Patents by Inventor Shiu Chung Ho

Shiu Chung Ho 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: 7564290
    Abstract: Disclosed are embodiments of a design structure for a voltage level shifter circuit that operates without forward biasing junction diodes, regardless of the sequence in which different power supplies are powered up. The circuit embodiments incorporate a pair of series connected switches (e.g., transistors) between an input terminal and a voltage adjusting circuit. Each switch is controlled by a different supply voltage from a different power supply. Only when both power supplies are powered-up and the different supply voltages are received at both switches will a first signal generated using one of the supply voltages be passed to a voltage adjusting circuit and thereafter converted into a second signal representative of the first signal, but generated using the second supply voltage. Incorporation of the pair of series connected switches into the voltage level shifter circuit prevents forward biasing of junction diodes in the circuit and thereby prevents current leakage from the power supplies.
    Type: Grant
    Filed: October 9, 2007
    Date of Patent: July 21, 2009
    Assignee: International Business Machines Corporation
    Inventors: Anirban Banerjee, Stephen F. Geissler, Shiu Chung Ho
  • Publication number: 20090146495
    Abstract: Disclosed are embodiments of a design structure for a voltage level shifter circuit that operates without forward biasing junction diodes, regardless of the sequence in which different power supplies are powered up. The circuit embodiments incorporate a pair of series connected switches (e.g., transistors) between an input terminal and a voltage adjusting circuit. Each switch is controlled by a different supply voltage from a different power supply. Only when both power supplies are powered-up and the different supply voltages are received at both switches will a first signal generated using one of the supply voltages be passed to a voltage adjusting circuit and thereafter converted into a second signal representative of the first signal, but generated using the second supply voltage. Incorporation of the pair of series connected switches into the voltage level shifter circuit prevents forward biasing of junction diodes in the circuit and thereby prevents current leakage from the power supplies.
    Type: Application
    Filed: January 8, 2009
    Publication date: June 11, 2009
    Applicant: International Business Machines Croporation
    Inventors: Anirban Banerjee, Stephen F. Geissler, Shiu Chung Ho
  • Publication number: 20090091368
    Abstract: Disclosed are embodiments of a design structure for a voltage level shifter circuit that operates without forward biasing junction diodes, regardless of the sequence in which different power supplies are powered up. The circuit embodiments incorporate a pair of series connected switches (e.g., transistors) between an input terminal and a voltage adjusting circuit. Each switch is controlled by a different supply voltage from a different power supply. Only when both power supplies are powered-up and the different supply voltages are received at both switches will a first signal generated using one of the supply voltages be passed to a voltage adjusting circuit and thereafter converted into a second signal representative of the first signal, but generated using the second supply voltage. Incorporation of the pair of series connected switches into the voltage level shifter circuit prevents forward biasing of junction diodes in the circuit and thereby prevents current leakage from the power supplies.
    Type: Application
    Filed: October 9, 2007
    Publication date: April 9, 2009
    Inventors: Anirban Banerjee, Stephen F. Geissler, Shiu Chung Ho
  • Patent number: 6927616
    Abstract: An integrated circuit designed to reduce on-chip noise coupling. In one embodiment, circuit (60) includes the following: a circuit transformer (62) capable of converting a noise sensitive input reference clock signal to an output signal having a voltage compatible with a predetermined sink voltage logic level; and a biased receiver network (64) having a PFET current mirror (74) coupled with a NFET current (72), the biased receiver transistor network designed to multiply the transformer signal to offset a mutual coupling loss of the transformer. In at least one alternative embodiment, the input reference clock signal originates at an off-chip clock generator circuit (42) and the output signal from receiver (64) is input to a PLL (44). In another alternative embodiment, the transformer is a monolithic integrated transformer. Another alternative embodiment of the present invention is a method of reducing on-chip noise coupling.
    Type: Grant
    Filed: October 31, 2003
    Date of Patent: August 9, 2005
    Assignee: International Business Machines Corporation
    Inventors: Shiu Chung Ho, Ivan L. Wemple, Stephen D. Wyatt