Patents by Inventor Yuyu Chang
Yuyu Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20110003574Abstract: Embodiments of the present invention provide constant output DC biasing circuits. Embodiments employ an open loop scheme, instead of a closed loop scheme as used in conventional circuits. In addition, embodiments generate a DC bias voltage that is independent of temperature, process, and power supply variations. Further, embodiments require low amounts of power and silicon.Type: ApplicationFiled: July 1, 2009Publication date: January 6, 2011Applicant: Broadcom CorporationInventors: Yuyu CHANG, Hooman DARABI
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Publication number: 20100317311Abstract: Embodiments of a SAW-less RF receiver front-end that includes a frequency translated notch filter (FTNF) are presented. An FTNF includes a passive mixer and a baseband impedance. The baseband impedance includes capacitors that form a low-Q band-stop filter. The passive mixer is configured to translate the baseband impedance to a higher frequency. The translated baseband impedance forms a high-Q notch filter and is presented at the input of the FTNF. The FTNF can be fully integrated in CMOS IC technology (or others, e.g., Bipolar, BiCMOS, and SiGe) and applied in wireless receiver systems including GSM, EDGE, Wideband Code Division Multiple Access (WCDMA), Bluetooth, and wireless LANs (e.g., IEEE 802.11). In addition, embodiments of an apparatus to protect SAW-less RF receiver front-ends are presented.Type: ApplicationFiled: June 10, 2009Publication date: December 16, 2010Applicant: Broadcom CorporationInventors: Ahmad MIRZAEI, Hooman DARABI, Yuyu CHANG
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Patent number: 7840198Abstract: Aspects of a method and system for processing signals in a high performance receive chain may include amplifying radio frequency signals in amplifier chains in a multistandard radio frequency front-end, comprising one or more shared processing stages, and combining, with substantially equal gain, a number of phase-shifted radio frequency signals of the radio frequency signals into substantially equal-gain-combined radio frequency signals. The substantially equal-gain-combined radio frequency signals may be demodulated to obtain inphase channels and quadrature channels. A number of inphase channels and quadrature channels may be processed in I-channel processing blocks and Q-channel processing blocks to generate an output analog baseband signal. The multistandard radio frequency front-end may be capable of processing Bluetooth® signals and Wireless Local Area Network (WLAN) signals.Type: GrantFiled: April 9, 2007Date of Patent: November 23, 2010Assignee: Broadcom Corp.Inventors: Arya Behzad, Adedayo Ojo, Yuyu Chang, Hung-Ming Chien, Kishore Rama Rao, Guruprasad Seetharam
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Patent number: 7782152Abstract: A frequency tuning device for use in a crystal oscillator circuit includes a first fine tuning array of capacitors, a second fine tuning array of capacitors and a coarse tuning array of capacitors coupled in parallel to produce a tuning capacitance for tuning the crystal oscillator. The first fine tuning array of capacitors includes a binary weighted switched capacitor network, the second fine tuning array of capacitors includes a thermometer coded switched capacitor network and the coarse tuning array of capacitors includes a binary weighted switched capacitor network with a different unit capacitance value than the first and second fine tuning arrays.Type: GrantFiled: September 30, 2008Date of Patent: August 24, 2010Assignee: Broadcom CorporationInventors: Hooman Darabi, Yuyu Chang, Zhimin Zhou, Morteza Vadipour
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Patent number: 7768359Abstract: A differential crystal oscillator circuit uses a bias transistor to generate a bias voltage from a bias current. The bias voltage is supplied to the control terminals of a differential pair of transistors. The differential transistors operate to produce a differential output between corresponding end terminals thereof, which is provided to a reference crystal oscillator to establish an oscillation frequency at the differential output.Type: GrantFiled: September 30, 2008Date of Patent: August 3, 2010Assignee: Broadcom CorporationInventors: Yuyu Chang, Hooman Darabi
