LG RT-23LZ55 Service Manual page 22

1. Video control and display data
Video signal is received from TUNER, AV port(AV1,AV2,S-Video,Component) and goes to the one-chip video
decoder (VCTI) which separate the R,G,B signal and passes on the signal to AD converter(AD9883) which
converts 4:4:4 video format into digital and gives output to the Picture Enhancer(FLI2300).This picture enhancer
improves the quality of the picture by changing the level of RGB signals.The output of this enhancer chip is fed
to the deinterlacer ,which in turn goes to the Scalar (GM5221).The scalar gives the output on the LVDS cable
which is connected to LCD module.
VCTi acts a micom and is responsible for video processing and audio signal processing.It accepts the RF signal
and separates sound and picture from it.
Scaler is reponsible for regulating the timing of signal to LCD panel and size and location of the signal.Graphic
control accepts the PC(Analog RGB) and DVI-D (Digital ) signal, Scalar is reponsible for regulating the timing of
signal to LCD panel and size and location of the signal.Graphic control accepts the PC(Analog RGB) and DVI-D
(Digital ) signal,the signal of PC input is connected to analog port in Scaler and the signal of DVI-D input is
connected to digital port. Thus it receives two input and switch between them to give output at the LVDS which
in turn gives output at the LCD module.
2. Power unit
The power board supplies a DC voltage of 33V, 24V, 12V to the main board.out of this 33v is used by the tuner
and 24v is used directly by the inverter and the sound amplifier IC. 24v also is converted into 5v by a regulator.
The 5v is changed into 3.3v and 1.8v by a regulator, both voltages(3.3v, 1.8v ) is used by VCTI, Scaler, FLI2300
and AD9883. The voltage of LCD Panel is 12v.
BLOCK DIAGRAM DESCRIPTION
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