LED Driver delivers up to 500 mA with 90% efficiency.
March 24, 2005 -
Optimized for driving white LEDs, LTC3453 synchronous buck-boost DC/DC converter accepts single Li-Ion battery input voltage of 2.7-4.2 V and offers constant frequency 1 MHz operation. It operates automatically in synchronous buck, synchronous boost, or buck-boost mode, depending on input voltage and LED max forward voltage. Independent high- and low-current settings for flash and torch/video modes can be programmed with current setting resistors and enable pins.
(Archive News Story - Products mentioned in this Archive News Story may or may not be available from the manufacturer.)
Original Press release
Linear Technology Corp.
1630 McCarthy Blvd.
Milpitas, CA, 95035
USA
Synchronous Buck-Boost High Power White LED Driver Delivers up to 500mA with 90% Efficiency
Milpitas, CA - March 9, 2005 - Linear Technology Corporation announces the LTC3453, a synchronous buck-boost DC/DC converter optimized for driving high current white LEDs at up to 500mA from a single Li-Ion battery input. The regulator operates automatically in either a synchronous buck, synchronous boost, or buck-boost mode, depending on input voltage and LED maximum forward voltage. This is of particular importance in high current LED applications because the LED forward voltage can vary from 2.7V to 4.9V depending on current levels and LED tolerances.
The LTC3453's buck-boost topology can deliver 90% efficiency over the entire Li-Ion voltage range of 2.7V to 4.2V. Independent high and low current settings for flash and torch/video modes respectively can be easily programmed with dual current setting resistors and dual enable pins.
Efficiency of 90% can be typically achieved over the range of a Li-Ion battery. LED current is programmable to one of four levels (including shutdown) with dual current setting resistors and dual enable pins. In shutdown, the supply current is only 6uA. The device protects itself under open or shorted LED conditions. A high constant operating frequency of 1MHz allows the use of a small external inductor. The LTC3453 is offered in a low profile (0.75mm), thermally enhanced 16-lead (4mm x 4mm) QFN package.
The LTC3453EDD is available from stock in a QFN-16 package. Pricing starts at $2.10 each for 1,000-piece quantities.
Summary of Features: LTC3453
High Efficiency: 90% Over Entire Single-Cell Li-Ion Battery Range
Wide VIN Range: 2.7V to 5.5V
Up to 500mA Continuous Output Current
Constant Frequency 1MHz Operation
Low Shutdown Current: 6uA
Internal Soft Start
Open/Shorted LED Protection
Overtemperature Protection
Small Thermally Enhanced 16-Lead (4mm x 4mm) QFN Package
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
Note: LT and LTC are registered trademarks of Linear Technology Corp.
Contacts
North America
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
Doug Dickinson
Tel: (408) 432 1900 ext. 2233
ddickinson@linear.com
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