Patents by Inventor Xiao Hong Du

Xiao Hong Du 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).

  • Patent number: 11533027
    Abstract: Data isolators are described. The data isolators include a differential receiver having cross-coupled single-ended amplifiers. The single-ended amplifiers may be referenced to a time-varying reference potential. The cross-coupling of the single-ended amplifiers may provide high speed, low power consumption operation of the data isolator.
    Type: Grant
    Filed: October 18, 2019
    Date of Patent: December 20, 2022
    Assignee: Analog Devices, Inc.
    Inventor: Xiao Hong Du
  • Publication number: 20210119590
    Abstract: Data isolators are described. The data isolators include a differential receiver having cross-coupled single-ended amplifiers. The single-ended amplifiers may be referenced to a time-varying reference potential. The cross-coupling of the single-ended amplifiers may provide high speed, low power consumption operation of the data isolator.
    Type: Application
    Filed: October 18, 2019
    Publication date: April 22, 2021
    Applicant: Analog Devices, Inc.
    Inventor: Xiao Hong Du
  • Patent number: 9813035
    Abstract: Systems and methods disclosed herein provide for enhancing the low frequency (DC) gain of an operational amplifier with multiple correlated level shifting capacitors. In an embodiment, the operational amplifier is level shifted with a first correlated level shifting capacitor in a first phase and, then, is level shifted again with at least a second correlated level shifting capacitor in at least a second, non-overlapping, consecutive phase. In an embodiment, the multiple correlated level capacitors are controlled by a switching circuit network.
    Type: Grant
    Filed: November 2, 2015
    Date of Patent: November 7, 2017
    Assignee: Analog Devices, Inc.
    Inventors: Zhichao Tan, Khiem Quang Nguyen, Xiao Hong Du
  • Publication number: 20170126189
    Abstract: Systems and methods disclosed herein provide for enhancing the low frequency (DC) gain of an operational amplifier with multiple correlated level shifting capacitors. In an embodiment, the operational amplifier is level shifted with a first correlated level shifting capacitor in a first phase and, then, is level shifted again with at least a second correlated level shifting capacitor in at least a second, non-overlapping, consecutive phase. In an embodiment, the multiple correlated level capacitors are controlled by a switching circuit network.
    Type: Application
    Filed: November 2, 2015
    Publication date: May 4, 2017
    Inventors: Zhichao Tan, Khiem Quang Nguyen, Xiao Hong Du
  • Patent number: 7652909
    Abstract: The signal margin of a small array 2T/2C memory is increased by writing the ferroelectric load capacitors on the bit lines to complementary states.
    Type: Grant
    Filed: October 21, 2007
    Date of Patent: January 26, 2010
    Assignee: Ramtron International Corporation
    Inventor: Xiao Hong Du
  • Patent number: 7570090
    Abstract: A power-on reset circuit includes a first PNP transistor having an emitter, a base, and a collector coupled to ground; a second PNP transistor having an emitter coupled to the base of the first transistor, and a base and collector coupled to ground; a third PNP transistor having an emitter, a base coupled to the base of the first transistor, and a collector coupled to ground; a first resistor coupled between VDD and an internal node; a second resistor coupled between VDD and the emitter of the first transistor; a third resistor coupled between the internal node and the emitter of the third transistor; and a comparator having a first input coupled to the internal node and a second input coupled to the emitter of the first transistor for generating a power-on reset signal.
    Type: Grant
    Filed: October 30, 2007
    Date of Patent: August 4, 2009
    Assignee: Ramtron International Corporation
    Inventor: Xiao Hong Du
  • Publication number: 20090108887
    Abstract: A power-on reset circuit includes a first PNP transistor having an emitter, a base, and a collector coupled to ground; a second PNP transistor having an emitter coupled to the base of the first transistor, and a base and collector coupled to ground; a third PNP transistor having an emitter, a base coupled to the base of the first transistor, and a collector coupled to ground; a first resistor coupled between VDD and an internal node; a second resistor coupled between VDD and the emitter of the first transistor; a third resistor coupled between the internal node and the emitter of the third transistor; and a comparator having a first input coupled to the internal node and a second input coupled to the emitter of the first transistor for generating a power-on reset signal.
    Type: Application
    Filed: October 30, 2007
    Publication date: April 30, 2009
    Applicant: RAMTRON INTERNATIONAL CORPORATION
    Inventor: Xiao Hong Du
  • Publication number: 20090103348
    Abstract: The signal margin of a small array 2T/2C memory is increased by writing the ferroelectric load capacitors on the bit lines to complementary states.
    Type: Application
    Filed: October 21, 2007
    Publication date: April 23, 2009
    Applicant: RAMTRON INTERNATIONAL CORPORATION
    Inventor: Xiao Hong Du
  • Patent number: 7313010
    Abstract: A ferroelectric reference circuit generates a reference voltage proportional to (P+U)/2 and is automatically centered between the bit line voltages corresponding to the P term and the U term across wide temperature and voltage ranges. To avoid fatiguing the reference ferroelectric capacitors generating (P+U)/2, the reference voltage is refreshed once every millisecond. To eliminate the variation of the reference voltage due to the leakage in the ferroelectric capacitors during this period of time, the reference voltage generated from the reference ferroelectric capacitors is digitized when it is refreshed. The digital value is fixed and converted to an analog value which is then fed into sense amplifiers for resolving the data states. The reference voltage is automatically at the center of the switching (P) and non-switching (U) signals and therefore the signal margin is maximized.
