55LP1M-WC (CHASSIS:CL-80) - LG TV Service Manual (repair manual). Page 24

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1) D-SUB RGB INPUT SELECT : This section is composed of

Signal selector IC(BA7657F_U121) and peripheral devices.
The BA7657F(U121) IC select RGB1 signal or RGB2   
signal and the signal is sent to gm1601H(402).

2) VIDEO INPUT SELECT : This section is composed of Video

switching IC(CXA204Q_U201) and peripheral devices.
Video switching IC(CXA2040Q_U201) select CVBS video or
S-video and the signal is sent to Video decoder (UPD64012)

3) 

DVI signal input is directly fed to SCALER,
DTV(Component1) signal input is given to Scaler IC(U402)
via MST9883C(U303).
DVD(Component2) signal input is given to Scaler IC via
Video Decoder IC(UPD64012_U801).

This section is composed gm1601H(U402) ,EEPROM IC
(U404, U115, U120) and peripheral devices.
gm1601H(U402) is controlling peripheral devices through IIC
Line.
Major functions of this block are : 
(1) Controlling of u-COM and Flash memory through DDC-

SCLA, DDC-SDAA of D-sub connector.

(2) Storage of EDID DATA in the EEPROM(U115, U120).

This section is composed of MST9883C(U303) and peripheral
devices. gm1601H(U402) is controlling MST9883C through IIC
Line.
This IC is converting DTV(YPbPR) signal in to 16 bit Interlace
signal and the signal is sent to De-interlace
IC(MDIN150H_U901)
This output signal have CONTRAST, BRIHTNESS,
SHARPNESS, COLOR, TINT information.

This section is composed of UPD64012(U801) and peripheral
devices.
gm1601H(U402) is controlling UPD64012 through IIC Line.
This IC is controlling CVBS input signal ,S-VIDEO(Y/C) input
signal and DVD(YCbCr) input signal and converting input
signals in to 16 bit interlace signal and the signal is sent to  De-
interlace IC(U901).
This output signal have CONTRAST, BRIHTNESS,
SHARPNESS, COLOR, TINT information.

This section is composed of MDIN150H(U901) and peripheral
devices.
gm1601H(U402) is controlling MDIN150H through IIC Line.
This IC is converting 16bit interlace input signal  in to 16bit De-
interlace signal and the signal is sent to Video Signal
Processor IC(gm1601H_U402).

This section is composed of MSP3420G(U501) and peripheral
devices.
gm1601H(U402) is controlling MSP3420G through IIC Line.
This IC is processing audio signal output of A/V Jack, PC Audio
Jack.
This IC's output signal is sent to Audio Amplifier IC
(TPA3004_U502). 

This section is composed of TPA3004(U502) OR TPA3001
(U507) and peripheral devices.
Audio Amplifier's function is amplification of sound signal
received from Audio Decoder.
Input Audio signal is amplified according to the DC Volume
control curve.

This section is composed of gm1601H(U402) and peripheral
devices.
gm1601H(SCALER_U402) have in built u-COM in IC.
(1) This IC include A/D Converter, Pre-Amp, PLL Circuit.
(2) This IC include TMDS Receiver and LVDS Transmitter.

TMDS Receiver is decoding input DVI Signal and LVDS
Transmitter is encoding the output Signal .
Also, gm1501H  have Format Converter (Scaling) function.
This IC convert Various sized Digital signal to LCD
Module's resolution (Full HD Format).

DC/DC Converters change Power output voltage (DC 5V, 12V,
24V) to 1.5V, 2.5V, 3.3V, 5V, 8V, 9V. 
(To be used by different IC on the main board.) 

This section is composed of LM35DT(U523), KIA358F(U524)
and peripheral devices.
The temperature at surface of LM35DT(U523) is sensed and
converted to HEX code by KIA358(U524).
gm1601H(U402) receives sensing HEX values from
KIA358F(U524)and control FAN.

This section is composed of Sensor Board Assy's
TLS2550(U702) and peripheral devices.
TLS2550(U702) IC senses amount of ambient light and
converts to HEX CODE.
gm1601H(U402) receives sensing HEX values and controls
System's Brightness.

Power supply receives AC voltage (100-240 V, 50/60Hz,) and
converts to System voltage that are 5V, 12V, 18V and 24V DC
voltage.
These voltages supports main board, inverter board and
module's T-con board. 
This Circuit contains PFC(Power Factor Correction) circuit. The
Minimum Power efficiency is about 75%.