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公开(公告)号：US11438697B2
公开(公告)日：2022-09-06
申请号：US16706287
申请日：2019-12-06
Inventor： John L. Melanson , Wai-Shun Shum , Leyi Yin
IPC: H04R3/04 , H03M3/00 , G10L21/0232
Abstract: A system may include a digital delta-sigma modulator configured to receive a digital audio input signal and quantize the digital audio input signal into a quantized signal, a filter configured to receive the quantized signal and perform filtering on the quantized signal to generate a filtered quantized signal, the filter having a variable group delay, and a current-mode digital-to-analog converter configured to receive the filtered quantized signal and convert the filtered quantized signal into an equivalent current-mode analog audio signal.
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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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公开(公告)号：US20220329216A1
公开(公告)日：2022-10-13
申请号：US17521268
申请日：2021-11-08
Inventor： Leyi Yin , John L. Melanson , Eric Lindemann , Amar Vellanki , Jianhao Chen , Venugopal Choukinishi , Wai-Shun Shum , Xiaofan Fei
Abstract: A multi-path audio amplification system that provides an output drive signal to electromechanical output transducers provides improved undistorted headroom, reduced path switching noise, and/or improved frequency response performance. Multiple signal amplification paths receive an audio input signal and have corresponding multiple output stages that have differing output impedances. A mode selector selects an active one of the multiple signal amplification paths is selected to supply the output drive signal. Outputs of the multiple output stages are coupled to the electromechanical transducer to provide the output drive signal and at least one of the multiple signal amplification paths includes an equalization filter for filtering the audio input signal to compensate for phase or gain differences referenced from the input to the outputs of the multiple output stages due to interaction between the differing output impedances and an impedance of the electromechanical transducer.
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公开(公告)号：US11047890B2
公开(公告)日：2021-06-29
申请号：US16121259
申请日：2018-09-04
Inventor： Gautham S. Sivasankar , Tejasvi Das , Emmanuel Marchais , Amar Vellanki , Leyi Yin , John L. Melanson , Venugopal Choukinishi
IPC: G01R25/00 , H03D13/00 , H03F3/183 , H03G3/30 , H04R3/00 , H03G3/00 , G01R19/25 , G01R21/133 , G01R29/18 , G01R31/317 , G01R31/30 , G01R19/04
Abstract: A method of determining a phase misalignment between a first signal generated from a first signal path and a second signal generated from a second signal path may include obtaining multiple samples of the first signal proximate to when the first signal crosses zero wherein the first signal can be approximated as linear; obtaining multiple samples of the second signal proximate to when the second signal crosses zero wherein the first signal can be approximated as linear; based on the multiple samples of the first signal, approximating a first time at which the first signal crosses zero; based on the multiple samples of the second signal, approximating a second time at which the second signal crosses zero; and determining the phase misalignment between the first signal and the second signal based on a difference between the first time and the second time.
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公开(公告)号：US11677360B2
公开(公告)日：2023-06-13
申请号：US17521268
申请日：2021-11-08
Inventor： Leyi Yin , John L. Melanson , Eric Lindemann , Amar Vellanki , Jianhao Chen , Venugopal Choukinishi , Wai-Shun Shum , Xiaofan Fei
CPC classification number: H03F3/183 , H04R3/04 , H04R29/001 , H03F2200/03 , H04R2430/01
Abstract: A multi-path audio amplification system that provides an output drive signal to electromechanical output transducers provides improved undistorted headroom, reduced path switching noise, and/or improved frequency response performance. Multiple signal amplification paths receive an audio input signal and have corresponding multiple output stages that have differing output impedances. A mode selector selects an active one of the multiple signal amplification paths is selected to supply the output drive signal. Outputs of the multiple output stages are coupled to the electromechanical transducer to provide the output drive signal and at least one of the multiple signal amplification paths includes an equalization filter for filtering the audio input signal to compensate for phase or gain differences referenced from the input to the outputs of the multiple output stages due to interaction between the differing output impedances and an impedance of the electromechanical transducer.
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公开(公告)号：US20210175894A1
公开(公告)日：2021-06-10
申请号：US16942062
申请日：2020-07-29
Inventor： John L. MELANSON , Johann G. GABORIAU , Lei Zhu , Wai-Shun Shum , Xiaofan Fei , Leyi Yin
Abstract: A differential output current digital-to-analog (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 a plurality of warming switches, each warming switch coupled to a respective bias transistor of a respective DAC element of the plurality of DAC elements, wherein the control circuit may further be configured to selectively control each such warming switch in order to selectively de-bias and bias a respective bias transistor of such warming switch when a respective DAC element of the respective bias transistor is output-disabled from generating the differential output current signal.
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公开(公告)号：US11050433B1
公开(公告)日：2021-06-29
申请号：US16945520
申请日：2020-07-31
Inventor： John L. Melanson , Johann G. Gaboriau , Lei Zhu , Wai-Shun Shum , Xiaofan Fei , Leyi Yin
Abstract: A system may include a current digital-to-analog converter (IDAC) configured to convert a digital input signal into an output current signal and a switched-mode power supply configured to provide electrical energy in the form of a supply voltage to the IDAC for operation of the IDAC, the switched-mode power supply configured to track a voltage signal derived from the digital input current signal and generate the supply voltage based on the voltage signal and a voltage headroom above the voltage signal.
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公开(公告)号：US11043959B1
公开(公告)日：2021-06-22
申请号：US16942062
申请日：2020-07-29
Inventor： John L. Melanson , Johann G. Gaboriau , Lei Zhu , Wai-Shun Shum , Xiaofan Fei , Leyi Yin
Abstract: A differential output current digital-to-analog (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 a plurality of warming switches, each warming switch coupled to a respective bias transistor of a respective DAC element of the plurality of DAC elements, wherein the control circuit may further be configured to selectively control each such warming switch in order to selectively de-bias and bias a respective bias transistor of such warming switch when a respective DAC element of the respective bias transistor is output-disabled from generating the differential output current signal.
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公开(公告)号：US10701486B1
公开(公告)日：2020-06-30
申请号：US16522439
申请日：2019-07-25
Inventor： John L. Melanson , Xiaofan Fei , Lei Zhu , Xin Zhao , Wei-Shun Shum , Leyi Yin , Ku He , Johann G. Gaboriau
IPC: H04R3/04
Abstract: A system may include a filter configured to receive a digital audio input signal quantized at between two and 257 quantization levels and sampled at at least 500 kilohertz, the filter further configured to perform filtering on the digital audio input signal to generate a filtered digital audio input signal, the filter having a selectable variable group delay, a digital-to-analog converter configured to receive the filtered digital audio input signal and convert the filtered digital audio input signal into an equivalent analog audio input signal, and a driver configured to receive the equivalent analog audio input signal and drive an analog audio output signal to a transducer.
