LG 23LX1RV-MC Service Manual page 20

1. Video Controller Unit & Display Data Conversion Unit
The video controller unit receives the video signals inputted through the tuner, AV port, and converts them into
an ITU656 signal through the microcomputer (VCTI) combined with the video decoder that integrates various
functions in one chip.
Either the analog RGB(FLI2300) signal or PC RGB signal is selected by the switching IC and inputted to a
scaler (GM2221), which is sent to the LCD module after being modified to an RGB signal through the integrated
LVDS Cable.
VCTi is the main microprocessor that handles video signal processing and sound signal processing.
It also manages the RF signals received from the tuner.
The scaler can control timing to fit into the LCD panel, and can also control the size and position of the
inputsignal.
2. Power Supply Unit
The power supply unit provides 24V, 12V and 5V DC power to the mainboard.
The PWM Step-Up DC/DC Converter circuit is used to generate the 33V used for the tuner.
Supplied 24V power is descended by the 13.5V step-down DDC. 13.5V provides source to sound amplifier IC.
24V power is also used to generate 5V and 3.3V power through the Step-Down DC/DC Converter and supplied
12V.
5V power is converted to 3.3V and 1.8V power through the regulator, which in turn supplies electrical power for
ICs such as VCTI and scaler.
BLOCK DIAGRAM DESCRIPTION
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