Patent
1992-12-14
1996-07-16
Harvey, Jack B.
G06F 1300
Patent
active
055376509
ABSTRACT:
Video subsystem power savings are achieved by shutting off power to unused subcircuits during blanking. Digital circuitry within the video subsystem not used during blanking is shut-down by turning off the clock thereto. Analog circuitry within a digital to analog converter is shut-down by turning off the constant current reference thereto. A functional unit containing digital circuitry within a serializer palette digital to analog converter (SPDAC) is shut-down by turning off the clock thereto during system operation in a mode where the functional unit is not utilized. A computer system having a monochrome display saves power by shutting off DAC digital circuitry clocks and DAC analog circuitry constant current references of all DACs but one. A portable computer with a liquid crystal display (LCD), a SPDAC for driving an external display and a LCD controller, saves power by shutting down video subsystem functional units and analog DAC circuitry not used for driving the LCD. Digital circuitry within the LCD controller is shut-down when an external display is being driven. In a portable computer operating in a SUSPEND state, video subsystem functional units are shut-down.
REFERENCES:
patent: 3510578 (1970-05-01), Bazin
patent: 4333105 (1982-06-01), Kaku et al.
patent: 4549214 (1985-10-01), Hinn
patent: 4583121 (1986-04-01), Yost
patent: 4716461 (1987-12-01), Hinn
patent: 4825388 (1989-04-01), Dailey et al.
patent: 5167024 (1992-11-01), Smith et al.
patent: 5270687 (1993-12-01), Killebrew, Jr.
patent: 5289575 (1994-02-01), Godfrey
patent: 5375209 (1994-12-01), Maher et al.
"82C426", CGA LCD/CRT Controller, Chips and Technologies, copyright 1990.
Eagle, D. J. & Morrish, A. J., "Increasing Lifetime and Reliability of CRT Displays", IBM Technical Disclosure Bulletin, vol. 34 No. 9, pp. 281-283, Feb. 1992.
Bowater, R. J. & Butler, N. D., "Wideline Display of Standard VGA 5-Wide Characters", IBM Technical Disclosure Bulletin, vol. 34 No. 2, pp. 367-370, Jul. 1991.
"Bt475 Bt477", Brooktree Product Data Book 1991, Copyright 1990. Brooktree Corporation.
"IMS G177", Preliminary Specification SGS-Thomson Microelectronics, Apr. 1991.
Grupp Richard J.
Rickard Kathryn E.
West Roderick M. P.
Harvey Jack B.
International Business Machines - Corporation
Reinke Wayne F.
Travis John
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