Patent ID: 8253858

Claim:
A multimedia device comprising a display component, the multimedia device configured to output video signals to the display component and an external display device, the multimedia device further comprising: a central processing unit, operable to generate the video signals, wherein the video signals comprise horizontal sync signals; a video output circuit, operable to output the video signals to the display component and the external display device; and a load detection circuit, connected to the central processing unit and an output of the video output circuit, operable to detect a connection between the video output circuit and the external display device so as to generate a control signal, the load detection circuit comprising: an isolation and buffer circuit, operable to isolate and buffer the video output circuit and the load detection circuit; a clamp circuit, operable to retrieve the horizontal sync signals from the video signals; an amplifier circuit, operable to amplifying the retrieved horizontal sync signals; an integrating circuit, operable to integrate the amplified horizontal sync signals and output direct current signals; and a voltage comparator circuit, operable to compare the direct current signals with a predetermined voltage and output the control signal to the central processing unit; wherein the central processing unit turns off the display component according to the control signal indicating that the video output circuit has been connected to the external display device.