LM2759 Datasheet, PDF (1/2 Pages) National Semiconductor (TI) – PRODUCT BRIEF 1A Switched Capacitor Flash LED Driver with I2C Compatible Interface

November 20, 2008
LM2759 PRODUCT BRIEF
1A Switched Capacitor Flash LED Driver with I²C
Compatible Interface
General Description
LM2759 is an integrated low-noise, high-current switched ca-
pacitor DC/DC converter with a regulated current source. The
device requires only four small ceramic capacitors making the
total solution area less than 22 mm² and the height less than
1 mm. The LM2759 is capable of driving loads up to 1A from
a single-cell Li-Ion battery. Maximum efficiency is achieved
over the input voltage range by actively selecting the proper
gain based on the LED forward voltage and current require-
ments.
The LED current can be programmed up to 1A via an I²C-
compatible interface, along with eight selectable Flash Time-
Out durations. One high-current Flash LED can be driven
either in a high-power Flash mode or a low-power Torch
mode. The Strobe pin allows the flash to be toggled via a
Flash enable signal from a camera module. The TX input pin
limits the Flash LED current to the Torch current level during
a RF PA pulse, to reduce high loads on the battery. Internal
soft-start circuitry limits the amount of inrush current during
start-up.
LM2759 is offered in a small 12-pin thermally enhanced LLP
package.
Notice: This document is not a full datasheet. For more
information regarding this product or to order samples,
please contact your National Semiconductor sales office
or visit http://www.national.com/support/dir.html.
Features
■ ^{Up to 1A Output Current}
■ ^{Solution Area < 22 mm2}
■ ^{No Inductor Required}
■ ^{90% Peak Efficiency}
■ ^{Adaptive 1x, 1.5x and 2x Gains for Maximum Efficiency}
■ ^{Load Disconnect in Shutdown}
■ ^{Accurate Input Current Control During Gain Transitions}
■ ^{Flash Time-Out}
■ ^{TX Input Pin Ensures Synchronization with RF Power}
Amplifier Pulse
■ ^{Torch, Flash, and Indicator Modes}
■ ^{External Flash Enable via Strobe Input Pin}
■ ^{Strobe Input Disable via I2C}
■ ^{Programmable Flash Pulse Duration, and Torch and Flash}
Currents via I²C-Compatible Interface
■ ^{1MHz Constant Frequency Operation}
■ ^{Low Profile 12–Pin LLP (3mm x 3mm x 0.8mm)}
Applications
■ ^{Camera Flash in Cellular Phones}
Typical Application Circuit
© 2008 National Semiconductor Corporation 300693
30069301
www.national.com