    Type: Grant
    Filed: June 23, 2006
    Date of Patent: December 25, 2007
    Assignee: Ramtron International Corporation
    Inventors: Shan Sun, Xiao-Hong Du, Fan Chu, Bob Sommervold
  • Patent number: 7271744
    Abstract: An encoder utilizes a coding method for use with ferroelectric or other nonvolatile counters which are subject to imprint ensures that all of the bits in the code are frequently switched and not left in a fixed data state. The general coding equation for this method is such that: for an even integer n, it is represented by the conventional binary code of n/2; for an odd integer n, it is represented by the conventional binary code of the one's compliment of (n?1)/2. With this method, every bit switches to its compliment when counting from an even number to an odd number so that imprint is substantially reduced.
    Type: Grant
    Filed: December 14, 2006
    Date of Patent: September 18, 2007
    Assignee: Ramtron International
    Inventors: Xiao Hong Du, Dennis C. Young
  • Patent number: 7233194
    Abstract: This invention is a new CMOS voltage booster (20) having an output which can be used in memories to boost the word line voltage above VDD or other voltage boosting applications. The CMOS booster includes a NMOS FET (MN1) to charge a boosting capacitor (C1) to VDD at the end of each memory access and includes a PMOS FET (MP1, MP2) to keep the voltage at the output at VDD during standby. By using this combination, the word line rise time, the size of the booster, and the power consumption during access are significantly reduced. The gate of the NMOS FET (MN1) is boosted above VDD+Vthn by a small capacitor (C2) to charge the word line boosting capacitor to VDD at the end of each memory access. The small capacitor (C2) is pre-charged to VDD by a NMOSFET (MN2) whose gate is connected to the word line boosting capacitor. The gate of each PMOS FET (MP1, MP2) is shorted to its source to turn if off during boostenig. Transistor (MP3) facilitates boosting the NMOS FET (MN1) above VDD.
    Type: Grant
    Filed: October 9, 2003
    Date of Patent: June 19, 2007
    Assignee: Texas Instruments Incorporated
    Inventors: Xiao Hong Du, Jarrod Eliason, Yunchen Qiu, Bill Kraus
  • Patent number: 7176824
    Abstract: An encoder utilizes a coding method for use with ferroelectric or other nonvolatile counters which are subject to imprint ensures that all of the bits in the code are frequently switched and not left in a fixed data state. The general coding equation for this method is such that: for an even integer n, it is represented by the conventional binary code of n/2; for an odd integer n, it is represented by the conventional binary code of the one's compliment of (n?1)/2. With this method, every bit switches to its compliment when counting from an even number to an odd number so that imprint is substantially reduced.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: February 13, 2007
    Assignee: Ramtron International
    Inventors: Xiao Hong Du, Dennis C. Young
  • Patent number: 7142627
    Abstract: A counting scheme for a non-volatile counter includes automatic point-of-reference generation implemented in a state machine. Two state variables are used to store the rotation history of the magnet. One variable stores the previous position of the magnet and the other stores the net angle traveled by the magnet from the reference point. The first pulse location after the counter is reset is automatically selected as the reference point until the next counter reset. When the nonvolatile counter counts up or down, i.e. when the magnet travels 360° in either direction, the second state variable is set to zero and the first state variable is set to the reference point, indicating the start of a new revolution.
    Type: Grant
    Filed: March 17, 2005
    Date of Patent: November 28, 2006
    Assignee: Ramtron International Corporation
    Inventors: Xiao-Hong Du, Craig Taylor
  • Publication number: 20060245286
    Abstract: A ferroelectric reference circuit generates a reference voltage proportional to (P+U)/2 and is automatically centered between the bit line voltages corresponding to the P term and the U term across wide temperature and voltage ranges. To avoid fatiguing the reference ferroelectric capacitors generating (P+U)/2, the reference voltage is refreshed once every millisecond. To eliminate the variation of the reference voltage due to the leakage in the ferroelectric capacitors during this period of time, the reference voltage generated from the reference ferroelectric capacitors is digitized when it is refreshed. The digital value is fixed and converted to an analog value which is then fed into sense amplifiers for resolving the data states. The reference voltage is automatically at the center of the switching (P) and non-switching (U) signals and therefore the signal margin is maximized.
    Type: Application
    Filed: June 23, 2006
    Publication date: November 2, 2006
    Inventors: Shan SUN, Xiao-Hong Du, Fan Chu, Bob Sommervold
  • Patent number: 7120220
    Abstract: A non-volatile counter circuit includes a state machine having a first input for receiving one or more control signals, a second input for receiving a current count value, a third input for receiving historical information, and an output for providing a next count value and an up/down control signal, and a non-volatile counter having an input coupled to the output of the state machine, and an output for providing a non-volatile count value. The non-volatile counter can be implemented onto a single integrated circuit using ferroelectric memory technology. The non-volatile counter circuit includes a first power supply node and a second power supply node for receiving power for operating the non-volatile-counter circuit through a first power supply or a second power supply, or both. The first and second power supplies can be low energy power supplies such as that provided by a sensor, or can be conventional power supplies.
