BUF11705 Datasheet, PDF (9/17 Pages) Burr-Brown (TI) – 22 - V Supply, 10 + 1 Channel Gamma Correction Buffer

BUF11705
www.ti.com
APPLICATION INFORMATION
The requirements on the number of gamma correction
channels vary greatly from panel to panel. Therefore,
the BUF11705 series of gamma correction buffer offers
different channel combinations using 10 gamma
channels plus one V_COM channel. The V_COM channel
can be used to drive the V_COM node on the LCD panel.
Gamma correction voltages are often generated using
a simple resistor ladder, as shown in Figure 21. The
BUF11705 buffers the various nodes on the gamma
SBOS349 − DECEMBER 2005
correction resistor ladder. The low output impedance of
the BUF11705 forces the external gamma correction
voltage on the respective reference node of the LCD
source driver. Figure 21 shows an example of the
BUF11705 in a typical block diagram driving an LCD
source driver with 10-channel gamma correction
reference inputs.
V_DD
BUF11705
R_S(1)
(2)
Source Driver
Gamma 1
(1)
(2)
(1)
(2)
Gamma 2
Gamma 3
(1)
(2)
(1)
(2)
(1)
(2)
Gamma 8
Gamma 9
Gamma 10
V_COM
(1) Optional resistor  increases stability.
(2) Optional capacitor.
Figure 21. LCD Source Driver Typical Block Diagram
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