Description Of Block Diagram - LG FLATRON L4200A Service Manual

1. Input Selection Circuit
1) Analog Input Selection
This block is composed of BA7657F(U103) and
peripheral devices.
There are analog H/V Syncs. BA7657F IC chooses
one input and outputs selected input through sync
selection pin
2) Video Input Selection
This block is composed of video S/W IC (CXA2040Q,
U3) , 3D- Comb filter(UPD64083,U805) and peripheral
devices. There are three inputs in CXA2040Q
IC(CVBS video , S-video signal,SCART SIGNAL).
CVBS video signal is separated to Y/C signal by 3D-
Comb filter. One selected video signal is transmitted a
video decoder IC (VPC3230, U201)
2. DDC controller
This block is composed of GM1501(U402) and
peripheral EEPROM IC(U107,U108).
GM1501(U402) controls peripheral devices through
IIC line.
Major functions are (1) to control Flash memory
through DDC-SCLA, DDC-SDAA of D-sub And (2) to
store EDID data in the EEPROM (U107,U108).
3. Video Decoder
This block is composed of VPC 3230 (U1) and
peripheral devices.
GM 1501 controls this IC through IIC Line.
This IC analyzes input signal of CVBS, Y/C and output
analyzed signal (8bit interlace signal) to De-interlace
block.
Analyzed signal has video control signals like
Contrast, Brightness, Sharpness, Color, tint signals
Including Adaptive Comb Filter.
4. Audio Decoder
This block is composed of MSP3420G (U501) and
peripheral devices.
GM 1501 controls this IC through IIC Line.
This IC analyzes audio input signal through A/V Jack
and PC audio.
The analyzed signals transmitted to audio amplifier
(TPA3004, U501).
5. Audio Amplifier
This block is composed of TPA3004 (U505) and
peripheral devices.
The function of the audio amplifier is that to amplify
audio L/R signal transmitted from audio decoder. The
audio signal is amplified according to pre-defined DC
volume control curve. Also, Headphone amplifier
(Tpa6110, U501) is controlled through Line-out.

DESCRIPTION OF BLOCK DIAGRAM

6. De-interlacer
This block is composed of FLI 2310(U301) and
peripheral devices.
GM1501 (U402) controls this IC through IIC Line.
And this IC converts 8 Bit Interlaced Y/UV signal and
signal that is from component port and changed to
24bit digital signal to De-interlaced signal.
It output converted signal to Format Converter IC(GM
1501, U402).
7. Format Converter
This block is composed of GM 1501(U402) and
peripheral devices. GM 1501(Scaler,U402) contains
MICOM.
1) This IC contain A/D converter, Pre-amp and PLL
circuit that converting analog video signal(0.7Vp-p)
through D-sub(J103) Pin to digital signal.
2) This IC Decode TMDS signals of 8 line from DVI-D
Pin (J202) and transmit to LVDS Transmitter.
GM 1501 is Format Converter IC that receives
Digital signal and outputs proper frame signal to
LCD Module Timing(1360°ø768,WXGA).
8. RS-232C PART
This block is composed of Max232c(U504) and
peripheral devices. Input port support communication
of between computer and monitor , output port support
communication of other monitors that linked by RS-
232c cable. By using this port computer can control
this monitor
And GM1501 can send/receive by using RX,TX port of
Max232C
9. DC/DC Converter block
DC/DC Converter convert the input 12V, 24V to proper
2.5V, 3.3V, 5V, 1.8V for main control system.
For shooting heat trouble, we use the DC/DC
converting IC.
10. Power Supply Block
This Block generates DC Voltages(5V, 12V, 18V and
24V) to Main Control system from AC Power(100-240
V, 50/60 Hz, 1.0 A).
This Circuit contains PFC(Power Factor correction)
circuit.
- 17 -