US 5,757,365 A · Power down mode for computer system

Abstract

A computer system includes a CPU and VGA/LCD controller interacting with a main system memory for processing input data and displaying it on an LCD panel screen that includes a plurality of row and column drive chips on the panel. Each column drive chip includes a panel driver memory and panel driver control logic. A frame rate modulated grey-scale data signal is fed from the processor and VGA/LCD controller to the panel driver memory. Timing signals, including horizontal and vertical clocks, and data shift signals, are fed to the panel driver control circuit to control the panel driver memory from which data is read out for display on the LCD panel screen. Upon detection of the absence of screen update information for two full frame periods the system enters a power down mode by re-mapping the grey-scale data to black-and-white data, stopping the data shift clock, and disabling portions of the VGA/LCD controller and its sequencer so that the latter enters a screen off mode. Stopping of the data shift clock causes the display panel and its panel driver memory to enter a self-refresh mode in which a frame of data stored in the panel driver memory is repetitively read out under control of the vertical and horizontal clock signals.

Claims22

Dependent claims

A power saving computer system comprising:

an information processor for storing and processing information, comprising:
a display controller for generating frames of update data, each frame of update data including a plurality of grey-scale pixel data groups, each pixel data group having an n-bit signal defining one of a plurality of grey-scale brightness grades;
a power-saving circuit responsive to absence of a predetermined number of frames of update data for temporarily disabling portions of said information processor;
and
remapping means in communication with said display controller and said power-saving circuit for remapping the grey-scale pixel data groups of a current frame of update data into corresponding black-and-white pixel data defining only one of two brightness grades in response to the absence of update data;
and
a display panel for selectively receiving the frames of update data from said information processor to generate an image on a panel screen, comprising:
a panel memory in communication with said display controller for storing at least the remapped current frame of update data;
and
refresh means in communication with said panel memory, said display controller, and said power-saving circuit to self-refresh the panel screen from update data stored in said panel memory in response to the absence of update data.

7 more elements

A power saving computer system comprising:

an information processor for storing and processing information and including a display controller;
a display panel for receiving frames of update data from said information processor;
means responsive to absence of a predetermined number of frames of update data for temporarily disabling portions of said information processor;
and
means for re-enabling said portions of said information processor upon reoccurrence of said update data,
wherein said display panel includes a panel screen and a panel driver memory connected to store and transmit data from said information processor to said panel screen, and means for causing said panel driver memory to self-refresh said panel screen from data stored in said panel driver memory in response to the absence of update data;
wherein said display panel includes a panel screen and a panel driver memory connected to store and transmit data from said information processor to said panel screen and including a panel driver connected to transmit panel display control information from said information processor to said panel driver memory;
wherein said information processor includes means for generating a vertical timing signal, a horizontal timing signal, and a data shift signal, wherein said panel driver includes means for receiving said timing signals and controlling flow of data into and out of said panel driver memory in response to said timing signals, and wherein said data shift signal controls transmission of data from said information processor into said panel driver memory, said means responsive to absence of update data including means for temporarily disabling transmission of said data shift signal to said panel driver, and including means for repetitively reading information stored in said panel driver memory to said display panel under control of said horizontal and vertical timing signals;
and
wherein said data includes a plurality of grey-scale pixel data groups each having an n-bit signal defining one of a plurality of grey-scale brightness grades, and grey-scale means in said information processor for causing said panel driver and panel driver memory to control said panel screen according to the brightness grade of the pixel data group of said data signal, said means for temporarily disabling including means for re-mapping said grey-scale means to provide a black-and-white signal output that controls said panel screen to display pixels having only one of two brightness grades.

7 more elements

In a computer system having an information processor that receives and processes information and transmits a data signal together with control and timing signals to a display panel for displaying frames of data, said information processor including a grey-scale controller for providing data defining a grey-scale display, wherein said control and timing signals include a data shift clock, a horizontal clock, and a vertical clock, and wherein said display panel includes a panel screen, a panel driver memory responsive to said data signal for storing at least one frame of said data, and a panel driver responsive to said control and timing signals for controlling said panel driver memory to read data from said panel driver memory to said panel screen, a method for reducing power consumption of said computer system, comprising the steps of:

monitoring transmission of said data signal from said information processor to said display panel;
and
causing said computer system to enter a power down mode upon detection of the absence of transmission of said data at a signal to said display panel for a predetermined number of frames of data, said step of causing said computer system to enter a power down mode comprising:
disabling parts of said information processor;
changing operation of said grey-scale controller to cause it to provide data defining a black-and-white display to said panel driver memory;
waiting for at least two full frames after detection of the absence of transmission of said data signal to ensure storage of one complete frame of black-and-white data in said panel driver memory;
disabling transmission of said data shift clock to said panel driver;
and
entering a self-refresh mode, said self-refresh mode comprising the steps of repetitively reading a frame of data from said panel driver memory to said panel screen under control of said horizontal and vertical clock signals.

6 more elements

Dependencies are inferred from the claim text.

Power down mode for computer system

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Power down mode for computer system

Life of this patent

Abstract

Claims22