Patents by Inventor Dean Liu

Dean Liu 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: 6762505
    Abstract: A 150 degree bump placement layout for an integrated circuit power grid is provided. This layout improves integrated circuit performance and reliability and gives an integrated circuit designer added flexibility and uniformity in designing the integrated circuit. Further, a patterned bump array for a top metal layer of an integrated circuit having a plurality of 150 degree bump placement structures is provided.
    Type: Grant
    Filed: November 29, 2001
    Date of Patent: July 13, 2004
    Assignee: Sun Microsystems
    Inventors: Sudhakar Bobba, Tyler Thorp, Dean Liu, Pradeep Trivedi
  • Patent number: 6753740
    Abstract: A calibration and adjustment system for post-fabrication control of a phase locked loop bias-generator is provided. The calibration and adjustment system includes an adjustment circuit operatively connected to the bias-generator, where the adjustment circuit is controllable to facilitate a modification of a voltage output by the bias-generator. Such control of the voltage output by the bias-generator allows a designer to achieve a desired phase locked loop performance characteristic after the phase locked loop has been fabricated. A representative value of the amount of adjustment desired in the bias-generator output may be stored and subsequently read to adjust the phase locked loop.
    Type: Grant
    Filed: May 17, 2002
    Date of Patent: June 22, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Claude Gauthier, Brian W. Amick, Pradeep Trivedi, Dean Liu
  • Patent number: 6748339
    Abstract: A method for estimating accuracy of an on-chip temperature sensor is provided. A representative power supply waveform having noise is input into a simulation of the on-chip temperature sensor and the accuracy of the on-chip temperature sensor is estimated from the simulation. A computer system for estimating accuracy of an on-chip temperature sensor is also provided. A computer-readable medium having instructions adapted to input a representative power supply waveform having noise into a simulation of an on-chip temperature sensor and estimate accuracy of the on-chip temperature sensor from the simulation is provided.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: June 8, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Brian Amick, Claude Gauthier, Dean Liu, Pradeep Trivedi
  • Patent number: 6731894
    Abstract: The present invention is directed to a shutter system for electrophotographic machines that effectively reduces the impact of ambient light on the photoreceptor, or image-bearing member. The shutter system of the present invention utilizes a shutter member that substantially covers the cartridge chamber when in a closed position. Preferably, the shutter member is disposed at the opening of the cartridge chamber. The shutter member is held in place by one or more support brackets and is biased to the closed position by one or more springs.
    Type: Grant
    Filed: May 17, 2002
    Date of Patent: May 4, 2004
    Assignee: Aetas Technology Inc.
    Inventor: Dean Liu
  • Patent number: 6727737
    Abstract: A delay locked loop design uses a diode operatively connected to a loop filter capacitor to control a leakage current of the loop filter capacitor. By positioning a diode in series with the loop filter capacitor, a voltage potential across the loop filter capacitor is reduced, thereby reducing the leakage current of the loop filter capacitor. Moreover, the leakage current of the loop filter capacitor is controlled in that it cannot exceed the current through the diode. Control and reduction of the loop filter capacitor leakage current leads to more reliable and stable delay locked loop behavior.
    Type: Grant
    Filed: July 19, 2002
    Date of Patent: April 27, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Pradeep Trivedi, Claude Gauthier, Dean Liu
  • Patent number: 6704680
    Abstract: A method for optimizing a decoupling capacitance for an on-chip temperature sensor is provided. A representative power supply waveform having noise is input into a simulation of the on-chip temperature sensor; a difference between a temperature representative input and a temperature dependent output of the on-chip temperature sensor is determined; and an amount of the decoupling capacitance is adjusted until the difference falls below a pre-selected value. A computer system for optimizing a decoupling capacitance for an on-chip temperature sensor is also provided. A computer-readable medium having recorded thereon instructions executable by a processor for optimizing a decoupling capacitance for an on-chip temperature sensor is further provided.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: March 9, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Brian Amick, Claude Gauthier, Pradeep Trivedi, Dean Liu
  • Patent number: 6691291
    Abstract: A method for estimating jitter in a delay locked loop is provided. The estimation is determined from a simulation that uses a representative power supply waveform having noise as an input. Further, a computer system for estimating jitter in a delay locked loop is provided. Further, a computer-readable medium having recorded thereon instructions adapted to estimate jitter in a delay locked loop is provided.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: February 10, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Claude Gauthier, Brian Amick, Dean Liu, Pradeep Trivedi
  • Patent number: 6686785
    Abstract: An integrated circuit has a plurality of sections, each having a phase detector and a control delay circuit. The phase detector, in response to a phase difference between a reference clock signal and a feedback signal from a portion of a clock grid, controls the delay of its associated clock delay circuit, which, in turn, outputs to the portion of the clock grid. The feedback signal to the phase detector may be connected to an output of a DLL or another portion of the clock grid controlled by a clock delay circuit not associated with the phase detector. Such an arrangement on the integrated circuit leads to clock grid skew reduction.
