AAT3128_08 Datasheet, PDF (7/12 Pages) Advanced Analogic Technologies – RGB LED Fashion Lighting Controller

ChargePump^TM
Functional Block Diagram
PRODUCT DATASHEET
AAT3128
RGB LED Fashion Lighting Controller
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 sim-
ple single wire serial S²Cwire interface to set one of 16
color lighting modes based on four distinct preset color
light mood schemes. In addition 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 con-
verter intended for RGB color LED lighting applications.
To maximize power conversion efficiency, an internal
sensing circuit monitors the voltage required for the con-
stant current source outputs and sets the load switch or
charge pump modes based on the input battery voltage.
As the battery discharges over time, the AAT3128 charge
pump is 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 transition to 2X mode. This load
switch to charge pump control system provides the
maximum power conversion efficiency for any given
operating condition.
The AAT3128 requires only four external components:
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 lighting
moods which may be selected via the EN/SET function.
These four lighting color moods are outlined in Table 1.
Each lighting color mood mode selects a preset group of
64 unique colors that the system controller repeatedly
sequences through at a selected fast or slow rate.
RGB LED brightness and color change timing may be
varied by a choice of two levels for both. The Brightness
control permits the full current to power the RGB LED
3128.2008.02.1.1
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