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Patent number: 7679431Abstract: Low flicker noise mixer and buffer. This design employs some native metal oxide semiconductor field-effect transistors (MOSFETs) (e.g., having no threshold voltage) within a passive mixer whose gates are driven using clock signals. These native MOSFETs maybe biased at one half of the power supply voltage to provide a lower noise figure. A cooperatively operating buffer employs appropriately places MOSFETs and resistors to ensure the desired gain. Relatively larger valued resistors can be employed to provide for higher voltage gain, and this can sometimes be accompanied with using a higher than typical power supply voltage. Source followers serve as output buffers and also ensure the required output DC voltage level as well. It is also noted that this design can be implemented using n-channel metal oxide semiconductor field-effect transistors (N-MOSFETs) of p-channel metal oxide semiconductor field-effect transistors (P-MOSFETs).Type: GrantFiled: November 26, 2007Date of Patent: March 16, 2010Assignee: Broadcom CorporationInventors: Yuyu Chang, Hooman Darabi
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Patent number: 7671685Abstract: Aspects of a method and system for a low power fully differential noise canceling low noise amplifier (NC LNA) are provided. The NC LNA may receive signals via a single ended input and may generate an amplified symmetric differential output from the received signals. The NC LNA may utilize capacitor dividers, such as a capacitor bank, in the single ended input in order to provide impedance transformation that enables low power operation and matching to an input port. The NC LNA may generate one portion of the amplified symmetric differential output via a voltage divider, which may comprise a plurality of capacitors, such as a capacitor bank. The NC LNA may be implemented utilizing one or more circuits.Type: GrantFiled: March 30, 2007Date of Patent: March 2, 2010Assignee: Broadcom CorporationInventor: Yuyu Chang
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Publication number: 20100039194Abstract: A frequency tuning device for use in a crystal oscillator circuit includes a first fine tuning array of capacitors, a second fine tuning array of capacitors and a coarse tuning array of capacitors coupled in parallel to produce a tuning capacitance for tuning the crystal oscillator. The first fine tuning array of capacitors includes a binary weighted switched capacitor network, the second fine tuning array of capacitors includes a thermometer coded switched capacitor network and the coarse tuning array of capacitors includes a binary weighted switched capacitor network with a different unit capacitance value than the first and second fine tuning arrays.Type: ApplicationFiled: September 30, 2008Publication date: February 18, 2010Applicant: BROADCOM CORPORATIONInventors: Hooman Darabi, Yuyu Chang, Zhimin Zhou, Morteza Vadipour
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Publication number: 20100026402Abstract: A differential crystal oscillator circuit uses a bias transistor to generate a bias voltage from a bias current. The bias voltage is supplied to the control terminals of a differential pair of transistors. The differential transistors operate to produce a differential output between corresponding end terminals thereof, which is provided to a reference crystal oscillator to establish an oscillation frequency at the differential output.Type: ApplicationFiled: September 30, 2008Publication date: February 4, 2010Applicant: BROADCOM CORPORATIONInventors: Yuyu Chang, Hooman Darabi
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Patent number: 7598813Abstract: Radio frequency amplifier with constant gain setting. A circuitry that includes triple well connected MOSFETs is employed to eliminate body effects therein. The voltage gain as presented herein, being implemented using a ratio of certain elements within the circuitry, is immune to variations in temperature, power supply voltage, and process variations. One implementation employs an array of selectable MOSFETs to allow for more than one gain setting to be provided by the amplifier. Such an amplifier has a variable/selectable gain setting. An appropriately placed MOSFET is employed to provide the desired input impedance (e.g., 50?). This design can be implemented using multiple n-channel metal oxide semiconductor field-effect transistors (N-MOSFETs) (some of which are triple well connected) and p-channel metal oxide semiconductor field-effect transistors (P-MOSFETs), or alternatively using P-MOSFETs and N-MOSFETs.Type: GrantFiled: November 26, 2007Date of Patent: October 6, 2009Assignee: Broadcom CorporationInventor: Yuyu Chang
