Method and apparatus for power management in video subsystems
US5537650A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 1992 |
| Grant date | Jul 16, 1996 |
| Priority date | — |
| Expiry date | Dec 14, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2330/021
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.