ViewSonic VX2240W-4, Service Manual, Page: 12 / 53

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4. Circuit Description
The NT68670 is a highly integrated flat panel display controller that interfaces analog, digital,
and video inputs. It combines a triple ADC, a DVI compliant TMDS receiver, a digital YUV
receiver, a high quality zoom and shrink engine , a multi-color on screen display (OSD)
controller , an advanced color engine ,an liquid crystal display accelerator over
–
driving that
embedded 1Mx16 SDRAM and many other functions in a single chip. It provides the user with a
simple, flexible and cost-effective solution for various flat panel display products.
The NT68670 operates at frequencies up to 170MHz, suitable for LCD monitor up to UXGA
resolution.The NT68670 also has a built-in noise reduction function to provide more stable video
quality, spread spectrum to provide low EMI solution, sRGB for video color space convert and
post pattern for manufacture test.
The display provided multi-interface with timing controller or without timing controller. With
timing controller provided single/double pixel clock RSDS interface; without timing controller
provide single/double pixel clock LVDS interface.
In addition, NT68670 includes an integrated 8-Bit Microcontroller (MCU). It contains an
8-bit 8031 micro-controller, 1,280-bytes internal data memory, four 7-bit resolution A/D
Converter, 10-channel
8-bit resolution PWM DAC, two16-bit timer/counters, and a UART. Except those, it has
two-channel hardware DDC solution, and VESA 2Bi/2B+ master/slave I2C bus interface.
EEprom
24C04
Scaler
NT68670HTFG
OSD control
board
LCD panel
D _SUB
EEprom
24C16
DVI
EEprom
24C02