In Cascade Amplifiers Patents (Class 330/98)
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Patent number: 11998326Abstract: A smart wearable device includes a detection apparatus and a case, the detection apparatus specifically includes one set of measuring parts and a plurality of sets of light emitting parts; the one set of measuring parts and the plurality of sets of light emitting parts are inlaid into the case and arranged into a polygon, where each of the plurality of sets of light emitting parts and the one set of measuring parts each occupies one of a plurality of angles of the polygon, and a central position of the polygon is at a specified distance to each angle of the polygon. A specific embodiment of the present invention provides a smart wearable device. One set of measuring parts and a plurality of sets of light emitting parts are disposed into a case and arranged into a polygon.Type: GrantFiled: January 27, 2022Date of Patent: June 4, 2024Assignee: Huawei Technologies Co., Ltd.Inventors: Xiaodong Ni, Yi Xi, Ao Shen, Wenxiong Wei
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Patent number: 11543292Abstract: Low-frequency Noise Cancellation Method for Optical Measurement Systems. The present disclosure provides a low frequency noise cancellation method for optical measurement system, An optical measurement system has a transmitter to drive an LED and a receiver connected to a photodiode. The LED driver will generate a pulse signal to drive the LED and act as the radiation source for the optical measurement. Consequently, the receiver will convert the received photo-diode current to a voltage signal. The signal will then be digitized by an ADC for further processing. A current DAC circuit IDAC is added at the front of the receiver and has the same timing control with the LED driver to cancel the DC portion of the received current.Type: GrantFiled: August 26, 2021Date of Patent: January 3, 2023Assignee: Analog Devices International Unlimited CompanyInventors: Jinhua Ni, Hui Shen
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Patent number: 11489705Abstract: Some examples described herein provide for an integrated circuit including a continuous time linear equalizer (CTLE) circuit and a method of operating the integrated circuit. In an example, an integrated circuit includes a transconductance amplifier stage and a transimpedance amplifier stage. The transconductance amplifier stage has a first input node and a first output node. The transconductance amplifier stage includes a first complementary device inverter. The transimpedance amplifier stage has a second input node and a second output node. The first output node is electrically connected to the second input node. The transimpedance amplifier stage includes a second complementary device inverter.Type: GrantFiled: September 11, 2020Date of Patent: November 1, 2022Assignee: XILINX, INC.Inventors: Ronan Sean Casey, Kevin Zheng, Catherine Hearne
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Patent number: 11264958Abstract: In some embodiments, a power amplification system can comprise a current source, an input switch configured to alternatively feed current from the current source to a high-power circuit path and a low-power circuit path, and a band switch including a switch arm for switching between a plurality of bands. Each of the high-power circuit path and the low-power circuit path can be connected to the switch arm.Type: GrantFiled: September 27, 2019Date of Patent: March 1, 2022Assignee: Skyworks Solutions, Inc.Inventor: Philip John Lehtola
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Patent number: 10938357Abstract: Embodiments provide an audio amplifier circuit with integrated (built-in) filter (e.g., a digital-to-analog converter (DAC) filter). The audio amplifier circuit may have a non-flat (e.g., low-pass) closed loop frequency response. The audio amplifier circuit may include a low pass filter coupled between an input terminal that receives the input analog audio signal and the input of the gain stage of the amplifier. In some embodiments, additional impedance networks may be included to produce a desired low-pass filter response, such as a second order filter, a third order filter, and/or another suitable filter response. Other embodiments may be described and/or claimed.Type: GrantFiled: September 26, 2019Date of Patent: March 2, 2021Assignee: THX LTD.Inventor: Owen Jones
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Patent number: 9118283Abstract: An amplifier circuit comprising a driver (204, 304) configured to provide a switched mode input signal, a switching mode power amplifier (206, 306) configured to receive the switched mode input signal and provide an output signal for an external load (210, 310); and a sensor (208, 308) configured to sense the impedance of the external load (210, 310) The driver is configured to set the duty cycle of the switched mode input signal in accordance with the sensed impedance of the external load (210, 310).Type: GrantFiled: September 13, 2013Date of Patent: August 25, 2015Assignee: NXP, B.V.Inventors: Koen Buisman, Mark Pieter van der Heijden, Mustafa Acar, Leo de Vreede
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Patent number: 8994464Abstract: An amplifier and oscillator system includes a MEMS resonator and a two stage amplifier topology. The MEMS resonator is configured to generate a resonator signal. The two-stage amplifier topology is configured to amplify the resonator signal with a selected trans-impedance gain. Additionally, the two stage amplifier topology yields a feedback resistance that provides the selected trans-impedance gain.Type: GrantFiled: October 9, 2012Date of Patent: March 31, 2015Assignee: Taiwan Semiconductor Manufacturing Co., Ltd.Inventors: Tung-Tsun Chen, Jui-Cheng Huang
