Patents by Inventor Li-Chung Chang

Li-Chung 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).

  • Publication number: 20160254789
    Abstract: A CMOS amplifier including electrostatic discharge (ESD) protection circuits is disclosed. In one embodiment, the CMOS amplifier may include a PMOS transistor, a NMOS transistor, primary protection diodes, and one or more auxiliary protection diodes to limit a voltage difference between terminals of the CMOS amplifier. In some embodiments, the auxiliary protection diodes may limit the voltage difference between an input terminal of the CMOS amplifier and a supply voltage, the input terminal of the CMOS amplifier and ground, and the input terminal and the output terminal of the CMOS amplifier.
    Type: Application
    Filed: February 26, 2015
    Publication date: September 1, 2016
    Inventors: Ahmed Abdel Monem Youssef, Prasad Srinivasa Siva Gudem, Eugene Robert Worley, Dongling Pan, Li-Chung Chang
  • Patent number: 9425832
    Abstract: A device includes a first amplifier circuit coupled to a first transformer and a second transformer, the first transformer selectively coupled to a first shared power distribution network through a first switch, the second transformer selectively coupled to a second shared power distribution network through a second switch.
    Type: Grant
    Filed: April 18, 2014
    Date of Patent: August 23, 2016
    Assignee: Qualcomm Incorporated
    Inventors: Ahmed Abdel Monem Youssef, Mehmet Uzunkol, Rui Xu, Ehab Ahmed Sobhy Abdel Ghany, Wingching Vincent Leung, Sang Hyun Woo, Allen He, Li-Chung Chang
  • Patent number: 9425746
    Abstract: A device includes an amplifier circuit comprising a plurality of amplification paths, and at least one switchable bypass capacitance coupled to an associated shared power distribution network, the at least one switchable bypass capacitance and at least one of the plurality of amplification paths responsive to a control signal configured to selectively ground the at least one switchable bypass capacitance and selectively enable the at least one of the amplification paths based on a selected operating mode.
    Type: Grant
    Filed: March 28, 2014
    Date of Patent: August 23, 2016
    Assignee: Qualcomm Incorporated
    Inventors: Mehmet Uzunkol, Rui Xu, Ahmed Abdel Monem Youssef, Wingching Vincent Leung, Ehab Ahmed Sobhy Abdel Ghany, Allen He, Sang Hyun Woo, Li-Chung Chang
  • Patent number: 9362958
    Abstract: A wireless communication device configured for receiving a multiple carrier signal is described. The wireless communication device includes a single-chip signal splitting carrier aggregation receiver architecture. The single-chip signal splitting carrier aggregation receiver architecture includes a primary antenna, a secondary antenna and a transceiver chip. The single-chip signal splitting carrier aggregation receiver architecture reuses a simultaneous hybrid dual receiver path.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: June 7, 2016
    Assignee: Qualcomm Incorporated
    Inventors: Prasad Srinivasa Siva Gudem, Gurkanwal Singh Sahota, Li-chung Chang, Christian Holenstein, Frederic Bossu
  • Patent number: 9350310
    Abstract: Techniques for providing a receiver front end supporting carrier aggregation with gain alignment and improved matching across modes. In an aspect, auxiliary circuitry is configurable to selectively enable or disable mutual coupling between a source degeneration inductor of an LNA input transistor and an auxiliary inductor. A negative turns ratio coupling is provided between the inductors, such that the effective inductance of the source degeneration inductor is lowered when mutually coupled to the auxiliary inductor. In a non-carrier aggregation (non-CA) mode, the auxiliary inductor is disabled, while in a carrier aggregation (CA) mode, the auxiliary inductor is enabled. In this manner, using a single transistor, gain alignment across non-CA and CA modes is achieved. Furthermore, matching is preserved across non-CA and CA modes using a single external matching component.
