AAT3177 Datasheet, PDF (1/16 Pages) Advanced Analogic Technologies – High Current, High Efficiency Charge Pump with Auto-Timer

ChargePump^TM
PRODUCT DATASHEET
AAT3177
High Current, High Efficiency Charge Pump with Auto-Timer
General Description
The AAT3177 is a high output current, high efficiency,
low noise, low profile charge pump DC/DC converter.
The device is ideal for multi-functional LED photo-flash
applications where solution cost, size, and efficiency are
critical.
The AAT3177 is capable of driving a regulated output
current up to 800mA. Output current levels can be eas-
ily programmed in 16 steps through AnalogicTech’s
Simple Serial Control™ (S²Cwire™) interface controlled
by a single microcontroller GPIO line. This allows smooth
transitions and flexible adjustment of brightness in flash
or other lighting modes. The maximum output current
can also be set with an external R_SET resistor.
The tri-mode (1X/1.5X/2X) operation of the internal
charge pump offers excellent power efficiency through-
out the output current range for both flash and movie
modes. Combined with a low external parts count (two
1μF flying capacitors and two small bypass capacitors at
V_IN and OUT), the AAT3177 is ideally suited for small
battery-powered applications.
The AAT3177 has a thermal management system to pro-
tect 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. The shutdown
feature disconnects the load from V_IN and reduces quies-
cent current to less than 1μA.
The AAT3177 is available in a Pb-free, thermally-
enhanced 12-pin 3x3mm TDFN package and is specified
over the -40°C to +85°C temperature range.
Features
• Up to 800mA Output Current
• Tri-Mode 1X/1.5X/2X in Current Mode
• 16 Current Level Steps Set by S²Cwire
• Flash Auto-Timer (Active for High Current Levels
Only)
• External R_SET to Set Maximum Current
• <1μA of Shutdown
• Small Application Circuit
• No Inductors
• Automatic Soft Start
• 12-Pin TDFN 3x3mm Package
• -40°C to +85°C Temperature Range
Applications
• Camcorders
• Camera Phones
• Digital Still Cameras
• PDAs and Notebook PCs
• Smart Phones
Typical Application
1μF
1μF
2.7V
to 5.5V
C1+ C1- C2+ C2+
VIN
OUT
CIN
4.7μF
AAT3177
EN
0.1μF
EN/SET
CT
GND
FL
RSET
COUT
2.2μF
Flash
LED
187K
3177.2008.06.1.0
www.analogictech.com
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