CHIPTRONIKS

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T-CON Details

1. T-CON definition and working principle

Driven PANEL PANEL itself needs to meet a variety of timing, we put this part

of the work in a circuit called T-CON (Timing Controller).

The Timing Controller converts the Display Data input from the System I / F

section and the associated signal into a signal output suitable for Column Driver-IC

and Row Driver-IC.

Timing Controller's overall circuit can be divided into Timing Control and Data

Control. The Timing Control Part is part of the Signal that generates Timing for the

Column and Row Drive IC types. Data Control Part is the input Data in accordance

with the Panel drive method and structure to generate the appropriate Data part.

2. T-CON work signal

1, receiving external signals (LVDS / DP)

2, data, control signal output

3, data processing, image enhancement

4, BIST (do not understand)

LVDS signal works:

For high-speed circuits, especially high-speed data bus, commonly used devices

are: ECL, BTL, GTL and GTL + and so on. These devices are mature and widely used,

but there is a common weakness, power consumption, emerging CMOS technology

low-voltage differential signaling devices (Low Voltage Differencial Signal referred

to as LVDS), it can be said LVDS devices for high-speed low-power circuit design.

LVDS devices work as follows: where the transmitter is a 3.5mA current source,

resulting in 3.5mA current through the differential line which way to the receiving end.

As the receiver for the DC performance for the high resistance, the current through

the receiver 100 ohm matching resistor to produce 350mV voltage, while the current

through the differential line to flow back to the other side. When the transmitter

changes state, it changes the current through the 100 ohm resistor current direction to

produce effective '0' and '1' state. LVDS features a current-driven mode with a low

voltage swing of 350mV to provide higher signal transmission rates and differential

CHIPTRONIKS

©VD INTELLISYS TECHNOLOGIES PVT. LTD.,126 Kingsway Camp,Delhi-110009

signal transmission for reduced noise and EMI: LVDS has the following main features:

A Low output voltage swing (350mV) B Low DV / dt 0.350V / 0.5ns = 0.7V / ns C.

The differential characteristic is that the magnetic interference can cancel each other,

eliminate common mode noise and reduce EMI.

3.T-CON power supply section

As shown, DC / DC CONVERTER & REFERENCE VOLTAGE can be divided into

the following types according to POWER:

1. FT-LCD turn on and off the power Vgh, Vgl (charge pump)

2. D / A conversion required reference voltage-Gamma voltage

3. Common voltage Vcom

1. Vgh, Vgl : Turn the power off and on

2. Gamma reference voltage

Gamma is simply to change the process from white to black into two N (6,8)

power equal parts.Gamma voltage is used to control the display of the Hui-order,

under normal circumstances G0 ~ G14, different Gamma voltage and Vcom voltage

difference between the liquid crystal rotation angle resulting in different brightness to

form the difference, Vcom voltage is the best situation is located G0 and G14 in the

middle, so that the LCD screen will be the best flashing conditions, the single is

basically very difficult to achieve. Liquid crystal requires dynamic voltage control,

otherwise easy to form inert. G0 ~ G14 Vcom voltage difference between just

constitute a similar sine wave voltage, to avoid the liquid crystal in the same

brightness of inert stagnation occurs.

3. Vcom voltage

Vcom voltage adjustment purposes, to eliminate gray-scale liquid crystal positive

and negative voltage asymmetry, thereby eliminating Flicker.

If the potential difference can not be eliminated, the screen afterimage may be one of

the causes other than the flicker described above.