    Type: Grant
    Filed: December 23, 2004
    Date of Patent: October 10, 2006
    Assignee: Ramtron International Corporation
    Inventors: Xiao-Hong Du, Craig Taylor
  • Patent number: 7116572
    Abstract: A ferroelectric reference circuit generates a reference voltage proportional to (P+U)/2 and is automatically centered between the bit line voltages corresponding to the P term and the U term across wide temperature and voltage ranges. To avoid fatiguing the reference ferroelectric capacitors generating (P+U)/2, the reference voltage is refreshed once every millisecond. To eliminate the variation of the reference voltage due to the leakage in the ferroelectric capacitors during this period of time, the reference voltage generated from the reference ferroelectric capacitors is digitized when it is refreshed. The digital value is fixed and converted to an analog value which is then fed into sense amplifiers for resolving the data states. The reference voltage is automatically at the center of the switching (P) and non-switching (U) signals and therefore the signal margin is maximized.
    Type: Grant
    Filed: November 9, 2004
    Date of Patent: October 3, 2006
    Assignee: Ramtron International Corporation
    Inventors: Shan Sun, Xiao-Hong Du, Fan Chu, Bob Sommervold
  • Publication number: 20060140331
    Abstract: A non-volatile counter circuit includes a state machine having a first input for receiving one or more control signals, a second input for receiving a current count value, a third input for receiving historical information, and an output for providing a next count value and an up/down control signal, and a non-volatile counter having an input coupled to the output of the state machine, and an output for providing a non-volatile count value. The non-volatile counter can be implemented onto a single integrated circuit using ferroelectric memory technology. The non-volatile counter circuit includes a first power supply node and a second power supply node for receiving power for operating the non-volatile-counter circuit through a first power supply or a second power supply, or both. The first and second power supplies can be low energy power supplies such as that provided by a sensor, or can be conventional power supplies.
    Type: Application
    Filed: December 23, 2004
    Publication date: June 29, 2006
    Inventors: Xiao-Hong Du, Craig Taylor
  • Publication number: 20060140332
    Abstract: A counting scheme for a non-volatile counter includes automatic point-of-reference generation implemented in a state machine. Two state variables are used to store the rotation history of the magnet. One variable stores the previous position of the magnet and the other stores the net angle traveled by the magnet from the reference point. The first pulse location after the counter is reset is automatically selected as the reference point until the next counter reset. When the nonvolatile counter counts up or down, i.e. when the magnet travels 360° in either direction, the second state variable is set to zero and the first state variable is set to the reference point, indicating the start of a new revolution.
    Type: Application
    Filed: March 17, 2005
    Publication date: June 29, 2006
    Inventors: Xiao-Hong Du, Craig Taylor
  • Publication number: 20060098470
    Abstract: A ferroelectric reference circuit generates a reference voltage proportional to (P+U)/2 and is automatically centered between the bit line voltages corresponding to the P term and the U term across wide temperature and voltage ranges. To avoid fatiguing the reference ferroelectric capacitors generating (P+U)/2, the reference voltage is refreshed once every millisecond. To eliminate the variation of the reference voltage due to the leakage in the ferroelectric capacitors during this period of time, the reference voltage generated from the reference ferroelectric capacitors is digitized when it is refreshed. The digital value is fixed and converted to an analog value which is then fed into sense amplifiers for resolving the data states. The reference voltage is automatically at the center of the switching (P) and non-switching (U) signals and therefore the signal margin is maximized.
    Type: Application
    Filed: November 9, 2004
    Publication date: May 11, 2006
    Inventors: Shan Sun, Xiao-Hong Du, Fan Chu, Bob Sommervold
  • Patent number: 6909318
    Abstract: This invention is a new CMOS voltage booster (20) having an output which can be used in memories to boost the word line voltage above VDD or other voltage boosting applications. The CMOS booster includes a NMOS FET (MN1) to charge a boosting capacitor (C1) to VDD at the end of each memory access and includes a PMOS FET (MP1, MP2) to keep the voltage at the output at VDD during standby. By using this combination, the word line rise time, the size of the booster, and the power consumption during access are significantly reduced. The gate of the NMOS FET (MN1) is boosted above VDD+Vthn by a small capacitor (C2) to charge the word line boosting capacitor to VDD at the end of each memory access. The small capacitor (C2) is pre-charged to VDD by a NMOSFET (MN2) whose gate is connected to the word line boosting capacitor. The gate of each PMOS FET (MP1, MP2) is shorted to ists source to turn if off during boostenig. Ttransistor (MP3) facilitates boosting the NMOS FET (MN1) above VDD.
    Type: Grant
    Filed: August 27, 2003
    Date of Patent: June 21, 2005
    Assignee: Texas Instruments Incorporated
    Inventors: Xiao Hong Du, Jarrod Eliason, Yunchen Qiu, Bill Kraus