AAT3129 datasheet(11/15 Pages) AAT

11 / 15 page

AAT3129

High Efficiency 1X/1.5X/2X Charge Pump

for RGB Color LED Applications

3129.2007.01.1.4

Color Registers R, G, and B

The individual color brightness is set using the

three R, G, and B registers. The data register con-

tents determine the on-time for each color channel

during a PWM cycle. The first level is 0, or off, and

is set with a single EN/SET rising edge. This setting

eliminates a given color from the spectrum. The

remaining 15 levels progressively increase the

brightness for a particular color by increasing that

channel’s on-time. Using the red channel as an

example, the resulting on-time is

on-time = (R - 1) · 128μs

where R is the data setting (from 1 to 16). The

same applies to G and B.

Intensity Register T

The overall intensity level is set by the T register.

Once a particular mixing of colors is set to produce

the desired color, the overall intensity can be

adjusted while keeping constant the ratio of colors

to one another. The brightest level is set by pro-

gramming the T register with 1 edge. Programming

the T register with 16 edges produces the dimmest

setting. The T register adjusts the overall intensity

by controlling the PWM off-time. Under the

dimmest setting, the off-time is the longest. The off-

time that results from the data in the T register is

off-time = (T - 1) · 512μs

Diode Current Timing

(R - 1) · 128

μs

(T - 1) · 512

μs

128

μs

(G - 1) · 128

μs

128

μs

(B - 1) · 128

μs

128

μs

SRC

Red

Green

Blue

SRC

Mode Register M

The mode register determines the method of

update for the R, G, and B channels. When the

mode register is set to 1, the addressed color

updates immediately. When the mode register is

set to 2, the colors will update when the T register

is written (synchronized updating).

Under immediate updating, an addressed channel

will update as soon as new data has latched for it.

Under synchronized updating, the channels that

have been assigned new data will not update until

data for the T register latches.

By using synchronized updating, discrete changes

in color can be achieved. Synchronized updating

allows the intensity for all three colors to be updat-

ed simultaneously. All three color registers can be

loaded with new data prior to the update. Then,

upon loading the T register, all three colors will

change to their new states together. This allows a

user to transition from one mixed color to another

without having to traverse intermediate colors.

Under immediate updating color changes can only

be achieved serially, or one color at a time.

AAT3129 Datasheet(PDF) 11 Page - Advanced Analog Technology, Inc.

AAT3129 Datasheet(HTML) 11 Page - Advanced Analog Technology, Inc.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Datasheet Download

Link URL