    Type: Grant
    Filed: May 24, 2013
    Date of Patent: May 24, 2016
    Assignee: Qualcomm Incorporated
    Inventors: Ahmed A Youssef, Li-Chung Chang
  • Patent number: 9300420
    Abstract: A receiver architecture for carrier aggregation is disclosed. In an exemplary design, an apparatus (e.g., a wireless device, a circuit module, etc.) includes a plurality of low noise amplifiers (LNAs), a plurality of switches, and at least one downconverter. The LNAs receive and amplify at least one input radio frequency (RF) signal and provide at least one amplified RF signal. The switches are coupled to the outputs of the plurality of LNAs. The at least one downconverter is coupled to the plurality of switches, downconverts the at least one amplified RF signal, and provides at least one downconverted signal. The switches reduce the number of downconverters needed to support reception of transmissions on multiple sets of carriers via multiple receive antennas. The LNAs and the switches may be implemented on at least one front-end module or a back-end module. The downconverter(s) are implemented on the back-end module.
    Type: Grant
    Filed: September 11, 2012
    Date of Patent: March 29, 2016
    Assignee: QUALCOMM Incorporated
    Inventors: Li-Chung Chang, Prasad Srinivasa Siva Gudem, Frederic Bossu, Christian Holenstein
  • Patent number: 9277641
    Abstract: Techniques for routing and shielding signal lines to improve isolation between the signal lines are disclosed. In an exemplary design, an apparatus includes first, second, and third signal lines and a switch. The first, second, and third signal lines are configurable to carry first, second, and third signals, respectively. The switch is coupled between the second signal line and AC ground and is closed when the second signal line is not carrying the second signal. The second signal line isolates the first and third signal lines when the switch is closed. Adjacent signal lines are not active at the same time. A signal line may include positive and negative signal lines, which may have at least one cross over in order to cancel coupling between the positive and negative signal lines.
    Type: Grant
    Filed: April 4, 2013
    Date of Patent: March 1, 2016
    Assignee: Qualcomm Incorporated
    Inventors: Ahmed Abdel Monem Youssef, Li-Chung Chang, Ehab Ahmed Sobhy Abdel Ghany, Rui Xu, Wingching Vincent Leung, Allen He
  • Patent number: 9252827
    Abstract: A wireless communication device configured for receiving a multiple carrier signal is described. The wireless communication device includes a primary signal splitting carrier aggregation architecture. The primary signal splitting carrier aggregation architecture includes a primary antenna and a transceiver chip. The primary signal splitting carrier aggregation architecture reuses a first diversity/simultaneous hybrid dual receiver path. The wireless communication device also includes a secondary signal splitting carrier aggregation architecture. The secondary signal splitting carrier aggregation architecture includes a secondary antenna and a receiver chip. The secondary signal splitting carrier aggregation architecture reuses a second diversity/simultaneous hybrid dual receiver path.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: February 2, 2016
    Assignee: QUALCOMM Incorporated
    Inventors: Prasad Srinivasa Siva Gudem, Udara C. Fernando, Li-Chung Chang
  • Publication number: 20150351131
    Abstract: An apparatus includes a first amplifier circuit and a second amplifier circuit. The first amplifier circuit has a first output coupled to a first load circuit in a multi-output mode, and the second amplifier circuit has a second output coupled to a second load circuit in the multi-output mode. The apparatus further includes a first divert circuit and a second divert circuit. The first divert circuit is configured to divert a first portion of a first amplified signal from the first amplifier circuit to the second load circuit in the multi-output mode. The second divert circuit is configured to divert a first portion of a second amplified signal from the second amplifier circuit to the first load circuit in the multi-output mode.
    Type: Application
    Filed: March 10, 2015
    Publication date: December 3, 2015
    Inventors: Sang Hyun Woo, Wingching Vincent Leung, Li-Chung Chang
  • Publication number: 20150341007
    Abstract: An apparatus includes a first amplification stage configured to amplify a first carrier signal and a second amplification stage configured to amplify a second carrier signal. The first amplification stage is direct-current (DC) coupled to the second amplification stage. First circuitry is coupled to the first amplification stage and configured to control a first gain of the first amplification stage. The first circuitry includes a first gain control transistor configured to selectively divert a first bleed current from a first output of the first amplification stage. Second circuitry is coupled to the second amplification stage and configured to control a second gain of the second amplification stage independently of the first gain. The second circuitry includes a second gain control transistor configured to selectively divert a second bleed current from a second output of the second amplification stage.
