Patent ID: 7394461

Claim:
A displaying apparatus communicating with a video card provided in a computer main body, comprising: a connector communicating with the video card provided in the computer main body; a video signal processing unit which processes picture signals supplied through the connector; a power circuit unit which converts commercial alternating current (AC) power into driving voltages; a controlling unit which controls power supplied to each signal processing unit of the displaying apparatus from the power circuit unit to selectively be on or off in response to existence or non-existence of a data display channel (DDC) voltage signal from the computer and a sensing of a synchronous signal output from the connector; and a selecting unit which selectively supplies either the DDC voltage signal supplied through the connector or a power control signal from the controlling unit to the power circuit unit to control the selective turning on or off of the power supplied to the signal processing unit, with the selective supplying being based on existence of the synchronous signal and the DDC voltage signal, wherein the selecting unit is a multiplexer (MUX) which selectively outputs one of the DDC voltage signal and the power control signal, wherein: the MUX comprises a register which includes set-up status information of the displaying apparatus, and the controlling unit controls the MUX to output either of the DDC voltage signal or the power control signal according to the register.