Q7C3 LCD Monitor Service Guide
Circuit Operation Theory
2
(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.
Scalar finally output the digital
RGB data, the Hsync, Vsync and pixel clock to LCD panel driver IC by RSDS interface. MCU also
embedded in PW133A 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.) PW133A IC :
There are A/D, Scaling, OSD, MCU functions in the PW133A 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
Rapid-lock digital clock recovery system. It also support detect mode and DPMS control. MCU