    Type: Application
    Filed: March 10, 2015
    Publication date: November 26, 2015
    Inventors: Ahmed Abdel Monem Youssef, Ehab Ahmed Sobhy Abdel Ghany, Li-Chung Chang
  • Publication number: 20150341859
    Abstract: An apparatus includes a first amplifier stage configured to amplify a first carrier signal. The apparatus includes a second amplifier stage configured to amplify a second carrier signal. A resistive-capacitive (RC) network is coupled to the first amplifier stage and to the second amplifier stage. The RC network includes a resistive element coupled to a capacitive element.
    Type: Application
    Filed: March 4, 2015
    Publication date: November 26, 2015
    Inventors: Ahmed Abdel Monem Youssef, Wingching Vincent Leung, Rui Xu, Udara Charman Fernando, Ketan Humnabadkar, Tsai-Chen Huang, Li-Chung Chang
  • Patent number: 9172402
    Abstract: A wireless communication device configured for receiving a wireless multiple-input and multiple-output signal. The wireless communication device includes a first multiple-input and multiple-output carrier aggregation receiver reuse architecture. The first multiple-input and multiple-output carrier aggregation receiver reuse architecture includes a first antenna, a second antenna and a transceiver chip. The first multiple-input and multiple-output carrier aggregation receiver reuse architecture reuses a first carrier aggregation receiver path. The wireless communication device also includes a second multiple-input and multiple-output carrier aggregation receiver reuse architecture. The second multiple-input and multiple-output carrier aggregation receiver reuse architecture includes a third antenna, a fourth antenna and a receiver chip. The second multiple-input and multiple-output carrier aggregation receiver reuse architecture reuses a second carrier aggregation receiver path.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: October 27, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Prasad Srinivasa Siva Gudem, Xiaoyin He, Tamer Adel Kadous, Li-Chung Chang
  • Patent number: 9166731
    Abstract: Techniques for providing low-cost and effective jammer rejection for a radio receiver. In an aspect, a notch filter is provided between a transformer and a differential mixer in the receiver. The notch frequency of the notch filter may be selected to correspond to an expected jammer frequency to effectively attenuate the jammer signal prior to down-conversion mixing by the mixer. The notch filter may be implemented using various techniques, e.g., an L-C combination having adjustable capacitance, and/or elliptic or Chebyshev filters.
    Type: Grant
    Filed: May 23, 2013
    Date of Patent: October 20, 2015
    Assignee: Qualcomm Incorporated
    Inventors: Li-Chung Chang, Ehab A Abdel Ghany, Ahmed A Youssef
  • Patent number: 9154243
    Abstract: Techniques for calibrating a receiver based on a local oscillator (LO) signal from another receiver are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes first and second local oscillator (LO) generators. The first LO generator generates a first LO signal used by a first receiver for frequency downconversion. The second LO generator generates a second LO signal used by a second receiver for frequency downconversion in a first operating mode. The second LO signal is used to generate a test signal for the first receiver in a second operating mode. The second LO signal may be provided as the test signal or may be amplitude modulated with a modulating signal to generate the test signal. The test signal may be used to calibrate residual sideband (RSB), second order input intercept point (IIP2), receive path gain, etc.
    Type: Grant
    Filed: February 26, 2013
    Date of Patent: October 6, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Udara C. Fernando, Li-Chung Chang, Vijay K. Chellappa, Frederic Bossu, Ketan Humnabadkar, Gurkanwal Singh Sahota
  • Patent number: 9154087
    Abstract: Amplifiers with configurable mutually-coupled source degeneration inductors are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes a gain transistor and a plurality of inductors, which may implement an amplifier. The gain transistor receives an input signal and provides an amplified signal. The plurality of inductors are mutually coupled, are coupled to the gain transistor, and provide a programmable source degeneration inductance for the gain transistor. The inductors may have a positive coupling coefficient and may provide a larger source degeneration inductance. Alternatively, the inductors may have a negative coupling coefficient and may provide a smaller source degeneration inductance.