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Patent number: 8766725Abstract: Apparatus and methods for frequency compensation of an amplifier are provided. In one embodiment, an integrated circuit (IC) includes an amplifier configured to amplify an input signal to generate an output signal. The IC further includes an output pad configured to receive an output signal from the amplifier and a control pad for controlling the closed-loop bandwidth of the amplifier. A compensation capacitor is electrically connected between an input of the inverting amplification block and an output of the inverting amplification block, and a switchable capacitor is electrically connected between the input of the inverting amplification block and the control pad. The control pad can be electrically connected to a DC voltage source or to the output pad to control the amplifier's closed-loop bandwidth.Type: GrantFiled: April 13, 2012Date of Patent: July 1, 2014Assignee: Analog Devices, Inc.Inventors: Stefano I. D'Aquino, Kimo Tam, Yukihisa Handa
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Patent number: 8729962Abstract: A millimeter wave power amplifier is disclosed. In an exemplary embodiment, a MM wave power amplifier (PA) includes a plurality of amplifier stages coupled together to receive a MM wave input signal and produce an amplified MM wave output signal, and one or more feedback elements coupled across the amplifier stages, each feedback element coupled across an odd number of the amplifier stages to increase an operating bandwidth of the PA.Type: GrantFiled: December 15, 2011Date of Patent: May 20, 2014Assignee: QUALCOMM IncorporatedInventors: Saihua Lin, Yongwang Ding, Cheol-Woong Lee
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Patent number: 8723602Abstract: The class-E amplifier can be tuned to pass only the fundamental frequency to the antenna by optimizing the second harmonics at the drain of the final PA driver transistor. A CPW in series with a capacitor between the PA transistor and the load forms a band pass filter that only allows the fundamental frequency to pass to the load of the antenna. A supply inductor to couple the drain of the final PA driver transistor to the power supply is tuned at the second harmonic with the parasitic capacitance of the drain of the PA transistor. A load capacitance is adjusted at the fundamental frequency to insure that the current waveform and voltage waveforms at the drain of the PA driver transistor do not overlap, thereby minimizing the parasitic power dissipation and allowing maximum energy to be applied to the antenna.Type: GrantFiled: August 10, 2012Date of Patent: May 13, 2014Assignee: Tensorcom, Inc.Inventor: Jiashu Chen
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Patent number: 8717083Abstract: A method including receiving an input signal; amplifying the input signal to generate an output signal using a cascade of a plurality of amplifier stages including a first amplifier stage and a last amplifier stage; generating a voltage signal by sensing the output signal in a noninvasive manner so that the sensing results in substantially no change to the output signal; generating a current signal from the voltage signal using a transconductance amplifier; and injecting the current signal into an output node of the first amplifier stage in a noninvasive manner so that the injecting results in substantially no change to an amplification function of the first amplifier stage.Type: GrantFiled: March 14, 2013Date of Patent: May 6, 2014Assignee: Realtek Semiconductor Corp.Inventor: Chia-Liang Lin
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Patent number: 8704601Abstract: The present invention includes a class-E power amplifier, comprising a driver stage (DS) including a first power amplifier with transistors, to which an input signal is inputted; a main stage (MS), including a second power amplifier with transistors, whose input is connected to the output of the DS; and a first LC resonator whose one end is connected to the output of the DS and the other end to the ground as an AC equivalent circuit and a second LC resonator whose one end is connected to the input of the MS and the other end to the ground as an AC equivalent circuit. In accordance with the present invention, as the voltage stress is reduced on the CMOS class-E power amplifier, the application of the high power supply voltage may be allowed and therefore the load impedance may be high while the same efficiency is maintained.Type: GrantFiled: December 15, 2010Date of Patent: April 22, 2014Assignee: SNU R&DB FoundationInventors: Sang Wook Nam, Yong Hoon Song, Sung Ho Lee, Jae Jun Lee, Eun II Cho
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Patent number: 8687821Abstract: An amplifier is disclosed, wherein the output stage is split between a primary output stage and a secondary stage. To minimize or eliminate any audible plop when the amplifier is switched on, the primary stage is connected, and the second stage is gradually connected using a switch. The gradual connection can be by means of varying the pulse-density of a pulse wave modulation on the switch, from fully open (0% pulse-density) to fully closed (100%). The inverse process can minimize or eliminate plop during switch-off. Separate feedback loops are switchable, from the primary and secondary stages; in a DC-coupled embodiment, the feedback loop from the secondary stage may include DC-offset cancelling circuitry, to both reduce or eliminate the plop and avoid and DC-offset current through the speaker.Type: GrantFiled: November 12, 2010Date of Patent: April 1, 2014Assignee: NXP B.V.Inventor: Han Martijn Schuurmans
