LTC3214 Datasheet, PDF (1/12 Pages) Linear Technology – 500mA Camera LED Charge Pump

LTC3214
500mA Camera
LED Charge Pump
FEATURES
■ _{Low Noise Constant Frequency Operation*}
■ _{High Efficiency: Up to 94%}
■ _{Multi-Mode Operation: 1x, 1.5x or 2x Boost Modes}
■ _{Automatic Mode Switching}
■ _{High Output Current: Up to 500mA}
■ _{Tiny Application Circuit (3mm × 3mm DFN Package,}
All Components <1mm High)
■ _{Automatic Soft-Start}
■ _{Output Disconnect}
■ _{Open, Shorted LED Protection}
■ _{No Inductors}
■ _{Internal 110mΩ LED Current Sense Resistor}
■ _{3mm × 3mm 10-Lead DFN Package}
U
APPLICATIO S
■ _{LED Torch/Camera Light Supply for Cell Phones,}
PDAs and Digital Cameras
■ _{General Lighting and/or Flash/Strobe Applications}
DESCRIPTIO
The LTC^®3214 is a low noise, high current charge pump
DC/DC converter capable of driving high current LEDs at
up to 500mA from a 2.9V to 4.5V input. Low external
parts count (two flying capacitors, one programming
resistor and two bypass capacitors at V_IN and CPO) make
the LTC3214 ideally suited for small, battery-powered
applications.
Built-in soft-start circuitry prevents excessive inrush cur-
rent during start-up. High switching frequency enables the
use of small external capacitors.
Output current level is programmed by an external resis-
tor. LED current is regulated using an internal 110mΩ
sense resistor. Automatic mode switching optimizes effi-
ciency by monitoring the voltage across the charge pump
and switching modes only when dropout is detected. The
part is available in a low profile 3mm x 3mm 10-lead DFN
package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. Patents including 6411531.
TYPICAL APPLICATIO
C1
2.2µF
C2
2.2µF
2.9V TO 4.5V
C_IN
2.2µF
DISABLE ENABLE
C1⁺ C1^– C2⁺ C2^–
V_IN
CPO
LTC3214
I_LED
EN
I_SET
0.11Ω
R_SET
3214 TA01a
LED: AOT2015
LED
C_CPO
4.7µF
I_LED
UP TO 500mA
Efficiency vs V_IN
100
100mA _200mA
90
300mA
80
70
60
50mA
50
40
30
20
10 ^{LED = AOT2015}
V_F = 2.9V TYP AT 100mA
0
2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5
V_IN (V)
3214 TA01b
3214fa
1