Circuit Description - ViewSonic VP2650WB Service Manual

4. Circuit Description

I. Introduction:
The VP2650wb is a 25.5" (1920x1200) TFT LCD monitor. It's a dual interface (include
analog and digital) and support USB function ( 4 port) and OSD Pivot function and support
over-driver function LCD monitor and it's compliant with VESA specification to offer a smart
power management and power saving function.
It also offers OSD menu for users to control the adjustable items and get some information
about this monitor. The VP2650wb also offers DDC/CI function to meet VESA standard and DVI
with HDCP function.
II. Circuit Implementations:
A.) THE MAIN BODY:
A-1.) Interface board block diagram:
Digital
(D)
Analog
D-SUB
(a) Circuit operations:
In analog signal input to scaling IC, t
signals of Red, Green and Blue to the digital signals of Red, Green and Blue. The scaling
IC has the internal A/D converter that converts analog signals to digital data.
The scaling IC has OSD and auto detecting input timing functions. OSD offers adjustable
functions to the end-users. Auto detecting timing function can detect change modes. It
outputs the digital R-G-B data, pixel clock and control signal to TCON of the LCD module. A
MCU, build in scaling IC (Genesis GM5862H-LF), is responsible for the system processing.
There are two external storing units, one is 24C16 to store the OSD function data and user
preset timings and HDCP key content, the other one is flash ROM (25LV040) to store the
ViewSonic Corporation
Digital
DDC
Diff Data & Clock
DSUB R,G, B
HS, VS
Analog
DDC
OSD
SDRAM
Pivot
GM5862H
A/D&TMDS&
Scaling& MCU
&OSD&HDCP
Flash EEPROM
Rom (HDCP)
he operation
21
Confidential - Do Not Copy
USB BD.
CTRL BD.
To LCD
MODULE
DRIVING
Block
theory
is to convert the analog
VP2650wb-1