Power management using automatic load/unload detection of DAC
AssigneeNVIDIA Corporation
InventorsOtto Steinbusch, Zahid Najam
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Abstract
An automatic load detection system. A first reference signal that may be known apriori can be used for load detection. For example, the first reference signal may be used for invisible portion of a frame. The DAC receives the first reference signal and outputs a signal that is based on the first reference signal. The output of the DAC may have two known values depending on whether the load is coupled to the DAC, e.g., by having a different impedance. Thus, the output signal may be used for detecting whether the load is uncoupled from the DAC. If it is determined that the load is uncoupled from the DAC, the clocking signal to the DAC may be turned off. Thus, DAC no longer consumes power when the load is uncoupled, thereby saving power.
Claims22
An automatic load detection system comprising:
- a display controller generating a control signal;
- a selector that selects pixel data or a first reference signal, wherein said selection is responsive to said control signal;
- a digital to analog converter (DAC) that receives a selection by said selector and outputs a signal, wherein said output signal has a first detectable value when said first reference signal is selected and a load is coupled to said DAC, and wherein said output signal has a second detectable value when said first reference signal is selected and said load is uncoupled from said DAC;
- and
- a comparator that compares said output signal to a second reference signal and outputting a comparison signal, wherein said comparison signal has a third value when said output signal has said first detectable value, and wherein said comparison signal has a fourth value when said output signal has said second detectable value, and wherein said fourth value indicates that said load is uncoupled from said DAC.
A method for automatic load detection, said method comprising:
- generating a control signal;
- in response to said control signal, selecting a first reference signal or pixel data;
- outputting a signal from said DAC, wherein said output signal has a first detectable value when said first reference signal is selected and said load is coupled to said DAC, and wherein said output signal has a second detectable value when said first reference signal is selected and said load is uncoupled from said DAC;
- comparing said output signal to a second reference signal;
- and
- outputting a comparison signal, wherein said comparison signal has a third value when said output signal has said first detectable value, and wherein said comparison signal has a fourth value when said output signal has said second detectable value, wherein said third value indicates that said load is coupled to said DAC, and wherein said fourth value indicates that said load is uncoupled from said DAC.
A system for automatically disabling a digital to analog converter (DAC) when a load is uncoupled from said DAC, said system comprising:
- a graphical processing unit (GPU);
- a display controller coupled to said GPU, wherein said display controller generates a control signal;
- a selector that selects pixel data or a first reference signal, wherein said selection is responsive to said control signal;
- said DAC that receives a selection by said selector and outputs a signal, wherein said output signal has a first detectable value when said first reference signal is selected and said load is coupled to said DAC, and wherein said output signal has a second detectable value when said first reference signal is selected and said load is uncoupled from said DAC;
- said load being selectively coupled to said DAC, wherein said load is operable to receive analog content from said DAC, and wherein said load is further operable to render said analog content;
- a comparator that compares said output signal to a second reference signal and outputting a comparison signal, wherein said comparison signal has a third value when said output signal has said first detectable value, and wherein said comparison signal has a fourth value when said output signal has said second detectable value;
- and
- a deactivating component operable to reduce power consumption of said DAC at least by turning off a clock to said DAC when said comparison signal has said fourth value or by gating said clock to a logic of said DAC.
Dependencies are inferred from the claim text.