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公开(公告)号：US10158942B2
公开(公告)日：2018-12-18
申请号：US15897177
申请日：2018-02-15
发明人： Lars Risbo , Ryan Erik Lind , Jasjot Singh Chadha
摘要： A system includes a class D amplifier and a current steering digital-to-analog converter (DAC) directly connected to the class D amplifier. The system also includes a common mode servo circuit coupled to a node interconnecting the current steering DAC to the class D amplifier. The common servo circuit amplifies a difference between a common mode signal determined from the node and a reference voltage and generates a feedback current to the node based on the amplified difference. A feed-forward common-mode compensation circuit is included to reduce an alternating current (AC) ripple from the class D amplifier. The feed-forward common-mode compensation circuit includes first and second resistors coupled to respective outputs of the class D amplifier. A current mirror is coupled to the first and second resistors and is configured to sink a current from the node to ground that approximates a common mode feedback current of the class D amplifier.
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公开(公告)号：US10148232B2
公开(公告)日：2018-12-04
申请号：US15606128
申请日：2017-05-26
申请人： Tymphany HK Limited
发明人： Sebastiaan de Vries
IPC分类号： H03F1/32 , H03F1/56 , H03F3/183 , H03F3/45 , H04R3/00 , H03F3/185 , H03F1/02 , H03F1/08 , H03F3/08 , H03F3/60 , H04R5/033 , H04R5/04 , H03F3/187 , H03F3/68
摘要： A pre-amplifier circuit including a microphone pre-amplifier stage with a direct injection (DI) unit that provides a high impedance source signal and a low impedance XLR connection operable without a line or mic switch.
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公开(公告)号：US10141898B2
公开(公告)日：2018-11-27
申请号：US15606211
申请日：2017-05-26
申请人： Tymphany HK Limited
发明人： Sebastiaan de Vries
IPC分类号： H03F1/56 , H03F3/183 , H03F3/45 , H04R3/00 , H03F1/32 , H03F3/185 , H03F1/02 , H03F1/08 , H03F3/08 , H03F3/60 , H04R5/033 , H04R5/04 , H03F3/187 , H03F3/68
摘要： A digital-to-analog converter (DAC) circuit includes a pair of output stages, each including a DAC configured to convert a digital audio signal into an analog audio signal. A low-pass filter circuit includes an operational amplifier in signal communication with the DAC. The operation amplifier generates a filtered analog signal based on the analog audio signal. An amplifier network generates an amplified audio signal based on the filtered analog signal. The operational amplifier includes a feedback circuit path including a first node connected to the output of the amplifier network and a second node connected to the input of the operational amplifier. The amplifier network is electrically nested in the feedback circuit path.
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公开(公告)号：US10135339B1
公开(公告)日：2018-11-20
申请号：US15879284
申请日：2018-01-24
申请人： Silanna Asia Pte Ltd
摘要： An open-loop switch-mode boost converter includes a switching signal generator circuit that receives a time-varying input signal and outputs a switching signal. A duty-cycle of the switching signal has a first non-linear relationship to an amplitude of the time-varying input signal. An amplifier receives the switching signal and outputs a time-varying output signal, an amplitude of which has a second non-linear relationship to the duty-cycle of the switching signal. The time-varying output signal has a linear relationship to the time-varying input signal based on the first non-linear relationship and the second non-linear relationship. A filter circuit receives the time-varying output signal and outputs a filtered time-varying output signal which has a maximum frequency component that is substantially the same as a maximum frequency component of the time-varying input signal. The switching signal generator circuit is communicatively isolated from the voltage output node and the filter output node.
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公开(公告)号：US20180331660A1
公开(公告)日：2018-11-15
申请号：US15976561
申请日：2018-05-10
申请人： Merus Audio ApS
发明人： Mikkel Høyerby
CPC分类号： H03F1/0255 , H03F3/185 , H03F3/2171 , H03F3/2173 , H03F2200/03 , H03F2200/171 , H03F2200/18 , H03F2200/267 , H03F2200/333 , H03F2200/351
摘要： A class D audio amplifier includes a modulator for receipt of an audio signal and converting the audio signal into a modulated audio signal having a predetermined carrier frequency. The class D audio amplifier additionally includes an output stage having a plurality of power transistors coupled in cascade between a first DC supply voltage and a second DC supply voltage, and a plurality of gate drivers configured to generate respective modulated gate drive signals to the plurality of power transistors. A controller is configured to adjust a level of a first modulated gate drive signal applied to a first power transistor of the output stage based on a level of the audio signal.