    Type: Grant
    Filed: October 11, 2001
    Date of Patent: February 3, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Dean Liu, Tyler J. Thorp, Pradeep R. Trivedi, Gin S. Yee, Claude R. Gauthier
  • Patent number: 6687881
    Abstract: A method for optimizing loop bandwidth in a delay locked loop is provided. A representative power supply waveform having noise is input into a simulation of the delay locked loop; an estimate of jitter is determined; and the loop bandwidth of the delay looked loop is adjusted until the jitter falls below a pre-selected value. Further, a computer system for optimizing loop bandwidth in a delay locked loop is provided. Further, a computer-readable medium having recorded thereon instructions adapted to optimize loop bandwidth in a delay locked loop is provided.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: February 3, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Claude Gauthier, Brian Amick, Dean Liu, Pradeep Trivedi
  • Publication number: 20040017873
    Abstract: A delay locked loop characterization technique for automatically characterizing a delay locked loop is provided. The technique tests the delay locked loop using a top-down approach in order to ensure the robustness of the delay locked loop. Top-level testing involves testing the performance of the delay locked loop in different process corners, and the results obtained from the top-level testing are then used to test sub-components of the delay locked loop.
    Type: Application
    Filed: July 25, 2002
    Publication date: January 29, 2004
    Inventors: Kian Chong, Dean Liu, Claude Gauthier
  • Publication number: 20040012428
    Abstract: A device that uses an input clock signal to generate an output clock signal with a desired frequency is provided. The device uses a voltage controlled delay element that outputs a reset signal to a flip-flop dependent on a bias signal and the input clock signal. When triggered, the flip-flop outputs a transition on the output clock signal, which, in turn, serves as an input to a duty cycle corrector that generates the bias signal dependent on the configuration of the duty cycle corrector. The duty cycle corrector may be configured to generate the bias signal so as to be able to operatively control the duty cycle of the output clock signal.
    Type: Application
    Filed: July 18, 2002
    Publication date: January 22, 2004
    Inventors: Gin Yee, Sudhakar Bobba, Claude Gauthier, Dean Liu, Lynn Ooi, Pradeep Trivedi
  • Publication number: 20040012420
    Abstract: A delay locked loop implementing design-for-test features to test for, among other, stuck-at-faults is provided. The delay locked loop uses multiplexers as design-for-test devices for controllability purposes and flip-flops as design-for-test devices for observability purposes. Such implementation of design-for-test features within a delay locked loop allows for pre-packaging delay locked loop verification and testing.
    Type: Application
    Filed: July 16, 2002
    Publication date: January 22, 2004
    Inventors: Aninda Roy, Claude Gauthier, Brian Amick, Dean Liu
  • Publication number: 20040012426
    Abstract: A delay locked loop design that uses a diode operatively connected to a loop filter capacitor to control a leakage current of the loop filter capacitor is provided. By positioning a diode in series with the loop filter capacitor, a voltage potential across the loop filter capacitor is reduced, thereby reducing the leakage current of the loop filter capacitor. Moreover, the leakage current of the loop filter capacitor is controlled in that it cannot exceed the current through the diode. Control and reduction of the loop filter capacitor leakage current leads to more reliable and stable delay locked loop behavior.
    Type: Application
    Filed: July 19, 2002
    Publication date: January 22, 2004
    Inventors: Pradeep Trivedi, Claude Gauthier, Dean Liu
  • Publication number: 20040015751
    Abstract: A technique for adjusting a communication system involves a link, where the link includes a data line arranged to transmit a data signal and a clock line adapted to transmit a clock signal. The technique uses one or more counters to test the transmission across the link. Dependent on one or more of these counters, a test circuit, connected to the link, compares a known test pattern signal to a latched test pattern signal transmitted on the data line. The test circuit includes an adjustment circuit arranged to generate an adjustable clock signal from the clock signal, where the adjustable clock signal determines when to latch the transmitted test pattern signal The test circuit adjusts a timing of the adjustable clock signal relative to the data signal of the link.
