Patent ID: 6559838
Filing Date: 2003-05-06
Classification: G09G

Abstract:
A power management system for a monitor having a display screen, the power management system comprising:a detector for determining, during successive periods in time, transition numbers indicating a number of transitions in a video signal for a predetermined area of the display screen; a comparator for comparing said transition numbers; and a controller for activating a power down mode of the monitor when at least two of said transition numbers are substantially equal, characterized in that the video signal comprises a first color signal, a second color signal, and a third color signal, and the detector comprises: a first slicer for receiving the first color signal, and a first pseudo-random generator for receiving an output signal of the first slicer, said first pseudo-random generator supplying a first sequence of numbers; a second slicer for receiving the second color signal, and a second pseudo-random generator for receiving an output signal of the second slicer, said second pseudo-random generator supplying a second sequence of numbers; and a third slicer for receiving the third color signal, and a third pseudo-random generator for receiving an output signal of the third slicer, said third pseudo-random generator supplying a third sequence of numbers, the first pseudo-random generator further having an input for receiving an output signal of the third pseudo-random generator such that the first sequence of numbers also depends on the third sequence of numbers.