Patents by Inventor Ravi Ranganathan

Ravi Ranganathan 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: 5754170
    Abstract: A graphics controller overlays a movie window over the graphics pixel data. Movie pixels are from a movie source and are muxed into the pixel path by a pixel mux near the end of the graphics pipeline. A comparison of the current pixel count to the pixel address of the start and ending boundaries of the movie window controls the pixel mux, which selects either graphics pixels or movie pixels for display to a screen. Since the graphics controller is pipelined, the pixel compare near the end of the pipeline does not restart the graphics pipeline early enough for it to pre-process the graphics pixels. The graphics pipeline does not stop during the movie window but instead performs dummy fetches from the graphics memory to a CRT FIFO in the graphics pipeline. Dummy fetches are fetches of graphics pixels that are not displayed. Since these fetches contain non-displayed pixels, they are not needed except to keep the fetch count counting even during the movie window.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: May 19, 1998
    Assignee: NeoMagic Corp.
    Inventor: Ravi Ranganathan
  • Patent number: 5703806
    Abstract: A CMOS integrated circuit that comprises a graphics controller system that consists of a graphics engine and video memory together with some interface blocks, a PCMCIA host adapter, an infrared interface for generating video images on a LCD or CRT display unit, and a video stream interface for receiving video signals. Since the video memory is integrated on the same integrated circuit as the graphics controller, no package pins are required for the memory interface. The pins thus saved are used to provide access to an on-chip PCMCIA host adapter. The internal memory interface is 128 bits wide. Simultaneous performance improvement and power dissipation reduction is achieved because of the wide memory interface and the elimination of the large parasitic capacitances associated with a package pin connection.
    Type: Grant
    Filed: August 16, 1996
    Date of Patent: December 30, 1997
    Assignee: NeoMagic Corporation
    Inventors: Deepraj S. Puar, Ravi Ranganathan
  • Patent number: 5650955
    Abstract: A CMOS integrated circuit that comprises a graphics controller system that consists of a graphics engine and video memory together with some interface blocks, a PCMCIA host adapter, an infrared interface for generating video images on a LCD or CRT display unit, and a video stream interface for receiving video signals. Since the video memory is integrated on the same integrated circuit as the graphics controller, no package pins are required for the memory interface. The pins thus saved are used to provide access to an on-chip PCMCIA host adapter. The internal memory interface is 128 bits wide. Simultaneous performance improvement and power dissipation reduction is achieved because of the wide memory interface and the elimination of the large parasitic capacitances associated with a package pin connection.
    Type: Grant
    Filed: August 16, 1996
    Date of Patent: July 22, 1997
    Assignee: NeoMagic Corporation
    Inventors: Deepraj S. Puar, Ravi Ranganathan
  • Patent number: 5615376
    Abstract: A video sub-system features reduced power consumption by periodically disabling the video controller clocks used for transferring pixel data to a screen. The video clocks are pulsed only when pixel data is being transferred to the screen, during the time that a horizontal line of pixels is being scanned on the screen. The video clocks are not pulsed during the horizontal and vertical blanking periods, when the electron beam in a cathode-ray-tube is being re-traced. The video clocks are also not pulsed during a recovery period for a flat-panel screen. A video memory contains pixel information for the entire screen and is controlled by a memory controller. The memory controller uses a memory clock to transfer all or part of a horizontal line of pixels to a video buffer. The pixel data is then read out of the video buffer to the screen in a serial fashion, synchronized to the video clock.
    Type: Grant
    Filed: August 3, 1994
    Date of Patent: March 25, 1997
    Assignee: NeoMagic Corp.
    Inventor: Ravi Ranganathan
  • Patent number: 5587672
    Abstract: A controller chip has dynamic logic which is driven by a suspendable clock. Power is reduced in a standby mode when the clock to the dynamic logic is stopped. However, power is still applied to the dynamic logic in standby mode so that the dynamic logic can be quickly resumed without the delay of re-charging the power-supply capacitances in the dynamic logic. Stopping the clock to dynamic logic can eventually cause loss of data. A more severe problem than data loss is power consumption. When the clock is stopped to dynamic logic, the isolated nodes leak and eventually their voltages change. When their voltages change by more than a transistor threshold voltage then both the p-channel and n-channel transistors in dynamic logic cells can turn on, forming a direct current paths between power and ground. Thus power consumption can increase dramatically in suspend mode. The isolated dynamic nodes of the dynamic logic are instead recharged periodically during suspend mode.
    Type: Grant
    Filed: September 25, 1995
    Date of Patent: December 24, 1996
    Assignee: NeoMagic Corp.
    Inventors: Ravi Ranganathan, Deepraj S. Puar