FPD33584 datasheet(7/30 Pages) NSC

7 / 30 page

Block Diagram

20043206

Functional Description

GENERAL OVERVIEW

The FPD33584 is a low power, low EMI, 384 output column

driver with 64 gray level capability (6-bit). It provides direct

drive for TFT-LCD displays, eliminating the need for V

com

modulation. Direct drive significantly reduces system power

consumption and also reduces component count while pro-

viding superior image quality and cross-talk margin. The

FPD33584 utilizes National’s Charge Conservation Technol-

ogy that recovers energy stored in the capacitance of the

column lines to reduce power consumption further.

The FPD33584 is designed for use in systems using dot

inversion as the method of polarity inversion. Column inver-

sion and N-line inversion are also supported. Other modes of

polarity inversion including line inversion and frame inversion

are not supported.

Digital video data inputs to the FPD33584 are received via a

low power, low EMI Reduced Swing Differential Signaling

(RSDS) bus. The RSDS digital video commands one of 64

gray level voltages on each output. Output voltages are

driven with individual high drive, low offset operational am-

plifiers. Data loading and line buffering is accomplished by

means of an internal, bi-directional shift register.

GAMMA CORRECTION

The FPD33584 is designed to offer compatibility with a wide

range of panel gamma characteristics. The output voltage

levels corresponding to each of the 64 gray level commands

can be externally adjusted to match the desired gamma

characteristics of the display by means of two internal

resistor-string DACs (RDACs). One RDAC provides the

high-polarity output voltages (voltages higher than V

com) and

the other provides the low-polarity output voltages (voltages

lower than V

com).

The FPD33584 is available with several R-DAC resistance

curve options, all of which have been carefully designed to

accurately match the natural, inverse gamma of a twisted

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