Circuit Operation Theory; Interface Board Diagram; Ic Introduction - BenQ G2220HD Product Service Manual

5.7. Circuit Operation Theory

A-1.) Interface board diagram:
(a) Circuit operation theory:
A basic operation theory for this interface board is to convert analog signals of Red, Green
and Blue to digital signals of Red, Green and Blue, and to provide DVI port equipped with
HDCP key, for receiving DVI signal to generate high quality image. 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 generates the pixel clock to the TCON. Finally
output the digital RGB data, the Hsync, Vsync and pixel clock to LCD panel driver IC.MCU
offers H/W DDC2BI function & controls system processing. EEPROM is stored DDC data,
OSD common data and user mode data.
(b) IC introduction:
(1) The NT68667UFG is a graphic processing IC for LCD monitor with panel resolution up to
WUXGA. It is configured with a triple-ADC/PLL, an integrated DVI receiver, a display
processing engine, an integrated micro-controller, and a LVDS interface. It also consist
power management control capability for green-mode requirement and spread-spectrum
support for EMI management.
(2) EEPROM: We use 24C16 to store all the adjustable data and user settings. The HDCP
KEY is stored in it.
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