a gate of the first transistor being coupled to an output of the first amplifier and a drain of the first transistor being coupled to an output node of circuit; a first resistive element coupled between a first input node of the circuit and an input of the first amplifier; a second amplifier; a second transistor, a gate of the second transistor being coupled to an output of the second amplifier and a drain of the second transistor being coupled to the output node of circuit; and a second resistive element coupled between a second input node of the circuit and an input of the second amplifier.

The invention relates to a method for adapting the applied volume gain in an amplifier controlling at least one loudspeaker of an enclosure according to the desired volume gain selected by a user on a scale increased by a maximum desired volume gain, including the following steps: determining (204) the effective intensity applied to at least one loudspeaker, calculating (206, 208) a maximum volume gain from: the desired volume gain, the effective intensity applied to the loudspeaker, thermal characteristics of the loudspeaker, the maximum desired volume gain, calculating (210) an increasing monotonic function providing an variable applied volume gain according to the desired volume gain such that the image of the maximum desired volume gain by the monotonic function is equal to the maximum volume gain, applying (212), to the amplifier, as applied volume gain, the minimum of the maximum volume gain and the variable applied volume gain for the desired volume gain.

In accordance with embodiments of the present disclosure, a system may include a controller configured to be coupled to an audio speaker, wherein the controller receives an output signal indicative of a physical quantity associated with the audio speaker, compares the output signal to an audio input signal to determine if differences between the output signal and the audio input signal are present indicating at least one of distortion of the output signal, non-linearities of the audio speaker, and overexcursion of the audio speaker, and controls an audio signal communicated from the controller to the audio speaker and based on the audio input signal responsive to determining that differences between the output signal and the audio input signal are present indicating at least one of distortion of the output signal, non-linearities of the audio speaker, and overexcursion of the audio speaker.

A sound control device mounted in a vehicle and control method include measuring a drive signal input to a speaker, wherein the drive signal is generated in response to an input signal including at least one of a noise control signal and an audio signal, estimating a state of a voice coil of the speaker including at least one of displacement and temperature of the voice coil, based on the drive signal and a model of the speaker, and adjusting the input signal based on the state of the voice coil.

A method may be provided for powering up or down a playback path comprising a digital-to-analog converter (DAC) for generating a non-ground-centered analog intermediate voltage centered at a common-mode voltage and coupled to a driver for generating a ground-centered playback path output voltage at an output of the driver wherein the output of the driver is clamped via a finite impedance to a ground voltage. The method may include transitioning continuously or in a plurality of discrete steps the analog intermediate voltage from an initial voltage to the common-mode voltage such that the transitioning is substantially inaudible at the output of the driver. A method for operating an output clamp of an output driver stage of a playback path may include transitioning continuously or in a plurality of discrete steps an impedance of the output clamp in order to match an output offset of the output driver stage in order to minimize audio artifacts appearing at an output of the output driver stage.

This control device for controlling a loudspeaker (14) in a loudspeaker enclosure, comprises: an input for an audio signal to be reproduced; a supply output for supplying an excitation signal for the loudspeaker; the calculation means (26, 36, 38, 70, 71, 80, 90) for calculating, at each time instant (t), at least one predicted current (i.sub.ref(t)) for the excitation signal for the loudspeaker (14) as a function of the audio signal.

It comprises an attenuator (71) that is capable of limiting the predicted current to a limited current value that is lower than a ceiling value by application, to the predicted current, of an attenuation gain which is a function of the predicted current.

An arcing detection system detects arcing within a semiconductor processing cleanroom environment. The arcing detection system includes an array of microphones positioned within the cleanroom environment. The microphones receive soundwaves within the cleanroom environment and generate audio signals based on the sound waves. The arcing system includes a control system that receives the audio signals from the microphones. The control system analyzes the audio signals and detects arcing within the cleanroom environment based on the audio signals. The control system can adjust a semiconductor process in real time responsive to detecting arcing.

A circuit and method is disclosed for filtering an audio signal. The circuit has a first quadrature source and multipliers for multiplying the input signal by the I and Q outputs of the quadrature source. The multiplied inputs are then passed through a pair of low pass filters, which may have an adjustable Q factor. The outputs of the low pass filters are then multiplied in a second pair of multipliers by the I and Q outputs, respectively, of a second quadrature source, which will typically be of the same frequency, but different amplitude and phase, of the first quadrature source. The twice-multiplied signals are then summed by an adder to provide an output signal. The circuit may be modified to include a companding circuit between the low pass filters and the second pair of multipliers that determines the amplitude of the input signal, filters it, and compands the signal in a compandor. The compandor may have adjustable parameters. The circuit thus allows for far greater flexibility and control of the processing of the input signal than prior art circuits.

An electronic apparatus that includes a first port configured to receive an incoming audio signal, a second port, and a controller configured to be coupled to the first port and the second port. The electronic apparatus further includes a switch configured to selectively decouple the controller from the second port when the first port receives the incoming audio signal. Decoupling the controller prevents an electrostatic discharge occurring on the second port from reaching the controller when the controller is receiving the incoming audio signal from the first port.

A predictive brownout prevention system may be configured to prevent brownout of an audio output signal. Particularly, the brownout prevention system may be configured to receive information indicative of an amplitude of the audio input signal, receive information indicative of a condition of the power supply, receive information indicative of one or more of the following: 1) adaptive estimates of power supply conditions; 2) anticipated effects of power supply capacitance; and 3) condition of a load impedance, determine from the received information whether a brownout condition exists, and responsive to determining the brownout condition exists, generate the selectable attenuation signal to reduce an amplitude of the audio output signal such that the signal path attenuates the audio input signal or a derivative thereof in order to prevent brownout prior to propagation to the audio output of a portion of the audio input signal having the brownout condition.