Cirrus Logic Inc.

Crystal Semiconductor Corporation

Other

Silicon Laboratories Inc.

Eric J Swanson

John L Melanson

Eric Jerome King

Douglas S Piasecki

Wai Laing Lee

Karl Ernesto Thompson

Ka Yin Leung

Donald A Kerth

Carlos Esteban Mu&ntilde;oz

Bruce Philip Del Signore

Navdeep S Sooch

Edwin De Angel

Kafai Leung

Charles D Thompson

Daniel John Allen

Scott Allan Woodford

David L Medlock

Bruce D Signore

Ed Schneider

Axel Thomsen

David J Knapp

Dan Bernard Kasha

Xiaofan Fei

Johann Guy Gaboriau

Xin Zhao

John Christopher Tucker

Lingli Zhang

Edmund Mark Schneider

Prashanth Drakshapalli

Robert Thomas Grisamore

Xue-Mei Gong

Russell A Hershbarger

Nicholas R Van Bavel

Aryesh Amar

Ruoxin Jiang

Karl I Nordling

Baker P Scott, Iii

Dan Shen

Bradley Allan Lambert

Robin Matthew Tsang

Kartika Prihadi

Thirumalai Rengachari

Salvador R Bernadas

Diwakar Vishakhadatta

Douglas R Holberg

Rod Holley

Carlos Estaban Mu&ntilde;oz

Tetsurou Sugimoto

David R Wellard

Jeffrey M Klaas

Anthony G Mellissinos

A headset power management system provides robust and low-power operation by detecting various connection conditions by measuring a voltage at the microphone terminal with and without injection of current from the headset. A power management circuit controls an operating state of the headset using a microphone terminal voltage detector and can determine whether a short circuit is present indicating a connection to a device that does not have a microphone input, a negative polarity voltage is present indicating that the device may be determining a connection and type of the headset using the microphone terminal, a normal connection, or whether the headset is not connected to a device at all. Depending on the connection state, some or all of the headset electronics may be disabled until a normal connection is detected. For example the microphone processing circuits may be disabled if the connection does not support a microphone input.

Headset management by microphone terminal characteristic detection

In accordance with embodiments of the present disclosure, a device may include a piezoelectric speaker for generating sound, a microphone, and a controller communicatively coupled to the speaker and the microphone. The controller may be configured to receive a first signal from the piezoelectric speaker, the first signal induced at least in part by sound incident on the speaker other than sound generated by the piezoelectric speaker, receive a second signal from the microphone, the second signal induced by sound incident on the microphone, process at least one of the first signal and the second signal to determine at least one characteristic of sound incident upon at least one of the piezoelectric speaker and the microphone, and select at least one of the microphone and the piezoelectric speaker as a signal source for incident sound based on the at least one characteristic.

Systems and methods for using a piezoelectric speaker as a microphone in a mobile device

In accordance with methods and systems of the present disclosure, a mobile device may include an enclosure adapted such that the enclosure is readily transported by a user of the mobile device, a speaker associated with the enclosure for generating sound, and a controller within the enclosure, communicatively coupled to the speaker. The controller may be configured to receive a signal from the speaker, the signal induced at least in part by sound incident on the speaker other than sound generated by the speaker and process the signal.

Systems and methods for using a speaker as a microphone

A wireless earpiece may include a local memory for storing audio files that can be played back by the user. The wireless earpiece may fit entirely within the user's ear canal. Audio files, for example music files, may be loaded on the wireless earpiece by docking the wireless earpiece with a mobile device, which includes a larger memory storing the user's library of music files. The stored audio files may be received from a mobile device that were automatically selected from a library of music files by the mobile device without intervention from the user. To provide stereo sound, two wireless earpieces may be worn by the user and docked separately with the mobile device. Each of the two wireless earpieces may store a single channel of an audio file, which is separated by the mobile device during synchronization.

Wireless earpiece with local audio cache

An interface for an array of digital microphones in an electronic device may include a head-end chip coupled to the digital microphones through a bus. The bus may be shared by each microphone of the array of microphones and be multiplexed to allow transmission of data from the microphones to the head-end chip and transmission of power from the head-end chip to the array of digital microphones. The head-end chip may perform signal processing on receive data from the array of digital microphones to create beamforming arrays. The array of microphones may include microphones with different characteristics to improve performance of the array of microphones.

Beamforming a digital microphone array on a common platform

Interface for a digital microphone array

Systems and methods for using a speaker as a microphone in a mobile device

In one embodiment a heating mechanism is provided with an integrated circuit for testing and calibration purposes. During production testing, heating elements may be activated in order to quickly bring an integrated circuit up to operating temperature for temperature testing or calibration. Once the operating test temperature has been reached, the circuit can be quickly and easily tested to show it is operable within the design temperature range and/or to obtain calibration data to correct for temperature drift. Calibration data may be used to create correction data, which may be stored within the integrated circuit. During normal operation, the correction data may be used to compensate for variations in operation due to temperature.

Bandgap with thermal drift correction

A wireless earpiece may include a local memory for storing audio files that can be played back by the user. The wireless earpiece may fit entirely within the user's ear canal. Audio files, for example music files, may be loaded on the wireless earpiece by docking the wireless earpiece with a mobile device, which includes a larger memory storing the user's library of music files. The wireless earpiece may also be charged while docked with the mobile device by receiving power from the mobile device's larger battery. To provide stereo sound, two wireless earpieces may be worn by the user and docked separately with the mobile device. Each of the two wireless earpieces may store a single channel of an audio file, which is separated by the mobile device during synchronization.

An offset correction circuit removes DC offset from an analog audio output signal by comparing transitions of digital audio values to which the analog output signal is related to the output of a monitor that monitors the analog output signal. The monitor may be a zero-crossing detector and the transitions of the digital signal that are compared may be transitions of the most-significant bit (MSB) of the digital audio values. A filtering algorithm or filter circuit may be used to average a result of the comparison of the transitions, so that the offset is slowly and accurately removed. A chopped or autozero comparator may be used to further reduce error in the offset determination.

Audio amplifier offset reduction using digital input/output comparisons

An audio switching power amplifier having an output pulse voltage selected in conformity with an indication of the output signal amplitude provides lower electromagnetic interference (EMI) in class-D amplifier implementations, in particular, in inductor-less designs. The output pulse voltage may be selected by providing multiple switching circuits, such as half or fully bridge switches, with each switching circuit connected to a different power supply. One of the switching circuits is activated by the switching controller, while the others are disabled, providing selection of the output pulse voltage. Selection of a lower pulse voltage, when the maximum voltage is not required, reduces the generated EMI. The switching frequency of the class-D amplifier may also be controlled in conformity with the output signal amplitude, so that at higher output levels a lower switching rate is selected, reducing the generated EMI.

Pulse-width modulated (PWM) audio power amplifier having output signal magnitude controlled pulse voltage and switching frequency

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Buda, TX, United States of America

Eric J Swanson