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Patent number: 8680918Abstract: A high-voltage driver amplifier for piezo haptics comprises an input amplifier having a gain greater than one, a first amplifier of an amplifier pair coupled to an output of the input amplifier, a second amplifier of the amplifier pair coupled to the output of the input amplifier, a first impedance coupled between an output of the first amplifier of the amplifier pair and an input of the input amplifier, and a second impedance coupled between the output of the first amplifier of the amplifier pair coupled to an output of the second amplifier of the amplifier pair. A substantially capacitive load is coupled to the output of the second amplifier. The substantially capacitive load is a piezo-capacitance, wherein the piezo-capacitance is employed in haptics. The second impedance, a shunt impedance, allows for a feedback of output variations between the first amplifier and the second amplifier over the first impedance.Type: GrantFiled: December 16, 2011Date of Patent: March 25, 2014Assignee: Texas Instruments IncorporatedInventors: Brett Earl Forejt, Mayank Garg, David John Baldwin
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Patent number: 8610495Abstract: Some embodiments of the invention relate a transimpedance amplifier circuit having a negative feedback network that provides additional filtering of an out-of-band transmitted signal is provided herein. In one embodiment, the transimpedance amplifier circuit has a first pole, transimpedance amplifier having a multi-stage operational amplifier with an input terminal and an output terminal. An RC feedback network extends from the output terminal to the input terminal. A negative feedback network, extending from an internal node of the multi-stage operational amplifier to an input terminal of the single pole, transimpedance amplifier provides a negative feedback signal with an amplitude having an opposite polarity as the out-of-band transmitted signal. The negative feedback signal suppresses the out-of-band-transmitted signals within the demodulator circuit, thereby improving linearity of the transimpedance amplifier circuit.Type: GrantFiled: December 16, 2011Date of Patent: December 17, 2013Assignee: Intel Mobile Communications GmbHInventors: Umut Basaran, Ashkan Naeini
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Publication number: 20130271219Abstract: Apparatus and methods for frequency compensation of an amplifier are provided. In one embodiment, an integrated circuit (IC) includes an amplifier configured to amplify an input signal to generate an output signal. The IC further includes an output pad configured to receive an output signal from the amplifier and a control pad for controlling the closed-loop bandwidth of the amplifier. A compensation capacitor is electrically connected between an input of the inverting amplification block and an output of the inverting amplification block, and a switchable capacitor is electrically connected between the input of the inverting amplification block and the control pad. The control pad can be electrically connected to a DC voltage source or to the output pad to control the amplifier's closed-loop bandwidth.Type: ApplicationFiled: April 13, 2012Publication date: October 17, 2013Applicant: Analog Devices, Inc.Inventors: Stefano I. D'Aquino, Kimo Tam, Yukihisa Handa
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Publication number: 20130214857Abstract: A circuit for self-calibrating a gain control system samples the output of a digital amplifier coupled in series with one or more analog amplifiers to correct errors in a discrete stepped gain control. A digital gain control circuit controls both the digital amplifier and at least one analog amplifier to produce a smooth linear and continuous gain, wherein perturbations in the digital control of gain are smoothed by a signal applied to gain control circuit by a gain step correction circuit.Type: ApplicationFiled: March 18, 2013Publication date: August 22, 2013Inventors: James Qiu, Sridhar Ramesh
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Patent number: 8508302Abstract: An electronic circuit includes: first through third transistors having a control terminal, first and second terminals; a first direct current path supplying a direct current having passed through between the first terminal and the second terminal of at least one of the second transistor and the third transistor to the second terminal of the transistor at former position compared to the transistor through which the direct current passed; a second direct current path that is different from the first direct current path and supplies a direct current having passed through between the first terminal and the second terminal of at least one of the second transistor and the third transistor to the second terminal of the transistor at former position compared to the transistor through which the direct current passed; and a common coupling point coupling the first direct current path and the second direct current path in common.Type: GrantFiled: September 23, 2011Date of Patent: August 13, 2013Assignees: Sumitomo Electric Industries, Ltd., Sumitomo Electric Device Innovations, Inc.Inventors: Seiji Fujita, Tsuneo Tokumitsu
