Patents by Inventor Che Leung

Che Leung 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: 20060203405
    Abstract: An ESD clamp circuit for use between separate power rails. An ESD clamp is based on a wide nMOSFET. A symmetrical circuit is designed vis-à-vis the two power rails, with respect to ground, allowing discharge of an ESD surge in both polarities of stress. An nMOSFET device drives the gate of a large nMOSFET (e.g., having a device width between 1000 and 10,000 microns). The large power rail-to-power rail nMOSFET has its gate controlled by the output inverter stage of either ESD detection circuit connected to a respective power supply rail. The gate is switched to a common ground during normal operation of the integrated circuit.
    Type: Application
    Filed: March 11, 2005
    Publication date: September 14, 2006
    Inventors: Dipankar Bhattacharya, John Kriz, Che Leung, Duane Loeper, Yehuda Smooha
  • Publication number: 20060176626
    Abstract: An ESD power clamp utilizes both a transient triggering method integrated together with a voltage level detection circuit to disable a MOSFET transistor forming the ESD power clamp unless the voltage level on a relevant power supply rail is higher than a predetermined level above the normal power supply voltage. When the voltage level of the power supply rail is higher than the predetermined level (e.g., 10% higher, 25% higher, etc.), then the power surge is presumed to be an ESD pulse, and thus the ESD power clamp is enabled to turn ON and discharge the ESD power surge.
    Type: Application
    Filed: February 4, 2005
    Publication date: August 10, 2006
    Inventors: William Griesbach, Che Leung
  • Publication number: 20060054994
    Abstract: The specification describes matched capacitor pairs that employ interconnect metal in an interdigitated form, and are made with an area efficient configuration. In addition, structural variations between capacitors in the capacitor pair are minimized to provide optimum matching. According to the invention, the capacitor pairs are interdigitated in a manner that ensures that the plates of each pair occupy common area on the substrate. Structural anomalies due to process conditions are compensated in that a given anomaly affects both capacitors in the same way. Two of the capacitor plates, one in each pair, are formed of comb structures, with the fingers of the combs interdigitated. The other plates are formed using one or more plates interleaved between the interdigitated plates.
    Type: Application
    Filed: November 2, 2005
    Publication date: March 16, 2006
    Inventors: Edward Harris, Canzhong He, Che Leung, Bruce McNeill
  • Publication number: 20060006496
    Abstract: The specification describes matched capacitor pairs that employ interconnect metal in an interdigitated form, and are made with an area efficient configuration. In addition, structural variations between capacitors in the capacitor pair are minimized to provide optimum matching. According to the invention, the capacitor pairs are interdigitated in a manner that ensures that the plates of each pair occupy common area on the substrate. Structural anomalies due to process conditions are compensated in that a given anomaly affects both capacitors in the same way. Two of the capacitor plates, one in each pair, are formed of comb structures, with the fingers of the combs interdigitated. The other plates are formed using one or more plates interleaved between the interdigitated plates.
    Type: Application
    Filed: July 8, 2004
    Publication date: January 12, 2006
    Inventors: Edward Harris, Canzhong He, Che Leung, Bruce McNeill
  • Publication number: 20050254158
    Abstract: Use of a depletion mode MOSFET to protect differential terminals of a disk drive read head transducer from an electrostatic discharge event, wherein MOSFET source and drain terminals are connected to the differential terminals. The MOSFET is normally “on” such that a conductive path is provided between the differential signal terminals during assembly of the transducer into a disk drive data storage system and during periods when the transducer is inoperative. The conductive path, limits the differential voltage between the terminals that is generated by a current pulse of an ESD event. The MOSFET is gated off during operation of the disk drive to permit a differential read signal, representing the read data bits, to be developed between the differential terminals.
    Type: Application
    Filed: September 30, 2004
    Publication date: November 17, 2005
    Inventors: Stephen Kuehne, James Howley, Che Leung, David Kelly