Texas Instruments Corporation

Infineon Technologies Austria Ag

Other

Thomas Holm Hansen

Lars Risbo

Mikkel Hoyerby

Venkateswar Reddy Kowkutla

Jun Honda

Kim Nordtorp Madsen

Claus Niels Neesgaard

Anker Bjørn-Josefsen

Douglas Allen Roberson

Niels Petersen

Pawan Garg

A method for designing a loudspeaker excursion estimator comprises measuring an excursion-related parameter for a loudspeaker, for each of a plurality of loudspeaker input signal levels and each of a plurality of loudspeaker input signal frequencies. The method further comprises, for each of the loudspeaker input signal frequencies and based on the measured excursion-related parameters, identifying a respective loudspeaker input signal level corresponding to a target maximum excursion-related parameter value. The method further comprises determining a filter response, based on the identified loudspeaker input signal levels and their respective loudspeaker input signal frequencies, and implementing a filter, based on the calculated filter response, for generating an excursion estimation based on loudspeaker input signal levels.

Measurement-based loudspeaker excursion limiting

An apparatus such as an electronic circuit includes an input operable to receive an input signal; a dynamic common mode adjustor operable to: i) derive a differential signal from the received input signal, and ii) control an offset of the differential signal as a function of the received input signal to produce an offset differential signal; and an output operable to output the offset differential signal. In one arrangement, the offset differential signal outputted from the output includes a first signal and a second signal; a difference between the second signal and the first signal proportionally varies with respect to the received input signal.

Dynamic common mode control

An error model can be utilized to mitigate errors associated with a conversion system, such as an analog-to-digital or digital-to analog converter. The error model is adaptively calibrated to approximate error characteristics associated with at least a portion of the conversion system, such as a digital-to analog converter. The error model can be generated on-line during system operation or off-line to improve performance of various types of signal converters and systems using such signal converters.

Calibration model to mitigate data conversion errors

A multiple-channel audio processor () and an associated plurality of power stages () in an audio system are disclosed. The audio processor () includes a plurality of audio amplifier channels (), each of which includes a pulse-code-modulation (PCM) to pulse-width-modulation (PWM) conversion function (), which generates PWM signals for application to the plurality of power stages (). The audio amplifier channels () each also include an interchannel delay function () for delaying the PWM edges relative to other channels (), for reducing noise. The audio amplifier channels () each also include delay adjust circuitry () for gradually increasing and decreasing the interchannel delay of the channel () on startup and shutdown. This permits a single control terminal (VALID) at the processor to globally enable and disable all of the power stages ().

On-the-fly introduction of inter-channel delay in a pulse-width-modulation amplifier

A system and method are provided for stopping a quantized signal from a noise-shaper with a significantly reduced inband transient, compared to a traditional random stop of a noise-shaped signal. The noise-shaped signal is stopped at a favorable time controlled by a detector that monitors the noise-shaped signal. The detector indicates the occurrence of a good time to stop the noise-shaper such that the transient due to the stop is minimized in a fashion that substantially reduces the inband disturbance.

Method and circuit for stop of signals quantized using noise-shaping

An audio system includes a switch mode amplifier that provides an output signal at an output for driving a load based on at least one control signal. A control system provides the at least one control signal to control the amplifier according to an operating mode of the audio system. In a first mode, the control system providing the at least one control signal to actively control an equivalent output impedance at the output of the amplifier, gradually adjusting the equivalent output impedance from a high-impedance state to a low impedance state, so as to mitigate a voltage drop across the load (e.g., including one or more speakers) when the amplifier is activated to a second mode corresponding to the low impedance state.

Reduction of audible artifacts in an audio system

An amplifier system can include a biasing amplifier that provides a first amplified signal to a DC blocking element that is connected with a load based on a first control signal. A power amplifier provides a second amplified signal for driving the load based on a second control signal. A control system controls the biasing amplifier to charge the DC blocking element so as to mitigate a voltage drop across the load (e.g., to substantially eliminate audible artifacts) when the power amplifier is activated to provide the second amplified signal.

System and method for reducing audible artifacts in an audio system

A system and method for reducing audible turn-on and turn-off transients in switching amplifiers employs a frequency shaped start sequence in front of a modulated zero-signal or a frequency shaped stop sequence following a modulated zero-signal.

Growing community of inventors

Værløse, Denmark

Thomas Holm Hansen