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Publication number: 20090237165Abstract: Cross-coupled low noise amplifier for cellular applications. A circuitry implementation that includes two pairs of metal oxide semiconductor field-effect transistors (MOSFETs) (either N-type of P-type) operates as an LNA, which can be used within any of a wide variety of communication devices. In one embodiment, this design is particularly adaptable to cellular telephone applications. A majority of the elements are integrated within the design and need not be implemented off-chip, and this can provide for a reduction in area required by the circuitry. A very high output impedance is provided by using two transistors (implemented in a triple well configuration) with resistive source degeneration. A higher than typical power supply voltage can be employed (if desired) to accommodate the voltage drops of the resistors and transistors.Type: ApplicationFiled: May 28, 2009Publication date: September 24, 2009Applicant: BROADCOM CORPORATIONInventors: Yuyu Chang, Hooman Darabi
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Patent number: 7541870Abstract: Cross-coupled low noise amplifier for cellular applications. A circuitry implementation that includes two pairs of metal oxide semiconductor field-effect transistors (MOSFETs) (either N-type of P-type) operates as an LNA, which can be used within any of a wide variety of communication devices. In one embodiment, this design is particularly adaptable to cellular telephone applications. A majority of the elements are integrated within the design and need not be implemented off-chip, and this can provide for a reduction in area required by the circuitry. A very high output impedance is provided by using two transistors (implemented in a triple well configuration) with resistive source degeneration. A higher than typical power supply voltage can be employed (if desired) to accommodate the voltage drops of the resistors and transistors.Type: GrantFiled: October 18, 2007Date of Patent: June 2, 2009Assignee: Broadcom CorporationInventors: Yuyu Chang, Hooman Darabi
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Publication number: 20090134942Abstract: Radio frequency amplifier with constant gain setting. A circuitry that includes triple well connected MOSFETs is employed to eliminate body effects therein. The voltage gain as presented herein, being implemented using a ratio of certain elements within the circuitry, is immune to variations in temperature, power supply voltage, and process variations. One implementation employs an array of selectable MOSFETs to allow for more than one gain setting to be provided by the amplifier. Such an amplifier has a variable/selectable gain setting. An appropriately placed MOSFET is employed to provide the desired input impedance (e.g., 50?). This design can be implemented using multiple n-channel metal oxide semiconductor field-effect transistors (N-MOSFETs) (some of which are triple well connected) and p-channel metal oxide semiconductor field-effect transistors (P-MOSFETs), or alternatively using P-MOSFETs and N-MOSFETs.Type: ApplicationFiled: November 26, 2007Publication date: May 28, 2009Applicant: BROADCOM CORPORATIONInventor: Yuyu Chang
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Publication number: 20090134932Abstract: Low flicker noise mixer and buffer. This design employs some native metal oxide semiconductor field-effect transistors (MOSFETs) (e.g., having no threshold voltage) within a passive mixer whose gates are driven using clock signals. These native MOSFETs maybe biased at one half of the power supply voltage to provide a lower noise figure. A cooperatively operating buffer employs appropriately places MOSFETs and resistors to ensure the desired gain. Relatively larger valued resistors can be employed to provide for higher voltage gain, and this can sometimes be accompanied with using a higher than typical power supply voltage. Source followers serve as output buffers and also ensure the required output DC voltage level as well. It is also noted that this design can be implemented using n-channel metal oxide semiconductor field-effect transistors (N-MOSFETs) of p-channel metal oxide semiconductor field-effect transistors (P-MOSFETs).Type: ApplicationFiled: November 26, 2007Publication date: May 28, 2009Applicant: BROADCOM CORPORATIONInventors: Yuyu Chang, Hooman Darabi
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Publication number: 20090104873Abstract: Fully integrated compact cross-coupled low noise amplifier. A circuitry implementation that includes two pairs of metal oxide semiconductor field-effect transistors (MOSFETs) (either N-type of P-type) operates as an LNA, which can be used within any of a wide variety of communication devices. A majority of the elements are integrated within the design and need not be implemented off-chip, and this can provide for a reduction in area required by the circuitry. A differential 100? input impedance is provided by this design. A higher than typical power supply voltage can be employed (if desired) to accommodate one possible implementation that includes two parallel implemented resistors to ground.Type: ApplicationFiled: October 18, 2007Publication date: April 23, 2009Applicant: BROADCOM CORPORATIONInventors: Yuyu Chang, Hooman Darabi
