The LTC3453 synchronous buck-boost dc-dc converter targets lithium-ion (Li-ion) battery-powered applications where it can drive white LEDs with up to 500 mA. It 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 2.7 to 4.9 V 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 2.7 to 4.2 V. Independent high and low current settings for flash and torch/video modes respectively can be programmed with dual current setting resistors and dual enable pins. The LTC3453EDD is available from stock in a QFN-16 package. Pricing starts at $2.10 each for 1000-piece quantities.
Linear Technology
www.linear.com