BUF16820 Datasheet, PDF (15/30 Pages) Burr-Brown (TI) – 14-Channel GAMMA VOLTAGE GENERATOR with Programmable VCOM Outputs and OTP Memory

BUF16820
www.ti.com
REPLACEMENT OF TRADITIONAL GAMMA
BUFFER
Traditional gamma buffers rely on a resistor string (often
using expensive 0.1% resistors) to set the gamma
voltages. During development, the optimization of these
gamma voltages can be time consuming. Programming
these gamma voltages with the BUF16820 can
significantly reduce the time required for gamma voltage
optimization. The final gamma values can be written into
the internal OTP memory to replace a traditional gamma
buffer solution. Figure 13a shows the traditional resistor
string; Figure 13b shows the more efficient alternative
method using the BUF16820.
The BUF16820 uses the most advanced high-voltage
CMOS process available today, which allows it to be
competitive with traditional gamma buffers.
SBOS356A − FEBRUARY 2006 − REVISED OCTOBER 2006
Programmability offers the following advantages:
D Shortens development time significantly.
D Increases reliability by eliminating more than 18
external components.
D Eliminates manufacturing variance between panels.
D Allows a single panel to be built for multiple
customers, with loading of customer-dependent
gamma curves during final production. This method
significantly lowers inventory cost and risk, and
simplifies inventory management.
D Allows demonstration of various gamma curves to
LCD monitor makers by simply uploading a different
set of gamma values.
D Allows simple adjustment of gamma curves during
production to accommodate changes in the panel
manufacturing process or end-customer require-
ments.
D Decreases cost and space.
a) Traditional
BUFxx704
b) BUF16820 Solution
PC
SDA
SCL
Timing
Controller
LCD Panel Electronics
SDA
SCL
BUF16820
V_COM1
V_COM2
V_COM
OUT1
OUT2
OUT13
Gamma
References
OUT14
Control Interface
Figure 13. Replacement of the Traditional Gamma Buffer
15