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Publication number: 20090102562Abstract: Cross-coupled low noise amplifier for cellular applications. A circuitry implementation that includes two pairs of metal oxide semiconductor field-effect transistors (MOSFETs) (either N-type of P-type) operates as an LNA, which can be used within any of a wide variety of communication devices. In one embodiment, this design is particularly adaptable to cellular telephone applications. A majority of the elements are integrated within the design and need not be implemented off-chip, and this can provide for a reduction in area required by the circuitry. A very high output impedance is provided by using two transistors (implemented in a triple well configuration) with resistive source degeneration. A higher than typical power supply voltage can be employed (if desired) to accommodate the voltage drops of the resistors and transistors.Type: ApplicationFiled: October 18, 2007Publication date: April 23, 2009Applicant: BROADCOM CORPORATIONInventors: Yuyu Chang, Hooman Darabi
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Patent number: 7411381Abstract: According to one general aspect, an apparatus includes a first resistor in a first current path of a resistor-capacitor (RC) circuit, the resistor connected to a power source. A variable capacitor is included in a second current path of the RC circuit and operably connected to the power source and a virtual ground generator. A comparison circuit is configured to make a determination regarding a voltage VR across the resistor to a ground relative to a voltage VC across the capacitor to a virtual ground from the virtual ground generator. A control circuit is configured to make an adjustment of a value of the variable capacitor, based on the determination.Type: GrantFiled: June 2, 2006Date of Patent: August 12, 2008Assignee: Broadcom CorporationInventors: Yuyu Chang, Hooman Darabi
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Publication number: 20080136463Abstract: Aspects of a method and system for an integrated LC resonant current gain boosting amplifier may include amplifying within a chip, via an on-chip LC current gain circuit, an alternating current (AC) generated by an on-chip voltage-to-current converter, and converting within the chip, via an on-chip current-to-voltage circuit; the amplified alternating current to an output voltage. The on-chip LC current gain circuit comprises only passive components, which may include one or more resistors, one or more capacitors, and one or more inductors.Type: ApplicationFiled: January 4, 2007Publication date: June 12, 2008Inventors: Yuyu Chang, Meng-An Pan
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Publication number: 20080136521Abstract: Aspects of a method and system for a low power fully differential noise canceling low noise amplifier (NC LNA) are provided. The NC LNA may receive signals via a single ended input and may generate an amplified symmetric differential output from the received signals. The NC LNA may utilize capacitor dividers, such as a capacitor bank, in the single ended input in order to provide impedance transformation that enables low power operation and matching to an input port. The NC LNA may generate one portion of the amplified symmetric differential output via a voltage divider, which may comprise a plurality of capacitors, such as a capacitor bank. The NC LNA may be implemented utilizing one or more circuits.Type: ApplicationFiled: March 30, 2007Publication date: June 12, 2008Inventor: Yuyu Chang
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Publication number: 20080139119Abstract: Aspects of a method and system for processing signals in a high performance receive chain may include amplifying radio frequency signals in amplifier chains in a multistandard radio frequency front-end, comprising one or more shared processing stages, and combining, with substantially equal gain, a number of phase-shifted radio frequency signals of the radio frequency signals into substantially equal-gain-combined radio frequency signals. The substantially equal-gain-combined radio frequency signals may be demodulated to obtain inphase channels and quadrature channels. A number of inphase channels and quadrature channels may be processed in I-channel processing blocks and Q-channel processing blocks to generate an output analog baseband signal. The multistandard radio frequency front-end may be capable of processing Bluetooth® signals and Wireless Local Area Network (WLAN) signals.Type: ApplicationFiled: April 9, 2007Publication date: June 12, 2008Inventors: Arya Behzad, Adedayo Ojo, Yuyu Chang, Hung-Ming Chien, Kishore Rama Rao, Guruprasad Seetharam