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公开(公告)号：US20220190789A1
公开(公告)日：2022-06-16
申请号：US17119228
申请日：2020-12-11
Inventor： Ramin Zanbaghi , John L. Melanson , Edmund M. Schneider
Abstract: A method for use in an analog circuit having a plurality of differential pairs of elements, wherein for each pair of the plurality of differential pairs of elements, the elements of the pair are designed to match but may have mismatch that induces error. The method includes, for each pair of at least two pairs of the plurality of differential pairs of elements: spectrally separating the mismatch-induced error of the pair from mismatch-induced error of a remainder of the plurality of differential pairs of elements, monitoring, by an analog-to-digital converter (ADC), an output of the analog circuit, and analyzing the monitored output to measure the mismatch-induced error of the pair.
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42.发明授权公开(公告)号：US11296666B1
公开(公告)日：2022-04-05
申请号：US16796475
申请日：2020-02-20
Inventor： Christian Larsen , John L. Melanson
Abstract: A high CMRR current monitoring circuit includes a first stage that receives a current sense signal, a voltage across a current sense resistor in series with an output of a class-D amplifier. First stage is powered by at least one floating supply and/or reference that tracks the amplifier output. First stage applies gain to the current sense signal to generate an intermediate signal. A second stage receives the intermediate signal and is powered by a ground-referenced supply and provides an amplified representation of the current sense signal. The floating supply is supplied by a capacitive-coupled power source driven by the ground-referenced supply. The second stage output may be a voltage relative to ground or a digital signal. The intermediate signal may be a current, digital signal, or amplified version of the current sense signal voltage. The first stage may be a transconductance amplifier and the second stage a transimpedance amplifier.
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公开(公告)号：US11290120B2
公开(公告)日：2022-03-29
申请号：US16987254
申请日：2020-08-06
Inventor： Seung Bae Lee , John L. Melanson , Anindya Bhattacharya , Prashanth Drakshapalli
Abstract: A data acquisition system (DAS) for processing an input signal from a resistive sensor (e.g., Hall effect sensor) includes a sensor signal path that digitizes the input signal. An input impedance of the sensor signal path attenuates the input signal. A gain error corrector applies a gain error correction factor in a digital domain of the DAS to the digitized input signal to compensate for a loading effect to the resistive sensor. The sensor signal path includes an inverting amplifier that provides low distortion for the input signal and an ADC (e.g., delta-sigma, SAR, pipelined, auxiliary) that digitizes the input signal. A sensor characterization path digitizes the sensor resistance which the gain error corrector uses, along with the inverting amplifier input impedance, to calculate the gain error correction factor.
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公开(公告)号：US11283337B2
公开(公告)日：2022-03-22
申请号：US16816790
申请日：2020-03-12
Inventor： Eric Lindemann , Carl Lennart Ståhl , Emmanuel Marchais , John L. Melanson
Abstract: A system may include a signal generator configured to generate a raw waveform signal and a modeling subsystem configured to implement a discrete time model of an electromagnetic load that emulates a virtual electromagnetic load and further configured to modify the raw waveform signal to generate a waveform signal for driving the electromagnetic load by modifying the virtual electromagnetic load to have a desired characteristic, applying the discrete time model to the raw waveform signal to generate the waveform signal for driving the electromagnetic load, and applying the waveform signal to the electromagnetic load.
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公开(公告)号：US11271583B2
公开(公告)日：2022-03-08
申请号：US16945288
申请日：2020-07-31
Inventor： John L. Melanson , Johann G. Gaboriau , Lei Zhu , Wai-Shun Shum , Xiaofan Fei , Leyi Yin
Abstract: A differential output current digital-to-analog converter (IDAC) circuit may include a delta-sigma modulator configured to receive a digital input signal, a control circuit responsive to the delta-sigma modulator configured to perform a DAC decode operation, a plurality of DAC elements responsive to the DAC decode operation, the plurality of DAC elements configured to, in concert, generate a differential output current signal based on the digital input signal to a load coupled to a pair of output terminals of the IDAC, and an output impedance coupled between the pair of output terminals such that the output impedance is in parallel with the load.
