500mA Camera LED Charge Pump

The LTC3214 is a low noise, high current charge pump DC/DC converter capable of driving high current LEDs at up to 500mA from a 2.9V to 4.5V input. Low external parts count (two flying capacitors, one programming resistor and two bypass capacitors at VIN and CPO) make the LTC3214 ideally suited for small, battery-powered applications.

Built-in soft-start circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small external capacitors.

Output current level is programmed by an external resistor. LED current is regulated using an internal 110mΩ sense resistor. Automatic mode switching optimizes efficiency by monitoring the voltage across the charge pump and switching modes only when dropout is detected. The part is available in a low profile 3mm x 3mm 10-lead DFN package.

Applications

* LED Torch/Camera Light Supply for Cell Phones, PDAs and Digital Cameras

* General Lighting and/or Flash/Strobe Applications

* Low Noise Constant Frequency Operation

* High Efficiency: Up to 94%

* Multi-Mode Operation: 1x, 1.5x or 2x Boost Modes

* Automatic Mode Switching

* High Output Current: Up to 500mA

* Tiny Application Circuit (3mm × 3mm DFN Package All Components <1mm High)

* Automatic Soft-Start

* Output Disconnect

* Open, Shorted LED Protection

* No Inductors

* Internal 110mΩ LED Current Sense Resistor 3mm × 3mm 10-Lead DFN Package