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Patent number: 8471721Abstract: A server rack includes a main body, an electronic scale, and an alarm. The main body is used for receiving a number of servers. The electronic scale includes a pressure sensor and a microcontroller. The main body presses on the pressure sensor so that the pressure sensor can measure the pressure from the main body to obtain a pressure signal. The microcontroller analyzes the pressure signal to calculating the total weight of the main body and the servers. The alarm stores a predetermined weight threshold, which is the total weight of the main body and the maximum servers that the main body can bear. The alarm also compares the measured total weight with the predetermined weight threshold. When the measured total weight is larger than the predetermined weight threshold, the alarm alarms.Type: GrantFiled: April 12, 2011Date of Patent: June 25, 2013Assignees: Hong Fu Jin Precision Industry (ShenZhen) Co., Ltd., Hon Hai Precision Industry Co., Ltd.Inventors: Song-Lin Tong, Guang-Dong Yuan, Hai-Qing Zhou
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Patent number: 8456215Abstract: A limiting amplifier and method are provided. In one implementation an apparatus includes a plurality of amplifier stages including a first amplifier stage and a last amplifier stage configured in a cascade arrangement, and a transconductance amplifier, wherein the first amplifier stage is configured to receive an input signal; the last amplifier stage outputs an output signal; the transconductance amplifier is configured receive a voltage signal from the last amplifier stage via a first resistor; and the transconductance amplifier is configured to output a current signal to an output node of the first amplifier stage via a second resistor in a negative feedback manner.Type: GrantFiled: September 25, 2011Date of Patent: June 4, 2013Assignee: Realtek Semiconductor Corp.Inventor: Chia-Liang Lin
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Patent number: 8421531Abstract: A low dissipation, low distortion amplifier includes a driver amplifier stage and a main output stage, with a plurality of impedance networks providing, among other things, feedback paths from outputs of the driver and main output stages to the input of the driver stage. The impedance networks also provide coupling paths from the outputs of the driver and main output stages to the load. The impedance networks can all be formed of resistors, capacitors, or network combinations thereof. An additional feedback path can be added from the load to the driver stage to flatten out the frequency response at low frequencies. The driver and main output stages may be operated in Class AB and B modes respectively, and/or in Class G or H modes. An intermediate amplifier driver stage may be added between the driver and main output stages.Type: GrantFiled: July 6, 2011Date of Patent: April 16, 2013Assignee: THX LtdInventors: Owen Jones, Lawrence R. Fincham
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Patent number: 8374560Abstract: Aspects of a method and system for processing signals in a high performance receive chain may include amplifying a plurality of radio frequency signals in one or more respective one or ones of a plurality of amplifier chains in a multistandard radio frequency front-end, which may comprise one or more shared processing stages. The plurality of radio frequency signals may be compliant with a plurality of radio frequency communication standards and may be received concurrently. The one or more shared processing stages may be shared between two or more of the plurality of amplifier chains. Each of the two or more of the plurality of amplifier chains may be operable to amplify signals compliant with different radio frequency communication standards.Type: GrantFiled: September 15, 2010Date of Patent: February 12, 2013Assignee: Broadcom CorporationInventors: Arya Behzad, Adedayo Ojo, Yuyu Chang, Hung-Ming Chien, Kishore Rama Rao, Guruprasad Seetharam
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Patent number: 8373509Abstract: Techniques to improve low noise amplifiers (LNAs) with noise canceling are described. LNA includes a first and a second amplifier which work together to noise cancel the noise generated at an input stage circuit. The input stage circuit receives an RF signal and is characterized by a first node and a second node. The first amplifier converts a noise voltage at the first node into a first noise current at an output of the first amplifier. The second amplifier is directly coupled to the output of the first amplifier and provides noise canceling by summing the first noise current with a second noise current generated by the second amplifier as a function of the noise voltage at the second node. The proposed techniques eliminate the need for large ac coupling capacitors and reduce the die size occupied by the LNA.Type: GrantFiled: February 9, 2012Date of Patent: February 12, 2013Assignee: QUALCOMM, IncorporatedInventors: Yi Zeng, Xiaoyong Li, Rahul A Apte
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Patent number: 8305140Abstract: Active resistive circuitry (10, 10A, 11, 11A 25, 30, 35, or 40) includes a first current divider circuit (11) having an input (15) coupled to a first signal (Vi). The first current divider circuit (11) includes a first amplifier (13) having a first input (?) coupled to the first signal (Vi). A symmetrically bilateral first bidirectional circuit (M1a,M1b; R1) is coupled between the first input (?) of the first amplifier (13) and an output (17) of the first amplifier (13), and functions as a feedback circuit of the first amplifier (13). A symmetrically bilateral second bidirectional circuit (M2a,M2b; R2) is coupled between the output (17) of the first amplifier (13) and an output (18) of the first current divider circuit (11).Type: GrantFiled: September 7, 2011Date of Patent: November 6, 2012Assignee: Texas Instruments IncorporatedInventors: Du Chen, Kemal S. Demirci
