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公开(公告)号：US20190037327A1
公开(公告)日：2019-01-31
申请号：US16046943
申请日：2018-07-26
Inventor： Anindya Bhattacharya , Bhoodev Kumar , John L. Melanson , Vivek Oppula , Anuradha Parsi , Qi Cai
Abstract: An apparatus for biasing a plurality of microphones includes a sensing circuit that actively senses a local ground reference for each microphone. An intermediate stage receives a constant non-local reference voltage as an input and responsively provides a respective constant local reference signal (e.g., current) with respect to each of the actively sensed local ground references. For each microphone, a respective microphone bias block uses the respective constant local reference signal to generate a respective constant local microphone bias voltage to bias the microphone. For each microphone, a variable RC network uses the respective constant local reference current to generate a constant local reference voltage for the microphone. Each RC network is controllable in response to the respective actively sensed local ground reference to independently set the respective local microphone bias voltage. A sensing circuit may actively sense the local microphone bias voltages to control local microphone bias voltage generation.
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公开(公告)号：US10014879B1
公开(公告)日：2018-07-03
申请号：US15827530
申请日：2017-11-30
Inventor： Ramin Zanbaghi , John L. Melanson
CPC classification number: H03M3/458 , G01R19/25 , G01R27/2605 , H03M1/12 , H03M3/362 , H03M3/384 , H03M3/402 , H03M3/43 , H03M3/438 , H03M3/454
Abstract: A method for measuring capacitance may include integrating charge with a charge integrator having a charge integrator input and output, filtering, with a loop filter having a loop filter input coupled to the charge integrator output and having a loop filter output, a first signal generated at the charge integrator output, quantizing, with quantizer having a quantizer input coupled to the loop filter output and a having quantizer output, a second signal generated at the loop filter output, processing, with a first feedback path having a first feedback path input coupled to the quantizer output and a first feedback path output coupled to the charge integrator input, a low-frequency spectrum of a quantizer output signal, and processing, with a second feedback path having a second feedback path input coupled to the quantizer output and a second feedback path output coupled downstream in a signal path of the apparatus relative to the charge integrator, a high-frequency spectrum of the quantizer output signal.
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公开(公告)号：US10009039B1
公开(公告)日：2018-06-26
申请号：US15681023
申请日：2017-08-18
Inventor： Ramin Zanbaghi , Daniel J. Allen , John L. Melanson , Aniruddha Satoskar
CPC classification number: H03M1/188 , H03H19/004 , H03M1/0626 , H03M1/181 , H04R3/00 , H04R3/04
Abstract: A system may comprise a high-pass filter having an input for receiving an input signal, an output for generating an output signal, a capacitor coupled between the input and the output, a switched-capacitor resistor coupled between the output and a reference voltage, and control circuitry configured to control the reference voltage to cancel current leakage into a circuit coupled to the output. The input, the output, the capacitor, and the switched-capacitor resistor may be arranged to generate the output signal as a high-pass filtered version of the input signal and the high-pass filter may be configured to operate in a plurality of modes comprising at least a high-impedance mode and a low-impedance mode in which the resistance of the switched-capacitor resistor is significantly smaller than the resistance when in the high-impedance mode.A system may include a plurality of processing paths having a first path configured to generate a first digital signal based on an analog input signal and a second path configured to generate a second digital signal based on the analog input signal, the second path having a high-pass filter for filtering the analog input signal prior to the analog input signal being processed by the remainder of the second path, and the high-pass filter having a corner frequency. Control circuitry may be configured to determine frequency-dependent weighted proportions of the first and second digital signals to be combined into an output digital signal based on a characteristic of the analog input signal. Frequency-dependent weighted proportions may be such that the digital output signal includes spectral content of the first digital signal below the corner frequency to account for spectral content of the second digital signal below the corner frequency being filtered.A system may include an input for receiving an input signal, an output for generating an output signal, a capacitor coupled between the input and the output, a variable resistor coupled to the output and having a plurality of modes including a first mode in which the variable resistor has a first resistance and a second mode in which the variable resistor has a second resistance, and control circuitry configured to determine a difference between the input signal and the output signal and switch between modes of the plurality of modes when the difference is less than a predetermined threshold.
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公开(公告)号：US09990173B2
公开(公告)日：2018-06-05
申请号：US15099277
申请日：2016-04-14
Inventor： Dylan Alexander Hester , Bala Vishnu Shankar Rao , Tarun Soni , John L. Melanson
CPC classification number: G06F3/165 , G11B27/038 , H04H60/04
Abstract: An audio processor may process dissimilarly formatted digital audio signals and produce an analog output for reproduction by a transducer, such as a speaker. The audio processor may be, for example, a digital-to-analog converter (DAC) with multiple digital inputs and a single analog output. The audio processor may also include other components, such as processing components, filters, equalizers, amplifiers, and the like. The audio processor may process audio, such as high fidelity DSD audio and lower fidelity PCM audio, and combine the differently formatted data into a single output. During processing, the audio processor may manipulate the different audio signals, such as by ducking a music playback to allow a notification sound to be played.
