AAT3123 Datasheet, PDF (1/18 Pages) List of Unclassifed Manufacturers – High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications

AAT3123/23A/24
High Efficiency 1X/1.5X Fractional Charge
Pump for White LED Applications
General Description
The AAT3123/23A/24 is a low noise, constant fre-
quency charge pump DC/DC converter that uses a
dual mode load switch (1X) and fractional (1.5X)
conversion to maximize efficiency for white LED
applications. The device can be used to produce
current levels up to 20mA to drive up to six LEDs
from a 2.7V to 5.5V input. Outputs may be operat-
ed individually or paralleled for driving higher-cur-
rent LEDs. A low external parts count (two 1µF fly-
ing capacitors and two small 1µF capacitors at V_IN
and OUT) make the AAT3123/23A/24 ideally suited
for small battery-powered applications.
AnalogicTech’s Simple Serial Control™ (S²Cwire™)
interface is used to enable, disable, and set the
LED drive current with a 32-level logarithmic scale
LED brightness control. The AAT3123/23A/24 has a
thermal management system to protect the device
in the event of a short-circuit condition at the output
pin. Built-in soft-start circuitry prevents excessive
inrush current during start-up. A high charge pump
switching frequency enables the use of very small
external capacitors. A low-current shutdown feature
disconnects the load from V_IN and reduces quies-
cent current to less than 1µA. The device also inte-
grates a test current/auto-disable feature for each
channel. The AAT3123/23A is available in a very
small, Pb-free 12-pin TSOPJW package. The six
output AAT3124 is available in a Pb-free 16-pin
4x4mm QFN package.
Typical Application
Features
ChargePump^™
• V_IN Range: 2.7V to 5.5V
• Dual Mode 1X and 1.5X Charge Pump for
Maximum Efficiency
• Drives Low-V_F and High-V_F Type LEDs
• Up to Six 20mA Outputs (AAT3124)
• Up to Four 20mA Outputs (AAT3123/23A)
• 32-Position Logarithmic Scale with Digital
Control
• Simple Serial Control (S²Cwire) Interface
• Low Noise Constant Frequency Operation
• 1MHz Switching Frequency
• Small Application Circuit
• Regulated Output Current
• Automatic Soft Start
• No Inductors
• I_Q <1µA in Shutdown
• Temperature Range: -40°C to +85°C
• 12-Pin TSOPJW Package (AAT3123/23A)
• 16-Pin 4x4mm QFN Package (AAT3124)
Applications
• Color (RGB) Lighting
• Programmable Current Source
• White LED Backlighting
• White Photo Flash for DSCs
V_BATTERY
VIN
C1+
C_IN
C_OUT
1µF
1µF
EN/SET
VOUT
C1-
C2+
AAT3124
C2-
D1
D2
D3
D4
EN/SET
D5
D6
GND
C1
1µF
C2
1µF
D6
D5
D4
D3
D2
D1
3123.2005.12.1.4
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