Linear Tech Releases DC/DC Converter for High Brightness LEDs
FlashlightNews.org - 01/17/2006
MILPITAS, Ca. -- Linear Technology Corp. announced the LTC3454, a synchronous buck-boost DC/DC converter designed for driving a single high-current white LED at up to 1A from a single Li-ion battery input.
The regulator operates automatically in a synchronous buck, synchronous boost or buck-boost mode, depending on input voltage and LED maximum forward voltage. According to the company, this is of particular importance in high current LED applications, as the LED forward voltage can vary from 2.7V to 4.9V depending on current level.
Using a proprietary architecture, the DC/DC converter can achieve an efficiency of 90 percent over the entire usable range of a Li-ion battery (2.7V to 4.2V).
Furthermore, the 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 less than 15A. A high constant operating frequency of 1MHz allows the use of a small inductor. The LTC3454 is offered in a 0.75mm, thermally enhanced 10-lead, 3-by-3mm DFN package.
Summary of Features: LTC3454
- High Efficiency: >90% Typical in Torch Mode, >80% in Flash Mode
- Wide VIN Range: 2.7V to 5.5V
- Up to 1A Continuous Output Current
- 3.5% LED Current Programming Accuracy
- Internal Soft-Start
- Open/Shorted LED Protection
- Constant Frequency 1MHz Operation
- Shutdown Current < 1uA
- Overtemperature Protection
- Small Thermally Enhanced 10-Lead (3mm x 3mm) DFN Package
The LTC3454 EDD is available from stock in a 3mm-by-3mm DFN package. Pricing starts at $1.95 each for 1,000-piece quantities.
Linear Technology