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公开(公告)号：US09973156B2
公开(公告)日：2018-05-15
申请号：US15285038
申请日：2016-10-04
Inventor： Eric J. King , Zhaohui He , John L. Melanson , Siddharth Maru
CPC classification number: H03F3/2171 , H02M5/293 , H02M2005/2932 , H03F1/0216 , H03F1/0227 , H03F1/32 , H03F3/185 , H03F3/2173 , H03F3/2178 , H03F2200/03 , H03F2200/153 , H03F2200/432 , H04R3/12
Abstract: A method may include processing a first signal derived from an input signal with a first path to generate a first path voltage at a first path output, processing a second signal derived from the input signal with a second path to generate a second path voltage at a second path output, the second path comprising a linear amplifier having at least one transistor for driving the second path voltage, generating the first signal and the second signal with a signal splitter, such that the second signal comprises information of the input signal absent from the first signal, and such that the second path voltage is of a sufficient magnitude such that the at least one transistor operates in a saturation region of the at least one transistor throughout a dynamic range of a load voltage equal to the difference of the first path voltage and the second path voltage.
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Patent Agency Ranking
公开(公告)号：US09955256B2
公开(公告)日：2018-04-24
申请号：US15195674
申请日：2016-06-28
Inventor： Jie Su , John L. Melanson
CPC classification number: H04R3/007 , H04R3/04 , H04R29/001 , H04R2430/01
Abstract: 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.
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公开(公告)号：US09880802B2
公开(公告)日：2018-01-30
申请号：US15003371
申请日：2016-01-21
Inventor： Aniruddha Satoskar , Daniel J. Allen , Edmund Mark Schneider , Tejasvi Das , Ku He , John L. Melanson
CPC classification number: G06F3/165 , G10L25/09 , H03M1/0617 , H03M1/12 , H03M1/188
Abstract: A processing path may include a controller and a plurality of processing paths including a first processing path and a second processing path. The first path may be configured to generate a first digital signal based on an analog input signal and the second path may be configured to generate a second digital signal based on the analog input signal, wherein the first path has a lower gain and a higher noise floor than the second path. The controller may be configured to determine that a transition between the first path and the second path needs to occur based on the analog input signal crossing a threshold or a prediction that the input signal will cross the threshold and in response to determining the transition between the first path and the second path needs to occur, blend the transition during or near zero cross points of the analog input signal.
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98.发明授权公开(公告)号：US09853103B2
公开(公告)日：2017-12-26
申请号：US15093574
申请日：2016-04-07
Inventor： Shanjen Pan , Marc L. Tarabbia , John L. Melanson
IPC: H01L29/84 , H01L29/10 , H01L29/808 , H01L29/66 , B81B3/00
CPC classification number: H01L29/1083 , B81B3/0027 , B81B2201/0257 , B81B2203/0127 , B81B2207/015 , H01L29/0649 , H01L29/0692 , H01L29/66901 , H01L29/808
Abstract: A JFET structure may be formed such that the channel region is isolated from the substrate to reduce parasitic capacitance. For example, instead of using a deep well as part of a gate structure for the JFET, the deep well may be used as an isolation region from the surrounding substrate. As a result, the channel in the JFET may be pinched laterally between doped regions located between the source and the drain of the JFET. In other example embodiments, the channel may be pinched vertically and the isolation between the JFET structure and the substrate is maintained. A JFET structure with improved isolation from the substrate may be employed in some embodiments as a low-noise amplifier. In particular, the low-noise amplifier may be coupled to small signal devices, such as microelectromechanical systems (MEMS)-based microphones.
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公开(公告)号：US09807504B2
公开(公告)日：2017-10-31
申请号：US15370576
申请日：2016-12-06
Inventor： John L. Melanson , Aniruddha Satoskar
CPC classification number: H04R3/04 , H03G3/3005 , H03G3/3089 , H03M1/12 , H03M1/121 , H03M1/188 , H03M3/468 , H03M3/488
Abstract: In accordance with embodiments of the present disclosure, a processing system comprising may include a plurality of processing paths and a filter. The plurality of processing paths may include a first processing path and a second processing path, wherein the first processing path is configured to generate a first digital signal based on an analog input signal and the second processing path is configured to generate a second digital signal based on the analog input signal. The filter may have a corner frequency and may be configured to generate a filtered digital output signal combining spectral components of the first digital signal lower than the corner frequency and spectral components of the second digital signal higher than the corner frequency to generate a filtered digital signal.
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公开(公告)号：US20170256248A1
公开(公告)日：2017-09-07
申请号：US15058866
申请日：2016-03-02
Inventor： Jeffrey D. Alderson , Jon D. Hendrix , Sang-Ik Terry Cho , Chin Huang Yong , John L. Melanson
IPC: G10K11/178
CPC classification number: G10K11/178 , G10K11/17885 , G10K2210/108 , G10K2210/1081 , G10K2210/3014 , G10K2210/3016 , G10K2210/3028 , G10K2210/3056
Abstract: A method may include adaptively generating an anti-noise signal for countering the effects of ambient audio sounds at an acoustic output of the transducer by adapting a response of an adaptive filter that filters a reference microphone signal in conformity with an error microphone signal and the reference microphone signal to minimize the ambient audio sounds in the error microphone, generating a scaled anti-noise signal by applying a scaling factor to the anti-noise signal, further adjusting the response of the adaptive filter independent of a source audio signal by altering an input to the coefficient control block of the adaptive filter to compensate for the scaling factor, and combining the scaled anti-noise signal with the source audio signal to generate an audio signal provided to the transducer.
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