特点
High Efficiency: 90% Typical Over Entire Li-Ion Battery Range
Wide V
IN
Range: 2.7V to 5.5V
Up to 500mA Continuous Output Current
Internal Soft-Start
Open/Shorted LED Protection
LED Current Matching Typically <2%
Constant Frequency 1MHz Operation
Low Shutdown Current: 6μA
Overtemperature Protection
Small Thermally Enhanced 16-Lead (4mm x 4mm) QFN Package
典型应用
典型应用
描述
The LTC ? 3453 is a synchronous buck-boost DC/DC converter optimized for driving up to 4 white LEDs at a combined current of up to 500mA from a single Li-Ion battery input. The regulator operates in either synchronous buck, synchronous boost, or buck-boost mode, depending on input voltage and LED maximum forward voltage. Optimum efficiency is achieved using a proprietary architecture that determines which LED requires the largest forward voltage drop at its programmed current, and regulates the common output rail for lowest dropout. Efficiency of 90% can be achieved over the entire usable range of a Li-Ion battery (2.7V to 4.2V).
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 6μA.
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.