    Type: Grant
    Filed: August 1, 2013
    Date of Patent: October 6, 2015
    Assignee: Qualcomm Incorporated
    Inventors: Zhang Jin, Ahmed A. Youssef, Li-Chung Chang
  • Patent number: 9154179
    Abstract: A receiver with bypass mode for improved sensitivity is disclosed. An apparatus is provided that includes a non-bypass signal path coupled to a receiver, the non-bypass signal path comprising a filter, a bypass signal path coupled to the receiver, the bypass signal path configure to bypass the filter, and a switch configured to couple an antenna to the non-bypass signal path during time intervals when signals transmitted by a related local transmitter are transmitted with a signal power that exceeds a threshold, and to couple the antenna to the bypass signal path during other time intervals. In another aspect, the switch is configured to couple the antenna to the non-bypass signal path during time intervals when a jamming signal in a selected frequency range is received with a signal power that exceeds a threshold, and to couple the antenna to the bypass signal path during other time intervals.
    Type: Grant
    Filed: June 29, 2011
    Date of Patent: October 6, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Prasad Srinivasa Siva Gudem, Tamer Adel Kadous, Sumit Verma, Li-chung Chang
  • Publication number: 20150280661
    Abstract: A device includes at least one first amplifier circuit configurable to receive and amplify an input radio frequency (RF) signal having a first carrier at a first input signal level and provide a first amplified RF signal, and at least one second amplifier circuit configurable to receive and amplify the input RF signal having a second carrier at a second input signal level and provide a second amplified RF signal, the at least one first amplifier circuit having a first input impedance, the at least one second amplifier circuit having a second input impedance.
    Type: Application
    Filed: March 28, 2014
    Publication date: October 1, 2015
    Applicant: QUALCOMM Incorporated
    Inventors: Rui Xu, Allen He, Wingching Vincent Leung, Ahmed Abdel Monem Youssef, Ehab Ahmed Sobhy Abdel Ghany, Sang Hyun Woo, Li-Chung Chang
  • Publication number: 20150280651
    Abstract: A device includes an amplifier circuit comprising a plurality of amplification paths, and at least one switchable bypass capacitance coupled to an associated shared power distribution network, the at least one switchable bypass capacitance and at least one of the plurality of amplification paths responsive to a control signal configured to selectively ground the at least one switchable bypass capacitance and selectively enable the at least one of the amplification paths based on a selected operating mode.
    Type: Application
    Filed: March 28, 2014
    Publication date: October 1, 2015
    Applicant: QUALCOMM Incorporated
    Inventors: Mehmet Uzunkol, Rui Xu, Ahmed Abdel Monem Youssef, Wingching Vincent Leung, Ehab Ahmed Sobhy Abdel Ghany, Allen He, Sang Hyun Woo, Li-Chung Chang
  • Patent number: 9130529
    Abstract: A device includes a first and a second low noise amplifier (LNA), a first degenerative inductance coupled between the first LNA and ground by a first ground connection, and a second degenerative inductance coupled between the second LNA and ground by a second ground connection, the first and second degenerative inductances configured to establish negative inductive coupling between the first and second degenerative inductances.
    Type: Grant
    Filed: January 17, 2014
    Date of Patent: September 8, 2015
    Assignee: Qualcomm Incorporated
    Inventors: Ehab Ahmed Sobhy Abdel Ghany, Sang Hyun Woo, Wingching Vincent Leung, Zhang Jin, Li-Chung Chang
  • Patent number: 9124228
    Abstract: Amplifiers with boosted or deboosted source degeneration inductance are disclosed. In an exemplary design, an apparatus includes an amplifier circuit and a feedback circuit. The amplifier circuit receives an input signal and provides an output signal and includes a source degeneration inductor. The feedback circuit is coupled between a node of the amplifier circuit and the source degeneration inductor. The feedback circuit provides feedback to vary an input impedance of an amplifier including the amplifier circuit and the feedback circuit. The feedback circuit may be programmable and may be enabled to provide feedback or disabled to provide no feedback. Alternatively, the feedback circuit may always be enabled to provide feedback. In either case, the feedback circuit may have a variable gain to provide a variable input impedance for the amplifier.
    Type: Grant
    Filed: April 4, 2013
    Date of Patent: September 1, 2015
    Assignee: Qualcomm Incorporated
    Inventors: Rui Xu, Li-Chung Chang