Asus PA246Q - Page 20

Service Manual PA246Q
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functions. A/D converter converts 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 T-CON.
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. A headphone audio circuit is also provided by interface board to add the
headphone output features.
(a) IC introduction
1. ST STDP8028 is an all-in-one LCD monitor controller supporting WUXGA, and integrates ST high
performance ADC, TMDS Rx with HDCP, scaling engine, OSD engine, LVDS Tx, and so on.
2. EEPROM: We use 24C32 to store all the adjustable data and user settings. The HDCP KEY is stored in
it.
3. Serial Flash: It controls all the functions of this interface board, just like the OSD display setting, the
adjustable items, adjusted data storage, the external IIC communication, support DDC2BI.
4. SMSC USB2649 IC: The 2-port USB HUB is fully compliant with USB 2.0 specification and will attach to
an upstream port as a Full-/High- Speed HUB.
B. Power Board Diagram
Fig.1
#1 EMI Filter
This circuit is designed to inhibit electrical and magnetic interference for meeting FCC, VDE, VCCI
standard requirements.