Cirrus Logic Inc.

Sagar Waman Kenkare

Vlad Bril

Alexander Julian Eglit

Rakesh Kumar Bindlish

Dwarka Partani

Thomas Shieh-Luen Ho

Edmund Christian Strauss

An integrated circuit such as a video controller may be provided with core logic circuitry using CMOS technology which may be operated at different supply voltages such as 3.3 or 5 Volts. At lower supply voltages, the CMOS circuitry may run slower. For a video controller, certain higher resolution, pixel depths, and refresh rates may require high speed operation of the video controller. A monitoring circuit monitors the video mode, pixel resolution, pixel depth, and refresh rate and determines which supply voltage may be used to operate the video controller at such levels. An output signal from the monitoring circuit may be used by a switching circuit to supply an appropriate supply voltage to the integrated circuit. At lower performance levels, the integrated circuit may be operated at lower voltages to conserve power.

Programmable core-voltage solution for a video controller

The display controller of the present invention reduces power consumption by suppressing clock signals to a display memory (comprising SGRAM or SDRAM) between screen refreshes and memory accesses. The present invention takes advantage of power-down modes provided for SGRAM and/or SDRAM memories which are used in the prior art to place a memory in an active suspend mode. Further energy savings are realized and memory bandwidth increased when using a display memory comprising two banks. When one bank of memory is being accessed, the other bank of memory is precharged and activated. Succeeding pages of memory are placed in alternate banks of display memory. Thus, then data is to be accessed from a next page of memory, the corresponding bank is already charged and ready to be accessed.

Method and apparatus for optimizing power consumption and memory

A memory controller, particularly for use in a video controller, is provided which reduces the effect of page misses during memory access. A video port FIFO is provided for buffering data from a video port to a display memory. A CRT FIFO is provided for buffering data from a display memory to a display. If, during a video port FIFO cycle, a page miss is encountered, the video port FIFO cycle is terminated and processing passes to a CRT FIFO CYCLE. If a page miss is encountered during a CRT FIFO cycle, the subsequent video port FIFO cycle will shortened by a number of memory cycles to compensate for the additional memory cycles required by the page miss. Additional data accumulated in the video port FIFO may be transferred to the display memory during a retrace interval. In this manner, memory bandwidth is optimized by removing a non-aligned page miss as the worst case of memory bandwidth utilization.

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Fremont, CA, United States of America

Sagar Waman Kenkare