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Patent Agency Ranking
公开(公告)号：US11255892B2
公开(公告)日：2022-02-22
申请号：US16658755
申请日：2019-10-21
Inventor： Tejasvi Das , Siddharth Maru , Xin Zhao , Matthew Beardsworth , Michael A. Kost , John L. Melanson
IPC: G01R29/18
Abstract: A system may include a sensor having a variable phase response, a dummy impedance having a known phase response, and a measurement circuit communicatively coupled to the sensor and configured to measure first phase information associated with the sensor, measure second phase information associated with the dummy impedance, and determine a phase response of the measurement circuit based on a comparison of the first phase information to the second phase information.
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公开(公告)号：US11239857B2
公开(公告)日：2022-02-01
申请号：US16943156
申请日：2020-07-30
Inventor： John L. Melanson
Abstract: An open-loop digital-to-analog converter (DAC) circuit may include a delta-sigma modulator, a decode block responsive to the delta-sigma modulator configured to perform a DAC decode operation, a plurality of DAC elements responsive to the DAC decode operation, an analog output driver responsive to the plurality of DAC elements, a test signal generator configured to generate a test signal that is responsive to inputs of the plurality of DAC elements, and a synchronizer configured to enable replication of the test signal at an external test system coupled to the open-loop DAC circuit in order to generate a matching test signal at the external test system that matches the test signal generated by the test signal generator.
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48.发明授权公开(公告)号：US11159888B1
公开(公告)日：2021-10-26
申请号：US17025971
申请日：2020-09-18
Inventor： Ziyan Zou , Anthony S. Doy , Ning Li , Kaichow Lau , George E. Hardy , John L. Melanson
Abstract: Methods, systems, circuits and computer program products provide an output signal to drive an electromechanical transducer that selectively contains a cooling component when a thermal limit of a voice coil of the electromechanical transducer is exceeded and which air-cools the transducer by convection. An indication of a temperature of a voice coil of the electromechanical transducer is determined and compared with a thermal limit of the transducer. If the thermal limit of the transducer is exceeded by the indication of the temperature of the voice coil, the cooling component is introduced to the output signal that drives the transducer. The cooling component is a signal having a frequency within a low-frequency resonance portion of the response of the electromechanical transducer, so that additional air convection is caused at the transducer to remove heat from the voice coil due to the cooling component of the output signal.
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公开(公告)号：US11153682B1
公开(公告)日：2021-10-19
申请号：US17025960
申请日：2020-09-18
Inventor： Ning Li , George E. Hardy , Kaichow Lau , Anthony S. Doy , Ziyan Zou , John L. Melanson
Abstract: An audio output system for providing an output signal to a micro-speaker provides energy reduction and thermal protection by removing components of an input signal from which the output signal is generated, so that the audio power output system does not expend power reproducing portions of the audio information that would not be perceived by a listener. The micro-speaker has a resonant frequency such that substantial content of the audio information lies below the resonant frequency. A processing subsystem receives the audio information and generates the output signal by filtering the audio information with a response simulating the micro-speaker and an acoustic path to the listener, and comparing the filtered audio information with a frequency-dependent threshold of hearing. The processing subsystem then removes portions of the audio information that have an amplitude below the frequency-dependent threshold of hearing.
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公开(公告)号：US10720138B2
公开(公告)日：2020-07-21
申请号：US15495746
申请日：2017-04-24
Inventor： Dayong Zhou , John L. Melanson
IPC: G10K11/178 , H04M1/60 , H04M1/03
Abstract: The overall performance of an ANC system may be improved by configuring the ANC system to perform adaption in the frequency domain. The ANC systems may be configured to update an algorithm of an adaptive filter based, at least in part, on the first input signal, the second input signal, and a feedback signal that is based on an output of the adaptive filter. Updating may include changing parameters of the algorithm based on a SDR based, at least in part, on the first input signal. Updating may also include normalizing a step size and processing at least full band information for the input signal in a frequency domain to generate coefficient values for the algorithm. Updating may also include applying a frequency domain magnitude constraint on adaptive filter coefficients.
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