LM3554_14 Datasheet, PDF (1/43 Pages) Texas Instruments – Synchronous Boost Converter with 1.2A Dual High Side LED Drivers and I2C Compatible

LM3554
www.ti.com
SNVS549A – JUNE 2009 – REVISED APRIL 2011
LM3554 Synchronous Boost Converter with 1.2A Dual High Side LED Drivers and I²C-
Compatible Interface
Check for Samples: LM3554
FEATURES
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•2 Dual High Side Current Sources
• Grounded Cathode Allowing for Better Heat
Sinking and LED Routing
• >90% Efficiency
• Ultra-Small Solution Size: < 23mm²
• Four Operating Modes: Torch, Flash, LED
Indicator and Voltage Output
• Accurate and Programmable LED Current from
37.5mA to 1.2A
• Programmable 4.5V or 5.0V Constant Output
Voltage
• Hardware Flash and Torch Enable
• LED Thermal Sensing and Current Scaleback
• Software Selectable Input Voltage Monitor
• Programmable Flash Timeout
• Dual Synchronization Inputs for RF Power
Amplifier Pulse Events
• Open and Short LED Detection
• Active High Hardware Enable for Protection
Against System Faults
• 400kHz I²C-Compatible Interface
• 16-Bump (1.7mm × 1.7mm × 0.6mm) micro
SMD
APPLICATIONS
• Camera Phone LED Flash Controller
• Class D Audio Amplifier Power
• LED Current Source Biasing
DESCRIPTION
The LM3554 is a 2MHz fixed frequency, current mode synchronous boost converter. The device is designed to
operate as a dual 600mA (1.2A total) constant-current driver for high-current white LEDs, or as a regulated 4.5V
or 5V voltage source.
The dual high-side current sources allow for grounded cathode LED operation. An adaptive regulation method
ensures the current source for each LED remains in regulation and maximizes efficiency.
The main features include: an I²C-compatible interface for controlling the LED current or the desired output
voltage, a hardware Flash enable input for direct triggering of the Flash pulse, and dual TX inputs which force the
Flash pulse into a low-current Torch mode allowing for synchronization to RF power amplifier events or other
high-current conditions. Additionally, an active high hardware enable (HWEN) input provides a hardware
shutdown during system software failures.
Five protection features are available within the LM3554 including a software selectable input voltage monitor, an
internal comparator for interfacing with an external temperature sensor, four selectable current limits to ensure
the battery current is kept below a predetermined peak level, an over-voltage protection feature to limit the output
voltage during LED open circuits, and an output short circuit protection which limits the output current during
shorts to GND. Additionally, the device provides various fault indicators including: a thermal fault flag indicating
the LED temperature has tripped the thermal threshold, a flag indicating a TX event has occurred, a flag
indicating the flash timeout counter has expired, a flag indicating the devices die temperature has reached the
thermal shutdown threshold, and a flag indicating an open or short LED.
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2009–2011, Texas Instruments Incorporated