AAT3128 Datasheet, PDF (7/13 Pages) Advanced Analogic Technologies – RGB LED Fashion Lighting Controller

AAT3128
RGB LED Fashion Lighting Controller
Functional Block Diagram
IN
RSET
Soft Start
1MHz
Oscillator
Voltage
Reference
EN/SET
S²Cwire
Interface
Control
Current Level
Program
and LED
Switch / Mood
1X
1.5X
2X
Charge
Pump
C1+
C1-
C2+
C2-
CP
ISRC1
ISRC2
DR
DG
DB
Functional Description
The AAT3128 is specifically designed to drive RGB
color LEDs. This device is externally programmed
via the simple single wire serial S²Cwire interface to
set one of 16 color lighting modes based on four
distinct preset color light mood schemes. In addi-
tion to the four color lighting moods, there are two
brightness levels and two lightning sequence
change speeds that may be selected.
The AAT3128 utilizes a tri mode load switch (1X)
and high efficiency (1.5X or 2X) charge pump boost
converter intended for RGB color LED lighting appli-
cations. To maximize power conversion efficiency,
an internal sensing circuit monitors the voltage
required for the constant current source outputs and
sets the load switch or charge pump modes based
on the input battery voltage. As the battery dis-
charges over time, the AAT3128 charge pump is
3128.2007.09.1.0
GND
enabled when the current source outputs near
dropout. The charge pump initially starts in 1.5X
mode. If the charge pump output droops enough for
the current source output to become close to
dropout, the charge pump will automatically transi-
tion to 2X mode. This load switch to charge pump
control system provides the maximum power con-
version efficiency for any given operating condition.
The AAT3128 requires only four external compo-
nents: two 1µF ceramic capacitors for the charge
pump flying capacitors (C1 and C2), one 1µF
ceramic input capacitor (C_IN) and one 1µF ceramic
output capacitor (C_P).
RGB LED Lighting Set-Up and Control
The AAT3128 has four preset RGB LED color light-
ing moods which may be selected via the EN/SET
function. These four lighting color moods are out-
lined in Table 1. Each lighting color mood mode
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