Patents by Inventor Girish Chandra Johari

Girish Chandra Johari 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: 6535944
    Abstract: A method of servicing a computer system without interrupting operation of the computer system, by connecting a computer component to a board of the computer system, detecting connection of the computer component to the system board using a control circuit, supplying power to the voltage input of the computer component in response to detecting the connection, and thereafter monitoring the power supplied to the voltage input of the computer component. The method may be used for core computer components such as CPU modules and voltage regulator modules. Power to the voltage input of the computer component is turned off in response to a determination that a current level of the power supplied to the voltage input exceeds a specified level. A fault signal is latched in an active state in response to the determination; the fault signal is reset when the component is removed from the system.
    Type: Grant
    Filed: March 30, 1999
    Date of Patent: March 18, 2003
    Assignee: International Business Machines Corporation
    Inventors: Girish Chandra Johari, Mark Wayne Mueller, Peter Matthew Thomsen, Lucinda Mae Walter
  • Patent number: 6449676
    Abstract: A power subsystem for a computer system allows a voltage regulator module (VRM) to be removably connected to a system board, while limiting disturbances on the voltage rails of the system board. The electrical disturbances are prevented by charging voltage outputs of the DC/DC circuit of the VRM prior to directly connecting the voltage outputs to the voltage rails. To ensure that the voltage outputs are properly charged, a VRM connector may be used in which the voltage output pins are shorter than charge pins which are coupled to respective capacitors and to the voltage outputs of the DC/DC circuit. In this manner, as the connector is mated with a corresponding connector on the system board, the capacitors are first charged via resistive paths connected to the voltage rails, prior to directly connecting the voltage outputs to the voltage rails. The VRMs are thus “hot-pluggable,” enabling a user to upgrade or service the system with no interruption.
    Type: Grant
    Filed: March 30, 1999
    Date of Patent: September 10, 2002
    Assignee: International Business Machines Corporation
    Inventors: Girish Chandra Johari, Mark Wayne Mueller, Peter Matthew Thomsen, Lucinda Mae Walter
  • Patent number: 6421259
    Abstract: A modular DC power distribution system. A physically discrete input conversion module is utilized for converting a source AC signal to a high voltage DC signal. Multiple universal mounting sites are provided in a power supply backplane for engaging one or more of such input conversion modules. Within the power supply backplane, the high voltage DC signal is delivered to a DC distribution bus. A physically discrete DC step-down module is utilized for converting the high voltage DC signal from the DC distribution bus to a point-of-load DC signal distributable to application boards. The power supply backplane includes multiple universal mounting sites wherein one or more DC step-down modules may be installed or removed. In another embodiment, the DC power distribution system of the present invention includes a pre-charge system for permitting the input conversion modules and the DC step-down modules to be hot plugged into the power supply backplane.
    Type: Grant
    Filed: December 28, 2000
    Date of Patent: July 16, 2002
    Assignee: International Business Machines Corporation
    Inventors: Terry Brooks, Girish Chandra Johari
  • Publication number: 20020085399
    Abstract: A modular DC power distribution system. A physically discrete input conversion module is utilized for converting a source AC signal to a high voltage DC signal. Multiple universal mounting sites are provided in a power supply backplane for engaging one or more of such input conversion modules. Within the power supply backplane, the high voltage DC signal is delivered to a DC distribution bus. A physically discrete DC step-down module is utilized for converting the high voltage DC signal from the DC distribution bus to a point-of-load DC signal distributable to application boards. The power supply backplane includes multiple universal mounting sites wherein one or more DC step-down modules may be installed or removed. In another embodiment, the DC power distribution system of the present invention includes a pre-charge system for permitting the input conversion modules and the DC step-down modules to be hot plugged into the power supply backplane.
    Type: Application
    Filed: December 28, 2000
    Publication date: July 4, 2002
    Applicant: International Business Machines Corporation
    Inventors: Terry Brooks, Girish Chandra Johari
  • Patent number: 6008631
    Abstract: A synchronous converter including a control module including a pulse generator configured to produce a pulse. An input port suitable for receiving an input voltage from a voltage source, is couple to a first conversion stage of the converter. The first conversion stage preferably includes a first pair of transistors, a first stage capacitor, and a first winding of a coupled inductor. The first pair of transistors are preferably driven by the control module pulse generator such that the first conversion stage is coupled to the input port during the first interval of the pulse and isolated from the input port during the second interval of the pulse and the gain of the first conversion stage is approximately equal to the duty cycle of the pulse. The converter further includes a second conversion stage preferably including a second pair of transistors, a second stage capacitor, and a second winding of the coupled inductor.
    Type: Grant
    Filed: March 18, 1999
    Date of Patent: December 28, 1999
    Assignee: International Business Machines Corporation
    Inventor: Girish Chandra Johari