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Patent number: 8274335Abstract: An apparatus for implementing a front end core for a transimpedance amplifier includes an input transimpedance stage that receives an FE core input signal and responsively generates an output transimpedance gain signal. A first output gain stage receives the output transimpedance gain signal and responsively generates an FE core output signal. A phase inverter stage also receives the output transimpedance gain signal and responsively generates an inverted output signal. A second output gain stage then receives the inverted output signal and responsively generates an inverted FE core output signal.Type: GrantFiled: April 14, 2011Date of Patent: September 25, 2012Assignee: Sony CorporationInventor: Jeremy Chatwin
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Publication number: 20120218043Abstract: An amplifier comprises a main amplification stage and an auxiliary amplification stage. An input of the main amplification stage and an input of the auxiliary amplification stage are coupled to a common node, and an output of the main amplification stage is coupled to an output node. During activation, before power is supplied to the main amplification stage, the output node is coupled to a reference voltage (VREF). A quiescent voltage is then established at the common node by coupling power to the auxiliary amplification stage. Only then is power coupled to the main amplification stage and the reference voltage (VREF) de-coupled from the output node.Type: ApplicationFiled: October 29, 2010Publication date: August 30, 2012Applicant: ST-Ericsson SAInventor: Robert Hwat Hian Teng
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Publication number: 20120169418Abstract: A low dissipation, low distortion amplifier includes a driver amplifier stage and a main output stage, with a plurality of impedance networks providing, among other things, feedback paths from outputs of the driver and main output stages to the input of the driver stage. The impedance networks also provide coupling paths from the outputs of the driver and main output stages to the load. The impedance networks can all be formed of resistors, capacitors, or network combinations thereof. An additional feedback path can be added from the load to the driver stage to flatten out the frequency response at low frequencies. The driver and main output stages may be operated in Class AB and B modes respectively, and/or in Class G or H modes. An intermediate amplifier driver stage may be added between the driver and main output stages.Type: ApplicationFiled: July 6, 2011Publication date: July 5, 2012Applicant: THX, LTDInventors: Owen Jones, Lawrence R. Fincham
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Patent number: 8189713Abstract: A wireless communication device includes an RF transceiver configured to up convert a base band signal to a transmitting RF signal, a configurable matrix power amplifier circuit configured to amplify the transmitting RF signal to produce an amplified RF signal, and an antenna configured to transmit a wireless signal in response to the amplified RF signal.Type: GrantFiled: January 18, 2010Date of Patent: May 29, 2012Assignee: Micro Mobio CorporationInventors: Inui Shinsuke, Ikuroh Ichitsubo, Shigeru Watanabe
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Patent number: 8164385Abstract: An amplifier circuit includes a first amplifier amplifying an input signal and outputting a first amplified signal, a second amplifier amplifying the first amplified signal and outputting a second amplified signal, and a feedback circuitry feeding back the second amplified signal to the input of the second amplifier. The feedback circuitry includes a feedback transistor that keeps the input level of the second amplifier constant.Type: GrantFiled: August 26, 2009Date of Patent: April 24, 2012Assignee: Fujitsu LimitedInventors: Yukito Tsunoda, Mariko Sugawara
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Patent number: 8159303Abstract: An operational amplifier includes an input stage amplifier that receives an input signal, an output stage amplifier that amplifies a signal output from the input stage amplifier and outputs the signal, a capacitor that is connected between an input node and an output node of the output stage amplifier, and a charge and discharge control circuit that controls a charge and discharge current of the capacitor.Type: GrantFiled: January 11, 2010Date of Patent: April 17, 2012Assignee: Renesas Electronics CorporationInventors: Kouichi Nishimura, Yoshihiko Hori
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Patent number: 8159293Abstract: A nested transimpedance amplifier circuit including a first power source, a second power source, a charge pump module and a transimpedance amplifier. The first power source is at a first voltage. The second power source is at a second voltage. The second voltage is different than the first voltage. The charge pump module (i) receives the first voltage and the second voltage and (ii) generates a third voltage based on the first voltage and the second voltage. The first transimpedance amplifier includes an input, an output and a first operational amplifier. The input of the first transimpedance amplifier receives an input voltage. The output of the first transimpedance amplifier outputs an output voltage. The first operational amplifier receives the third voltage. The first transimpedance amplifier generates the output voltage based on the third voltage and the input voltage.Type: GrantFiled: August 17, 2010Date of Patent: April 17, 2012Assignee: Marvell International Ltd.Inventor: Sehat Sutardja
