BenQ Q7T3-FP737S Service Manual page 97

Q7T3(AUO Panel) LCD Monitor Service Guide
Red
Green
Blue
Vsync
Hsync
(/H+V)
SCL
SDA
(a) Circuit operation theory:
A basic operation theory for this interface board is to convert analog signals of Red, Green,
Blue. The scaling IC has internal A/D converter, internal OSD and auto detect input timing
functions. A/D converter is convert analog signal to digital data. OSD is offering adjustable
functions to end-user. Detect timing is for detect change mode. Scaler generate the pixel clock to
the LVDS transmitter. Finally output the digital RGB data, the Hsync, Vsync and pixel clock to
LCD panel driver IC by LVDS transmitter. MCU also embedded in Gm2120 offers H/W DDC2Bi
function & controls system processing. EEPROM is stored DDC data, OSD common data and
user mode data. Flash-Rom is stored the source code which is accessed by MCU to run program.
(b) IC introduction:
1.) DDC (Display Data Channel) function: We use DDC IC to support DDC/2B function. DDC data
is stored in 24C02(EEPROM). Those data related to LCD monitor specification. PC can read
them by "SDA" and "SCL" serial communication for I ² C communication for DDC2B.
2.) Gm2120 IC: There are A/D, Scaling, OSD, MCU functions in the Gm2120 IC. Scaling IC is
revolutionary scaling engine, capable of expanding any source resolution to a highly uniform
and sharp image, combined with the critically proven integrated 8 bit triple-ADC and patented
Interface Board
DDC
Circuit Operation Theory
A/D
MCU
Scaling
OSD
gm2120
To
LCD
module
2