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公开(公告)号：US20180316315A1
公开(公告)日：2018-11-01
申请号：US15772115
申请日：2015-12-08
发明人： Takuma TORII , Koji YAMANAKA , Masaki KONO , Junichi UDOMOTO
摘要： A multifinger transistor in which source fingers (201 to 206) and drain fingers (301 to 305) are arranged alternately with each of gate fingers (101 to 110) being sandwiched between one of the source fingers and one of the drain fingers is used. Line (10) and line (20) are attached to the source fingers (201 to 206) in an area on a gate side and causing a phase rotation such that the nearer to a central part a gate finger is, the more inductive the gate finger is.
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公开(公告)号：US10110181B2
公开(公告)日：2018-10-23
申请号：US15423093
申请日：2017-02-02
摘要： A fixed frequency class-D audio amplifier includes the L-C output filter in a high order feedback loop. An audio amplifier integrated circuit includes an output driver, an output terminal, a first input terminal, a second order filter, and a summing amplifier. The output driver is configured to drive a speaker coil through an L-C filter. The output terminal is to couple the output driver to an input side of the L-C filter. The first input terminal is to couple an output side of the L-C filter to the integrated circuit. The second order filter includes a first filter stage, and a second filter stage coupled to an output of the first filter stage. The summing amplifier includes a first input coupled to the first input terminal, and a second input coupled to an output of the second filter stage.
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公开(公告)号：US10027294B2
公开(公告)日：2018-07-17
申请号：US15257939
申请日：2016-09-07
申请人： MEDIATEK INC.
发明人： Wen-Chieh Wang , Yu-Hsin Lin
摘要： A class-D amplifier includes a loop filter, a pulse-width modulation (PWM) circuit, an output circuit, and a common-mode control circuit. The loop filter receives an input signal of the class-D amplifier to generate a filtered signal. The PWM circuit converts a non-PWM signal into a PWM signal, wherein the non-PWM signal is derived from at least the filtered signal. The output circuit generates an output signal of the class-D amplifier according to the PWM signal. The common-mode control circuit monitors a common-mode level of the output signal to generate a common-mode control signal for PWM common-mode control.
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公开(公告)号：US10020778B1
公开(公告)日：2018-07-10
申请号：US15651314
申请日：2017-07-17
发明人： Ku He , Tejasvi Das , John L. Melanson
CPC分类号： H03F1/0205 , H03F1/0272 , H03F1/0277 , H03F3/185 , H03F3/187 , H03F3/2171 , H03F3/2175 , H03F2200/03 , H03F2200/432 , H04R3/04
摘要： An amplifier may include a first stage configured to receive an input signal at an amplifier input and generate an intermediate signal which is a function of the input signal, and a final output stage configured to generate an output signal which is a function of the intermediate signal at an amplifier output, and a signal feedback network coupled between the amplifier output and input. The final output stage may be switchable among a plurality of modes including at least a first mode in which the final output stage generates the output signal as a modulated output signal which is a function of the intermediate signal, and a second mode in which the final output stage generates the output signal as an unmodulated output signal which is a function of the intermediate signal. Control circuitry may reduce audio artifacts associated with switching between modes.
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公开(公告)号：US10008994B2
公开(公告)日：2018-06-26
申请号：US15480645
申请日：2017-04-06
申请人： NXP B.V.
发明人： Marco Berkhout , Lûtsen Ludgerus Albertus Hendrikus Dooper , Maarten van Dommelen , Han Martijn Schuurmans
CPC分类号： H03G3/3015 , H03F1/0227 , H03F1/26 , H03F3/185 , H03F3/217 , H03F3/2175 , H03F2200/03 , H03F2200/102 , H03F2200/351 , H03F2200/372 , H03G3/3089 , H03M3/506
摘要： An audio amplifier system is described comprising: a variable gain audio processor for processing digital audio signal, a digital to analog converter coupled to the audio processor, and configured to receive the processed digital audio signal, a variable gain amplifier having an input coupled to the output of the digital to analog converter and operably connected to a power supply, a controller coupled to the variable gain audio processor and the variable gain amplifier and configured to switch the audio amplifier system between a first operating mode having a first power supply voltage value and a second operating mode having a second higher power supply voltage value; wherein the controller is operable in the first operating mode to set the audio amplifier system gain to a desired gain value and in the second operating mode to maintain the desired gain value.
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