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Patent number: 8102214Abstract: Provided is controlled-gain wideband feedback low-noise amplifier. The controlled-gain wideband feedback low-noise amplifier includes: a feedback amplifier configured to isolate an input signal and an output signal obtained by amplifying the input signal, feed back the output signal to the input signal to amplify wideband input signals, resonate a low-frequency band signal among the wideband input signals to amplify the low-frequency band signal among the wideband input signals, and be switched in accordance with a control signal to control an amplification gain of the low-frequency band signal among the wideband input signals; and a cascode amplifier configured to amplify a high-frequency band signal among the wideband signals inputted from the feedback amplifier, and be switched in accordance with a control signal to control an amplification gain of the high-frequency band signal among the wideband signals.Type: GrantFiled: August 25, 2010Date of Patent: January 24, 2012Assignee: Electronics and Telecommunications Research InstituteInventors: Bong-Hyuk Park, Kwang-Chun Lee
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Patent number: 8098840Abstract: A multi-channel output device for a multimedia device includes a plurality of reception ends, an amplifier having an input end and an output end, a plurality of sound output devices for outputting sound, a first switching unit coupled between the plurality of reception ends and the input end of the amplifier for coupling a reception end of the plurality of reception ends to the input end of the amplifier according to a control signal, a second switching unit coupled between the output end of the amplifier and the plurality of sound output devices for coupling the output end of the amplifier to a sound output device of the plurality of sound output devices according to the control signal, and a control unit coupled to the first switching unit and the second switching unit for outputting the control signal.Type: GrantFiled: December 23, 2008Date of Patent: January 17, 2012Assignee: Anpec Electronics CorporationInventor: Chiung-Ching Ku
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Patent number: 8081032Abstract: A low noise amplifier (LNA) includes an LNA input that receives a signal from an antenna. The LNA also includes an internal amplifier with an input that is coupled to the LNA input, as well as an internal filter with an input coupled to the output of the internal amplifier and an output coupled to the input of the internal amplifier. The coupling of the output of the internal filter to the input of the internal amplifier provides feedback to the input of the internal amplifier. The internal filter is configured to pass signals within a frequency range through to the output of the internal filter.Type: GrantFiled: August 29, 2008Date of Patent: December 20, 2011Assignee: Project FT, Inc.Inventor: Farbod Aram
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Patent number: 8072262Abstract: A chopper-stabilized circuit (1) includes pre-chopping circuitry (26) for chopping an input signal (Vin) at a first frequency to generate a first signal. Input chopping circuitry (9) chops the first signal at a second frequency substantially greater than the first frequency to produce a second signal. The first frequency is a sub-harmonic of the second frequency. Post-chopping circuitry (30) chops the second chopped signal at the first frequency to produce a third signal that is applied to an input of a signal conditioning circuit (2). The output chopping circuitry (10) chops an output of the signal conditioning circuit at the second frequency to generate a fourth signal. The fourth signal is filtered.Type: GrantFiled: June 28, 2010Date of Patent: December 6, 2011Assignee: Texas Instruments IncorporatedInventors: Rodney T. Burt, Joy Y. Zhang
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Patent number: 8058931Abstract: An apparatus for an improved operational amplifier. The disclosed improved operational amplifier comprises an operational amplifier, a first feedback circuit, and one or more secondary feedback circuits. The operational amplifier include a plurality of serially coupled gain stages and is configured so that an output of each gain stage drives an input of a next gain stage and an output of a last gain stage drives a load external to the improved operational amplifier. The first feedback circuit is coupled between an output of a designated gain stage and an output of a previous gain stage to provide a first feedback to the previous gain stage. Each secondary feedback circuit provides an additional feedback to the output of the previous gain stage.Type: GrantFiled: April 27, 2010Date of Patent: November 15, 2011Assignee: Linear Technology CorporationInventor: Ping Zhou
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Patent number: 8013676Abstract: A high-efficiency power amplifier is provided, including a drive amplifier and a final power amplifier, and further including a first digital pre-distortion (DPD) correction module and a second DPD correction module. The first DPD correction module is configured to pre-distort nonlinear characteristics of drive signals output by the drive amplifier, and the second DPD correction module is connected to the first DPD correction module in series, and is configured to pre-distort nonlinear characteristics of amplified signals output by the final power amplifier. Another high-efficiency power amplifier is also provided, including a drive amplifier and a final power amplifier, and further including a second multi-path control module, a fourth DPD correction module, and a second gating module. The overall efficiency of the high-efficiency power amplifier is increased by improving the working efficiency of the drive amplifier.Type: GrantFiled: June 16, 2010Date of Patent: September 6, 2011Assignee: Huawei Technologies Co., Ltd.Inventors: Yongge Su, Siqing Ye, Dandong He, Weimin Yin, Xikun Zhang, Xiaolun Wang, Qianhua Wei
