LP55271 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization

September 2006
LP55271
Tiny LED Driver for Camera Flash and 4 LEDs with I²C
Programmability, Connectivity Test and Audio
Synchronization
General Description
The LP55271 is a lighting management unit for handheld
devices with I²C compatible control interface. The LP55271
has a step-up DC/DC converter with high current output and
it drives display and keypad backlights and powers the cam-
era flash LED. In addition the DC/DC converter has the
output current to power for example an audio amplifier si-
multaneously. The chip has four 8-bit programmable high
efficiency constant current LED drivers and a FLASH LED
driver. Built-in audio synchronization feature allows the user
to synchronize one of the LEDs to audio input.
The LP55271 has an integrated 370 mA flash driver with a
safety stop feature and 46 mA torch mode. An external
enable pin is provided for the synchronizing the flash with the
camera action. An external software independent test inter-
face provides a fast way to find a broken path or short on
LED circuits. Very small microSMD package together with
minimum number of external components is a best fit for
handheld devices.
Features
n High current boost DC-DC converter (up to 1A output
current)
n Programmable boost output voltage
n 370 mA flash LED constant current driver with low
tolerance and a safety circuit
n Synchronization pin for the flash timing
n Two single-ended audio inputs with gain control
n Four constant current 15 mA LED drivers with 8-bit
programmable brightness control
n Audio synchronization feature
n I²C compatible control interface
n Built-in LED connectivity test to maximize manufacturing
yield
n Small microSMD-30 package (2.5 mm x 3.0 mm x 0.6
mm)
Applications
n Camera FLASH, funlight and backlight driving in battery
powered devices
Typical Application
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