AAT2830/31
800mA Total Display Solution
for Portable Devices
Functional Block Diagram
C1+ C1–
C2+ C2–
OUT
CT
IN
Tri-Mode Charge
Pump Control
Flash Ref
FL1
FL2
FL3
FL4
V
F
Monitoring
4
3
6
PGND
BL1
EN/SET
AS
2
Cwire
Control
Main Ref
BL2
BL3
BL4
Sub Ref
BL5
BL6
BSET
DAC
R
RGB Ref
G
B
AGND
Functional Description
The AAT2830/31 is a multi-function power solution
for display systems in portable devices. It includes
six individual driving channels for backlight LEDs,
four for flash LEDs, and three for RGB fashion or
auxiliary, or status LEDs. All of these functions are
powered by a high efficiency tri-mode charge pump
engine that is capable of 800mA load current, ideal
for driving high brightness white LEDs.
The six backlight outputs can be turned on or off
together (BL1-BL6), in two groups or individually. The
two-group operation allows LEDs to be turned on and
off in two banks: the main group (BL1-BL4) and sub-
group (B5-B6) displays. An individual on/off feature
supports applications other than main/sub-display
backlights, such as keypad, navigate key, side key
backlight, and RGB LEDs. The maximum backlight
current is programmable with an external resistor.
The maximum flash current is set by the AS
2
Cwire
interface, and the four flash LED outputs can be
turned on or off together (FL1-FL4) or as a group of
one (FL1) and three (FL2-FL4). The flash time can
either be controlled via the EN/SET pin or by an
internal programmable timer. Maximum flash time
is set by an external capacitor, C
T
. The RGB out-
puts can programmed with up to 4096 (AAT2830)
or 64 (AAT2831) different combinations of colors
and intensities. R, G, and B outputs are individually
controlled and can be used for alternative func-
tions, such as keyboard lighting, "fun" lights, etc.
The RGB channels can be programmed with up to
4096 or 64 different combinations of colors and light-
ing intensities (brightness). R, G, and B channels are
individually controlled and can be used for alternative
functions, such as keyboard lighting, "fun" lighting, etc.
AS
2
Cwire Serial Interface
Each current channel input on the AAT2830/31 is
controlled by AnalogicTech's AS
2
Cwire serial digital
interface. The AS
2
Cwire interface uses the number of
rising edges on the EN/SET pin to address and load
the LED configuration registers. AS
2
Cwire latches
data or addresses after the EN/SET pin has been
held logic high for longer than T
LAT
(500µs).
Addresses and data are differentiated by the number
of EN/SET rising edges. Since the data registers are
4 bits each, the differentiating number of pulses is 2
4
2830.2007.09.1.0
9
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