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Patent number: 8004355Abstract: A low dissipation, low distortion amplifier includes a driver amplifier stage and a main output stage, with a plurality of impedance networks providing, among other things, feedback paths from outputs of the driver and main output stages to the input of the driver stage. The impedance networks also provide coupling paths from the outputs of the driver and main output stages to the load. The impedance networks can all be formed of resistors, capacitors, or network combinations thereof. An additional feedback path can be added from the load to the driver stage to flatten out the frequency response at low frequencies. The driver and main output stages may be operated in Class AB and B modes respectively, and/or in Class G or H modes. An intermediate amplifier driver stage may be added between the driver and main output stages.Type: GrantFiled: February 25, 2010Date of Patent: August 23, 2011Assignee: THX Ltd.Inventors: Owen Jones, Lawrence R. Fincham
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Patent number: 7986185Abstract: A rail-to-rail Miller compensation method without feed forward path includes forming a first compensation branch including a first amplifier, wherein an input of the first amplifier is electrically connected with an output of a second stage gain amplifier, the second stage gain amplifier is electrically connected the first stage gain amplifier in series forming an operational amplifier; and forming a second compensation branch including a second amplifier, wherein a dual relation is provided between an input stage of the first amplifier and that of the second amplifier, namely, if the input stage of the first amplifier is N-type, the input stage of the second amplifier is P-type, and vice versa. The present invention is capable of achieving the rail-to-rail output range without affecting the system stability. The N-type and P-type inputs are simultaneously applied to the input of the amplifier of the compensation branches.Type: GrantFiled: June 3, 2010Date of Patent: July 26, 2011Assignee: IPGoal Microelectronics (SiChuan) Co., Ltd.Inventor: Junwei Huang
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Patent number: 7978007Abstract: The invention relates to a feedback network (60) for cascade amplifiers (200), which comprises an active stage (30) to feed signal back to a first internal node (65) at the output of the first amplifier stage (61) of the cascade. The invention further relates to a feedback network (60) which comprises said active feedback stage (30) with said first internal amplifier node (65) connection and a feedback resistor (10) connected from said cascade amplifier output port (out) to its input port (in).Type: GrantFiled: December 29, 2008Date of Patent: July 12, 2011Inventor: Esa Tiiliharju
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Patent number: 7948309Abstract: An amplifier circuit includes a transconductance amplifier at an input side of the amplifier circuit, a transimpedance amplifier connected to an output of the transconductance amplifier, and a voltage amplifier connected to an output of the transimpedance amplifier. The transconductance amplifier and the transimpedance amplifier form a low-impedance node at an interface thereof. A feedback circuit is connected between an output of the voltage amplifier and the low-impedance node between the transconductance amplifier and the transimpedance amplifier. The transconductance amplifier, the transimpedance amplifier, and the voltage amplifier form a main amplifier stage. The feedback circuit senses an imbalance in an output of the main amplifier stage, whereby a correction signal is integrated and negatively fed back to the low-impedance node between the transconductance amplifier and the transimpedance amplifier.Type: GrantFiled: January 16, 2009Date of Patent: May 24, 2011Assignee: University of MacauInventors: Pui-In Mak, Seng-Pan U, Rui P. Martins
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Publication number: 20110095817Abstract: Disclosed is a signal amplifying device which includes an overcurrent detection circuit, a first inverting amplifying circuit amplifying an input signal, and a second inverting amplifying circuit amplifying an output of the first inverting amplifying circuit. The overcurrent detection circuit includes a comparison circuit and a decision circuit. The comparison circuit compares the voltage of the input signal with the voltage of an output of the second inverting amplifying circuit, and generates a signal responsive to the comparison result. The decision circuit detects overcurrent from the signal output by the comparison circuit.Type: ApplicationFiled: October 7, 2010Publication date: April 28, 2011Applicant: OKI SEMICONDUCTOR CO., LTD.Inventor: Toshimi YAMADA
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Patent number: 7893760Abstract: An amplifier circuit including: a multistage amplifier unit including an input-stage transistor and an output-stage transistor and configured to amplify an input signal and to output an amplified signal; and a feedback unit including a first feedback transistor, a second feedback transistor, and a feedback resistor, and configured to feed back the amplified signal to an input of the output-stage transistor in the multistage amplifier unit via the first feedback transistor, the second feedback transistor, and the feedback resistor.Type: GrantFiled: August 26, 2009Date of Patent: February 22, 2011Assignee: Fujitsu LimitedInventors: Mariko Sugawara, Yukito Tsunoda
