Toshiba 20VL44 Service Manual page 9

L5-A Low-to-Mid End LCD-TV BOARD OVERVIEW
L5-A Low-to-Mid End LCD TV board incorporates the LCD Controller gm2221, to create a
high quality, stand-alone LCD-based TV system for consumer applications. Figure 1
illustrates the Block diagram of the board.
This board supposed to have two versions:
1. Low-End (to drive 14''-15'' 4:3 panels)
2. Mid-End (to drive 17''-20'' 4:3 and 17''-22''-23'' 16:9 panels)
LOW TO MID END LCD TV WITH GM2221
QSS
Multimedia
Tuner CVBS
EXT. CVBS, S-video
Scart RGB, FB
3.3V 2.5V 1.8V
5V
8V
Step Down
& Lineer
Regulators
12V
L5-A board supports 5 types of video and graphics inputs. These inputs are: Analog
terrestrial tuner input for multisystem PAL/SECAM transmission, SCART input (x2), S-VHS
input, RCA input and analog PC video input.
The analog RGB signals coming from the PC input (via D-Sub15 connector P401) are
directly connected to the gm2221 analog input port.
One EDID IC (U400) is provided on board to support VESA standard plug-and play
compatibility.
RGB, HS, VS
Graphics
Upto SXGA at 75Hz
UXGA at 60Hz
SDA,SCL
Chroma
Decoder
VPC 3230D
FLASH
Teletext
Decoder +MCU
SDA5550
SDRAM
Figure 1 System Block Diagram
GM2221
EDID
VGA ADC+PLL
ITU 656
De-interlace
Scaling
ITU 656
MCU X86
8-bit OSD(4bit\pixel)
2 LVDS Tx
HP
L/R
FLASH
NVRAM
1p, 2p\clk
LVDS
24-bit TTL
HS, VS, DE
Upto SXGA at 75Hz
QSS
Ext L/R
Audio
Decoder
MSP 3410G
Main
L/R
AudioAmp
HP
TDA1517P
TDA1308T
L
15",
17",
20''
4:3
17''
22''
16:9
TFT
LCD
R