LM3555

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SNVS594E – JANUARY 2009 – REVISED NOVEMBER 2011

LM3555 Synchronous Boost Converter with 500 mA High Side LED Driver and Dual-Mode

Control Interface

Check for Samples: LM3555

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FEATURES

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Broken Inductor Detection

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High-Voltage High-Side Current Source Allows

for Grounded Cathode LED Operation

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Output Over-Voltage Protection

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Synchronous Boost Converter

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Output and LED Short-Circuit Protection

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Peak Converter Efficiency >90%

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Accurate and Programmable LED Current

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12-Bump, 1.575 mm x 2.1 mm x 0.6 mm micro

ranging from 60 mA to 500 mA

SMD Package (TLA12BCA)

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Adaptive LED Current Range Based on LED

APPLICATIONS

Configuration

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Dedicated Indicator Current Source

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Camera Phone LED Flash

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Dedicated Torch and Strobe Pins

DESCRIPTION

The LM3555 is a 2 MHz fixed frequency, current mode synchronous boost converter designed to drive either a

single flash LED at 500 mA or two series flash LEDs at 400 mA. A high-voltage current source allows the LEDs

to be terminated to the GND plane eliminating the need for an additional return trace back to the IC.

A dual mode control interface allows the user to configure the LM3555 with a general-purpose interface using

indicator, assist light and flash modes. A dedicated Strobe pin provides a direct interface to trigger the flash

event, while an external Torch pin provides an additional method for enabling the LEDs in a constant current

mode.

The LM3555 can adaptively scale the maximum flash level delivered to the LED/LEDs based upon the flash

configuration, whether it be a single LED or two LEDs in series.

Eight protection features are available on the LM3555 ranging from over-voltage protection to broken inductor

detection. The LM3555 has four selectable inductor current limits to help the user select an inductor that is

appropriate for the design.

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PRODUCTION DATA information is current as of publication date.

Copyright © 2009–2011, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.