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Patent number: 7859330Abstract: Systems and methods for characterizing amplifiers. A system for characterizing an amplifier in accordance with the present invention comprises a Gaussian signal source for generating a signal in the frequency domain, a notch filter, coupled to the Gaussian Noise source, wherein the notch filter has a notch at a specified frequency and a frequency bandwidth, the frequency bandwidth encompassing the specified frequency, an Inverse Fast Fourier Transform device, coupled to an output of the notch filter, a normalization device, coupled to the Inverse Fast Fourier Transform device, an amplifier under test, coupled to the normalization device, for amplifying the signal generated by the Gaussian signal source, and a measurement device, coupled to an output of the amplifier, for measuring a power output of the amplifier in the frequency bandwidth and a noise output at the specified notch frequency, and for calculating the ratio between the power output and the noise output.Type: GrantFiled: April 9, 2009Date of Patent: December 28, 2010Assignee: The DIRECTV Group, Inc.Inventors: Guangcai Zhou, Tung-Sheng Lin, Dennis Lai, Joseph Santoru, Ernest C. Chen, Shamik Maitra, Cecilia Comeaux
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Publication number: 20100321112Abstract: Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier.Type: ApplicationFiled: June 19, 2009Publication date: December 23, 2010Applicant: CONEXANT SYSTEMS, INC.Inventors: Xin Fan, Christian Larsen, Lorenzo Crespi
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Patent number: 7821335Abstract: The variable gain amplifier includes a bias circuit (BC) 1, a matching circuit (MC) 2, a variable gain resistive feedback amplifier (FA) 3 and an output follower (EA) 4. The resistance values of the load resistance Rc and feedback resistance Rf are changed in cooperation. In a case of making the load resistance Rc a high resistance to set the low noise amplifier to a high gain, the feedback resistance Rf is also made a high resistance, the feedback time constant ?fb(c1)?2?·RfCbe/(1+gmRc) of the closed loop of the resistive negative feedback amplifier 3 becomes substantially constant, and then the amplifier has a gain small in frequency dependency over a wide bandwidth. In a case of making the load resistance Rc a low resistance to set the low noise amplifier to a low gain, the feedback resistance Rf is also made a low resistance. The feedback resistance Rf with the low resistance increases the negative feedback quantity, and thus the amplifier is set to a low gain.Type: GrantFiled: October 16, 2008Date of Patent: October 26, 2010Assignee: Renesas Electronics CorporationInventors: Nobuhiro Shiramizu, Toru Masuda
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Patent number: 7808311Abstract: A nested transimpedance amplifier circuit includes a first-order nested transimpedance amplifier having an input and an output. The first-order nested transimpedance amplifier is configured to be powered by a first voltage. A charge pump module is configured to receive the first voltage and a second voltage. The second voltage is different from the first voltage. The charge pump module generates a third voltage based on the first voltage and the second voltage. A first operational amplifier has an input and an output. The input of the first operational amplifier communicates with the output of the zero-order transimpedance amplifier, and the first operational amplifier is configured to be powered by the third voltage.Type: GrantFiled: November 30, 2009Date of Patent: October 5, 2010Assignee: Marvell World Trade Ltd.Inventor: Sehat Sutardja
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Publication number: 20100237936Abstract: An amplifier circuit, includes: a first amplifier; a second amplifier; a first capacitor connected to the first amplifier; a second capacitor having one terminal connected to the first amplifier, another terminal connected to the second input terminal; and a first switch circuit switching a connection of the output terminal, the another terminal of the first capacitor, the first input terminal and the second input terminal, and switching supplying a reference potential supply, the first switch circuit including: a first state connecting the first input terminal to the second input terminal, connecting the output terminal to the another terminal of the first capacitor, and supplying the second input terminal with the reference potential, a second state connecting the first input terminal to the another terminal of the first capacitor and providing the output terminal and the second input terminal in an open state.Type: ApplicationFiled: March 11, 2010Publication date: September 23, 2010Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Toru Takeda
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Patent number: 7791411Abstract: An amplifier arrangement and a method for amplifying a signal, the arrangement including a transistor to amplify an input signal and to provide an intermediate signal. The intermediate signal is amplified to form an output signal which is fed back to the transistor.Type: GrantFiled: June 19, 2007Date of Patent: September 7, 2010Assignee: Austriamicrosystems AGInventors: Thomas Carl Fröhlich, Nicole Heule
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Publication number: 20100164618Abstract: The invention relates to a feedback network (60) for cascade amplifiers (200), which comprises an active stage (30) to feed signal back to a first internal node (65) at the output of the first amplifier stage (61) of the cascade. The invention further relates to a feedback network (60) which comprises said active feedback stage (30) with said first internal amplifier node (65) connection and a feedback resistor (10) connected from said cascade amplifier output port (out) to its input port (in).Type: ApplicationFiled: December 29, 2008Publication date: July 1, 2010Inventor: Esa Tiiliharju