    Type: Application
    Filed: July 16, 2002
    Publication date: January 22, 2004
    Inventors: Claude R. Gauthier, Aninda K. Roy, Brian W. Amick, Dean Liu
  • Patent number: 6671863
    Abstract: A method for optimizing loop bandwidth in a phase locked loop is provided. A representative power supply waveform having noise is input into a simulation of the phase locked loop; an estimate of jitter is determined; and the loop bandwidth of the phase looked loop is adjusted until the jitter falls below a pre-selected value. Further, a computer system for optimizing loop bandwidth in a phase locked loop is provided. Further, a computer-readable medium having recorded thereon instructions adapted to optimize loop bandwidth in a phase locked loop is provided.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: December 30, 2003
    Assignee: Sun Microsystems, Inc.
    Inventors: Claude Gauthier, Brian Amick, Dean Liu, Pradeep Trivedi
  • Patent number: 6664828
    Abstract: A post-silicon technique for adjusting a current of a charge pump in a phase locked loop is provided. The technique involves use of an adjustment circuit operatively connected to the charge pump, where the adjustment circuit is controllable to facilitate an internal biasing of the charge pump. Such control of the charge pump current in a phase locked loop allows a designer to achieve desired PLL performance characteristics after the PLL has been fabricated.
    Type: Grant
    Filed: April 24, 2002
    Date of Patent: December 16, 2003
    Assignee: Sun Microsystems, Inc.
    Inventors: Claude Gauthier, Brian Amick, Pradeep Trivedi, Dean Liu
  • Patent number: 6664831
    Abstract: A charge pump design that facilitates post-fabrication control of delay locked loop charge pump current is provided. The charge pump includes an adjustment device responsive to user controlled signals that are varied to achieve a desired amount of charge pump current. Such control of the charge pump current in a delay locked loop allows a designer to achieve a desired DLL performance characteristic after the DLL has been fabricated.
    Type: Grant
    Filed: April 24, 2002
    Date of Patent: December 16, 2003
    Assignee: Sun Microsystems, Inc.
    Inventors: Claude Gauthier, Brian Amick, Dean Liu, Pradeep Trivedi
  • Patent number: 6662126
    Abstract: A method and apparatus to determine skew of an on-chip signal without physical probing of the on-chip signal on the chip is provided. The method and apparatus use an externally generated reference signal that is distributed to one or more on-chip samplers that input the on-chip signal. Then, by modulating the externally generated reference signal, transitions of the on-chip signal can be detected at the one or more on-chip samplers so that the skew of the on-chip signal can be determined.
    Type: Grant
    Filed: August 14, 2001
    Date of Patent: December 9, 2003
    Assignee: Sun Microsystems, Inc.
    Inventors: Dean Liu, Gin S. Yee, Tyler J. Thorp, Pradeep R. Trivedi
  • Publication number: 20030215263
    Abstract: A spacing device for image processing systems to maintain a development gap between an image-receiving member and a developer roller thereby facilitating efficient development and consistently maintaining high image quality and methods for manufacturing and using the same. The spacing device comprises one or more spacing members that have preselected lengths and that are configured to be coupled with, and extend from, an imaging-receiving module and/or a developer cartridge of an image processing system. When the image processing system is properly assembled, a predetermined development gap is formed between an image-receiving member of the imaging-receiving module and a developer roller of the developer cartridge, and the spacing members are disposed substantially between, and in contact with, the imaging-receiving module and the developer cartridge. The spacing members, being formed from a substantially rigid material, are configured to maintain the predetermined development gap.
    Type: Application
    Filed: May 18, 2002
    Publication date: November 20, 2003
    Applicant: AETAS TECHNOLOGY INC
    Inventor: Dean Liu
  • Publication number: 20030215042
    Abstract: An adjustment and calibration system for post-fabrication treatment of a phase locked loop input receiver is provided. The adjustment and calibration system includes at least one adjustment circuit, to which the phase locked loop input receiver is responsive, and a storage device that selectively stores control information (1) associated with a state of the adjustment circuit and/or (2) from a tester that writes such control information to the storage device, where the control information stored in the storage device is subsequently selectively read out in order to adjust the adjustment circuit to a state corresponding to the control information.
    Type: Application
    Filed: May 17, 2002
    Publication date: November 20, 2003
    Inventors: Claude R. Gauthier, Brian W. Amick, Pradeep Trivedi, Dean Liu